| 基于GPM卫星的广东汛期降水日变化特征与评估 |
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| 引用本文： | 张华龙,肖柳斯,陈生,吴乃庚.基于GPM卫星的广东汛期降水日变化特征与评估[J].热带气象学报,2020,36(3):335-346. |
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| 作者姓名： | 张华龙 肖柳斯 陈生 吴乃庚 |
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| 作者单位： | 1.广东省气象台，广东 广州 510641 |
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| 基金项目： | 广东省科技计划项目2019B020208016国家自然科学基金项目41875182国家自然科学基金项目41705035广州市科技计划项目201804020038广东省气象局科学技术研究项目GRMC2018Z05 |
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| 摘 要： | 新一代全球降水观测计划GPM作为TRMM卫星的继承者，在物理探测和降水反演算法上具有明显进步。以广东省雨量自动站为基准，对2014—2018年间GPM的格点降水估测产品IMERG（V5B）的日变化特征和估测误差进行分析。结果表明，IMERG能清晰反映广东前、后汛期的降水双峰型特征，但对下午降水峰值明显高估，峰值出现时间滞后；而对于沿海早晨峰值降水则明显低估，对于降水极值，低估更加显著。IMERG对两个峰值的估测误差受不同因素影响，下午峰值降水的相对偏差与地形密切相关，珠江三角洲平原为稳定高估区，地形高度越高，低估幅度越大；而早晨峰值降水极值负偏差与地形高度、降水量的相关性均较小。对出现显著负偏差的早晨沿海降水样本日进行925 hPa风场合成，可知IMERG明显低估时，对应区域上游较强的超低空西南气流与风速夜间增长。IMERG对这一季风活动背景降水的低估构成了其估测早晨降水误差的主要来源。
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| 关 键 词： | GPM IMERG 降水日变化 季风降水 地形误差 |
| 收稿时间： | 2019-05-29 |
CHARACTERISTICS AND EVALUATION OF DIURNAL RAINFALL VARIATION IN RAINY SEASONS IN GUANGDONG BASED ON GPM SATELLITE |
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| ZHANG Hua-long,XIAO Liu-si,CHEN Sheng,WU Nai-geng.CHARACTERISTICS AND EVALUATION OF DIURNAL RAINFALL VARIATION IN RAINY SEASONS IN GUANGDONG BASED ON GPM SATELLITE[J].Journal of Tropical Meteorology,2020,36(3):335-346. |
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| Authors: | ZHANG Hua-long XIAO Liu-si CHEN Sheng WU Nai-geng |
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| Institution: | Guangdong Meteorological Observatory, Guangzhou 510641, China;2. School of Atmospheric Sciences, Sun Yat-sen University, Zhuhai 519082, China; 4. Guangzhou Observatory, Guangzhou 511430, China; 5. Guangdong Laboratory of Southern Marine Science and Engineering (Zhuhai), Zhuhai 519082, China;2. School of Atmospheric Sciences, Sun Yat-sen University, Zhuhai 519082, China; 5. Guangdong Laboratory of Southern Marine Science and Engineering (Zhuhai), Zhuhai 519082, China; 6. Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies, Sun Yat-sen University, Guangzhou 510275, China; Guangzhou Institute of Tropical and Marine Meteorology, CMA, Guangzhou 510641, China |
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| Abstract: | As the successor to the Tropical Rainfall Measuring Mission (TRMM), the new generation Global Precipitation Measurement Mission (GPM) is considered to have made significant progress in precipitation estimation. The complex features of rainfall diurnal variation and estimation errors of the GPM grid precipitation estimation product IMERG (V5B) are examined using hourly rain gauge data in Guangdong Province during 2014—2018. The bimodal characteristics of diurnal rainfall in the annually first and second rainy seasons are clearly shown. IMERG products report more afternoon rainfall than the rain gauge shows, and the peak predicted is later than the real peak. However, they significantly underestimate the morning rainfall at coasts. The estimation errors of these two peaks are due to different reasons. As for afternoon rainfall, errors are spatially relevant to complex terrain. Particularly, the Pearl River Delta plain is a stable overestimation region, and the higher the terrain, the greater the underestimate. The negative deviation of morning rainfall has little correlation with terrain height or precipitation level. All daily precipitation samples with significant negative deviation are collected and the average 925 hPa wind fields are averagely combined. In areas where a clear negative bias is observed, the low-level circulation is mainly manifested as strong ultra-low southwest airstream and obvious nocturnal increase of the low-level wind field. IMERG's underestimation in the background of such monsoon activity constitutes the main source of its estimation error of morning peak rainfall in Guangdong. |
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| Keywords: | GPM IMERG rainfall diurnal variation monsoon precipitation terrain error |
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