中国不同强度降雨量的多属性时序变化特征及其对ENSO的响应

ENSO是影响全球和区域降雨最显著的海气环流因子之一,且具有明显的周期性发展变化特征。基于1961～2016年中国545个气象观测站的日值降水数据,依据中国气象局中央气象台划定的日降雨强度标准,将降雨分为8种强度类型,诊断其8种不同强度降雨量的多属性时序变化特征,及其在不同时频域上对ENSO的响应。结果表明:(1)1961～2016年中国低强度降雨量以减少趋势为主,高强度降雨量则以增加趋势为主。不同强度降(暴)雨量对总降(暴)雨量的贡献率也有类似变化特征。由低强度降雨向高强度降雨转变过程中,中间强度降雨量及其贡献率呈现出先增后减的现象。说明中国降雨在朝着极端化方向发展。(2)除大雨与总降雨外,其它强度降雨量均存在4年及以内的振荡周期,其与ENSO发生发展周期具有较好的一致性。(3)除小雨外,其它强度降雨量的突变均通过了0.05显著性水平的检验,其中中雨、大雨、暴雨、大暴雨、特大暴雨、总暴雨和总降雨量分别在1967、1972、1995、1995、1996、1994和1973年发生了突变。上述突变中,低强度降雨量突变多在拉尼娜年发生,而高强度降雨量则多在厄尔尼诺年发生。(4)除小雨外,其它强度降雨量在1961～2016年与ENSO具有良好的相关性,均通过了0.05显著性水平的检验。在不同时频域上,中国不同强度降雨量与ENSO多在4年及其更短尺度上具有较好的一致性变化特征。尤其在低能量波谱区的高强度降雨和总降雨量与ENSO在长期变化上一致性较高。

Multi-attribute Temporal Variation of Rainfall With Different Intensities in China and Its Response to ENSO

Abstract：ENSO is one of the most significant air-sea factors affecting global and regional rainfall, and has obvious periodic characteristics. Based on the daily precipitation data of 545 meteorological stations in China from 1961 to 2016 and according to the daily rainfall intensity standard defined by the Central Meteorological Observatory of the China Meteorological Administration, this study classified the rainfall into eight intensity types, diagnosed the multi-attribute temporal variation characteristics of eight different intensity rainfall amounts and their responses to ENSO in different time and frequency domains. The results showed that: Firstly, low intensity rainfall amounts in China mainly decreased from 1961 to 2016, while high intensity rainfall amounts mainly increased. The contribution rate of rainfall amounts with different intensity to total rainfall amounts also had similar variation characteristics, so as the contribution rate of storm rainfall amounts with different intensity to total storm rainfall amounts. During the transition from low intensity rainfall to high intensity rainfall, the intermediate intensity rainfall amounts and its contribution rate increased first and then decreased. The above showed that rainfall in China was developing towards extreme direction. Secondly, except for heavy rainfall and total rainfall amounts, other rainfall amounts with different intensity had oscillation periods of 4 years or less, which was in good agreement with the occurrence and development cycle of ENSO events. Thirdly, except for light rainfall amounts, the abrupt changes of other rainfall amounts with different intensity had passed the test of 0.05 significance level. Among them, moderate rainfall, heavy rainfall, heavy rainfall, storm rainfall, heavy storm rainfall, extremely storm rainfall, total storm rainfall and total rainfall amounts changed abruptly in the year of 1967, 1972, 1995, 1995, 1996, 1994 and 1973, respectively. Among the abrupt changes mentioned above, most of the abrupt changes of low intensity rainfall occurred in La Nina year, while those of high intensity rainfall occurred in El Nino year. Fourthly, except for light rainfall, other rainfall amounts with different intensity had a good correlation with ENSO from 1961 to 2016, and passed the test of 0.05 significance level. In different time and frequency domains, rainfall with different intensity in China and ENSO had better consistency in four years and shorter scales. Especially in the low energy spectral region, the high intensity rainfall amounts and total rainfall amounts were consistent with ENSO in the long term change.