The influence of ENSO on the summer climate change in China and its mechanism from the observed data is discussed. It is discovered that in the developing stage of ENSO, the SST in the western tropical Pacific is cold...The influence of ENSO on the summer climate change in China and its mechanism from the observed data is discussed. It is discovered that in the developing stage of ENSO, the SST in the western tropical Pacific is colder in summer, the convective activities may be weak around the South China Sea and the Philippines. As a consequence, the subtropical high shifted southward. Therefore, a drought may be caused in the Indo-China peninsula and in the South China. Moreover, in midsummer the subtropical high is weak over the Yangtze River valley and Huaihe River valley, and the flood may be caused in the area from the Yangtze River valley to Huaihe River valley. On the contrary, in the decaying stage of ENSO. the convective activities may be strong around the Philippines, and the subtropical high shifted northward, a drought may be caused in the Yangtze River valley and Huaihe River valley.展开更多
Based on the data of monthly mean air temperature and precipitation from about 400 stations in 1951—1995.and the data of maximum and minimum air temperatures,relative humidity,total cloud cover and low-cloud cover,su...Based on the data of monthly mean air temperature and precipitation from about 400 stations in 1951—1995.and the data of maximum and minimum air temperatures,relative humidity,total cloud cover and low-cloud cover,sunshine duration,evaporation,wind speed,snow-covered days and depth,and soil temperatures in 8 layers from 0 m down to 3.2 m from 200 odd stations in 1961 —1995.the climate change and its characteristics in China in recent 45 years have been analyzed and studied comprehensively.This paper,as the first part of the work.has analyzed the climate change and regularities of such meteorological elements as mean air temperature,maximum and minimum air temperatures,precipitation,relative humidity and sunshine duration.The possible mechanism on climate change in China and the climate change and regularities of other meteorological elements will be discussed in another paper as the second part.展开更多
Climate change adaptation and relevant policy-making need reliable projections of future climate.Methods based on multi-model ensemble are generally considered as the most efficient way to achieve the goal.However,the...Climate change adaptation and relevant policy-making need reliable projections of future climate.Methods based on multi-model ensemble are generally considered as the most efficient way to achieve the goal.However,their efficiency varies and inter-comparison is a challenging task,as they use a variety of target variables,geographic regions,time periods,or model pools.Here,we construct and use a consistent framework to evaluate the performance of five ensemble-processing methods,i.e.,multimodel ensemble mean(MME),rank-based weighting(RANK),reliability ensemble averaging(REA),climate model weighting by independence and performance(ClimWIP),and Bayesian model averaging(BMA).We investigate the annual mean temperature(Tav)and total precipitation(Prcptot)changes(relative to 1995–2014)over China and its seven subregions at 1.5 and 2℃warming levels(relative to pre-industrial).All ensemble-processing methods perform better than MME,and achieve generally consistent results in terms of median values.But they show different results in terms of inter-model spread,served as a measure of uncertainty,and signal-to-noise ratio(SNR).ClimWIP is the most optimal method with its good performance in simulating current climate and in providing credible future projections.The uncertainty,measured by the range of 10th–90th percentiles,is reduced by about 30%for Tav,and 15%for Prcptot in China,with a certain variation among subregions.Based on ClimWIP,and averaged over whole China under 1.5/2℃global warming levels,Tav increases by about 1.1/1.8℃(relative to 1995–2014),while Prcptot increases by about 5.4%/11.2%,respectively.Reliability of projections is found dependent on investigated regions and indices.The projection for Tav is credible across all regions,as its SNR is generally larger than 2,while the SNR is lower than 1 for Prcptot over most regions under 1.5℃warming.The largest warming is found in northeastern China,with increase of 1.3(0.6–1.7)/2.0(1.4–2.6)℃(ensemble’s median and range of the 10th–90th percentiles)under 1.5/2℃warming,followed by northern and northwestern China.The smallest but the most robust warming is in southwestern China,with values exceeding 0.9(0.6–1.1)/1.5(1.1–1.7)℃.The most robust projection and largest increase is achieved in northwestern China for Prcptot,with increase of 9.1%(–1.6–24.7%)/17.9%(0.5–36.4%)under 1.5/2℃warming.Followed by northern China,where the increase is 6.0%(–2.6–17.8%)/11.8%(2.4–25.1%),respectively.The precipitation projection is of large uncertainty in southwestern China,even with uncertain sign of variation.For the additional half-degree warming,Tav increases more than 0.5℃throughout China.Almost all regions witness an increase of Prcptot,with the largest increase in northwestern China.展开更多
