The Yangtze River Delta（YRD） has experienced significant urban expansion in recent years, while the Meiyu belt of China has demonstrated a decadal northward shifting trend. Thus, it is of interest to assess how urba...The Yangtze River Delta（YRD） has experienced significant urban expansion in recent years, while the Meiyu belt of China has demonstrated a decadal northward shifting trend. Thus, it is of interest to assess how urban expansion affects Meiyu precipitation and hopefully to reveal the underlying physical mechanisms involved. In this study, the urban extents over the YRD in 2001 and 2010 are derived based on land use/land cover（LULC） category data and nighttime light image data. Two parallel groups of10-summer（2001-2010） numerical simulations are carried out with the urban extents over the YRD in2001 and 2010, respectively. The results show that the urban expansion in the YRD tends to result in increased（decreased） Meiyu precipitation over the Huaihe River（Yangtze River） basin with intensities of0.2-1.2 mm day-1. Further analysis indicates that the spatiotemporal pattern of the Meiyu precipitation change induced by the urban expansion resembles the third empirical orthogonal function（EOF） mode of the observed Meiyu precipitation. Analyses of the possible underlying physical mechanisms reveal that urban expansion in the YRD leads to changes in the surface energy balance and warming（cooling） of tropospheric（stratospheric） air temperature over eastern China. Anomalous upward（downward） motion and moisture convergence（divergence） over the Huaihe River（Yangtze River） basin occur, corresponding to the increases（decreases） of the Meiyu precipitation over the Huaihe River（Yangtze River） basin.展开更多
本文基于中国1:100万植被图、马里兰大学AVHRR森林覆盖资料和中国753个气象站点40年的降水气温资料,发展了一套用于气候模拟的中国陆面覆盖资料(Chinese land cover derived fromvegetation map,简称CLCV)。该套资料与CLM(Community Lan...本文基于中国1:100万植被图、马里兰大学AVHRR森林覆盖资料和中国753个气象站点40年的降水气温资料,发展了一套用于气候模拟的中国陆面覆盖资料(Chinese land cover derived fromvegetation map,简称CLCV)。该套资料与CLM(Community Land Model)原来所用的MODIS(Moderate Resolution I maging Spectro-radiometer)陆面覆盖资料相比有较大不同:其中裸土比例减少了14.5%,森林、灌木、草原和农作物比例分别增加了3.3%、4.8%、4.4%和0.3%,冰川、湖泊和湿地比例分别增加了0.4%、0.8%和0.6%。将CLCV和MO-DIS资料分别与全国土地资源概查汇总结果分省统计资料和基于中国1km土地利用图的土地利用资料比较表明,CLCV与两者较为接近。最后,利用CLM模式分别采用CLCV与MODIS陆面覆盖资料在中国区域内进行数值模拟,结果显示,使用CLCV资料所模拟的蒸散增加了约7.7mm/a;地表反照率、感热和径流分别减小了约0.7%、0.3W/m2和7.6mm/a;与MODIS卫星反演地表反照率和GRDC(Global Runoff Data Centre)径流资料比较表明,利用CLCV资料所模拟的地表反照率有一定改进,并能基本模拟出径流分布趋势。展开更多
基金Supported by the National Basic Research and Development(973)Program of China(2011CB952002 and 2010CB428504)
文摘The Yangtze River Delta（YRD） has experienced significant urban expansion in recent years, while the Meiyu belt of China has demonstrated a decadal northward shifting trend. Thus, it is of interest to assess how urban expansion affects Meiyu precipitation and hopefully to reveal the underlying physical mechanisms involved. In this study, the urban extents over the YRD in 2001 and 2010 are derived based on land use/land cover（LULC） category data and nighttime light image data. Two parallel groups of10-summer（2001-2010） numerical simulations are carried out with the urban extents over the YRD in2001 and 2010, respectively. The results show that the urban expansion in the YRD tends to result in increased（decreased） Meiyu precipitation over the Huaihe River（Yangtze River） basin with intensities of0.2-1.2 mm day-1. Further analysis indicates that the spatiotemporal pattern of the Meiyu precipitation change induced by the urban expansion resembles the third empirical orthogonal function（EOF） mode of the observed Meiyu precipitation. Analyses of the possible underlying physical mechanisms reveal that urban expansion in the YRD leads to changes in the surface energy balance and warming（cooling） of tropospheric（stratospheric） air temperature over eastern China. Anomalous upward（downward） motion and moisture convergence（divergence） over the Huaihe River（Yangtze River） basin occur, corresponding to the increases（decreases） of the Meiyu precipitation over the Huaihe River（Yangtze River） basin.
文摘本文基于中国1:100万植被图、马里兰大学AVHRR森林覆盖资料和中国753个气象站点40年的降水气温资料,发展了一套用于气候模拟的中国陆面覆盖资料(Chinese land cover derived fromvegetation map,简称CLCV)。该套资料与CLM(Community Land Model)原来所用的MODIS(Moderate Resolution I maging Spectro-radiometer)陆面覆盖资料相比有较大不同:其中裸土比例减少了14.5%,森林、灌木、草原和农作物比例分别增加了3.3%、4.8%、4.4%和0.3%,冰川、湖泊和湿地比例分别增加了0.4%、0.8%和0.6%。将CLCV和MO-DIS资料分别与全国土地资源概查汇总结果分省统计资料和基于中国1km土地利用图的土地利用资料比较表明,CLCV与两者较为接近。最后,利用CLM模式分别采用CLCV与MODIS陆面覆盖资料在中国区域内进行数值模拟,结果显示,使用CLCV资料所模拟的蒸散增加了约7.7mm/a;地表反照率、感热和径流分别减小了约0.7%、0.3W/m2和7.6mm/a;与MODIS卫星反演地表反照率和GRDC(Global Runoff Data Centre)径流资料比较表明,利用CLCV资料所模拟的地表反照率有一定改进,并能基本模拟出径流分布趋势。
