Based on the National Center for Atmospheric Research (NCAR) Climate System Model version 1 (CSM-1), a Flexible coupled General Circulation Model version 0 (FGCM-0) is developed in this study through replacing CSM-1’...Based on the National Center for Atmospheric Research (NCAR) Climate System Model version 1 (CSM-1), a Flexible coupled General Circulation Model version 0 (FGCM-0) is developed in this study through replacing CSM-1’s oceanic component model with IAP L30T63 global oceanic general circulation model and some necessary modifications of the other component models. After the coupled model FGCM-0 is spun up for dozens of years, it has been run for 60 years without flux correction. The model does not only show the reasonable long-term mean climatology, but also reproduce a lot of features of the interannual variability of climate, e.g. the ENSO-like events in the tropical Pacific Ocean and the dipole mode pattern in the tropical Indian Ocean. Comparing FGCM-0 with the NCAR CSM-1, some common features are found, e.g. the overestimation of sea ice in the North Pacific and the simulated double ITCZ etc. The further analyses suggest that they may be attributed to errors in the atmospheric model.展开更多
Monsoon and arid regions in the Asia-Africa-Australia(A-A-A) realm occupy more than 60% of the total area of these continents. Geological evidence showed that significant changes occurred to the A-A-A environments of ...Monsoon and arid regions in the Asia-Africa-Australia(A-A-A) realm occupy more than 60% of the total area of these continents. Geological evidence showed that significant changes occurred to the A-A-A environments of the monsoon and arid regions, the land-ocean configuration in the Eastern Hemisphere, and the topography of the Tibetan Plateau(TP) in the Cenozoic. Motivated by this background, numerical experiments for 5 typical geological periods during the Cenozoic were conducted using a coupled ocean-atmosphere general circulation model to systemically explore the formations and evolutionary histories of the Cenozoic A-A-A monsoon and arid regions under the influences of continental drift and plateau uplift. Results of the numerical experiments indicate that the timings and causes of the formations of monsoon and arid regions in the A-A-A realm were very different. The northern and southern African monsoons existed during the mid-Paleocene, while the South Asian monsoon appeared in the Eocene after the Indian Subcontinent moved into the tropical Northern Hemisphere. In contrast, the East Asian monsoon and northern Australian monsoon were established much later in the Miocene. The establishment of the tropical monsoons in northern and southern Africa, South Asia, and Australia were determined by both the continental drift and seasonal migration of the Inter-Tropical Convergence Zone(ITCZ), while the position and height of the TP were the key factor for the establishment of the East Asian monsoon. The presence of the subtropical arid regions in northern and southern Africa,Asia, and Australia depended on the positions of the continents and the control of the planetary scale subtropical high pressure zones, while the arid regions in the Arabian Peninsula and West Asia were closely related to the retreat of the Paratethys Sea. The formation of the mid-latitude arid region in the Asian interior, on the other hand, was the consequence of the uplift of the TP.These results from this study provide insight to the import展开更多
Climate drift in preindustrial control （PICTL） simulations can lead to spurious climate trends and large uncertainties in historical and future climate simulations in coupled models. This study examined the long- te...Climate drift in preindustrial control （PICTL） simulations can lead to spurious climate trends and large uncertainties in historical and future climate simulations in coupled models. This study examined the long- term behaviors and stabilities of the PICTL simulations in the two versions of FGOALS2 （the Flexible Global Ocean-Atmosphere-Land System model Version 2）, which have been submitted to the Coupled Model Inter- comparison Project Phase 5 （CMIP5）. As verified by examining time series of thermal fields and their linear trends, the PICTL simulations showed stable long-term integration behaviors and no obvious climate drift [the magnitudes of linear trends of SST were both less than 0.04℃ （100 yr）-1] over multiple centuries. The changed SSTs in a century （that corresponded to the linear trends） were less than the standard deviations of annual mean values, which implied the internal variability was not affected. These trend values were less than 10~0 of those of global averaged SST from observations and historical runs during the periods of slow and rapid warming. Such stable long-term integration behaviors reduced the uncertainty of the estimation of global warming rates in the historical and future climate projections in the two versions of FGOALS2. Compared with the trends in the Northern Hemisphere, larger trends existed in the SST and sea ice extents at the middle to high latitudes of the Southern Hemisphere （SH）. To estimate the historical and future climate trends in the SH or at some specific regions in FGOALS2, corrections needed to be carried out. The similar long-term behaviors in the two versions of FGOALS2 may be attributed to proper physical processes in the ocean model.展开更多
