气候变化领域集成服务门户(CCPortal): On the impact of C-band in place of L-band radar for SMAP downscaling

CCPortal

DOI	10.1016/j.rse.2020.112111
	On the impact of C-band in place of L-band radar for SMAP downscaling
	Ghafari E.; Walker J.P.; Das N.N.; Davary K.; Faridhosseini A.; Wu X.; Zhu L.
发表日期	2020
ISSN	00344257
卷号	251
英文摘要	The National Aeronautics and Space Administration (NASA) Soil Moisture Active Passive (SMAP) mission was launched on 31st January 2015, with the aim of providing global soil moisture maps at 9 km spatial resolution by combining L-band radar and radiometer observations. However, after the SMAP radar became inoperable, NASA decided to utilize the Sentinel 1A/1B C-band SAR data in its place. The new version of baseline brightness temperature (Tb) downscaling algorithm for SMAP is tested using L-band airborne data to evaluate the capabilities of the C-band Sentinel-1A SAR relative to L-band radar data in downscaling the SMAP Tb for achieving high resolution brightness temperature. In this study, the downscaling algorithm used L-band airborne Synthetic Aperture Radar (SAR) backscatter (σ) collected from the fifth Soil Moisture Active Passive Experiment (SMAPEx-5) in south-eastern Australia to downscale 36 km L-band SMAP radiometer Tb pixels to 3 km and 9 km. The downscaling results were then compared with the published results using Sentinel-1A C-band backscatter, and evaluated against airborne 1 km resolution L-band passive microwave brightness temperature collected from SMAPEx-5. The results show that for vertical polarization the average Root Mean Square Error (RMSE) of downscaled Tb when compared with reference airborne Tb across 4 days at 9 km resolution were 4.9 K for L-band and 6.0 K for C-band, and increased to 9.3 K for L-band and 9.6 K for C-band at 3 km spatial resolution. Moreover, the correlation coefficient (R) of downscaled and reference Tb across the 4 days was 0.92 for L-band and 0.88 for C-band at 9 km, decreasing to 0.75 for L-band and 0.72 for C-band at 3 km spatial resolution. Accordingly, the RMSE increased and the correlation coefficient decreased when using C-band radar data in place of that at L-band. However, overall there is expected to be only a slight decrease in performance of the downscaling algorithm by using the Sentinel 1A data in place of the SMAP radar. © 2020
英文关键词	Backscatter; Brightness temperature; C-band; Downscaling; L-band; Sentinel-1A; SMAP; SMAPEx
语种	英语
scopus关键词	Backscattering; Image resolution; Luminance; Mean square error; NASA; Radiometers; Soil moisture; Temperature; Airborne synthetic aperture radars; Brightness temperatures; Correlation coefficient; Passive microwave brightness temperatures; Root mean square errors; Soil moisture active passive (SMAP); South-eastern Australia; Vertical polarization; Synthetic aperture radar; algorithm; backscatter; brightness temperature; downscaling; radar; radiometer; satellite data; satellite mission; soil moisture; spatial resolution; spatiotemporal analysis; synthetic aperture radar; Australia
来源期刊	Remote Sensing of Environment
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/179107
作者单位	Department of Civil Engineering, Monash University, Melbourne, Australia; Department of Water Engineering, Ferdowsi University, Mashhad, Iran; Jet Propulsion Laboratory, NASA, California Institute of Technology, Pasadena, CA 91109, United States; Centre for Water Systems, College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, United Kingdom
推荐引用方式 GB/T 7714	Ghafari E.,Walker J.P.,Das N.N.,et al. On the impact of C-band in place of L-band radar for SMAP downscaling[J],2020,251.
APA	Ghafari E..,Walker J.P..,Das N.N..,Davary K..,Faridhosseini A..,...&Zhu L..(2020).On the impact of C-band in place of L-band radar for SMAP downscaling.Remote Sensing of Environment,251.
MLA	Ghafari E.,et al."On the impact of C-band in place of L-band radar for SMAP downscaling".Remote Sensing of Environment 251(2020).