青海省海东市不同等级降水和旱涝关系研究

青海省海东市是青海省重要的粮食生产基地,干旱直接影响着农业的有序发展。利用1961—2015年青海省海东市5个气象站逐日降水资料,笔者分析各级雨量和雨日及Z指数的变化趋势,并研究各级雨量和雨日对旱涝的影响。结果表明：（1）夏（冬）半年降水以小雨（雪）和中雨（雪）为主;夏半年小雨和大到暴雨（中雨）的雨量及雨日呈减小（增加）趋势,冬半年各级雨量及雨日均呈减小趋势;（2）夏、冬半年Z指数均表现为不显著的减小趋势;（3）采用偏相关系数和相对贡献率分析,夏半年中雨和大到暴雨雨量及雨日对Z指数有显著的影响,冬半年小雪的雨量和雨日对Z指数变化影响最大;（4）采用合成分析法的标准化值,在偏涝年,各级雨量和雨日基本都为正值,夏半年差异主要表现在大到暴雨和中雨雨量和雨日,而冬半年差异主要表现在小雪雨量和雨日;在偏旱年,各级降水雨量和雨日基本都为负值,夏半年差异主要表现在中雨雨量和雨日,冬半年差异主要表现在小雪和中雪雨量和雨日。

The Relationship Between Different Grades of Precipitation and Drought and Flood in Haidong, Qinghai

Haidong is an important grain production base in Qinghai, and drought directly affects the orderly development of agriculture. Based on the daily precipitation data of 5 meteorological stations in Haidong from 1961 to 2015, we analyzed the variation trend of rain days and precipitation of different grades and Z index, and studied the effects of rain days and precipitation of different grades on drought and flood. The results showed that: (1) half-year precipitation in summer (winter) was dominated by light rain (snow) and moderate rain (snow), the precipitation and rain days of light rain and heavy rain (moderate rain) in summer half year were decreasing (increasing) and the precipitation and rain days at all grades in winter half year were decreasing; (2) the Z index in summer, winter half year showed an insignificant trend of decrease; (3) according to the analysis of partial correlation coefficient and relative contribution rate, the precipitation and rain days of medium rain and heavy rain in summer half year had significant influence on Z index, while the precipitation and rain days of light snow in winter half year had the greatest influence on Z index change; (4) the synthetic analysis showed that the precipitation and rain days of different grades were basically positive in flood years, the differences of precipitation and rain days of different grades was mainly shown in the heavy rain and moderate rain in summer half year, and the differences in winter half year was mainly reflected in the precipitation and rain days of light snow; in the dry year, the precipitation and rain days at all grades were basically negative, the differences in summer half year was mainly reflected in precipitation and rain days of moderate rain, while the differences in winter half years was mainly reflected in the precipitation and rain days of light snow and moderate snow.