Based on observations of urban mass concentration of fine particulate matter smaller than 2.5 μm in diameter （PM2.5）, ground meteorological data, vertical measurements of winds, temperature, and relative humidity ...Based on observations of urban mass concentration of fine particulate matter smaller than 2.5 μm in diameter （PM2.5）, ground meteorological data, vertical measurements of winds, temperature, and relative humidity （RH）, and ECMWF reanalysis data, the major changes in the vertical structures of meteorological factors in the boundary layer （BL） during the heavy aerosol pollution episodes （HPEs） that occurred in winter 2016 in the urban Beijing area were analyzed. The HPEs are divided into two stages： the transport of pollutants under prevailing southerly winds, known as the transport stage （TS）, and the PM2.5 explosive growth and pollution accumulation period characterized by a temperature inversion with low winds and high RH in the lower BL, known as the cumulative stage （CS）. During the TS, a surface high lies south of Beijing, and pollutants are transported northwards. During the CS, a stable BL forms and is characterized by weak winds, temperature inversion, and moisture accumulation. Stable atmospheric stratifica- tion featured with light/calm winds and accumulated moisture （RH 〉 80%） below 250 m at the beginning of the CS is closely associated with the inversion, which is strengthened by the considerable decrease in near-surface air temperat- ure due to the interaction between aerosols and radiation after the aerosol pollution occurs. A significant increase in the PLAM （Parameter Linking Aerosol Pollution and Meteorological Elements） index is found, which is linearly re- lated to PM mass change. During the first 10 h of the CS, the more stable BL contributes approximately 84% of the explosive growth of PM2.5 mass. Additional accumulated near-surface moisture caused by the ground temperature de- crease, weak turbulent diffusion, low BL height, and inhibited vertical mixing of water vapor is conducive to the sec- ondary aerosol formation through chemical reactions, including liquid phase and heterogeneous reactions, which fur- ther increases the PM2.5 concentration levels. Th展开更多
China is now confronting the intertwined challenges of air pollution and climate change.Given the high synergies between air pollution abatement and climate change mitigation,the Chinese government is actively promoti...China is now confronting the intertwined challenges of air pollution and climate change.Given the high synergies between air pollution abatement and climate change mitigation,the Chinese government is actively promoting synergetic control of these two issues.The Synergetic Roadmap project was launched in 2021 to track and analyze the progress of synergetic control in China by developing and monitoring key indicators.The Synergetic Roadmap 2022 report is the first annual update,featuring 20 indicators across five aspects:synergetic governance system and practices,progress in structural transition,air pollution and associated weather-climate interactions,sources,sinks,and mitigation pathway of atmospheric composition,and health impacts and benefits of coordinated control.Compared to the comprehensive review presented in the 2021 report,the Synergetic Roadmap 2022 report places particular emphasis on progress in 2021 with highlights on actions in key sectors and the relevant milestones.These milestones include the proportion of non-fossil power generation capacity surpassing coal-fired capacity for the first time,a decline in the production of crude steel and cement after years of growth,and the surging penetration of electric vehicles.Additionally,in 2022,China issued the first national policy that synergizes abatements of pollution and carbon emissions,marking a new era for China's pollution-carbon co-control.These changes highlight China's efforts to reshape its energy,economic,and transportation structures to meet the demand for synergetic control and sustainable development.Consequently,the country has witnessed a slowdown in carbon emission growth,improved air quality,and increased health benefits in recent years.展开更多
It is well recognized that carbon dioxide and air pollutants share similar emission sources so that synergetic policies on climate change mitigation and air pollution control can lead to remarkable co-benefits on gree...It is well recognized that carbon dioxide and air pollutants share similar emission sources so that synergetic policies on climate change mitigation and air pollution control can lead to remarkable co-benefits on greenhouse gas reduction,air quality improvement,and improved health.In the context of carbon peak,carbon neutrality,and clean air policies,this perspective tracks and analyzes the process of the synergetic governance of air pollution and climate change in China by developing and monitoring 18 indicators.The 18 indicators cover the following five aspects:air pollution and associated weather-climate conditions,progress in structural transition,sources,inks,and mitigation pathway of atmospheric composition,health impacts and benefits of coordinated control,and synergetic governance system and practices.By tracking the progress in each indicator,this perspective presents the major accomplishment of coordinated control,identifies the emerging challenges toward the synergetic governance,and provides policy recommendations for designing a synergetic roadmap of Carbon Neutrality and Clean Air for China.展开更多
On 20 July 2021,northern Henan Province in China experienced catastrophic flooding as a result of an extremely intense rainstorm,with a record-breaking hourly rainfall of 201.9 mm during 0800–0900 UTC and daily accum...On 20 July 2021,northern Henan Province in China experienced catastrophic flooding as a result of an extremely intense rainstorm,with a record-breaking hourly rainfall of 201.9 mm during 0800–0900 UTC and daily accumulated rainfall in Zhengzhou City exceeding 600 mm(“Zhengzhou 7.20 rainstorm”for short).The multi-scale dynamical and thermodynamical mechanisms for this rainstorm are investigated based on station-observed and ERA-5 reanalysis datasets.The backward trajectory tracking shows that the warm,moist air from the northwestern Pacific was mainly transported toward Henan Province by confluent southeasterlies on the northern side of a strong typhoon In-Fa(2021),with the convergent southerlies associated with a weaker typhoon Cempaka(2021)concurrently transporting moisture northward from South China Sea,supporting the rainstorm.In the upper troposphere,two equatorward-intruding potential vorticity(PV)streamers within the planetary-scale wave train were located over northern Henan Province,forming significant divergent flow aloft to induce stronger ascending motion locally.Moreover,the converged moist air was also blocked by the mountains in western Henan Province and forced to rise so that a deep meso-β-scale convective vortex(MβCV)was induced over the west of Zhengzhou City.The PV budget analyses demonstrate that the MβCV development was attributed to the positive feedback between the rainfall-related diabatic heating and high-PV under the strong upward PV advection during the Zhengzhou 7.20 rainstorm.Importantly,the MβCV was forced by upper-level larger-scale westerlies becoming eastward-sloping,which allowed the mixtures of abundant raindrops and hydrometeors to ascend slantwise and accumulate just over Zhengzhou City,resulting in the record-breaking hourly rainfall locally.展开更多
Assimilation of the Advanced Geostationary Radiance Imager(AGRI)clear-sky radiance in a regional model is performed.The forecasting effectiveness of the assimilation of two water vapor(WV)channels with conventional ob...Assimilation of the Advanced Geostationary Radiance Imager(AGRI)clear-sky radiance in a regional model is performed.The forecasting effectiveness of the assimilation of two water vapor(WV)channels with conventional observations for the“21·7”Henan extremely heavy rainfall is analyzed and compared with a baseline test that assimilates only conventional observations in this study.The results show that the 24-h cumulative precipitation forecast by the assimilation experiment with the addition of the AGRI exceeds 500 mm,compared to a maximum value of 532.6 mm measured by the national meteorological stations,and that the location of the maximum precipitation is consistent with the observations.The results for the short periods of intense precipitation processes are that the simulation of the location and intensity of the 3-h cumulative precipitation is also relatively accurate.The analysis increment shows that the main difference between the two sets of assimilation experiments is over the ocean due to the additional ocean observations provided by FY-4A,which compensates for the lack of ocean observations.The assimilation of satellite data adjusts the vertical and horizontal wind fields over the ocean by adjusting the atmospheric temperature and humidity,which ultimately results in a narrower and stronger WV transport path to the center of heavy precipitation in Zhengzhou in the lower troposphere.Conversely,the WV convergence and upward motion in the control experiment are more dispersed;therefore,the precipitation centers are also correspondingly more dispersed.展开更多
