干旱区生态环境知识资源中心(Arid): On the Relationship Between Radar Backscatter and Radiometer Brightness Temperature From SMAP

Arid

DOI	10.1109/TGRS.2021.3115140
	On the Relationship Between Radar Backscatter and Radiometer Brightness Temperature From SMAP
	Zeng, Jiangyuan; Shi, Pengfei; Chen, Kun-Shan; Ma, Hongliang; Bi, Haiyun; Cui, Chenyang
通讯作者	Zeng, JY (corresponding author), Chinese Acad Sci, Aerosp Informat Res Inst, State Key Lab Remote Sensing Sci, Beijing 100101, Peoples R China.
来源期刊	IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
ISSN	0196-2892
EISSN	1558-0644
出版年	2022
英文摘要	The synergy of active and passive microwave measurements has attracted considerable attention in recent years since they offer complementary information on the characteristics of the observed target (e.g., soil moisture), which motivates the launch of NASA's Soil Moisture Active Passive (SMAP) mission. An assumption of a near-linear relationship between active and passive measurements has been made in the SMAP active-passive baseline algorithm, which is essential to downscale coarse-resolution radiometer brightness temperature (TB) using high-resolution radar backscatter (sigma SUPERSCRIPT ZERO) but has not yet been fully tested under a wide range of ground conditions. Motivated by this, we first examined the validity of the linear assumption by using concurrent and coincident SMAP active and passive observations under diverse environmental factors (e.g., land cover, climate types, terrain and its complexity, soil texture, vegetation coverage, soil moisture, and its dynamics). We also adopted SMAP enhanced TB to evaluate the performance of the disaggregated TB at the same grid resolution of 9 km. The results reveal there is a generally good linear relationship between sigma SUPERSCRIPT ZERO (no matter in dB or in linear unit) and TB at a global scale. There is no significant difference in the correlation among the four polarization combinations ( $sigma SUPERSCRIPT ZERO_{hh}$ versus TB $_{h}$ , $sigma SUPERSCRIPT ZERO_{hh}$ versus TB $_{v}$ , $sigma SUPERSCRIPT ZERO_{vv}$ versus TB $_{h}$ , and $sigma SUPERSCRIPT ZERO_{vv}$ versus TB $_{v}$ ) with the $sigma SUPERSCRIPT ZERO_{vv}$ and TB $_{h}$ combination displaying an overall slightly higher correlation. The linear relationship between sigma SUPERSCRIPT ZERO and TB is significantly affected by environmental factors. Particularly in bare soils and densely vegetated areas (e.g., large forest fraction and vegetation coverage), and arid and polar climate zones, the linear correlation between active and passive measurements worsens, whereas it is favorable in moderate vegetation and soil moisture as well as large soil moisture dynamic conditions. Interestingly, the linear correlation generally decreases as sand content increases while increases with the increase of clay content. The absolute linear correlation coefficient is higher with larger soil moisture dynamics. When compared to SMAP enhanced TB, it shows the linear assumption may have more influence on the correlation (i.e., temporal evolution) of downscaled TB than its absolute accuracy. These findings can enhance the understanding of the geophysical relationship between radar and radiometer signatures, and thus benefit active-passive joint algorithms for future satellite missions.
英文关键词	Radar Microwave radiometry Vegetation mapping Soil moisture Spaceborne radar Microwave measurement Environmental factors Active microwave passive microwave soil moisture active passive (SMAP) soil moisture (SM) synergy
类型	Article
语种	英语
收录类别	SCI-E
WOS记录号	WOS:000732868500001
WOS关键词	SOIL-MOISTURE RETRIEVAL ; AMSR-E ; ALGORITHM ; RESOLUTION ; PERFORMANCE ; ROUGHNESS ; PRODUCT
WOS类目	Geochemistry & Geophysics ; Engineering, Electrical & Electronic ; Remote Sensing ; Imaging Science & Photographic Technology
WOS研究方向	Geochemistry & Geophysics ; Engineering ; Remote Sensing ; Imaging Science & Photographic Technology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/374586
作者单位	[Zeng, Jiangyuan; Shi, Pengfei; Chen, Kun-Shan] Chinese Acad Sci, Aerosp Informat Res Inst, State Key Lab Remote Sensing Sci, Beijing 100101, Peoples R China; [Shi, Pengfei] Univ Chinese Acad Sci, Coll Resources & Environm, Beijing 100049, Peoples R China; [Chen, Kun-Shan] Guilin Univ Technol, Coll Geomant & Geoinformat, Guilin 541004, Peoples R China; [Ma, Hongliang] Wuhan Univ, State Key Lab Informat Engn Surveying Mapping & R, Wuhan 430079, Peoples R China; [Bi, Haiyun] China Earthquake Adm, State Key Lab Earthquake Dynam, Inst Geol, Beijing 100029, Peoples R China; [Cui, Chenyang] Suzhou Ind Pk Surveying Mapping & Geoinformat Co, Suzhou 215000, Jiangsu, Peoples R China
推荐引用方式 GB/T 7714	Zeng, Jiangyuan,Shi, Pengfei,Chen, Kun-Shan,et al. On the Relationship Between Radar Backscatter and Radiometer Brightness Temperature From SMAP[J],2022.
APA	Zeng, Jiangyuan,Shi, Pengfei,Chen, Kun-Shan,Ma, Hongliang,Bi, Haiyun,&Cui, Chenyang.(2022).On the Relationship Between Radar Backscatter and Radiometer Brightness Temperature From SMAP.IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING.
MLA	Zeng, Jiangyuan,et al."On the Relationship Between Radar Backscatter and Radiometer Brightness Temperature From SMAP".IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING (2022).