Infrastructure systems play a fundamental role in reducing greenhouse gas(GHG)emissions to avert global climate change(Kennedy et al.,2014).Transportations are recognized as one of the key factors for facilitating cli...Infrastructure systems play a fundamental role in reducing greenhouse gas(GHG)emissions to avert global climate change(Kennedy et al.,2014).Transportations are recognized as one of the key factors for facilitating climate change mitigation(Shaw et al.,2014).Approximately 19%of global energy consumption and 23%of energy-related carbon dioxide(CO2)emissions come from the transportation sector(IEA,2012).The demands are still increasing at an annual average rate of 1.4%(EIA,2016).Scholars展开更多
Tne global change of climate and its influence on the cropping system in China have been investigated in this paper.It is found that the temperature was increased during the last decade and the precipitation decreased...Tne global change of climate and its influence on the cropping system in China have been investigated in this paper.It is found that the temperature was increased during the last decade and the precipitation decreased in northern China and increased in southern China during the last 30 years.The sea level has been rising by about 21—26 cm in the coastal areas south of 30°N in China during the last 100 years. The most of results as simulated by the general circulation models(GCMs)show that the temperature increase would amount to about 2°—4°C in the most parts of China and precipitation and soil moisture might be decreased in northern China and increased in sourthern China due to doubling of carbon dioxide(CO_2). The effects of doubled CO_2 on growth period and climatic yield capability in China have been estimated roughly.It is shown that the regions of the growth period in China would be moved northward about five degrees latitude and the climatic yield capability might be increased by about 10％ in the most parts of China.展开更多
文摘The influence of ENSO on the summer climate change in China and its mechanism from the observed data is discussed. It is discovered that in the developing stage of ENSO, the SST in the western tropical Pacific is colder in summer, the convective activities may be weak around the South China Sea and the Philippines. As a consequence, the subtropical high shifted southward. Therefore, a drought may be caused in the Indo-China peninsula and in the South China. Moreover, in midsummer the subtropical high is weak over the Yangtze River valley and Huaihe River valley, and the flood may be caused in the area from the Yangtze River valley to Huaihe River valley. On the contrary, in the decaying stage of ENSO. the convective activities may be strong around the Philippines, and the subtropical high shifted northward, a drought may be caused in the Yangtze River valley and Huaihe River valley.
文摘Based on the data of monthly mean air temperature and precipitation from about 400 stations in 1951—1995.and the data of maximum and minimum air temperatures,relative humidity,total cloud cover and low-cloud cover,sunshine duration,evaporation,wind speed,snow-covered days and depth,and soil temperatures in 8 layers from 0 m down to 3.2 m from 200 odd stations in 1961 —1995.the climate change and its characteristics in China in recent 45 years have been analyzed and studied comprehensively.This paper,as the first part of the work.has analyzed the climate change and regularities of such meteorological elements as mean air temperature,maximum and minimum air temperatures,precipitation,relative humidity and sunshine duration.The possible mechanism on climate change in China and the climate change and regularities of other meteorological elements will be discussed in another paper as the second part.
基金supported by the National Natural Science Foundation of China(Grant No.42275184)the National Key Research and Development Program of China(Grant No.2017YFA0603804)the Postgraduate Research and Practice Innovation Program of Government of Jiangsu Province(Grant No.KYCX22_1135).