Nematodes play an important role in ecosystems;however,very little is known about their assembly processes and the factors influencing them.We studied nematode communities in bulk soils from three Asian mountain ecosy...Nematodes play an important role in ecosystems;however,very little is known about their assembly processes and the factors influencing them.We studied nematode communities in bulk soils from three Asian mountain ecosystems to determine the assembly processes of free-living nematode metacommunities and their driving factors.On each mountain,elevations span a range of climatic conditions with the potential to reveal assembly processes that predominate across multiple biomes.A phylogenetic null modeling framework was used to analyze 18S rRNA gene amplicons to quantify various assembly processes.We found that phylogenetic turnover between nematode communities on all mountains was dominated by stochastic processes,with“undominated processes”being the most predominant stochastic factor.Elevation has a significant impact on the relative importance of deterministic and stochastic processes.A variety of climatic and edaphic variables significantly influenced the variations in community assembly processes with elevation,even though their impacts were not consistent between the mountains.Overall,our results indicate that free-living nematode metacommunities in a wide range of environments are largely structured by stochastic processes rather than by niche-based deterministic processes,suggesting that metacommunities of soil free-living nematodes may respond to climate change in a largely unpredictable way.展开更多
Following the instant square conservative scheme, implicit, explicit and semiimplicit schemes have also been formulated. Based on the theory of perfect square conservative scheme, which has assimilated the reasonable ...Following the instant square conservative scheme, implicit, explicit and semiimplicit schemes have also been formulated. Based on the theory of perfect square conservative scheme, which has assimilated the reasonable part of the idea of formulating the explicit scheme by adjustable dissipation, and the idea of actualizing the implicit scheme via 'instant linearization', a general compensation formulation展开更多
Whether large trends exist in pre-industrial control （PICTL） runs is critically important for evaluating simulations of present climate change. This study examined the long-term trends in PICTL surface air temperatu...Whether large trends exist in pre-industrial control （PICTL） runs is critically important for evaluating simulations of present climate change. This study examined the long-term trends in PICTL surface air temperature （SAT） in CMIP5 models. Small trends （〈0.06 ℃/100 year） in the globally averaged SAT （GASAT） exist in most CMIP5 models. Of these, positive （negative） trends result from positive （negative） net radiation fluxes at the TOA. This conclusion was further confirmed by the significant positive correlations between the TOA and the SAT tendency. The PICTL GASAT trends constitute less than 10% of the historical trends, indicating that such trends are of negligible importance in estimates of historical global warming in most models. Spatially, relative to the historical trends, the PICTL trends comprise a nontrivial fraction （〉20%） in the Southern Ocean between 50°S and 65°S and in the northern Atlantic and Pacific oceans north of 40°N, with large inter-model spread. The long-term behavior of SAT is significantly related to ocean circulation adjustment in the mid-high latitudes.展开更多
Climate drift refers to spurious long-term changes that may be inherent in coupled models when external forcing factors are fixed. Understanding the sources of this drift and tuning the drift are crucial for obtaining...Climate drift refers to spurious long-term changes that may be inherent in coupled models when external forcing factors are fixed. Understanding the sources of this drift and tuning the drift are crucial for obtaining reasonable simulations from coupled models. To prepare for the upcoming Coupled Model Intercomparison Project Phase 6, a new coupled model has been constructed based on the Community Earth System Model and the Grid-point Atmospheric Model of IAP LASG version 2. However, the surface temperature predicted by the new model is too underestimated, and this underestimation is caused by a type of climate drift, i.e., ‘‘initial shock.'' This study analyzes the source of the cold surface temperature from the perspective of energy balance and attempts to reduce the surface temperature drift by tuning the relative humidity threshold for low cloud.展开更多