Ground freeze-thaw processes have significant impacts on infiltration,runoff and evapotranspiration.However,there are still critical knowledge gaps in understanding of hydrological processes in permafrost regions,espe...Ground freeze-thaw processes have significant impacts on infiltration,runoff and evapotranspiration.However,there are still critical knowledge gaps in understanding of hydrological processes in permafrost regions,especially of the interactions among permafrost,ecology,and hydrology.In this study,an alpine permafrost basin on the northeastern Qinghai-Tibet Plateau was selected to conduct hydrological and meteorological observations.We analyzed the annual variations in runoff,precipitation,evapotranspiration,and changes in water storage,as well as the mechanisms for runoff gen-eration in the basin from May 2014 to December 2015.The annual flow curve in the basin exhibited peaks both in spring and autumn floods.The high ratio of evapotranspiration to annual precipitation(>1.O)in the investigated wetland is mainly due to the considerably underestimated‘observed'precipitation caused by the wind-induced instrumental error and the neglect of snow sublimation.The stream flow from early May to late October probably came from the lateral discharge of subsurface flow in alpine wetlands.This study can provide data support and validation for hydrological model simulation and prediction,as well as water resource assessment,in the upper Yellow River Basin,especially for the headwater area.The results also provide case support for permafrost hydrology modeling in ungauged or poorly gauged watersheds in the High Mountain Asia.展开更多
Luoyang is a typical heavy industrial city in China,with a coal-dominated energy structure and serious air pollution.Following the implementation of the clean air actions,the physic-ochemical characteristics and sourc...Luoyang is a typical heavy industrial city in China,with a coal-dominated energy structure and serious air pollution.Following the implementation of the clean air actions,the physic-ochemical characteristics and sources of PM_(2.5) have changed.A comprehensive study of PM_(2.5) was conducted from October 16,2019 to January 23,2020 to evaluate the effectiveness of previous control measures and further to provide theory basis for more effective policies in the future.Results showed that the aerosol pollution in Luoyang in autumn and win-ter is still serious with the average concentration of 91.1 μg/m^(3),although a large reduction(46.9%)since 2014.With the contribution of nitrate increased from 12.5%to 25.1%and sul-fate decreased from 16.7%to 11.2%,aerosol pollution has changed from sulfate-dominate to nitrate-dominate.High NO_(3)^(-)/SO_(4)^(2-)ratio and the increasing of NO_(3)^(-)/SO_(4)^(2-)ratio with the aggravation of pollution indicating vehicle exhaust playing an increasingly important role in PM_(2.5) pollution in Luoyang,especially in the haze processes.Secondary inorganic ions contributed significantly to the enhancement of PM_(2.5) during the pollution period.The high value of Cl^(-)/Na^(+)and EC concentration indicate coal combustion in Luoyang is still serious.The top three contributor sources were secondary inorganic aerosols(33.3%),coal combus-tion(13.6%),and industrial emissions(13.4%).Close-range transport from the western and northeastern directions were more important factors in air pollution in Luoyang during the sampling period.It is necessary to strengthen the control of coal combustion and reduce vehicle emissions in future policies.展开更多
This study incorporated the Weather Research and Forecasting（WRF） model double-moment 6-class（WDM6） microphysics scheme into the mesoscale version of the Global/Regional Assimilation and Pr Ediction System（GRAPES...This study incorporated the Weather Research and Forecasting（WRF） model double-moment 6-class（WDM6） microphysics scheme into the mesoscale version of the Global/Regional Assimilation and Pr Ediction System（GRAPES_Meso）. A rainfall event that occurred during 3–5 June 2015 around Beijing was simulated by using the WDM6, the WRF single-moment 6-class scheme（WSM6）, and the NCEP 5-class scheme, respectively. The results show that both the distribution and magnitude of the rainfall simulated with WDM6 were more consistent with the observation. Compared with WDM6, WSM6 simulated larger cloud liquid water content, which provided more water vapor for graupel growth, leading to increased precipitation in the cold-rain processes. For areas with the warmrain processes, the sensitivity experiments using WDM6 showed that an increase in cloud condensation nuclei（CCN）number concentration led to enhanced CCN activation ratio and larger cloud droplet number concentration（Nc） but decreased cloud droplet effective diameter. The formation of more small-size cloud droplets resulted in a decrease in raindrop number concentration（Nr）, inhibiting the warm-rain processes, thus gradually decreasing the amount of precipitation. For areas mainly with the cold-rain processes, the overall amount of precipitation increased; however, it gradually decreased when the CCN number concentration reached a certain magnitude. Hence, the effect of CCN number concentration on precipitation exhibits significant differences in different rainfall areas of the same precipitation event.展开更多
The use of technical HCH （1, 2, 3, 4, 5, 6-hexachlorocyclohexane）, DDT （dichlorodiphenyltrichloroethane） and lindane in Heilongjiang River Basin （HRB） of China was studied. Between 1952 and 1984 the total usage ...The use of technical HCH （1, 2, 3, 4, 5, 6-hexachlorocyclohexane）, DDT （dichlorodiphenyltrichloroethane） and lindane in Heilongjiang River Basin （HRB） of China was studied. Between 1952 and 1984 the total usage in the HRB was 108900 t for technical HCH, and 4900 t for DDT, respectively, and the use of DDT due to dicofol application in the HRB was 220 t from 1984 to 2003. The usage of lindane in HRB was 109 t from 1991 to 2000. The results show that the highest technical HCH use （41800 t） in HRB was on maize, accounting for 38.3% of the total usage on all crops, followed by the use on wheat （28000 t, 25.7%） and on soybean （26600 t, 24.4%）. The highest DDT use （2300 t） was on soybean, accounting for 46.8% of the total usage on all crops, followed by the use on maize （1500 t, 31.3%） and on sorghum （600 t, 13.2%）. The major use of lindane was mainly on wheat. Gridded usage inventories of these three OCPs （organochlorine pesticides）, in HRB with a 1/6° latitude by 1/4° longitude resolution have been created by using different gridded cropland as surrogates. Some soil samples have also been collected in HRB. Data of usage and soil concentrations of 5： HCH in HRB match quite well to those in Shanghai region, and much higher soil concentration of 5： DDT in Shanghai region could be due to much heavier dicofol use in this region.展开更多
Because of its unique geographical location and ecological function, the Liaohe Delta Wetland is important in maintaining regional ecological balance and security. Monitoring and evaluating changes in the wetland are ...Because of its unique geographical location and ecological function, the Liaohe Delta Wetland is important in maintaining regional ecological balance and security. Monitoring and evaluating changes in the wetland are therefore of great importance. We used medium-and high-resolution satellite data, meteorological station data, and site measurement data to analyze changes in the area and spatial distribution of Phragmites australis and Suaeda salsa in the Liaohe Delta Wetland from 1998 to 2017, as well as their growth response to the climate change. The results showed that during 1998–2017, the areas of both P. australis and S. salsa wetlands alternated through periods of decreasing,increasing, and then decreasing trends. The annual change in the area and spatial distribution range of S. salsa fluctuated more than that of P. australis. The annual variation of normalized difference vegetation index(NDVI) in P. australis wetland showed an upward trend from 1998 to 2017. The area of P. australis cover that was improved, unchanged, and decreased accounted for 81.8%, 12.3%, and 5.9%, respectively, of the total area;evaporation and wind speed were the main meteorological factors affecting the NDVI;and contribution rates of the climate change and human activities to the NDVI were 73.2% and 26.8%, respectively. The area with vegetation cover being mainly S.salsa that was improved, unchanged, and decreased accounted for 63.3%, 18.3%, and 18.4%, respectively, of the total area;and no meteorological factors significantly affected the NDVI of S. salsa in the region. The interaction between vegetation growth and meteorological factors may help to explain the increasing trend in vegetation cover.The improvement in wetland vegetation also led to carbon sequestration and an increase in sequestration capacity.展开更多