文摘Climate change adaptation and relevant policy-making need reliable projections of future climate.Methods based on multi-model ensemble are generally considered as the most efficient way to achieve the goal.However,their efficiency varies and inter-comparison is a challenging task,as they use a variety of target variables,geographic regions,time periods,or model pools.Here,we construct and use a consistent framework to evaluate the performance of five ensemble-processing methods,i.e.,multimodel ensemble mean(MME),rank-based weighting(RANK),reliability ensemble averaging(REA),climate model weighting by independence and performance(ClimWIP),and Bayesian model averaging(BMA).We investigate the annual mean temperature(Tav)and total precipitation(Prcptot)changes(relative to 1995–2014)over China and its seven subregions at 1.5 and 2℃warming levels(relative to pre-industrial).All ensemble-processing methods perform better than MME,and achieve generally consistent results in terms of median values.But they show different results in terms of inter-model spread,served as a measure of uncertainty,and signal-to-noise ratio(SNR).ClimWIP is the most optimal method with its good performance in simulating current climate and in providing credible future projections.The uncertainty,measured by the range of 10th–90th percentiles,is reduced by about 30%for Tav,and 15%for Prcptot in China,with a certain variation among subregions.Based on ClimWIP,and averaged over whole China under 1.5/2℃global warming levels,Tav increases by about 1.1/1.8℃(relative to 1995–2014),while Prcptot increases by about 5.4%/11.2%,respectively.Reliability of projections is found dependent on investigated regions and indices.The projection for Tav is credible across all regions,as its SNR is generally larger than 2,while the SNR is lower than 1 for Prcptot over most regions under 1.5℃warming.The largest warming is found in northeastern China,with increase of 1.3(0.6–1.7)/2.0(1.4–2.6)℃(ensemble’s median and range of the 10th–90th percentiles)under 1.5/2℃warming,followed by northern and northwestern China.The smallest but the most robust warming is in southwestern China,with values exceeding 0.9(0.6–1.1)/1.5(1.1–1.7)℃.The most robust projection and largest increase is achieved in northwestern China for Prcptot,with increase of 9.1%(–1.6–24.7%)/17.9%(0.5–36.4%)under 1.5/2℃warming.Followed by northern China,where the increase is 6.0%(–2.6–17.8%)/11.8%(2.4–25.1%),respectively.The precipitation projection is of large uncertainty in southwestern China,even with uncertain sign of variation.For the additional half-degree warming,Tav increases more than 0.5℃throughout China.Almost all regions witness an increase of Prcptot,with the largest increase in northwestern China.
基金supported by the National Natural Science Foundation of China (Grant No.71390525)
文摘Infrastructure systems play a fundamental role in reducing greenhouse gas(GHG)emissions to avert global climate change(Kennedy et al.,2014).Transportations are recognized as one of the key factors for facilitating climate change mitigation(Shaw et al.,2014).Approximately 19%of global energy consumption and 23%of energy-related carbon dioxide(CO2)emissions come from the transportation sector(IEA,2012).The demands are still increasing at an annual average rate of 1.4%(EIA,2016).Scholars
文摘Tne global change of climate and its influence on the cropping system in China have been investigated in this paper.It is found that the temperature was increased during the last decade and the precipitation decreased in northern China and increased in southern China during the last 30 years.The sea level has been rising by about 21—26 cm in the coastal areas south of 30°N in China during the last 100 years. The most of results as simulated by the general circulation models(GCMs)show that the temperature increase would amount to about 2°—4°C in the most parts of China and precipitation and soil moisture might be decreased in northern China and increased in sourthern China due to doubling of carbon dioxide(CO_2). The effects of doubled CO_2 on growth period and climatic yield capability in China have been estimated roughly.It is shown that the regions of the growth period in China would be moved northward about five degrees latitude and the climatic yield capability might be increased by about 10％ in the most parts of China.
