珠江流域1960—2012年极端气温的时空变化特征

Temporal and Spatial Variation Characteristics of Extreme Temperature in the Pearl River Basin during 1960-2012

根据珠江流域43个气象站点(1960—2012年)16个极端气温指标数据,采用线性回归、Mann-Kendall(M-K)和小波分析法分析珠江流域极端气温的时空变化特征。变化趋势分析表明,除结冰日数(ID0)、月最高气温极小值(TXn)、冷昼日数(TX10p)和作物生长期(GSL)4个指标呈现出不显著的变化趋势外,夏日日数(SU25)、热浪日数(TR20)尤其是暖夜日数则呈明显上升趋势(P<0.05);空间变化分析表明,冷夜日数(TN10p)、冷日持续指数(CSDI)和昼夜温差幅度(DTR)以及冷昼日数(TX10p)在整个珠江流域大致呈下降趋势,其余10个指标大致呈上升趋势,呈现出较好的流域一致性;突变分析表明,除了ID0、TX10p和GSL三个指标之外,其余指标均通过了显著性检验,大多数突变点发生于1980年代,其中夏日日数(SU25)、热浪日数(TR20)的突变点分别为2001和1994年;周期分析表明,大部分指标呈现多个周期震荡,且都以2~4 a为主周期。SCSMI(南中国海夏季季风指数)与ENSO是造成研究区极端高气温的重要因素。

Extreme and high frequency weather events caused by the global warming, have brought huge influences to human activities as well as ecological environment. Within this context, analyzing extreme temperature event that is one of the extreme weather events is of paramount importance for human activities. The Pearl River Basin, one of the richest basins in China, locates in the subtropical monsoon region where the climate characteristics are quite complicated. Meanwhile, as global climate changes, the extreme temperature event in the basin should bring some new change which, however, is still unknown. Therefore, the purpose of this paper is to analyze the temporal and spatial variation characteristics of the extreme temperature event in the Pearl River Basin. In this paper, 16 indexes related to extreme temperature were selected.The data about these indexes at 43 weather stations(1960-2012) have been collected and processed to guarantee the rationality of the results. Linear regression, Mann- Kendall as well as wavelet analysis were used to analyze the temporal variation characteristics of the extreme temperature. Kriging, one of the spatial interpolation technologies, was also used to analyze the spatial variation characteristics. The results show that: 1) for the temporal trend, the indexes of ID0, TXn, TX10 p and GSL showed non- significant trend whereas the others showed significant increasing or decreasing trend(P<0.05). 2) Spatially, the indexes of TN10 p, CSDI, DTR and TX10 p showed an overall downward trend whereas the others showed an overall upward trend in the basin, with non- significant spatial variations. 3) The mutation analysis disclosed that except the indexes of ID0, TX10 p and GSL, the other indexes all passed significance inspection and most of the abrupt change points happened in 1980 s but that of TR20 and SU25 occurred in 1994 and 2001 respectively. 4) The wavelet analysis discovered that there existed multiple periodic oscillations for the values of most indexes and the primary periods were 2-4years. SCSMI and ENSO are the main factors caused the extreme temperature event in the study area. This study has the potential to provide valuable references for agricultural protection, water resources management, drought disaster control, and other crucial applications in the Pearl River Basin.