Evaluation and Improvement of FY-4A AGRI Quantitative Precipitation Estimation for Summer Precipitation over Complex Topography of Western China

Satellite quantitative precipitation estimation (QPE) can make up for the insufficiency of ground observations for monitoring precipitation. Using an Advanced Geosynchronous Radiation Imager (AGRI) on the FengYun-4A (FY-4A) satellite and rain gauges (RGs) for observations in the summer of 2020. The...

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Autores principales:	Jing Ren, Guirong Xu, Wengang Zhang, Liang Leng, Yanjiao Xiao, Rong Wan, Junchao Wang
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	FY-4A satellite quantitative precipitation estimation brightness temperature dynamic time integration method complex topography Science Q
Acceso en línea:	https://doaj.org/article/919f038a1fa64595bb0486406b1534b7
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spelling	oai:doaj.org-article:919f038a1fa64595bb0486406b1534b72021-11-11T18:54:47ZEvaluation and Improvement of FY-4A AGRI Quantitative Precipitation Estimation for Summer Precipitation over Complex Topography of Western China10.3390/rs132143662072-4292https://doaj.org/article/919f038a1fa64595bb0486406b1534b72021-10-01T00:00:00Zhttps://www.mdpi.com/2072-4292/13/21/4366https://doaj.org/toc/2072-4292Satellite quantitative precipitation estimation (QPE) can make up for the insufficiency of ground observations for monitoring precipitation. Using an Advanced Geosynchronous Radiation Imager (AGRI) on the FengYun-4A (FY-4A) satellite and rain gauges (RGs) for observations in the summer of 2020. The existing QPE of the FY-4A was evaluated and found to present poor accuracy over the complex topography of Western China. Therefore, to improve the existing QPE, first, cloud classification thresholds for the FY-4A were established with the dynamic clustering method to identify convective clouds. These thresholds consist of the brightness temperatures (TBs) of FY-4A water vapor and infrared channels, and their TB difference. Then, quantitative cloud growth rate correction factors were introduced to improve the QPE of the convective-stratiform technique. This was achieved using TB hourly variation rates of long-wave infrared channel 12, which is able to characterize the evolution of clouds. Finally, the dynamic time integration method was designed to solve the inconsistent time matching between the FY-4A and RGs. Consequently, the QPE accuracy of the FY-4A was improved. Compared with the existing QPE of the FY-4A, the correlation coefficient between the improved QPE of the FY-4A and the RG hourly precipitation increased from 0.208 to 0.492, with the mean relative error and root mean squared error decreasing from −47.4% and 13.78 mm to 8.3% and 10.04 mm, respectively. However, the correlation coefficient is not sufficiently high; thus, the algorithm needs to be further studied and improved.Jing RenGuirong XuWengang ZhangLiang LengYanjiao XiaoRong WanJunchao WangMDPI AGarticleFY-4A satellitequantitative precipitation estimationbrightness temperaturedynamic time integration methodcomplex topographyScienceQENRemote Sensing, Vol 13, Iss 4366, p 4366 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	FY-4A satellite quantitative precipitation estimation brightness temperature dynamic time integration method complex topography Science Q
spellingShingle	FY-4A satellite quantitative precipitation estimation brightness temperature dynamic time integration method complex topography Science Q Jing Ren Guirong Xu Wengang Zhang Liang Leng Yanjiao Xiao Rong Wan Junchao Wang Evaluation and Improvement of FY-4A AGRI Quantitative Precipitation Estimation for Summer Precipitation over Complex Topography of Western China
description	Satellite quantitative precipitation estimation (QPE) can make up for the insufficiency of ground observations for monitoring precipitation. Using an Advanced Geosynchronous Radiation Imager (AGRI) on the FengYun-4A (FY-4A) satellite and rain gauges (RGs) for observations in the summer of 2020. The existing QPE of the FY-4A was evaluated and found to present poor accuracy over the complex topography of Western China. Therefore, to improve the existing QPE, first, cloud classification thresholds for the FY-4A were established with the dynamic clustering method to identify convective clouds. These thresholds consist of the brightness temperatures (TBs) of FY-4A water vapor and infrared channels, and their TB difference. Then, quantitative cloud growth rate correction factors were introduced to improve the QPE of the convective-stratiform technique. This was achieved using TB hourly variation rates of long-wave infrared channel 12, which is able to characterize the evolution of clouds. Finally, the dynamic time integration method was designed to solve the inconsistent time matching between the FY-4A and RGs. Consequently, the QPE accuracy of the FY-4A was improved. Compared with the existing QPE of the FY-4A, the correlation coefficient between the improved QPE of the FY-4A and the RG hourly precipitation increased from 0.208 to 0.492, with the mean relative error and root mean squared error decreasing from −47.4% and 13.78 mm to 8.3% and 10.04 mm, respectively. However, the correlation coefficient is not sufficiently high; thus, the algorithm needs to be further studied and improved.
format	article
author	Jing Ren Guirong Xu Wengang Zhang Liang Leng Yanjiao Xiao Rong Wan Junchao Wang
author_facet	Jing Ren Guirong Xu Wengang Zhang Liang Leng Yanjiao Xiao Rong Wan Junchao Wang
author_sort	Jing Ren
title	Evaluation and Improvement of FY-4A AGRI Quantitative Precipitation Estimation for Summer Precipitation over Complex Topography of Western China
title_short	Evaluation and Improvement of FY-4A AGRI Quantitative Precipitation Estimation for Summer Precipitation over Complex Topography of Western China
title_full	Evaluation and Improvement of FY-4A AGRI Quantitative Precipitation Estimation for Summer Precipitation over Complex Topography of Western China
title_fullStr	Evaluation and Improvement of FY-4A AGRI Quantitative Precipitation Estimation for Summer Precipitation over Complex Topography of Western China
title_full_unstemmed	Evaluation and Improvement of FY-4A AGRI Quantitative Precipitation Estimation for Summer Precipitation over Complex Topography of Western China
title_sort	evaluation and improvement of fy-4a agri quantitative precipitation estimation for summer precipitation over complex topography of western china
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/919f038a1fa64595bb0486406b1534b7
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Evaluation and Improvement of FY-4A AGRI Quantitative Precipitation Estimation for Summer Precipitation over Complex Topography of Western China

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