1951—2012年中国降水集中度和集中期的时空格局

Variations in the spatiotemporal patterns of precipitation concentration degree and precipitation concentration period from 1951 to 2012 in China

以1978年为分界点,对1978年前后的以周为单位的降水集中度和集中期的时空格局和变化趋势进行研究.结果表明：1）中国的降水集中度首先具有明显南北分异规律,其次在中国北部具有明显东西差异;最后,中国整体降水集中度波动呈现减小趋势,且1978年之前波动较大,1978年之后趋于平稳.2）中国的降水集中期主要集中在一年中的第26—30周左右,并在1978年前后有1~3周不同幅度的滞后和提前,且南方以推迟为主,北方以提前为主;中国整体降水集中期波动呈现微弱减少趋势,且1978年前显著减少,但1978年后显著增加.

The year of 1978 was taken as a dividing point in the study of variations in precipitation concentration degree （PCD） and precipitation concentration period （PCP）. It was found that PCD had a significant north-south pattern, but PCD had a significant east-west pattern in Northern China. Fluctuations in PCD showed a decreasing trend, PCD fluctuations were larger pre-1978 and smaller post-1978. PCP mainly fell between 26 and 30 weeks, 1-3 weeks of advance or lag were noted. Southern-based PCP mainly postponed, Northern-based PCP advanced. PCP showed a weak decreasing trend, with significant reduction pre-1978 and significant increase post-1978.