The asymmetrical structure of typhoon-induced ocean eddies（TIOEs） in the East China Sea（including the Yellow Sea）and the accompanying air–sea interaction are studied using reanalysis products. Thirteen TIOEs are ...The asymmetrical structure of typhoon-induced ocean eddies（TIOEs） in the East China Sea（including the Yellow Sea）and the accompanying air–sea interaction are studied using reanalysis products. Thirteen TIOEs are analyzed and divided into three groups with the k-prototype method： Group A with typhoons passing through the central Yellow Sea; Group B with typhoons re-entering the sea from the western Yellow Sea after landing on continental China; and Group C with typhoons occurring across the eastern Yellow Sea near to the Korean Peninsula. The study region is divided into three zones（Zones Ⅰ, Ⅱ and Ⅲ） according to water depth and the Kuroshio position. The TIOEs in Group A are the strongest and could reverse part of the Kuroshio stream, while TIOEs in the other two groups are easily deformed by topography. The strong currents of the TIOEs impact on the latent heat flux distribution and upward transport, which facilitates the typhoon development. The strong divergence within the TIOEs favors an upwelling-induced cooling. A typical TIOE analysis shows that the intensity of the upwelling of TIOEs is proportional to the water depth, but its magnitude is weaker than the upwelling induced by the topography. In Zones Ⅰ and Ⅱ, the vertical dimensions of TIOEs and their strong currents are much less than the water depths.In shallow water Zone Ⅲ, a reversed circulation appears in the lower layer. The strong currents can lead to a greater, faster,and deeper energy transfer downwards than at the center of TIOEs.展开更多
Anthropogenic aerosols have significant impacts on the environment and human health in the Yangtze River Delta region, one of the most densely populated regions in the world. A biomass-buming plume swept across this a...Anthropogenic aerosols have significant impacts on the environment and human health in the Yangtze River Delta region, one of the most densely populated regions in the world. A biomass-buming plume swept across this area （Shanghai） in May 2009, leading to changes in the physical and optical properties of aerosols, which were investigated using ground-based remote sensing and in situ measurements via comparisons with dust pollution and background conditions. Experiments show that the biomass-burning plume led to an increase in the average aerosol optical depth （AOD） at 500 nm from 0.73 to 1.00 （37% higher）, an absorption Angstrom exponent （AAE） of 1.48, and an increase in the Angstrom exponent （ce） up to 1.53. Furthermore, local dust aerosols derived from road dust and]or construction dust also led to higher values of AOD （2.68） and AAE （2.16）, and a daily average value of a of 1.05. For the biomass-burning plume, the aerosol particles exhibited significant variations in short-wavelength spectra. The single scattering albedo at 670 nm decreased remarkably under the influence of the biomass-burning plume, indicating the significant absorptive ability of the biomass-burning pollution and higher ratio of absorption aerosols within the plume. Under the effects of the biomass-burning, the volume concentration of fine-mode aerosols increased significantly and the PM-fineIPM-coarse volume concentration ratio reached 12.33. This relatively large change in fine-mode particles indicates that biomass-burning has a greater impact on fine-mode aerosols than on coarse-mode aerosols.展开更多
The quality control(QC) of ocean observational data, essential to establish a high-quality global ocean database, is one of the basic data pre-processing steps in oceanography research, marine monitoring, and forecast...The quality control(QC) of ocean observational data, essential to establish a high-quality global ocean database, is one of the basic data pre-processing steps in oceanography research, marine monitoring, and forecasting. With the introduction of various advanced instruments in recent decades, oceanographic surveys have expanded from coastal regions to open oceans.However, as ocean in-situ observations are obtained using different instruments that offer heterogeneous data qualities, it is paramount that bad data could be accurately and efficiently identified via QC to provide a reliable global ocean database. In this review, we briefly summarize the latest progress of QC for oceanic in-situ observations, and mainly focus on temperature and salinity data. The similarities and differences between QC schemes developed by various ocean organizations are introduced. We also discuss the performances of the various QC schemes and identify the key challenges. Based on the discussions, several recommendations are proposed for future improvements in the QC for ocean observations.展开更多
Person re-identification(ReID)aims to recognize the same person in multiple images from different camera views.Training person ReID models are time-consuming and resource-intensive;thus,cloud computing is an appropria...Person re-identification(ReID)aims to recognize the same person in multiple images from different camera views.Training person ReID models are time-consuming and resource-intensive;thus,cloud computing is an appropriate model training solution.However,the required massive personal data for training contain private information with a significant risk of data leakage in cloud environments,leading to significant communication overheads.This paper proposes a federated person ReID method with model-contrastive learning(MOON)in an edge-cloud environment,named FRM.Specifically,based on federated partial averaging,MOON warmup is added to correct the local training of individual edge servers and improve the model’s effectiveness by calculating and back-propagating a model-contrastive loss,which represents the similarity between local and global models.In addition,we propose a lightweight person ReID network,named multi-branch combined depth space network(MB-CDNet),to reduce the computing resource usage of the edge device when training and testing the person ReID model.MB-CDNet is a multi-branch version of combined depth space network(CDNet).We add a part branch and a global branch on the basis of CDNet and introduce an attention pyramid to improve the performance of the model.The experimental results on open-access person ReID datasets demonstrate that FRM achieves better performance than existing baseline.展开更多
In this paper,we describe and analyze two datasets entitled“Homogenised monthly and daily temperature and precipitation time series in China during 1960–2021”and“Homogenised monthly and daily temperature and preci...In this paper,we describe and analyze two datasets entitled“Homogenised monthly and daily temperature and precipitation time series in China during 1960–2021”and“Homogenised monthly and daily temperature and precipitation time series in Greece during 1960–2010”.These datasets provide the homogenised monthly and daily mean(TG),minimum(TN),and maximum(TX)temperature and precipitation(RR)records since 1960 at 366 stations in China and 56stations in Greece.The datasets are available at the Science Data Bank repository and can be downloaded from https://doi.org/10.57760/sciencedb.01731 and https://doi.org/10.57760/sciencedb.01720.For China,the regional mean annual TG,TX,TN,and RR series during 1960–2021 showed significant warming or increasing trends of 0.27℃(10 yr)^(-1),0.22℃(10 yr)^(-1),0.35℃(10 yr)^(-1),and 6.81 mm(10 yr)-1,respectively.Most of the seasonal series revealed trends significant at the 0.05level,except for the spring,summer,and autumn RR series.For Greece,there were increasing trends of 0.09℃(10 yr)-1,0.08℃(10 yr)^(-1),and 0.11℃(10 yr)^(-1)for the annual TG,TX,and TN series,respectively,while a decreasing trend of–23.35 mm(10 yr)^(-1)was present for RR.The seasonal trends showed a significant warming rate for summer,but no significant changes were noted for spring(except for TN),autumn,and winter.For RR,only the winter time series displayed a statistically significant and robust trend[–15.82 mm(10 yr)^(-1)].The final homogenised temperature and precipitation time series for both China and Greece provide a better representation of the large-scale pattern of climate change over the past decades and provide a quality information source for climatological analyses.展开更多
