The cooling and humidifying effects of urban parks are an essential component of city ecosystems in terms of regulating microclimates or mitigating urban heat islands(UHIs).Air temperature and relative humidity are tw...The cooling and humidifying effects of urban parks are an essential component of city ecosystems in terms of regulating microclimates or mitigating urban heat islands(UHIs).Air temperature and relative humidity are two main factors of thermal environmental comfort and have a critical impact on the urban environmental quality of human settlements.We measured the 2-m height air temperature and relative humidity at the Beijing Olympic Park and a nearby building roof for more than 1 year to elucidate seasonal variations in air temperature and relative humidity,as well as to investigate the outdoor thermal comfort.The results showed that the lawn of the park could,on average,reduce the air temperature by(0.80±0.19)℃,and increase the relative humidity by(5.24±2.91)% relative to the values measured at the building roof during daytime.During the nighttime,the lawn of the park reduced the air temperature by(2.64±0.64)℃ and increased the relative humidity by(10.77±5.20)%.The park was cooler and more humid than surrounding building area,especially in night period(more pronounced cooling with 1.84℃).Additionally,the lawn of the park could improve outdoor thermal comfort through its cooling and humidifying effects.The level of thermal comfort in the park was higher than that around the building roof for a total of 11 days annually in which it was above one or more thermal comfort levels(average reduced human comfort index of 0.92)except during the winter.展开更多
Air pollution surveys of formaldehyde（HCHO） were conducted in 2324 rooms decorated within one year in 2007-2009 in Hangzhou,China.The mean HCHO concentration（C HCHO） was 0.107 ± 0.095 mg/m 3,and 38.9% of samp...Air pollution surveys of formaldehyde（HCHO） were conducted in 2324 rooms decorated within one year in 2007-2009 in Hangzhou,China.The mean HCHO concentration（C HCHO） was 0.107 ± 0.095 mg/m 3,and 38.9% of samples exceeded the Chinese National Standard GB 50325-2010.Over the past 3 years,the C HCHO decreased with time（p 〈 0.05）.Relationships of potential factors to indoor C HCHO were also evaluated.C HCHO was related to temperature（T）,relative humidity（RH）,time duration of the windows and doors being closed before sampling（DC）,time duration from the end of decoration to sampling（DR） and source characteristics（d）.A model to relate indoor C HCHO to these five factors（T,RH,DC,DR,d） was established based on 298 samples（R 2 = 0.87）.Various factors contributed to C HCHO in the following order：T,43.7%;d,31.0%;DC,10.2%;DR,8.0%;RH,7.0%;specifically,meteorological conditions（i.e.,RH plus T） accounted for 50.7%.The coefficient of T and RH,R TH,was proposed to describe their combined influence on HCHO emission,which also had a linear relationship（R 2 = 0.9387） with HCHO release in a simulation chamber test.In addition,experiments confirm that it is a synergistic action as T and RH accelerate the release of HCHO,and that is a significant factor influencing indoor HCHO pollution.These achievements could lead to reference values of measures for the efficient reduction of indoor HCHO pollution.展开更多
Temperature affects the structural response of asphalt concrete(AC) pavement To evaluate the performance,it is important to accurately predict the pavement surface temperature.This study develops three regression mode...Temperature affects the structural response of asphalt concrete(AC) pavement To evaluate the performance,it is important to accurately predict the pavement surface temperature.This study develops three regression models to determine the surface temperature of an asphalt pavement using field measured data such as air temperature,wind speed,wind direction,relative humidity,and solar radiation.Three models namely,24-h model,day-time model and night-time model were developed based on one-year continuous data.The weather data were measured from October 2012 to October 2013 at an instrumented pavement section on Interstate I-40 near Albuquerque,New Mexico.The developed regression models were validated using October 2014 to June 2015 weather data,which were not used in developing the regression models.Surface temperatures predicted using the developed regression models were then compared to those predicted using the pavement mechanistic-empirical(ME) software’s default model.It is observed that the regression models are better predictors of pavement surface temperatures than the ME default models.A parametric study was also performed in this study to identify the effects of weather parameters on the pavement surface temperature prediction.The authors of this study expect that this study will be useful in pavement design especially in cold regions.展开更多
