【摘要】 利用云贵高原东部84个地面气象观测站2011年和2013年4—9月逐日降水和温度资料、NCEP/NCAR再分析资料以及积温干燥度公式和视水汽汇公式,对2011年(拉尼娜年)汛期(4—9月)和2013年(中性年)汛期(4—9月)云贵高原东部干旱天气的基本特征和环流异常进行分析。结果表明,2011年汛期平均降水量比2013年汛期少,但均具有时空分布不均的特点;2011年汛期降水量偏少,主要是4—5月和7—9月的降水贡献大,2013年汛期降水量偏少,主要是7—8月的降水贡献大,且积温干燥度指数较好地反映了2011年和2013年汛期的干旱程度。2011年、2013年汛期的南亚高压均偏强、面积均偏大、东侧脊点位置均偏东,但2011年汛期的西太平洋副热带高压的强度、面积均比2013年汛期的偏强、偏大,是2011年汛期干旱天气比2013年汛期偏重的重要原因。孟加拉湾、南海以及西太平洋中低层的水汽输送偏弱是云贵高原东部2011年和2013年汛期降水少的主要原因,且云贵高原东部上空的水汽辐散中心与其降水量有较好的对应关系;700 h Pa的水汽输送异常减少对2011年和2013年汛期干旱的发生起决定性作用,云贵高原东部2011年汛期700 h Pa层上的水汽辐散比2013年汛期的强,导致其降水量比2013年汛期的少。视水汽汇揭示了2011年汛期干旱程度比2013年更严重的事实。500 h Pa环流场、700 h Pa水汽输送场对于云贵高原东部较长时间的旱涝预报具有一定的参考价值。更多还原

【Abstract】 Based on the daily precipitation and temperature data in 2011 and 2013 of 84 meteorological stations in the eastern Yunnan-Guizhou,reanalysis data of NCEP/NCAR and the formula of accumulated temperature drying degree.The basic characteristics and the abnormal circulation of drought disaster in the eastern YunnanGuizhou of flood season(April to Sepetember) in 2011(La Nina) and 2013(neutral) were analyzed.The results show that the flood season rainfall in 2011 is less than the 2013 with the characteristics of inhomogeneous space-time distribution.The rainfall of April to May,July to Sepetember make an important contribution to the drought in 2011 and July to August in 2013 by comparison,as well as,the index of accumulated temperature drying degree reflects the degree of drought of 2011 and 2013 well.The South Asia High was abnormal stronger,larger area,east ridge point are East is the Common ground of 2011 and 2013,but the intensity and area of Western Pacific Subtropical High in 2011 is stronger than the 2013 which is the important reason that drought in2011 more severe than 2013.The low layer moisture transport of the bay of Bengal,South China Sea and the Western Pacific were weak than usual is the main reason of scarce precipitation in 2011 and 2013 in the eastern Yunnan-Guizhou precipitation less the main reason,and there is a good corresponding relationship between the precipitation and the water divergence center in the eastern Yunnan-Guizhou.The water vapor transport on 700 hPa play a decisive role in the flood season drought of 2011 and 2013,and the divergence is stronger in 2011 than 2013 which case the severer drought in 2011.The apparent moisture content revealed that the drought in 2011 is more serious than that in 2013.In addition,the 500 hPa circulation field and 700 hPa water vapor transport field have some reference value for the long time forecast of drought and flood in the eastern Yunnan-Guizhou.更多还原