Studies have investigated the effects of heat and temperature variability(TV)on mortality.However,few assessed whether TV modifies the heat-mortality association.Data on daily temperature and mortality in the warm sea...Studies have investigated the effects of heat and temperature variability(TV)on mortality.However,few assessed whether TV modifies the heat-mortality association.Data on daily temperature and mortality in the warm season were collected from 717 locations across 36 countries.TV was calculated as the standard deviation of the average of the same and previous days’minimum and maximum temperatures.展开更多
In this study, the clear sky hourly global and net solar irradiances at the surface determined using SUNFLUX, a simple parameterization scheme, for three stations （Gaize, Naqu, and Lhasa） on the Tibetan Plateau were...In this study, the clear sky hourly global and net solar irradiances at the surface determined using SUNFLUX, a simple parameterization scheme, for three stations （Gaize, Naqu, and Lhasa） on the Tibetan Plateau were evaluated against observation data. Our modeled results agree well with observations. The correlation coefficients between modeled and observed values were 〉 0.99 for all three stations. The relative error of modeled results, in average was 〈 7%, and the root-mean-square variance was 〈 27 W m-2. The solar irradiances in the radiation model were slightly overestimated compared with observation data; there were at least two likely causes. First, the radiative effects of aerosols were not included in the radiation model. Second, solar irradiances determined by thermopile pyranometers include a thermal offset error that causes solar radiation to be slightly underestimated. The solar radiation absorbed by the ozone and water vapor was estimated. The results show that monthly mean solar radiation absorbed by the ozone is 〈 2% of the global solar radiation （〈 14 W m-2）. Solar radiation absorbed by water vapor is stronger in summer than in winter. The maximum amount of monthly mean solar radiation absorbed by water vapor can be up to 13% of the global solar radiation （95 W m-2）. This indicates that water vapor measurements with high precision are very important for precise determination of solar radiation.展开更多
A discrepancy remains in the first two leading empirical orthogonal function(EOF) modes of the tropical Pacific sea surface temperature anomaly(SSTA) based on observations since the 1980s. The EOF1 mode, representing ...A discrepancy remains in the first two leading empirical orthogonal function(EOF) modes of the tropical Pacific sea surface temperature anomaly(SSTA) based on observations since the 1980s. The EOF1 mode, representing the El Ni?o-Southern Oscillation(ENSO), is a robust result. However, the EOF2 features either El Ni?o Modoki(EM) or ENSO evolution during different periods, which is probably associated with the impacts of global warming. The underlying question is what the EOF2 mode of the tropical Pacific would be without global warming. Using the CMIP5 preindustrial scenario to exclude the influence of global warming, we find that the EOF1 mode of the tropical Pacific SSTA represents ENSO and that the EOF2 mode is not EM. According to the lead–lag correlation between the ENSO and EOF2 modes, the linkage between these two modes is as follows: …El Ni?o → EOF2 → La Ni?a →–EOF2 → El Ni?o…. By analyzing the evolution of sea surface temperature, surface wind, and subsurface ocean temperature anomalies, we find the mechanism linking the ENSO and EOF2 modes is the air–sea interaction associated with the ENSO cycle. This result suggests that the EOF2 mode represents an aspect of ENSO evolution under preindustrial conditions. Therefore, this study further indicates that the EM is probably due to the influence of global warming.展开更多
As root water uptake（RWU）is an important link in the water and heat exchange between plants and ambient air,improving its parameterization is key to enhancing the performance of land surface model simulations.Althou...As root water uptake（RWU）is an important link in the water and heat exchange between plants and ambient air,improving its parameterization is key to enhancing the performance of land surface model simulations.Although different types of RWU functions have been adopted in land surface models,there is no evidence as to which scheme most applicable to maize farmland ecosystems.Based on the 2007–09 data collected at the farmland ecosystem field station in Jinzhou,the RWU function in the Common Land Model（Co LM）was optimized with scheme options in light of factors determining whether roots absorb water from a certain soil layer（W_x）and whether the baseline cumulative root efficiency required for maximum plant transpiration（W_c）is reached.The sensibility of the parameters of the optimization scheme was investigated,and then the effects of the optimized RWU function on water and heat flux simulation were evaluated.The results indicate that the model simulation was not sensitive to W_x but was significantly impacted by W_c.With the original model,soil humidity was somewhat underestimated for precipitation-free days;soil temperature was simulated with obvious interannual and seasonal differences and remarkable underestimations for the maize late-growth stage;and sensible and latent heat fluxes were overestimated and underestimated,respectively,for years with relatively less precipitation,and both were simulated with high accuracy for years with relatively more precipitation.The optimized RWU process resulted in a significant improvement of Co LM’s performance in simulating soil humidity,temperature,sensible heat,and latent heat,for dry years.In conclusion,the optimized RWU scheme available for the Co LM model is applicable to the simulation of water and heat flux for maize farmland ecosystems in arid areas.展开更多
基金Supported by the National Key Project of the Ministry of Science and Technology of China(2016YFC0203306)Basic Scientific Research Project of the Chinese Academy of Meteorological Sciences(2016Z001)
文摘Based on observations of urban mass concentration of fine particulate matter smaller than 2.5 μm in diameter （PM2.5）, ground meteorological data, vertical measurements of winds, temperature, and relative humidity （RH）, and ECMWF reanalysis data, the major changes in the vertical structures of meteorological factors in the boundary layer （BL） during the heavy aerosol pollution episodes （HPEs） that occurred in winter 2016 in the urban Beijing area were analyzed. The HPEs are divided into two stages： the transport of pollutants under prevailing southerly winds, known as the transport stage （TS）, and the PM2.5 explosive growth and pollution accumulation period characterized by a temperature inversion with low winds and high RH in the lower BL, known as the cumulative stage （CS）. During the TS, a surface high lies south of Beijing, and pollutants are transported northwards. During the CS, a stable BL forms and is characterized by weak winds, temperature inversion, and moisture accumulation. Stable atmospheric stratifica- tion featured with light/calm winds and accumulated moisture （RH 〉 80%） below 250 m at the beginning of the CS is closely associated with the inversion, which is strengthened by the considerable decrease in near-surface air temperat- ure due to the interaction between aerosols and radiation after the aerosol pollution occurs. A significant increase in the PLAM （Parameter Linking Aerosol Pollution and Meteorological Elements） index is found, which is linearly re- lated to PM mass change. During the first 10 h of the CS, the more stable BL contributes approximately 84% of the explosive growth of PM2.5 mass. Additional accumulated near-surface moisture caused by the ground temperature de- crease, weak turbulent diffusion, low BL height, and inhibited vertical mixing of water vapor is conducive to the sec- ondary aerosol formation through chemical reactions, including liquid phase and heterogeneous reactions, which fur- ther increases the PM2.5 concentration levels. Th
基金supported by the National Natural Science Foundation of China,China(72243008,41921005,and 72140003)the Energy Foundation,China.
