1960—2017年沈阳地区春播期降水变化特征

基于1960—2017年沈阳市5个气象观测站4—5月降水量资料,采用线性趋势法和累积距平分析了沈阳市春播期(4—5月)降水量演变特征,并分析首场透雨及最大连续无有效降水日数演变特征及对春播期降水量影响,对春播期降水量资源变化特征进行相关分析。结果表明:近58a沈阳春播期降水量整体呈现弱的增加趋势,平均每10a增加3.1mm,2004年开始降水量迅速增加,且波动性较大,降水量异常偏多或偏少年份较多,易诱发春旱春涝事件。春播期首场透雨出现日期平均每10a偏晚0.051d,首场透雨日期偏晚,将导致春播期前期雨水条件不足,引起土壤干旱,不利于春播开展。最大连续无有效降水日数呈波动性增加趋势,平均每10a增加0.56d,对4月降水量影响较大,虽然春播期降水资源总量增加,但存在降水资源时间分配不均的问题,且长时间无有效降水事件频发,将导致春播期干旱灾害事件发生风险加大,导致适播期延后。

Characteristics of precipitation during the spring sowing period in Shenyang from 1960 to 2017

Using linear inclination estimation and accumulative anomaly analysis methods,the temporal characteristic of precipitation during the spring sowing period and its relationship with the first soaking rain and the maximum continuous days without available precipitation were analyzed.The results show that the precipitation during the spring sowing period increased slowly with a rate of 3.1 mm/10 a in Shenyang from 1960 to 2017.The precipitation during the spring sowing period increased rapidly with larger fluctuations since 2004.The increase of abnormal precipitation years induced spring drought (or flood) events occurring frequently.The first soaking rain during the spring sowing period of Shenyang delayed with a rate of-0.051 d/10 a,which usually leads to the shortage of soil water during the spring sowing period and are unfavorable for spring sowing.The maximum continuous days without available precipitation increased with a rate of 0.56 d/10 a,which had significant impacts on precipitation in April.Although the total amount of precipitation during the spring sowing period had an increasing trend,its temporal distribution was uneven.Above all,the uneven distribution of precipitation and the frequently occurrence of continuous days without available precipitation will increase drought disaster risk during the spring sowing period and the sowing date may be delayed.