Soil moisture is an important parameter for the interaction between soil and atmosphere. It is the sec- ond important factor that influences climate change, next to sea surface temperature （SST）. Most previous studi...Soil moisture is an important parameter for the interaction between soil and atmosphere. It is the sec- ond important factor that influences climate change, next to sea surface temperature （SST）. Most previous studies focused on the monsoon regions in East China, and only a few laid emphases on arid environments. In Xinjiang, which is located in Northwest China, the climate is typically arid and semi-arid. During the past 20 years, the pre- cipitation in Xinjiang has shown a significant increasing trend, and it is closely related to oasis irrigation. This paper aims at discussing whether abnormal soil moisture in spring can be the signal to forecast summer precipitation. The effects of abnormal soil moisture due to farm irrigation in spring in arid environments on regional climate are inves- tigated by using a regional climate model （RegCM3）. The results indicate that positive soil moisture anomaly in irrigated cropland surface in May led to an increase in precipitation in spring as well as across the whole summer. The impact could last for about four months. The effects of soil moisture on the surface air temperature showed a time-lagging trend. The summer air temperature declined by a maximum amplitude of 0.8℃. The increased soil moisture could enhance evaporation and ascending motion in the low troposphere, which brought in more precipi- tation. The soil moisture affected regional weather and climate mainly by altering the surface sensible and latent heat fluxes.展开更多
依据新疆地区53个雨量站1957-2009年日降水资料,根据研究需要,定义了8个极端降水指标。运用K-S法确定降水指标最适概率分布函数,确定10年一遇极端降水量值;在此基础上,采用Copula非参数估计方法,通过Akaike information criterion(AIC)...依据新疆地区53个雨量站1957-2009年日降水资料,根据研究需要,定义了8个极端降水指标。运用K-S法确定降水指标最适概率分布函数,确定10年一遇极端降水量值;在此基础上,采用Copula非参数估计方法,通过Akaike information criterion(AIC)法确定两降水指标联合分布函数,系统分析1980年以后极端降水单变量极值及降水极值二维联合概率分布特征变化的时空演变特征,研究结果表明:①新疆有湿润化趋势,北疆湿润化趋势比南疆显著;②从降水天数和极端降水天数角度来看,新疆极端强弱降水同时出现的概率减小,从极端降水雨量和强度来看新疆中部、南疆西部、北疆东部及北部极端强弱降水同时出现的可能性减小,而天山西部与南疆北部的可能性增加;③1980年后新疆地区发生涝的概率增大,发生旱的概率减少。展开更多
新疆地区生态环境脆弱且对气候变化敏感,在全球气候变化背景下,新疆生态环境及水资源可持续发展方面均面临巨大的挑战。以新疆降水为重点研究对象,应用欧洲中期数值预报中心(European Centre for Medium-range Weather Forecasts,ECMWF...新疆地区生态环境脆弱且对气候变化敏感,在全球气候变化背景下,新疆生态环境及水资源可持续发展方面均面临巨大的挑战。以新疆降水为重点研究对象,应用欧洲中期数值预报中心(European Centre for Medium-range Weather Forecasts,ECMWF)的全球再分析气象数据(ECMWF Re-Analysis-Interim)探究新疆的降水变化规律。研究结果表明:新疆地区南北疆、山地、平原、盆地、荒漠和沙漠不同地域的气候差异极为显著,北疆的降水量多于南疆,西部的降水量多于东部。其中,西部伊犁地区降水量达东部哈密地区的近6倍;此外,山区降水量远多于盆地,天山山区的年降水量约235.65 mm。通过分析1979—2013年降水量数据时间序列和月、季度、年各气候区划的降水量均值和变化趋势发现,新疆不同气候区划的降水量差异显著。其中,天山北坡气候区降水充沛,多年平均降水量达278.52 mm,为新疆降水量最多的气候区,阿尔泰山气候区次之,多年平均降水量达221.91 mm,北疆准噶尔盆地气候区的年降水量为181.87 mm,而南疆塔里木盆地气候区的多年平均降水量仅为66.03 mm。本研究总体认为:新疆降水量时空分布呈现北疆多、南疆少,山地多、平原少,夏季多、冬季少的时空分布特征。研究结果将为新疆水资源对气候变化的响应研究起到重要的推动作用。展开更多
基金supported by the National Natural Science Foundation of China(40875010,41005050)the Xinjiang Science and Technology Support Project(200891129)the Global Change National Key Scientific Research Project(2011 CB952002)
文摘Soil moisture is an important parameter for the interaction between soil and atmosphere. It is the sec- ond important factor that influences climate change, next to sea surface temperature （SST）. Most previous studies focused on the monsoon regions in East China, and only a few laid emphases on arid environments. In Xinjiang, which is located in Northwest China, the climate is typically arid and semi-arid. During the past 20 years, the pre- cipitation in Xinjiang has shown a significant increasing trend, and it is closely related to oasis irrigation. This paper aims at discussing whether abnormal soil moisture in spring can be the signal to forecast summer precipitation. The effects of abnormal soil moisture due to farm irrigation in spring in arid environments on regional climate are inves- tigated by using a regional climate model （RegCM3）. The results indicate that positive soil moisture anomaly in irrigated cropland surface in May led to an increase in precipitation in spring as well as across the whole summer. The impact could last for about four months. The effects of soil moisture on the surface air temperature showed a time-lagging trend. The summer air temperature declined by a maximum amplitude of 0.8℃. The increased soil moisture could enhance evaporation and ascending motion in the low troposphere, which brought in more precipi- tation. The soil moisture affected regional weather and climate mainly by altering the surface sensible and latent heat fluxes.
文摘依据新疆地区53个雨量站1957-2009年日降水资料,根据研究需要,定义了8个极端降水指标。运用K-S法确定降水指标最适概率分布函数,确定10年一遇极端降水量值;在此基础上,采用Copula非参数估计方法,通过Akaike information criterion(AIC)法确定两降水指标联合分布函数,系统分析1980年以后极端降水单变量极值及降水极值二维联合概率分布特征变化的时空演变特征,研究结果表明:①新疆有湿润化趋势,北疆湿润化趋势比南疆显著;②从降水天数和极端降水天数角度来看,新疆极端强弱降水同时出现的概率减小,从极端降水雨量和强度来看新疆中部、南疆西部、北疆东部及北部极端强弱降水同时出现的可能性减小,而天山西部与南疆北部的可能性增加;③1980年后新疆地区发生涝的概率增大,发生旱的概率减少。