文摘China is now confronting the intertwined challenges of air pollution and climate change.Given the high synergies between air pollution abatement and climate change mitigation,the Chinese government is actively promoting synergetic control of these two issues.The Synergetic Roadmap project was launched in 2021 to track and analyze the progress of synergetic control in China by developing and monitoring key indicators.The Synergetic Roadmap 2022 report is the first annual update,featuring 20 indicators across five aspects:synergetic governance system and practices,progress in structural transition,air pollution and associated weather-climate interactions,sources,sinks,and mitigation pathway of atmospheric composition,and health impacts and benefits of coordinated control.Compared to the comprehensive review presented in the 2021 report,the Synergetic Roadmap 2022 report places particular emphasis on progress in 2021 with highlights on actions in key sectors and the relevant milestones.These milestones include the proportion of non-fossil power generation capacity surpassing coal-fired capacity for the first time,a decline in the production of crude steel and cement after years of growth,and the surging penetration of electric vehicles.Additionally,in 2022,China issued the first national policy that synergizes abatements of pollution and carbon emissions,marking a new era for China's pollution-carbon co-control.These changes highlight China's efforts to reshape its energy,economic,and transportation structures to meet the demand for synergetic control and sustainable development.Consequently,the country has witnessed a slowdown in carbon emission growth,improved air quality,and increased health benefits in recent years.
基金This work was supported by the National Natural Science Foundation of China(41921005,42130708,and 72140003)and the Energy Foundation.
文摘It is well recognized that carbon dioxide and air pollutants share similar emission sources so that synergetic policies on climate change mitigation and air pollution control can lead to remarkable co-benefits on greenhouse gas reduction,air quality improvement,and improved health.In the context of carbon peak,carbon neutrality,and clean air policies,this perspective tracks and analyzes the process of the synergetic governance of air pollution and climate change in China by developing and monitoring 18 indicators.The 18 indicators cover the following five aspects:air pollution and associated weather-climate conditions,progress in structural transition,sources,inks,and mitigation pathway of atmospheric composition,health impacts and benefits of coordinated control,and synergetic governance system and practices.By tracking the progress in each indicator,this perspective presents the major accomplishment of coordinated control,identifies the emerging challenges toward the synergetic governance,and provides policy recommendations for designing a synergetic roadmap of Carbon Neutrality and Clean Air for China.
基金supported by the National Natural Science Foundation of China(Grant Nos.42288101,and 42175076)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB40000000)the Open Research Fund Program of Plateau Atmosphere and Environment Key Laboratory of Sichuan Province(Project PAEKL-2022-K02).
文摘On 20 July 2021,northern Henan Province in China experienced catastrophic flooding as a result of an extremely intense rainstorm,with a record-breaking hourly rainfall of 201.9 mm during 0800–0900 UTC and daily accumulated rainfall in Zhengzhou City exceeding 600 mm(“Zhengzhou 7.20 rainstorm”for short).The multi-scale dynamical and thermodynamical mechanisms for this rainstorm are investigated based on station-observed and ERA-5 reanalysis datasets.The backward trajectory tracking shows that the warm,moist air from the northwestern Pacific was mainly transported toward Henan Province by confluent southeasterlies on the northern side of a strong typhoon In-Fa(2021),with the convergent southerlies associated with a weaker typhoon Cempaka(2021)concurrently transporting moisture northward from South China Sea,supporting the rainstorm.In the upper troposphere,two equatorward-intruding potential vorticity(PV)streamers within the planetary-scale wave train were located over northern Henan Province,forming significant divergent flow aloft to induce stronger ascending motion locally.Moreover,the converged moist air was also blocked by the mountains in western Henan Province and forced to rise so that a deep meso-β-scale convective vortex(MβCV)was induced over the west of Zhengzhou City.The PV budget analyses demonstrate that the MβCV development was attributed to the positive feedback between the rainfall-related diabatic heating and high-PV under the strong upward PV advection during the Zhengzhou 7.20 rainstorm.Importantly,the MβCV was forced by upper-level larger-scale westerlies becoming eastward-sloping,which allowed the mixtures of abundant raindrops and hydrometeors to ascend slantwise and accumulate just over Zhengzhou City,resulting in the record-breaking hourly rainfall locally.
基金supported by the National Key R&D Program of China(Grant Nos.2017YFC1501803 and 2017YFC1502102)。
文摘Assimilation of the Advanced Geostationary Radiance Imager(AGRI)clear-sky radiance in a regional model is performed.The forecasting effectiveness of the assimilation of two water vapor(WV)channels with conventional observations for the“21·7”Henan extremely heavy rainfall is analyzed and compared with a baseline test that assimilates only conventional observations in this study.The results show that the 24-h cumulative precipitation forecast by the assimilation experiment with the addition of the AGRI exceeds 500 mm,compared to a maximum value of 532.6 mm measured by the national meteorological stations,and that the location of the maximum precipitation is consistent with the observations.The results for the short periods of intense precipitation processes are that the simulation of the location and intensity of the 3-h cumulative precipitation is also relatively accurate.The analysis increment shows that the main difference between the two sets of assimilation experiments is over the ocean due to the additional ocean observations provided by FY-4A,which compensates for the lack of ocean observations.The assimilation of satellite data adjusts the vertical and horizontal wind fields over the ocean by adjusting the atmospheric temperature and humidity,which ultimately results in a narrower and stronger WV transport path to the center of heavy precipitation in Zhengzhou in the lower troposphere.Conversely,the WV convergence and upward motion in the control experiment are more dispersed;therefore,the precipitation centers are also correspondingly more dispersed.
基金supported by the Natural Science Foundation of China(41971091)Autonomous Province of Bozen/Bolzano-Department for Innovation,Research and University in the frame of the International Mobility for Researchers Programme(13585/2023).
文摘Ground freeze-thaw processes have significant impacts on infiltration,runoff and evapotranspiration.However,there are still critical knowledge gaps in understanding of hydrological processes in permafrost regions,especially of the interactions among permafrost,ecology,and hydrology.In this study,an alpine permafrost basin on the northeastern Qinghai-Tibet Plateau was selected to conduct hydrological and meteorological observations.We analyzed the annual variations in runoff,precipitation,evapotranspiration,and changes in water storage,as well as the mechanisms for runoff gen-eration in the basin from May 2014 to December 2015.The annual flow curve in the basin exhibited peaks both in spring and autumn floods.The high ratio of evapotranspiration to annual precipitation(>1.O)in the investigated wetland is mainly due to the considerably underestimated‘observed'precipitation caused by the wind-induced instrumental error and the neglect of snow sublimation.The stream flow from early May to late October probably came from the lateral discharge of subsurface flow in alpine wetlands.This study can provide data support and validation for hydrological model simulation and prediction,as well as water resource assessment,in the upper Yellow River Basin,especially for the headwater area.The results also provide case support for permafrost hydrology modeling in ungauged or poorly gauged watersheds in the High Mountain Asia.