Soybean (Glycine max. (L.) Merr.) sap flow during the growth stages in relation to soil moisture, nutrition, and weather conditions determine the plant development. Modeling this process helps to better understand the...Soybean (Glycine max. (L.) Merr.) sap flow during the growth stages in relation to soil moisture, nutrition, and weather conditions determine the plant development. Modeling this process helps to better understand the plant water-nutrition uptake and improve the decisions of efficient irrigation management and other inputs for effective soybean production. Field studies of soybean sap flow took place in 2017-2021 at Marianna, Arkansas using heat balance stem flow gauges to measure the sap flow during the reproductive growth stages R3-R7. Plant water uptake was measured using the lysimeter-container method. The uniform sap flow-based hydraulic system in the soil-root-stem-leaf pathway created negative water tensions with osmotic processes and water surface tensions in stomata cells as water evaporation layers increase are the mechanism of the plant water uptake. Any changes the factors like soil water tension, solar radiation, or air relative humidity immediately, within a few seconds, affect the system’s balance and cause simultaneously appropriate reactions in different parts of the system. The plant water use model was created from plant emergence, vegetative to final reproductive growth stages depending on soil-weather conditions, plant morphology, and biomass. The main factors of the model include solar radiation, air temperature, and air relative humidity. The effective sap flow uptake occurs around 0.8 KPa VPD. Further research is needed to optimize the model’s factors to increase the plant growth dynamics and yield productivity.展开更多
The combined stress of high temperature and high relative air humidity is one of the most serious agrometeorological disasters that restricts the production capacity of protected agriculture.However,there is little in...The combined stress of high temperature and high relative air humidity is one of the most serious agrometeorological disasters that restricts the production capacity of protected agriculture.However,there is little information about the precise interaction between them on tomato fruit quality.The objectives of this study were to explore the effects of the combined stress of high temperature and relative humidity on the sugar and acid metabolism and fruit quality of tomato fruits,and to determine the best relative air humidity for fruit quality under high temperature environments.Four temperature treatments(32℃,35℃,38℃,41℃),three relative air humidity(50%,70%,90%)and four duration(3,6,9,12 d)orthogonal experiments were conducted,with 28℃,50%as control.The results showed that under high temperature and relative air humidity,the activity of sucrose metabolizing enzymes in young tomato fruits changed,which reduced fruits soluble sugar content;in addition,enzyme activities involved phosphopyruvate carboxylase(PEPC),mitochondria aconitase(MDH)and citrate synthetase(CS)increased which increased the content of organic acids(especially malic acid).Eventually,vitamin C,total sugar and sugar-acid ratio decreased significantly,while the titratable acid increased,resulting in a decrease in fruit flavor quality and nutritional quality in ripe fruit.Specifically,a temperature of 32℃and a relative air humidity of 70%were the best cultivation conditions for tomato reproductive growth period under high temperature.Our results indicating that fruit quality reduced under high temperature at the flowering stage,while increasing the relative air humidity to 70%could alleviate this negative effect.Our results are benefit to better understand the interaction between microclimate parameters under specific climatic conditions in the greenhouse environment and their impact on tomato flavor quality.展开更多
Climate feedbacks have been usually estimated using changes in radiative effects associated with increased global-mean surface temperature. Feedback uncertainties, however, are not only functions of global-mean surfac...Climate feedbacks have been usually estimated using changes in radiative effects associated with increased global-mean surface temperature. Feedback uncertainties, however, are not only functions of global-mean surface temperature increase. In projections by global climate models, it has been demonstrated that the geographical variation of sea surface temperature change brings significant uncertainties into atmospheric circulation and precipitation responses at regional scales. Here we show that the spatial pattern of surface warming is a major contributor to uncertainty in the combined water vapour-lapse rate feedback. This is demonstrated by computing the global-mean radiative effects of changes in air temperature and relative humidity simulated by 31 climate models using a methodology based on radiative kernels. Our results highlight the important contribution of regional climate change to the uncertainty in climate feedbacks, and identify the regions of the world where constraining surface warming patterns would be most effective for higher skill of climate projections.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.41871343)Major Project of National Natural Science Foundation of China(No.41590842)Strategic Priority Research Program A of the Chinese Academy of Sciences(No.XDA23100201)