The authors put forward some ideas on the strata and age of the wind-drift sand geomorphy in the east Taklimakan Desert as well as the cause on the basis of the extensive investigations on the strata of the wind-drift...The authors put forward some ideas on the strata and age of the wind-drift sand geomorphy in the east Taklimakan Desert as well as the cause on the basis of the extensive investigations on the strata of the wind-drift sand geomorphy in the Taklimakan Desert mainly according to the record, the result of particle analysis and chronological data in T<sub>8710</sub> section located in the dense drifting sand area in the east Taklimakan Desert.展开更多
The warming of Antarctica observed in recent years is one of the consequences of deep degassing associated with the northward drift of the Earth’s core. Ascending streams of hydrogen and other gases move along the te...The warming of Antarctica observed in recent years is one of the consequences of deep degassing associated with the northward drift of the Earth’s core. Ascending streams of hydrogen and other gases move along the tectonic faults of the lithosphere. When they get into an oxidizing environment, there is an increase in the amount of water in the ocean and air, which is accompanied by a decrease in oxygen concentrations and the release of huge amounts of energy. The provisions of the proposed theory were tested using the method of mental critical experiment. The reality of atmospheric effects of subsurface degassing is confirmed by the facts of synchronous destruction of ozone in the stratosphere and an increase in the temperature of the surface air layer. These events usually coincide with releases of ozone-depleting and heat-generating hydrogen from the subsurface.展开更多
基金This study is jointly supported by Chinese Academy of Sciences under Grant "Hundred Talents" for "Validation of Coupled Climate
文摘Based on the National Center for Atmospheric Research (NCAR) Climate System Model version 1 (CSM-1), a Flexible coupled General Circulation Model version 0 (FGCM-0) is developed in this study through replacing CSM-1’s oceanic component model with IAP L30T63 global oceanic general circulation model and some necessary modifications of the other component models. After the coupled model FGCM-0 is spun up for dozens of years, it has been run for 60 years without flux correction. The model does not only show the reasonable long-term mean climatology, but also reproduce a lot of features of the interannual variability of climate, e.g. the ENSO-like events in the tropical Pacific Ocean and the dipole mode pattern in the tropical Indian Ocean. Comparing FGCM-0 with the NCAR CSM-1, some common features are found, e.g. the overestimation of sea ice in the North Pacific and the simulated double ITCZ etc. The further analyses suggest that they may be attributed to errors in the atmospheric model.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41690115 & 41572150)the Strategic Priority Research Program (A) of Chinese Academy of Sciences (Grant No. XDA20070103)+1 种基金supported by the U.K. National Centre for Atmospheric Science-Climate (NCAS-Climate) at the University of Readingsupported by the University of San Diego (FRG # 2017-18)
文摘Monsoon and arid regions in the Asia-Africa-Australia(A-A-A) realm occupy more than 60% of the total area of these continents. Geological evidence showed that significant changes occurred to the A-A-A environments of the monsoon and arid regions, the land-ocean configuration in the Eastern Hemisphere, and the topography of the Tibetan Plateau(TP) in the Cenozoic. Motivated by this background, numerical experiments for 5 typical geological periods during the Cenozoic were conducted using a coupled ocean-atmosphere general circulation model to systemically explore the formations and evolutionary histories of the Cenozoic A-A-A monsoon and arid regions under the influences of continental drift and plateau uplift. Results of the numerical experiments indicate that the timings and causes of the formations of monsoon and arid regions in the A-A-A realm were very different. The northern and southern African monsoons existed during the mid-Paleocene, while the South Asian monsoon appeared in the Eocene after the Indian Subcontinent moved into the tropical Northern Hemisphere. In contrast, the East Asian monsoon and northern Australian