新疆博州地区气候生长季降水变化分析

摘 要：对新疆博州（博尔塔拉蒙古自治州）地区1958-2005年作物生长季降水资料的分析结果表明：博州地区作物生长季降水量存在显著增加趋势，特别是20世纪90年代以来降水偏多年略多于偏少年；降水存在5～7 a、16 a 和30 a 左右的周期变化；90年代以来，由于博河上游地区5月份降水偏少，而且博河中游地区第一场"透雨"日期又快速推后以及透雨次数减少等原因，造成河谷一带春夏干旱尤为突出；而在6-8月份，博河上游地区降水量与大雨日数的显著增加却极易诱发山区洪灾；秋季月降水量的普遍增加对作物的采收晾晒不利，但是山区秋季降水的增加有利于秋水转为春用。

Precipitation Change During the Growing Season of Crops in Bole Prefecture, Xinjiang

Based on the precipitation data from four meteorological stations in Bole Prefecture during 1958-2005, precipitation changes in the growing season of crops were analyzed. The results show that there was a remarkable rise trend for the precipitation in the growing season of crops, with flood years slightly more than drought years since 1990s; the periods of 5-7 years, 16 years, and 30 years were dominant for the mean regional precipitation; the spring-summer drought was very prominent in the Bole River valley since 1990s, which was mainly caused by the precipitation reduction in the upstream of Bole River in May, the delay of the first soaking rain and the decrease of the soaking rain frequency in the midstream of the Bole River. The flood in mountainous area was easily induced by the significant increase in rainfall amount and the frequency of heavy rain from June to August in the upstream of Bole River. The increase in autumn precipitation was unfavorable for crop picking and airing, but it was advantageous for being stored and used in the next spring.