潮白河流域1980~2012年干旱评价及其影响分析

The Drought Assessment and Its Impact Analysis in Chaobai River Basin from 1980 to 2012

摘要: 本文基于1980~2012年丰宁、张家口和塘沽气象站的连续观测资料，分析潮白河流域内潮河区、白河区和下游区等三个二级区的温度、降水和蒸散发量等气候因子的变化趋势。选取相对湿润度指数(M)和连续无雨日天数两种干旱评价指标，对研究区年度干旱和季节性干旱进行评价，分析干旱的时空演变规律及其影响。结果表明：1) 潮白河流域从上世纪80年代以来有变暖趋势。潮河区以轻旱年为主，但在1998年之后干旱呈现明显加重趋势；白河区均为轻旱年或中旱年，下游区干旱年际波动较大，两个二级区的干旱指数线性趋势不显著，可分为一个动荡期和两个上升期。2) 从季节性干旱变化趋势来看，潮河区和白河区夏季干旱有加重趋势，其他各季干旱情况均有所好转，尤其是秋季降水量结余比例有增加趋势。季节性干旱中春旱频次最高，其次为冬旱。随着年度干旱等级升高，秋旱和夏旱、大旱和特大旱发生频率随之升高。秋旱和夏旱发生较少，但对年度干旱等级影响较大。

Abstract: Based on the daily meteorological data of Fengning, Zhangjiakou and Tanggu meteorological stations in Chaobai River basin from1980 to 2012, the variation trends of temperature, precipitation and evaporation were analyzed. We made assessments of annual drought and seasonal drought by using the relative moisture index and the consecutive days without rain drought evaluation methods, and then analyzed the space-time evolution regularity of drought and its influence. The results showed that: 1) The Chaobai River basin had a warming trend since 80s of last century. The Chaohe area was mainly light drought years, but it showed an increasing trend from 1998 to 2012. The Baihe area was all mild drought years or dry years and the Downstream area drought had a large interannual fluctuation. The drought index linear trend of these two secondary zones was not significant, and the M values can be divided into a turbulent period and two rise periods. 2) From the seasonal drought trend, we can see that the summer drought showed an increasing trend in Chaohe area and Baihe area, and other seasonal drought conditions had better trends, especially in autumn. Spring drought had the highest frequency, followed by the winter drought. As the level of annual drought increased, the occurrence frequencies of the summer drought, autumn drought, great drought and super drought increased. Autumn drought and summer drought occurred less, but they had a greater impact on the level of annual drought.