基金This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDA19020303)the Beijing Natural Science Foundation(No.8202050)。
文摘Luoyang is a typical heavy industrial city in China,with a coal-dominated energy structure and serious air pollution.Following the implementation of the clean air actions,the physic-ochemical characteristics and sources of PM_(2.5) have changed.A comprehensive study of PM_(2.5) was conducted from October 16,2019 to January 23,2020 to evaluate the effectiveness of previous control measures and further to provide theory basis for more effective policies in the future.Results showed that the aerosol pollution in Luoyang in autumn and win-ter is still serious with the average concentration of 91.1 μg/m^(3),although a large reduction(46.9%)since 2014.With the contribution of nitrate increased from 12.5%to 25.1%and sul-fate decreased from 16.7%to 11.2%,aerosol pollution has changed from sulfate-dominate to nitrate-dominate.High NO_(3)^(-)/SO_(4)^(2-)ratio and the increasing of NO_(3)^(-)/SO_(4)^(2-)ratio with the aggravation of pollution indicating vehicle exhaust playing an increasingly important role in PM_(2.5) pollution in Luoyang,especially in the haze processes.Secondary inorganic ions contributed significantly to the enhancement of PM_(2.5) during the pollution period.The high value of Cl^(-)/Na^(+)and EC concentration indicate coal combustion in Luoyang is still serious.The top three contributor sources were secondary inorganic aerosols(33.3%),coal combus-tion(13.6%),and industrial emissions(13.4%).Close-range transport from the western and northeastern directions were more important factors in air pollution in Luoyang during the sampling period.It is necessary to strengthen the control of coal combustion and reduce vehicle emissions in future policies.
基金Supported by the National Key Project(2016YFC0203306)National Natural Science Foundation of China(41590874)+2 种基金National(Key)973 Program(2014CB441201)Chinese Academy of Meteorological Sciences’ Project(2017Z001)Key Project of Air Pollution Cause and Control(DQGG0104)
文摘This study incorporated the Weather Research and Forecasting（WRF） model double-moment 6-class（WDM6） microphysics scheme into the mesoscale version of the Global/Regional Assimilation and Pr Ediction System（GRAPES_Meso）. A rainfall event that occurred during 3–5 June 2015 around Beijing was simulated by using the WDM6, the WRF single-moment 6-class scheme（WSM6）, and the NCEP 5-class scheme, respectively. The results show that both the distribution and magnitude of the rainfall simulated with WDM6 were more consistent with the observation. Compared with WDM6, WSM6 simulated larger cloud liquid water content, which provided more water vapor for graupel growth, leading to increased precipitation in the cold-rain processes. For areas with the warmrain processes, the sensitivity experiments using WDM6 showed that an increase in cloud condensation nuclei（CCN）number concentration led to enhanced CCN activation ratio and larger cloud droplet number concentration（Nc） but decreased cloud droplet effective diameter. The formation of more small-size cloud droplets resulted in a decrease in raindrop number concentration（Nr）, inhibiting the warm-rain processes, thus gradually decreasing the amount of precipitation. For areas mainly with the cold-rain processes, the overall amount of precipitation increased; however, it gradually decreased when the CCN number concentration reached a certain magnitude. Hence, the effect of CCN number concentration on precipitation exhibits significant differences in different rainfall areas of the same precipitation event.
文摘The use of technical HCH （1, 2, 3, 4, 5, 6-hexachlorocyclohexane）, DDT （dichlorodiphenyltrichloroethane） and lindane in Heilongjiang River Basin （HRB） of China was studied. Between 1952 and 1984 the total usage in the HRB was 108900 t for technical HCH, and 4900 t for DDT, respectively, and the use of DDT due to dicofol application in the HRB was 220 t from 1984 to 2003. The usage of lindane in HRB was 109 t from 1991 to 2000. The results show that the highest technical HCH use （41800 t） in HRB was on maize, accounting for 38.3% of the total usage on all crops, followed by the use on wheat （28000 t, 25.7%） and on soybean （26600 t, 24.4%）. The highest DDT use （2300 t） was on soybean, accounting for 46.8% of the total usage on all crops, followed by the use on maize （1500 t, 31.3%） and on sorghum （600 t, 13.2%）. The major use of lindane was mainly on wheat. Gridded usage inventories of these three OCPs （organochlorine pesticides）, in HRB with a 1/6° latitude by 1/4° longitude resolution have been created by using different gridded cropland as surrogates. Some soil samples have also been collected in HRB. Data of usage and soil concentrations of 5： HCH in HRB match quite well to those in Shanghai region, and much higher soil concentration of 5： DDT in Shanghai region could be due to much heavier dicofol use in this region.
基金Supported by the Provincial Industrialization Application Project of China High-Resolution Earth Observation System (CHEOS) of State Administration of Science,Technology and Industry for National Defense,PRC (70-Y40G09-9001-18/20)Provincial Key Research and Development Project of Department of Science and Technology of Liaoning Province (2018108004)+1 种基金Climate Change Project of China Meteorological Administration (CCSF201910)China Meteorological Administration Construction Project in 2019 (Construction and Demonstration of Wetland Ecological Remote Sensing Application Capacity in Liaoning Province)。
文摘Because of its unique geographical location and ecological function, the Liaohe Delta Wetland is important in maintaining regional ecological balance and security. Monitoring and evaluating changes in the wetland are therefore of great importance. We used medium-and high-resolution satellite data, meteorological station data, and site measurement data to analyze changes in the area and spatial distribution of Phragmites australis and Suaeda salsa in the Liaohe Delta Wetland from 1998 to 2017, as well as their growth response to the climate change. The results showed that during 1998–2017, the areas of both P. australis and S. salsa wetlands alternated through periods of decreasing,increasing, and then decreasing trends. The annual change in the area and spatial distribution range of S. salsa fluctuated more than that of P. australis. The annual variation of normalized difference vegetation index(NDVI) in P. australis wetland showed an upward trend from 1998 to 2017. The area of P. australis cover that was improved, unchanged, and decreased accounted for 81.8%, 12.3%, and 5.9%, respectively, of the total area;evaporation and wind speed were the main meteorological factors affecting the NDVI;and contribution rates of the climate change and human activities to the NDVI were 73.2% and 26.8%, respectively. The area with vegetation cover being mainly S.salsa that was improved, unchanged, and decreased accounted for 63.3%, 18.3%, and 18.4%, respectively, of the total area;and no meteorological factors significantly affected the NDVI of S. salsa in the region. The interaction between vegetation growth and meteorological factors may help to explain the increasing trend in vegetation cover.The improvement in wetland vegetation also led to carbon sequestration and an increase in sequestration capacity.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41276033 and 41276032)the Jiangsu Science and Technology Support Project (Grant No. BE2014729)+2 种基金project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe 2015 Jiangsu Program for Innovation Research and Entrepreneurship Groupsthe National Program on Global Change and Air-Sea Interaction (GASI-IPOVAI-06)
文摘The asymmetrical structure of typhoon-induced ocean eddies（TIOEs） in the East China Sea（including the Yellow Sea）and the accompanying air–sea interaction are studied using reanalysis products. Thirteen TIOEs are analyzed and divided into three groups with the k-prototype method： Group A with typhoons passing through the central Yellow Sea; Group B with typhoons re-entering the sea from the western Yellow Sea after landing on continental China; and Group C with typhoons occurring across the eastern Yellow Sea near to the Korean Peninsula. The study region is divided into three zones（Zones Ⅰ, Ⅱ and Ⅲ） according to water depth and the Kuroshio position. The TIOEs in Group A are the strongest and could reverse part of the Kuroshio stream, while TIOEs in the other two groups are easily deformed by topography. The strong currents of the TIOEs impact on the latent heat flux distribution and upward transport, which facilitates the typhoon development. The strong divergence within the TIOEs favors an upwelling-induced cooling. A typical TIOE analysis shows that the intensity of the upwelling of TIOEs is proportional to the water depth, but its magnitude is weaker than the upwelling induced by the topography. In Zones Ⅰ and Ⅱ, the vertical dimensions of TIOEs and their strong currents are much less than the water depths.In shallow water Zone Ⅲ, a reversed circulation appears in the lower layer. The strong currents can lead to a greater, faster,and deeper energy transfer downwards than at the center of TIOEs.
