华南地区对流性和大尺度降水特征分析

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  • 广东省气候中心,广东 广州 510641

网络出版日期: 2024-10-21

基金资助

国家自然科学基金气象联合基金(U2142205);广东省气象局青年基金项目(GRMC2021Q09

Characteristics Analysis of Convective Precipitation and Large-scale Precipitation in South China based on ERA5 Data

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  • Climate Center of Guangdong ProvinceGuangzhou 510641GuangdongChina

Online published: 2024-10-21

摘要

华南是中国年降水量最多的区域之一。在全球变暖的背景下,降水在区域和尺度上已发生较大的变化,干湿季降水的范围在扩大,华南区域性极端降水事件的影响范围呈显著上升趋势,但不同的降水类型变化及影响并不相同。为进一步了解华南地区不同类型降水在全球变暖背景下如何响应变化,本文基于ERA5再分析降水资料采用线性相关、趋势分析、小波分析等方法研究了1960-2022年华南地区对流性降水和大尺度降水特征。研究表明:(1)华南冬季以大尺度降水为主,其他季节以对流性降水为主。(2)华南对流性降水和大尺度降水在冬季均呈增加趋势,其他季节对流性降水大部分呈减少趋势。冬季华南对流性降水在20世纪80年代至21世纪初存在较为显著的2~4年周期变化;春季对流性降水在20世纪90年代至21世纪初存在由偏多转偏少的年代际特征;在秋季,显著的周期变化主要在20世纪90年代以前。大尺度降水周期变化特征除冬季外,其余季节均与对流性降水较为一致。(3)广东和广西4-10 月的总降水主要是对流性降水产生(对流性降水占总降水的 65% 左右),8 月占比最多(广东71. 8%,广西69. 0%);海南前汛期对流性降水占比(5月最高80%以上)明显高于后汛期,即使进入秋冬季,对流性降水占比依然维持在50%左右。(4)海南对流性降水和大尺度降水的日变化强度最强,广西的对流性降水强度最弱。广东、广西和海南的降水最强时段分别发生在 13:00(北京时,下同)-17:0015:00-17:0014:00-16:00。大尺度降水广东集中在09:00-17:00;广西地区从04:00开始加强,午后开始减弱,最强时段为 10:00 前后;海南在 8 月前最强时段为 12:00-17:009 月下旬后最强时段为15:00-16:00。综上分析可见,不同季节不同类型的降水表现特征并不相同,因此今后降水研究中有必要继续考虑不同类型降水的影响。

本文引用格式

杜 晖, 王娟怀, 黄惺惺, 胡娅敏 . 华南地区对流性和大尺度降水特征分析[J]. 高原气象, 0 : 1 . DOI: 10. 7522/j. issn. 1000- 0534. 2024. 00031

Abstract

South ChinaSCis one of the regions with the most annual precipitation in China. Under the back‐ ground of global warmingthere had been significant changes in precipitation at regional and scale levelsthe area of dry- and wet-season precipitation was expandingand regional extreme precipitation events showed a significant upward trend in SCbut the changes and impacts of different types of precipitation were not the same. To better understand how different types of precipitation in SC respond to global warmingthis paper investigated the characteristics of convective precipitationCPand large-scale precipitationLSPin SC based on ERA5 reanalysis precipitation dataset from 1960 to 2022 using linear correlationtrend analysis and wavelet analysis. The results showed that:(1SC was dominated by LSP in winter while CP in other seasons.2CP and LSP in SC showed an increasing trend in winterbut most of CP showed a decreasing trend in other seasons. CP in SC had a relatively significant 2~4 years cycle from the 1980s to the beginning of the 21st century in winteras well as there was an interdecadal characteristic of shifting from more to less in the 1990s to the beginning of the 21st century in springbut the significant cyclical variations were mainly found in the period before the 1990s in autumn. In all seasons except winterthe changes in LSP were consistent with CP.3The total precipitationTPfrom April to October in Guangdong and Guangxi was mainly CPCP accounts for about 65% of TP),with the largest proportion in August71. 8% in Guangdong and 69. 0% in Guangxi. On the other handthe proportion of CP in the first rainy seasonup to 80% in Maywas significantly higher than in the second rainy season in Hain‐ an. Additionallythe proportion of CP remained at about 50% even in autumn and winter.4The diurnal variation intensity of CP and LSP was strongest in Hainan while the intensity of CP was the weakest in Guangxi. The peak periods of the strongest precipitation in GuangdongGuangxiand Hainan occured respectively from 13:00 to 17:00Beijing timethe sameas followed),15:00 to 17:00and 14:00 to 16:00. The LSP peaked between 09:00 and 17:00 in Guangdongand it started to strengthen from 04:00 and weakened in the afternoonwith the strongest period around 10:00 in Guangxifor Hainanthe strongest period was 12:00-17:00 before Augustbut 15:00-16:00 after late September. In conclusionthe characteristics of precipitation varied with different seasons and types. Thereforeit was necessary to continue considering the impact of different types of precipitation in future research.

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