摘要
This study aims to investigate the recent drought in southwestern China and its association with environmental changes in moisture transport （MT） and atmospheric circulation. Climatic Research Unit grid data, in situ observations in China, and ERA-interim reanalysis are used to study the characteristics of the drought and the associated mechanism. Recent precipitation trends show a pattern of ＂Northern wetting and Southern drying＂, similar to the anti-phase of the climate pattern prevailing during 1980--2000 in China's Mainland; southwestern China incurred a severe drought during 2009-20l 3. Wavelet analysis reveals that the drought coincides with a warm-dry phase of temperature and precipitation on a period of about 20 years and beyond 100 years, where contributions account for 43% and 57% of the deficiency of the precipitation, averaged for 2003-2012, respectively. A further investigation reveals that the drought results chiefly from the decline of the southwestern monsoon MT toward southwestern China, in addition to mid-latitude circulation changes, which leads to more blockings near the Ural Mountains and the Sea of Okhotsk in the rainy season and negative anomalies around Lake Baikal and northeast China in the dry season. These anomalies are likely to be correlated with global sea surface temperature changes and need to be studied further.
This study aims to investigate the recent drought in southwestern China and its association with environmental changes in moisture transport （MT） and atmospheric circulation. Climatic Research Unit grid data, in situ observations in China, and ERA-interim reanalysis are used to study the characteristics of the drought and the associated mechanism. Recent precipitation trends show a pattern of ＂Northern wetting and Southern drying＂, similar to the anti-phase of the climate pattern prevailing during 1980--2000 in China's Mainland; southwestern China incurred a severe drought during 2009-20l 3. Wavelet analysis reveals that the drought coincides with a warm-dry phase of temperature and precipitation on a period of about 20 years and beyond 100 years, where contributions account for 43% and 57% of the deficiency of the precipitation, averaged for 2003-2012, respectively. A further investigation reveals that the drought results chiefly from the decline of the southwestern monsoon MT toward southwestern China, in addition to mid-latitude circulation changes, which leads to more blockings near the Ural Mountains and the Sea of Okhotsk in the rainy season and negative anomalies around Lake Baikal and northeast China in the dry season. These anomalies are likely to be correlated with global sea surface temperature changes and need to be studied further.
基金
Project supported by the National Basic Research and Development Program of China(Grant No.2013CB430201)
the National Natural Science Foundation of China(Grant Nos.41075058 and 41475075)
the China Meteorological Administration Special Public Welfare Research Fund(Grant No.GYHY201106016)
