气候变化领域集成服务门户(CCPortal): High-Resolution Water Vapor Maps Obtained by Merging Interferometric Synthetic Aperture Radar and GPS Measurements

CCPortal

DOI	10.1029/2020JD033430
	High-Resolution Water Vapor Maps Obtained by Merging Interferometric Synthetic Aperture Radar and GPS Measurements
	Cao Y.; Li Z.; Duan M.; Wei J.
发表日期	2021
ISSN	2169897X
卷号	126 期号:1
英文摘要	Previous research has demonstrated several successful meteorological applications of interferometric synthetic aperture radar (InSAR) by mapping high-resolution precipitable water vapor (PWV) over large areas with satisfactory precision (e.g., 1–2 mm). InSAR, however, can only measure temporal changes in the PWV, that is, the differential PWV (ΔPWV) between two SAR acquisition epochs. The construction of absolute PWV maps using InSAR observations remains an intractable problem. We present here a new method for constructing high-resolution PWV maps by fusing InSAR and global positioning system (GPS) measurements. Our method involves: (1) extracting temporal differences in the zenith wet delays (ΔZWD) from InSAR observations with the assistance of synchronous GPS measurements, and (2) using a constrained minimum variance estimator (CMVE) to construct the high-resolution maps of the absolute ZWDs by fusing the InSAR-ΔZWD and the GPS-ZWD samples, and finally (3) transforming the high-resolution ZWDs to PWVs using an elevation-dependent proportionality. Only a single interferogram was needed in our method, so we did not use any temporal (i.e., time-series) hypotheses, for example, we did not assume that the average value of the temporal turbulent ZWDs was equal to zero. We validated the new method over the Southern California region using four Sentinel-1 interferograms related to eight SAR images acquired in different seasons and in different years. We also used synchronous GPS measurements from the Southern California integrated GPS network. Eight high-resolution maps of PWVs related to the eight SAR acquisitions were generated, covering ∼250 km in area at a ∼160 m spatial resolution. Comparisons between the CMVE method and the other two methods (GPS-only-based interpolation and time-series InSAR stacking) were conducted. Experimental results showed that the CMVE method performed significantly better than conventional methods for constructing high-resolution PWV maps, which is of great interest to a wide community of geophysicists and meteorologists. © 2020. American Geophysical Union. All Rights Reserved.
英文关键词	atmospheric water vapor; global positioning system (GPS); interferometric synthetic aperture radar (InSAR); precipitable water vapor (PWV); tropospheric delay
语种	英语
来源期刊	Journal of Geophysical Research: Atmospheres
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/185544
作者单位	School of Geosciences and Info-Physics, Central South University, Changsha, Hunan, China
推荐引用方式 GB/T 7714	Cao Y.,Li Z.,Duan M.,et al. High-Resolution Water Vapor Maps Obtained by Merging Interferometric Synthetic Aperture Radar and GPS Measurements[J],2021,126(1).
APA	Cao Y.,Li Z.,Duan M.,&Wei J..(2021).High-Resolution Water Vapor Maps Obtained by Merging Interferometric Synthetic Aperture Radar and GPS Measurements.Journal of Geophysical Research: Atmospheres,126(1).
MLA	Cao Y.,et al."High-Resolution Water Vapor Maps Obtained by Merging Interferometric Synthetic Aperture Radar and GPS Measurements".Journal of Geophysical Research: Atmospheres 126.1(2021).