梅雨特征量对气候变暖的响应

Response of Meiyu characteristics to climatic warming

选取江淮流域梅汛期降水变率一致的34个代表站,划分了1960—1977年(偏冷期)、1978—1996年(过渡期)和1997—2011年(偏暖期)这3个时期,采用统计分析与合成分析的方法,研究了梅雨特征量对气候变暖的响应情况。结果表明:3个时期入梅时间、出梅时间、梅期长度和梅期降水量分别呈现晚-早-晚、早-晚-略晚、短-长-短和少-多-少的变化特点。梅雨强度和梅期雨日数占梅期长度百分比呈现递减趋势。梅期暴雨日数占梅期雨日数百分比、梅期无雨日数占梅期长度百分比和梅期最长连续无雨日数占梅期长度百分比呈现递增趋势。研究了气候变暖后500 h Pa大气环流的变化与入梅时间、出梅时间、梅期长度和梅期降水量变化的联系。

34 representative stations with consistent precipitation variability over Changjiang-Huaihe River Valley were selected and cold period of 1960-1977, transitional period of 1978-1996 and warm period of 1997-2011 were divided to analyze the response of Meiyu characteristics to climatic warming by methods of statistic and synthesis analyses. Results show that the Meiyu onset, Meiyu ending date, Meiyu length period, Meiyu rainfall amount are characterized by late-early-late, eady-late-a little late , short- long-short, and little-much-little variation trends, respectively. Meiyu intensity and pecentage of rain days during Meiyu period are declining. Percentages of Meiyu torrential rain days in Meiyu rain days, no rain days in Meiyu length and the maximum continuous no rain days in the Meiyu length show rising trends. The relationship between variations of atmospheric circulation at 500 hPa in response to climatic warming and variations of onset date, ending date, Meiyu length as well as Meiyu rainfall amount was also studied.