1880―2015 年汕头降水量变化趋势与全球气候变暖的关系

根据汕头气象站 1880―2015 年逐月降水量资料，采用滤波、线性倾向计算、趋势系数计算、相关分析、谱分析等方法，分析该站近 135 a 来降水量的变化趋势及其与全球气候变暖的关系，结果得出：1）汕头站近 135a 来的全年及前汛期、后汛期的降水量变化存在 2~7、10 和 30 a 左右的周期变化，没有显著的上升或下降趋势；2）近 135 a 来汕头的降水量变化与同期全球气候变暖对应关系较为复杂，暖期（1977―2015 年）与冷期（1900―1938 年）相比，汛期（4―9 月）雨量增加 68.1 mm，其他月份（旱期）减少 64.1 mm，年雨量仅增加 4 mm；3）按现用广东省气象局降水气候评价标准，全球气候变暖背景下汕头前汛期降水量正常年景的频率增加、后汛期降水量偏少的概率增多。

Trends of Rainfall at Shantou and Their Relationships with Global Surface Temperature during 1880–2015

In recent years, some investigations have been carried out to study the inter-decadal variability of precipitation in China. The earliest record of rainfall was from 1880 and a total of 127 years of complete records were taken for Shantou. This long precipitation sequence was very important for exploring the rainfall regime for the whole eastern region of Guangdong Province. The long-term changes in precipitation during a whole year, the pre-flood period (Apr.-Jun.), or the post-flood period (Jul.-Sep.), and their relationships with global surface temperature during 1880-2015 were analyzed using precipitation data from the Central Weather Bureau (for years of 1881-1943) and Shantou Meteorology Station (for years of 1951-2015) and global surface temperature data from HadCRUT 4 dataset. The methods of filtering analysis, linear regression analysis, spectral analysis and correlation analysis were adopted in this study. The following findings were highlighted: 1) The inter-annual and inter-decadal variations in precipitation during a whole year, the pre-flood period or the post-flood period were obvious during 1880-2015, and the primary periods for the annual precipitation sequence were 6, 8, 13, and 26 years during 1880-1938 and were 7, 8, 11 and 17 years during 1951-2015. There was no significant long-term increasing or decreasing tendency basing on this long precipitation sequence. For example, the precipitation during a whole year, the pre-flood period or the post-flood period fluctuated after treatment in filtering analysis. 2) The relationship between precipitation during a whole year, the pre-flood period or the post-flood period and global warming was complicated. There was a significant positive correlation between precipitation and global surface temperature during cold periods (1880-1939), especially in the pre-flood periods (Apr.-Jun.). There was no significant correlation between precipitation and global surface temperature during warm periods (1977-2015). But the variation magnitude of precipitation in the pre-flood period and the post-flood period increased with the increase of temperature, which suggested that the risk of drought or flood would increase accordingly. 3) According to the long-term changes in precipitation during a whole year, the pre-flood period or the post-flood period and the current precipitation evaluation standard adopted by the Guangdong Meteorology Administration, the frequency of normal precipitation in the pre-flood period would increase under the background of global warming, and the probability of less precipitation in the post-flood period would increase at the same time. These results were important for exploring the variation characters of precipitation for the eastern region of Guangdong over a long term period and useful for evaluating the possible effect of global warming on precipitation at Shantou in the near future.