monsoon were established much later in the Miocene. The establishment of the tropical monsoons in northern and southern Africa, South Asia, and Australia were determined by both the continental drift and seasonal migration of the Inter-Tropical Convergence Zone(ITCZ), while the position and height of the TP were the key factor for the establishment of the East Asian monsoon. The presence of the subtropical arid regions in northern and southern Africa,Asia, and Australia depended on the positions of the continents and the control of the planetary scale subtropical high pressure zones, while the arid regions in the Arabian Peninsula and West Asia were closely related to the retreat of the Paratethys Sea. The formation of the mid-latitude arid region in the Asian interior, on the other hand, was the consequence of the uplift of the TP.These results from this study provide insight to the import
基金supported by the National Key Program for Developing Basic Sciences(Grant Nos.2010CB950502 and 2013CB956204)the"Strategic Priority Research Program-Climate Change:Carbon Budget and Related Issues"of the Chinese Academy of Sciences(Grant No.XDA05110302)the National Natural Science Foundation of China(Grant Nos.40906012 and 41023002)
文摘Climate drift in preindustrial control （PICTL） simulations can lead to spurious climate trends and large uncertainties in historical and future climate simulations in coupled models. This study examined the long- term behaviors and stabilities of the PICTL simulations in the two versions of FGOALS2 （the Flexible Global Ocean-Atmosphere-Land System model Version 2）, which have been submitted to the Coupled Model Inter- comparison Project Phase 5 （CMIP5）. As verified by examining time series of thermal fields and their linear trends, the PICTL simulations showed stable long-term integration behaviors and no obvious climate drift [the magnitudes of linear trends of SST were both less than 0.04℃ （100 yr）-1] over multiple centuries. The changed SSTs in a century （that corresponded to the linear trends） were less than the standard deviations of annual mean values, which implied the internal variability was not affected. These trend values were less than 10~0 of those of global averaged SST from observations and historical runs during the periods of slow and rapid warming. Such stable long-term integration behaviors reduced the uncertainty of the estimation of global warming rates in the historical and future climate projections in the two versions of FGOALS2. Compared with the trends in the Northern Hemisphere, larger trends existed in the SST and sea ice extents at the middle to high latitudes of the Southern Hemisphere （SH）. To estimate the historical and future climate trends in the SH or at some specific regions in FGOALS2, corrections needed to be carried out. The similar long-term behaviors in the two versions of FGOALS2 may be attributed to proper physical processes in the ocean model.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(No.NRF-2018R1C1B6007755)supported by a grant(No.20SCIPC158976-01)from the Construction Technology Research Program funded by the Ministry of Land,Infrastructure,and Transport of the Korean government+2 种基金the Natural Science Foundation of Guangxi,China(No.2018GXNSFDA 281006)the National Natural Science Foundation of China(No.41966005)the One Hundred Talents Project of Guangxi,China(No.6020303891251)。
文摘Nematodes play an important role in ecosystems;however,very little is known about their assembly processes and the factors influencing them.We studied nematode communities in bulk soils from three Asian mountain ecosystems to determine the assembly processes of free-living nematode metacommunities and their driving factors.On each mountain,elevations span a range of climatic conditions with the potential to reveal assembly processes that predominate across multiple biomes.A phylogenetic null modeling framework was used to analyze 18S rRNA gene amplicons to quantify various assembly processes.We found that phylogenetic turnover between nematode communities on all mountains was dominated by stochastic processes,with“undominated processes”being the most predominant stochastic factor.Elevation has a significant impact on the relative importance of deterministic and stochastic processes.A variety of climatic and edaphic variables significantly influenced the variations in community assembly processes with elevation,even though their impacts were not consistent between the mountains.Overall,our results indicate that free-living nematode metacommunities in a wide range of environments are largely structured by stochastic processes rather than by niche-based deterministic processes,suggesting that metacommunities of soil free-living nematodes may respond to climate change in a largely unpredictable way.
