Downscaling of ESA CCI soil moisture in Taihu Lake Basin: are wetness conditions and non-linearity important?

The coarse spatial resolutions of satellite-based soil moisture (SM) products restrict their applications at smaller spatial scales. In this study, the monthly European Space Agency Climate Change Initiative SM data (ESA CCI SM) from 2000 to 2016 was downscaled from 25- to 1-km resolution in the Tai...

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Autores principales: Ya Liu, Qing Zhu, Kaihua Liao, Xiaoming Lai, Junbang Wang
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Publicado: IWA Publishing 2021
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spelling oai:doaj.org-article:bdd01ba794a44b19a57935695a66bf6a2021-11-05T19:01:35ZDownscaling of ESA CCI soil moisture in Taihu Lake Basin: are wetness conditions and non-linearity important?2040-22442408-935410.2166/wcc.2020.131https://doaj.org/article/bdd01ba794a44b19a57935695a66bf6a2021-08-01T00:00:00Zhttp://jwcc.iwaponline.com/content/12/5/1564https://doaj.org/toc/2040-2244https://doaj.org/toc/2408-9354The coarse spatial resolutions of satellite-based soil moisture (SM) products restrict their applications at smaller spatial scales. In this study, the monthly European Space Agency Climate Change Initiative SM data (ESA CCI SM) from 2000 to 2016 was downscaled from 25- to 1-km resolution in the Taihu Lake Basin, a typical humid area with complex terrain and land uses. The normalized difference vegetation index (NDVI) and land surface temperature (LST) were used as auxiliary data. The regional monthly mean ESA CCI SM values were classified into low value (0.24–0.30 m3m–3), mid-value (0.30–0.33 m3m–3) and high value (0.33–0.39 m3m–3) months by the K-means clustering algorithm. The linear (multiple linear regression) and non-linear (support vector machine) downscaling models were compared. In addition, whether building downscaling models based on wetness conditions could improve the accuracies was tested. Results showed that without considering wetness conditions, the linear method was slightly better than the non-linear method. However, linear models constructed based on wetness conditions performed the best, which demonstrated that wetness conditions should be considered in the downscaling process. Results of this study would improve the accuracies in downscaling satellite-based SM data, facilitating their applications at regional scales. HIGHLIGHTS The quality of ESA CCI SM was evaluated in Taihu Basin Lake.; Linear and non-linear downscaling methods were compared.; Wetness conditions should be considered in the downscaling process.;Ya LiuQing ZhuKaihua LiaoXiaoming LaiJunbang WangIWA Publishingarticleremote sensingsoil hydrologysoil moisturetaihu lake basinwatershedEnvironmental technology. Sanitary engineeringTD1-1066Environmental sciencesGE1-350ENJournal of Water and Climate Change, Vol 12, Iss 5, Pp 1564-1579 (2021)
institution DOAJ
collection DOAJ
language EN
topic remote sensing
soil hydrology
soil moisture
taihu lake basin
watershed
Environmental technology. Sanitary engineering
TD1-1066
Environmental sciences
GE1-350
spellingShingle remote sensing
soil hydrology
soil moisture
taihu lake basin
watershed
Environmental technology. Sanitary engineering
TD1-1066
Environmental sciences
GE1-350
Ya Liu
Qing Zhu
Kaihua Liao
Xiaoming Lai
Junbang Wang
Downscaling of ESA CCI soil moisture in Taihu Lake Basin: are wetness conditions and non-linearity important?
description The coarse spatial resolutions of satellite-based soil moisture (SM) products restrict their applications at smaller spatial scales. In this study, the monthly European Space Agency Climate Change Initiative SM data (ESA CCI SM) from 2000 to 2016 was downscaled from 25- to 1-km resolution in the Taihu Lake Basin, a typical humid area with complex terrain and land uses. The normalized difference vegetation index (NDVI) and land surface temperature (LST) were used as auxiliary data. The regional monthly mean ESA CCI SM values were classified into low value (0.24–0.30 m3m–3), mid-value (0.30–0.33 m3m–3) and high value (0.33–0.39 m3m–3) months by the K-means clustering algorithm. The linear (multiple linear regression) and non-linear (support vector machine) downscaling models were compared. In addition, whether building downscaling models based on wetness conditions could improve the accuracies was tested. Results showed that without considering wetness conditions, the linear method was slightly better than the non-linear method. However, linear models constructed based on wetness conditions performed the best, which demonstrated that wetness conditions should be considered in the downscaling process. Results of this study would improve the accuracies in downscaling satellite-based SM data, facilitating their applications at regional scales. HIGHLIGHTS The quality of ESA CCI SM was evaluated in Taihu Basin Lake.; Linear and non-linear downscaling methods were compared.; Wetness conditions should be considered in the downscaling process.;
format article
author Ya Liu
Qing Zhu
Kaihua Liao
Xiaoming Lai
Junbang Wang
author_facet Ya Liu
Qing Zhu
Kaihua Liao
Xiaoming Lai
Junbang Wang
author_sort Ya Liu
title Downscaling of ESA CCI soil moisture in Taihu Lake Basin: are wetness conditions and non-linearity important?
title_short Downscaling of ESA CCI soil moisture in Taihu Lake Basin: are wetness conditions and non-linearity important?
title_full Downscaling of ESA CCI soil moisture in Taihu Lake Basin: are wetness conditions and non-linearity important?
title_fullStr Downscaling of ESA CCI soil moisture in Taihu Lake Basin: are wetness conditions and non-linearity important?
title_full_unstemmed Downscaling of ESA CCI soil moisture in Taihu Lake Basin: are wetness conditions and non-linearity important?
title_sort downscaling of esa cci soil moisture in taihu lake basin: are wetness conditions and non-linearity important?
publisher IWA Publishing
publishDate 2021
url https://doaj.org/article/bdd01ba794a44b19a57935695a66bf6a
work_keys_str_mv AT yaliu downscalingofesaccisoilmoistureintaihulakebasinarewetnessconditionsandnonlinearityimportant
AT qingzhu downscalingofesaccisoilmoistureintaihulakebasinarewetnessconditionsandnonlinearityimportant
AT kaihualiao downscalingofesaccisoilmoistureintaihulakebasinarewetnessconditionsandnonlinearityimportant
AT xiaominglai downscalingofesaccisoilmoistureintaihulakebasinarewetnessconditionsandnonlinearityimportant
AT junbangwang downscalingofesaccisoilmoistureintaihulakebasinarewetnessconditionsandnonlinearityimportant
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