文摘The cooling and humidifying effects of urban parks are an essential component of city ecosystems in terms of regulating microclimates or mitigating urban heat islands(UHIs).Air temperature and relative humidity are two main factors of thermal environmental comfort and have a critical impact on the urban environmental quality of human settlements.We measured the 2-m height air temperature and relative humidity at the Beijing Olympic Park and a nearby building roof for more than 1 year to elucidate seasonal variations in air temperature and relative humidity,as well as to investigate the outdoor thermal comfort.The results showed that the lawn of the park could,on average,reduce the air temperature by(0.80±0.19)℃,and increase the relative humidity by(5.24±2.91)% relative to the values measured at the building roof during daytime.During the nighttime,the lawn of the park reduced the air temperature by(2.64±0.64)℃ and increased the relative humidity by(10.77±5.20)%.The park was cooler and more humid than surrounding building area,especially in night period(more pronounced cooling with 1.84℃).Additionally,the lawn of the park could improve outdoor thermal comfort through its cooling and humidifying effects.The level of thermal comfort in the park was higher than that around the building roof for a total of 11 days annually in which it was above one or more thermal comfort levels(average reduced human comfort index of 0.92)except during the winter.
基金supported by the National Natural Science Foundation of China (No. 20890111,21137003,20977075)the National High-Tech Research and Development Program (863) of China (No. 2010AA064902)
文摘Air pollution surveys of formaldehyde（HCHO） were conducted in 2324 rooms decorated within one year in 2007-2009 in Hangzhou,China.The mean HCHO concentration（C HCHO） was 0.107 ± 0.095 mg/m 3,and 38.9% of samples exceeded the Chinese National Standard GB 50325-2010.Over the past 3 years,the C HCHO decreased with time（p 〈 0.05）.Relationships of potential factors to indoor C HCHO were also evaluated.C HCHO was related to temperature（T）,relative humidity（RH）,time duration of the windows and doors being closed before sampling（DC）,time duration from the end of decoration to sampling（DR） and source characteristics（d）.A model to relate indoor C HCHO to these five factors（T,RH,DC,DR,d） was established based on 298 samples（R 2 = 0.87）.Various factors contributed to C HCHO in the following order：T,43.7%;d,31.0%;DC,10.2%;DR,8.0%;RH,7.0%;specifically,meteorological conditions（i.e.,RH plus T） accounted for 50.7%.The coefficient of T and RH,R TH,was proposed to describe their combined influence on HCHO emission,which also had a linear relationship（R 2 = 0.9387） with HCHO release in a simulation chamber test.In addition,experiments confirm that it is a synergistic action as T and RH accelerate the release of HCHO,and that is a significant factor influencing indoor HCHO pollution.These achievements could lead to reference values of measures for the efficient reduction of indoor HCHO pollution.
基金funded by the New Mexico Department of Transportation (NMDOT).
文摘Temperature affects the structural response of asphalt concrete(AC) pavement To evaluate the performance,it is important to accurately predict the pavement surface temperature.This study develops three regression models to determine the surface temperature of an asphalt pavement using field measured data such as air temperature,wind speed,wind direction,relative humidity,and solar radiation.Three models namely,24-h model,day-time model and night-time model were developed based on one-year continuous data.The weather data were measured from October 2012 to October 2013 at an instrumented pavement section on Interstate I-40 near Albuquerque,New Mexico.The developed regression models were validated using October 2014 to June 2015 weather data,which were not used in developing the regression models.Surface temperatures predicted using the developed regression models were then compared to those predicted using the pavement mechanistic-empirical(ME) software’s default model.It is observed that the regression models are better predictors of pavement surface temperatures than the ME default models.A parametric study was also performed in this study to identify the effects of weather parameters on the pavement surface temperature prediction.The authors of this study expect that this study will be useful in pavement design especially in cold regions.
