西南地区北热带代表站干季气象干旱分析

Meteorological drought of north tropic representative station during dry season in southeastern China

基于我国西南地区北热带基准站勐腊站1957—2015年雨季开始、结束期及逐日降水资料,对其干季基本气候特征进行统计分析;采用ASI与历史干旱资料对比的方法确定勐腊站干季气象干旱的标准,并分析其气象干旱特征。结果表明,勐腊站干季雨量相对较少,且较集中,透雨间隔较长,易出现干旱;≤30 d的ASI出现381次,>30 d的ASI出现58次,大多数透雨间隔不易出现干旱;建立勐腊站气象干旱标准(ASI>75d,特旱;65 d<ASI≤75 d,重旱;50 d<ASI≤65 d,中旱;30 d<ASI≤50 d,轻旱);1958—2015年间,勐腊站共出现了58次气象干旱;轻、中旱的发生频次较高,几乎各年代均出现过特旱,与前33 a相比,近25 a有特旱减少,重旱增加的趋势。

Based on Mengla＇ s daily precipitation data and the data of the start and end of the rainy season during 1957-2015, the basic climatic characteristics in the dry season were analyzed; Comparing ASI with historical drought, the standard of meteorological drought in Mengla was determined. The results show that Mengla has less, but more concentrated precipitation in dry season, resulting in longer soaker interval and drought; Most of soaker intervals could not cause drought, times of ASI of more than 65 days are much less than that of ASI of less than or equal to 30 days; Establish the standard of meteorological drought （ASI 〉 75d, severe drought; 65 〈 ASIa75 d , heavy drought; 50 〈 ASIa65 d, medium drought; 30 〈 ASIa〈50 d, light drought） ; 58 times of drought showed up in Mengla during 1958 - 2015; Light drought and medium drought occurred frequently, severe drought almost hap- pened every 10 years; Compared with the previous 33 years, times of severe drought trend to reduce, and times of heavy drought increase in recent 25 years.