基金supported by research grants from the National Natural Science Foundation of China (NSFC,Grant numbers:40705013 and 41005007)China Special Fund for Meteorological Research in the Public Interest(Grant no.GYHY201106023)+1 种基金Shanghai Science and Technology Committee Research Special Funds(Grant nos.10JC1401600 and 12dz1202702)Shanghai Meteorological Service Project(Grant no.QM201204)
文摘Anthropogenic aerosols have significant impacts on the environment and human health in the Yangtze River Delta region, one of the most densely populated regions in the world. A biomass-buming plume swept across this area （Shanghai） in May 2009, leading to changes in the physical and optical properties of aerosols, which were investigated using ground-based remote sensing and in situ measurements via comparisons with dust pollution and background conditions. Experiments show that the biomass-burning plume led to an increase in the average aerosol optical depth （AOD） at 500 nm from 0.73 to 1.00 （37% higher）, an absorption Angstrom exponent （AAE） of 1.48, and an increase in the Angstrom exponent （ce） up to 1.53. Furthermore, local dust aerosols derived from road dust and]or construction dust also led to higher values of AOD （2.68） and AAE （2.16）, and a daily average value of a of 1.05. For the biomass-burning plume, the aerosol particles exhibited significant variations in short-wavelength spectra. The single scattering albedo at 670 nm decreased remarkably under the influence of the biomass-burning plume, indicating the significant absorptive ability of the biomass-burning pollution and higher ratio of absorption aerosols within the plume. Under the effects of the biomass-burning, the volume concentration of fine-mode aerosols increased significantly and the PM-fineIPM-coarse volume concentration ratio reached 12.33. This relatively large change in fine-mode particles indicates that biomass-burning has a greater impact on fine-mode aerosols than on coarse-mode aerosols.
基金This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB42040402)the Open Fund of State Key Laboratory of Satellite Ocean Environment Dynamics,Second Institute of Oceanography,MNR(Grant No.QNHX2133)+2 种基金the National Key R&D Program of China(Grant No.2017YFA0603202)the Key Deployment Project of Centre for Ocean Mega-Research of Science,CAS(Grant No.COMS2019Q01)the National Natural Science Foundation of China(Grant No.42076202).
文摘The quality control(QC) of ocean observational data, essential to establish a high-quality global ocean database, is one of the basic data pre-processing steps in oceanography research, marine monitoring, and forecasting. With the introduction of various advanced instruments in recent decades, oceanographic surveys have expanded from coastal regions to open oceans.However, as ocean in-situ observations are obtained using different instruments that offer heterogeneous data qualities, it is paramount that bad data could be accurately and efficiently identified via QC to provide a reliable global ocean database. In this review, we briefly summarize the latest progress of QC for oceanic in-situ observations, and mainly focus on temperature and salinity data. The similarities and differences between QC schemes developed by various ocean organizations are introduced. We also discuss the performances of the various QC schemes and identify the key challenges. Based on the discussions, several recommendations are proposed for future improvements in the QC for ocean observations.
基金supported by the the Natural Science Foundation of Jiangsu Province of China under Grant No.BK20211284the Financial and Science Technology Plan Project of Xinjiang Production and Construction Corps under Grant No.2020DB005.
文摘Person re-identification(ReID)aims to recognize the same person in multiple images from different camera views.Training person ReID models are time-consuming and resource-intensive;thus,cloud computing is an appropriate model training solution.However,the required massive personal data for training contain private information with a significant risk of data leakage in cloud environments,leading to significant communication overheads.This paper proposes a federated person ReID method with model-contrastive learning(MOON)in an edge-cloud environment,named FRM.Specifically,based on federated partial averaging,MOON warmup is added to correct the local training of individual edge servers and improve the model’s effectiveness by calculating and back-propagating a model-contrastive loss,which represents the similarity between local and global models.In addition,we propose a lightweight person ReID network,named multi-branch combined depth space network(MB-CDNet),to reduce the computing resource usage of the edge device when training and testing the person ReID model.MB-CDNet is a multi-branch version of combined depth space network(CDNet).We add a part branch and a global branch on the basis of CDNet and introduce an attention pyramid to improve the performance of the model.The experimental results on open-access person ReID datasets demonstrate that FRM achieves better performance than existing baseline.
基金funded by the Hellenic and Chinese Governments,in the frame of the Greek-Chinese R&T Cooperation Programme project“Comparative study of extreme climate indices in China and Europe/Greece,based on homogenised daily observations—CLIMEX”(Contract T7ΔKI-00046)the National Key Technologies Research and Development Program“Comparative study of changing climate extremes between China and Europe/Greece based on homogenised daily observations”(Grant No.2017YFE0133600)。
文摘In this paper,we describe and analyze two datasets entitled“Homogenised monthly and daily temperature and precipitation time series in China during 1960–2021”and“Homogenised monthly and daily temperature and precipitation time series in Greece during 1960–2010”.These datasets provide the homogenised monthly and daily mean(TG),minimum(TN),and maximum(TX)temperature and precipitation(RR)records since 1960 at 366 stations in China and 56stations in Greece.The datasets are available at the Science Data Bank repository and can be downloaded from https://doi.org/10.57760/sciencedb.01731 and https://doi.org/10.57760/sciencedb.01720.For China,the regional mean annual TG,TX,TN,and RR series during 1960–2021 showed significant warming or increasing trends of 0.27℃(10 yr)^(-1),0.22℃(10 yr)^(-1),0.35℃(10 yr)^(-1),and 6.81 mm(10 yr)-1,respectively.Most of the seasonal series revealed trends significant at the 0.05level,except for the spring,summer,and autumn RR series.For Greece,there were increasing trends of 0.09℃(10 yr)-1,0.08℃(10 yr)^(-1),and 0.11℃(10 yr)^(-1)for the annual TG,TX,and TN series,respectively,while a decreasing trend of–23.35 mm(10 yr)^(-1)was present for RR.The seasonal trends showed a significant warming rate for summer,but no significant changes were noted for spring(except for TN),autumn,and winter.For RR,only the winter time series displayed a statistically significant and robust trend[–15.82 mm(10 yr)^(-1)].The final homogenised temperature and precipitation time series for both China and Greece provide a better representation of the large-scale pattern of climate change over the past decades and provide a quality information source for climatological analyses.