文摘Soybean (Glycine max. (L.) Merr.) sap flow during the growth stages in relation to soil moisture, nutrition, and weather conditions determine the plant development. Modeling this process helps to better understand the plant water-nutrition uptake and improve the decisions of efficient irrigation management and other inputs for effective soybean production. Field studies of soybean sap flow took place in 2017-2021 at Marianna, Arkansas using heat balance stem flow gauges to measure the sap flow during the reproductive growth stages R3-R7. Plant water uptake was measured using the lysimeter-container method. The uniform sap flow-based hydraulic system in the soil-root-stem-leaf pathway created negative water tensions with osmotic processes and water surface tensions in stomata cells as water evaporation layers increase are the mechanism of the plant water uptake. Any changes the factors like soil water tension, solar radiation, or air relative humidity immediately, within a few seconds, affect the system’s balance and cause simultaneously appropriate reactions in different parts of the system. The plant water use model was created from plant emergence, vegetative to final reproductive growth stages depending on soil-weather conditions, plant morphology, and biomass. The main factors of the model include solar radiation, air temperature, and air relative humidity. The effective sap flow uptake occurs around 0.8 KPa VPD. Further research is needed to optimize the model’s factors to increase the plant growth dynamics and yield productivity.
基金National Natural Science Foundation of China under Grant No.41775104National Key Research and Development Plan of China under Grant No.2019FYD1002202.
文摘The combined stress of high temperature and high relative air humidity is one of the most serious agrometeorological disasters that restricts the production capacity of protected agriculture.However,there is little information about the precise interaction between them on tomato fruit quality.The objectives of this study were to explore the effects of the combined stress of high temperature and relative humidity on the sugar and acid metabolism and fruit quality of tomato fruits,and to determine the best relative air humidity for fruit quality under high temperature environments.Four temperature treatments(32℃,35℃,38℃,41℃),three relative air humidity(50%,70%,90%)and four duration(3,6,9,12 d)orthogonal experiments were conducted,with 28℃,50%as control.The results showed that under high temperature and relative air humidity,the activity of sucrose metabolizing enzymes in young tomato fruits changed,which reduced fruits soluble sugar content;in addition,enzyme activities involved phosphopyruvate carboxylase(PEPC),mitochondria aconitase(MDH)and citrate synthetase(CS)increased which increased the content of organic acids(especially malic acid).Eventually,vitamin C,total sugar and sugar-acid ratio decreased significantly,while the titratable acid increased,resulting in a decrease in fruit flavor quality and nutritional quality in ripe fruit.Specifically,a temperature of 32℃and a relative air humidity of 70%were the best cultivation conditions for tomato reproductive growth period under high temperature.Our results indicating that fruit quality reduced under high temperature at the flowering stage,while increasing the relative air humidity to 70%could alleviate this negative effect.Our results are benefit to better understand the interaction between microclimate parameters under specific climatic conditions in the greenhouse environment and their impact on tomato flavor quality.
基金The National Natural Science Foundation of China under contract No. 41675070the Shanghai Eastern Scholar Program under contract No. TP2015049+1 种基金the Expert Development Fund under contract No. 2017033the China Scholarship Council under contract No. 201506330007.
文摘Climate feedbacks have been usually estimated using changes in radiative effects associated with increased global-mean surface temperature. Feedback uncertainties, however, are not only functions of global-mean surface temperature increase. In projections by global climate models, it has been demonstrated that the geographical variation of sea surface temperature change brings significant uncertainties into atmospheric circulation and precipitation responses at regional scales. Here we show that the spatial pattern of surface warming is a major contributor to uncertainty in the combined water vapour-lapse rate feedback. This is demonstrated by computing the global-mean radiative effects of changes in air temperature and relative humidity simulated by 31 climate models using a methodology based on radiative kernels. Our results highlight the important contribution of regional climate change to the uncertainty in climate feedbacks, and identify the regions of the world where constraining surface warming patterns would be most effective for higher skill of climate projections.