基金scientific projects for China's Seventh and Eighth Five-Year-Plan1991-1992 Director's Foundation of IAP, Academia Sinica.
文摘Following the instant square conservative scheme, implicit, explicit and semiimplicit schemes have also been formulated. Based on the theory of perfect square conservative scheme, which has assimilated the reasonable part of the idea of formulating the explicit scheme by adjustable dissipation, and the idea of actualizing the implicit scheme via 'instant linearization', a general compensation formulation
基金supported by the National Key Basic Research Program of China[grant numbers 2010CB950502 and 2013CB956204]the‘Strategic Priority Research Program-Climate Change:Carbon Budget and Related Issues’of the Chinese Academy of Sciences[grant number XDA05110302]the National Natural Science Foundation of China[grant numbers 41376019 and 41376039]
文摘Whether large trends exist in pre-industrial control （PICTL） runs is critically important for evaluating simulations of present climate change. This study examined the long-term trends in PICTL surface air temperature （SAT） in CMIP5 models. Small trends （〈0.06 ℃/100 year） in the globally averaged SAT （GASAT） exist in most CMIP5 models. Of these, positive （negative） trends result from positive （negative） net radiation fluxes at the TOA. This conclusion was further confirmed by the significant positive correlations between the TOA and the SAT tendency. The PICTL GASAT trends constitute less than 10% of the historical trends, indicating that such trends are of negligible importance in estimates of historical global warming in most models. Spatially, relative to the historical trends, the PICTL trends comprise a nontrivial fraction （〉20%） in the Southern Ocean between 50°S and 65°S and in the northern Atlantic and Pacific oceans north of 40°N, with large inter-model spread. The long-term behavior of SAT is significantly related to ocean circulation adjustment in the mid-high latitudes.
基金supported by the CAS Strategic Priority Research Program (XDA05110304)the National 973 Basic Research Program of China (2015CB954102)the National Natural Science Foundation of China (41330527, 41205079, and 41305040)
文摘Climate drift refers to spurious long-term changes that may be inherent in coupled models when external forcing factors are fixed. Understanding the sources of this drift and tuning the drift are crucial for obtaining reasonable simulations from coupled models. To prepare for the upcoming Coupled Model Intercomparison Project Phase 6, a new coupled model has been constructed based on the Community Earth System Model and the Grid-point Atmospheric Model of IAP LASG version 2. However, the surface temperature predicted by the new model is too underestimated, and this underestimation is caused by a type of climate drift, i.e., ‘‘initial shock.'' This study analyzes the source of the cold surface temperature from the perspective of energy balance and attempts to reduce the surface temperature drift by tuning the relative humidity threshold for low cloud.
文摘The authors put forward some ideas on the strata and age of the wind-drift sand geomorphy in the east Taklimakan Desert as well as the cause on the basis of the extensive investigations on the strata of the wind-drift sand geomorphy in the Taklimakan Desert mainly according to the record, the result of particle analysis and chronological data in T<sub>8710</sub> section located in the dense drifting sand area in the east Taklimakan Desert.
文摘The warming of Antarctica observed in recent years is one of the consequences of deep degassing associated with the northward drift of the Earth’s core. Ascending streams of hydrogen and other gases move along the tectonic faults of the lithosphere. When they get into an oxidizing environment, there is an increase in the amount of water in the ocean and air, which is accompanied by a decrease in oxygen concentrations and the release of huge amounts of energy. The provisions of the proposed theory were tested using the method of mental critical experiment. The reality of atmospheric effects of subsurface degassing is confirmed by the facts of synchronous destruction of ozone in the stratosphere and an increase in the temperature of the surface air layer. These events usually coincide with releases of ozone-depleting and heat-generating hydrogen from the subsurface.