基金This study was supported by the Australian Research Council(DP210102076)the Australian National Health and Medical Research Council(APP2000581)+12 种基金Y.W and B.W.were supported by the China Scholarship Council(nos.202006010044 and 202006010043)S.L.was supported by an Emerging Leader Fellowship of the Australian National Health and Medical Research Council(no.APP2009866)Y.G.was supported by Career Development Fellowship(no.APP1163693)and Leader Fellowship(no.APP2008813)of the Australian National Health and Medical Research CouncilJ.K.and A.U.were supported by the Czech Science Foundation(project no.20-28560S)N.S.was supported by the National Institute of Environmental Health Sciences-funded HERCULES Center(no.P30ES019776)Y.H.was supported by the Environment Research and Technology Development Fund(JPMEERF15S11412)of the Environmental Restoration and Conservation AgencyM.d.S.Z.S.C.and P.H.N.S.were supported by the São Paulo Research Foundation(FAPESP)H.O.and E.I.were supported by the Estonian Ministry of Education and Research(IUT34-17)J.M.was supported by a fellowship of Fundação para a Ciência e a Tecnlogia(SFRH/BPD/115112/2016)A.G.and F.S.were supported by the Medical Research Council UK(grant ID MR/R013349/1),the Natural Environment Research Council UK(grant ID NE/R009384/1),and the EU’s Horizon 2020 project,Exhaustion(grant ID 820655)A.S.and F.d.D.were supported by the EU’s Horizon 2020 project,Exhaustion(grant ID 820655)V.H.was supported by the Spanish Ministry of Economy,Industry and Competitiveness(grant ID PCIN-2017-046)A.T.byMCIN/AEI/10.13039/501100011033(grant CEX2018-000794-S).Statistics South Africa kindly provided the mortality data,but had no other role in the study.
文摘Studies have investigated the effects of heat and temperature variability(TV)on mortality.However,few assessed whether TV modifies the heat-mortality association.Data on daily temperature and mortality in the warm season were collected from 717 locations across 36 countries.TV was calculated as the standard deviation of the average of the same and previous days’minimum and maximum temperatures.
基金supported by the National Natural Science Foundation of China(GrantNos.40905038,40921003,40775020,and40905071)
文摘In this study, the clear sky hourly global and net solar irradiances at the surface determined using SUNFLUX, a simple parameterization scheme, for three stations （Gaize, Naqu, and Lhasa） on the Tibetan Plateau were evaluated against observation data. Our modeled results agree well with observations. The correlation coefficients between modeled and observed values were 〉 0.99 for all three stations. The relative error of modeled results, in average was 〈 7%, and the root-mean-square variance was 〈 27 W m-2. The solar irradiances in the radiation model were slightly overestimated compared with observation data; there were at least two likely causes. First, the radiative effects of aerosols were not included in the radiation model. Second, solar irradiances determined by thermopile pyranometers include a thermal offset error that causes solar radiation to be slightly underestimated. The solar radiation absorbed by the ozone and water vapor was estimated. The results show that monthly mean solar radiation absorbed by the ozone is 〈 2% of the global solar radiation （〈 14 W m-2）. Solar radiation absorbed by water vapor is stronger in summer than in winter. The maximum amount of monthly mean solar radiation absorbed by water vapor can be up to 13% of the global solar radiation （95 W m-2）. This indicates that water vapor measurements with high precision are very important for precise determination of solar radiation.
基金supported by the National Key Research and Development Program on Monitoring,Early Warning and Prevention of Major Natural Disasters(2018YFC1506006)the National Natural Science Foundation of China Project(41805054,41875108,41805041,41705065)the Scientific Research Fund of the Chengdu University of Information Technology(KYTZ201724,KYTZ201602,KYTZ201727)
文摘A discrepancy remains in the first two leading empirical orthogonal function(EOF) modes of the tropical Pacific sea surface temperature anomaly(SSTA) based on observations since the 1980s. The EOF1 mode, representing the El Ni?o-Southern Oscillation(ENSO), is a robust result. However, the EOF2 features either El Ni?o Modoki(EM) or ENSO evolution during different periods, which is probably associated with the impacts of global warming. The underlying question is what the EOF2 mode of the tropical Pacific would be without global warming. Using the CMIP5 preindustrial scenario to exclude the influence of global warming, we find that the EOF1 mode of the tropical Pacific SSTA represents ENSO and that the EOF2 mode is not EM. According to the lead–lag correlation between the ENSO and EOF2 modes, the linkage between these two modes is as follows: …El Ni?o → EOF2 → La Ni?a →–EOF2 → El Ni?o…. By analyzing the evolution of sea surface temperature, surface wind, and subsurface ocean temperature anomalies, we find the mechanism linking the ENSO and EOF2 modes is the air–sea interaction associated with the ENSO cycle. This result suggests that the EOF2 mode represents an aspect of ENSO evolution under preindustrial conditions. Therefore, this study further indicates that the EM is probably due to the influence of global warming.
基金Supported by the National Natural Science Foundation of China(41305058)Cultivation Plan for Young Agricultural Science and Technology Talents of Liaoning Province(2015060 and 2014060)Key Agricultural Science and Industrialization Project of the Science and Technology Department of Liaoning Province(2014210003)
文摘As root water uptake（RWU）is an important link in the water and heat exchange between plants and ambient air,improving its parameterization is key to enhancing the performance of land surface model simulations.Although different types of RWU functions have been adopted in land surface models,there is no evidence as to which scheme most applicable to maize farmland ecosystems.Based on the 2007–09 data collected at the farmland ecosystem field station in Jinzhou,the RWU function in the Common Land Model（Co LM）was optimized with scheme options in light of factors determining whether roots absorb water from a certain soil layer（W_x）and whether the baseline cumulative root efficiency required for maximum plant transpiration（W_c）is reached.The sensibility of the parameters of the optimization scheme was investigated,and then the effects of the optimized RWU function on water and heat flux simulation were evaluated.The results indicate that the model simulation was not sensitive to W_x but was significantly impacted by W_c.With the original model,soil humidity was somewhat underestimated for precipitation-free days;soil temperature was simulated with obvious interannual and seasonal differences and remarkable underestimations for the maize late-growth stage;and sensible and latent heat fluxes were overestimated and underestimated,respectively,for years with relatively less precipitation,and both were simulated with high accuracy for years with relatively more precipitation.The optimized RWU process resulted in a significant improvement of Co LM’s performance in simulating soil humidity,temperature,sensible heat,and latent heat,for dry years.In conclusion,the optimized RWU scheme available for the Co LM model is applicable to the simulation of water and heat flux for maize farmland ecosystems in arid areas.
