Evaluation of microwave soil moisture data for monitoring live fuel moisture content (LFMC) over the coterminous United States
Evaluation of microwave soil moisture data for monitoring live fuel moisture content (LFMC) over the coterminous United States
Live fuel moisture content (LFMC), which is the ratio of water in the fresh biomass to the dry biomass, is a key variable that affects wildfire behaviour. Previous studies have assessed soil moisture as a predictor of LFMC over small areas with limited data, but a comprehensive evaluation at sub-continental scale is still lacking, and the explanatory utility has not been evaluated under different aridity conditions. In this study, the utility was evaluated using microwave soil moisture data from the ESA ECV_SM product from 1979 to 2018 and LFMC data from over 1000 sites in the coterminous United States. A time-lagged robust linear regression model was adopted, and the results were compared with analysis from in situ soil moisture measurements at adjacent sites. The results suggested that at most sites the LFMC correlates best with soil moisture within 60 days prior to LFMC sampling, and that the correlation is lower in areas with complex terrain. LFMC can be estimated from soil moisture with a mean RMSE of around 20%. The correlation between LFMC and soil moisture is significant (p<0.01) in most regions, and is mostly stable in different years. The major fuel types with a high response to soil moisture include pine, redcedar, sagebrush, oak, manzanita, chamise, mesquite and juniper, depending on the region. The LFMC ~ soil moisture correlation varies with the aridity condition, and soil moisture has a higher explanatory utility on LFMC under dry conditions. An analysis using SMAP Level-4 product indicated that the surface and root-zone soil moisture perform similarly in LFMC estimation. This study suggests that microwave soil moisture data contain sufficient information on LFMC, and may serve as a reference for the development of more sophisticated LFMC estimation methods.
ESA ECV SM, Live fuel moisture content, Microwave, SMAP Level-4, Soil moisture
Lu, Yang
6d9d9d4f-3177-4265-b03b-34d7129ec95c
Wei, Chunzhu
7cea57d0-bc07-4cdd-8567-dfded2ccf54e
1 June 2021
Lu, Yang
6d9d9d4f-3177-4265-b03b-34d7129ec95c
Wei, Chunzhu
7cea57d0-bc07-4cdd-8567-dfded2ccf54e
Lu, Yang and Wei, Chunzhu
(2021)
Evaluation of microwave soil moisture data for monitoring live fuel moisture content (LFMC) over the coterminous United States.
Science of the Total Environment, 771, [145410].
(doi:10.1016/j.scitotenv.2021.145410).
Abstract
Live fuel moisture content (LFMC), which is the ratio of water in the fresh biomass to the dry biomass, is a key variable that affects wildfire behaviour. Previous studies have assessed soil moisture as a predictor of LFMC over small areas with limited data, but a comprehensive evaluation at sub-continental scale is still lacking, and the explanatory utility has not been evaluated under different aridity conditions. In this study, the utility was evaluated using microwave soil moisture data from the ESA ECV_SM product from 1979 to 2018 and LFMC data from over 1000 sites in the coterminous United States. A time-lagged robust linear regression model was adopted, and the results were compared with analysis from in situ soil moisture measurements at adjacent sites. The results suggested that at most sites the LFMC correlates best with soil moisture within 60 days prior to LFMC sampling, and that the correlation is lower in areas with complex terrain. LFMC can be estimated from soil moisture with a mean RMSE of around 20%. The correlation between LFMC and soil moisture is significant (p<0.01) in most regions, and is mostly stable in different years. The major fuel types with a high response to soil moisture include pine, redcedar, sagebrush, oak, manzanita, chamise, mesquite and juniper, depending on the region. The LFMC ~ soil moisture correlation varies with the aridity condition, and soil moisture has a higher explanatory utility on LFMC under dry conditions. An analysis using SMAP Level-4 product indicated that the surface and root-zone soil moisture perform similarly in LFMC estimation. This study suggests that microwave soil moisture data contain sufficient information on LFMC, and may serve as a reference for the development of more sophisticated LFMC estimation methods.
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Evaluation of microwave soil moisture data for monitoring live fuel moisture content (LFMC) over the coterminous United States
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e-pub ahead of print date: 29 January 2021
Published date: 1 June 2021
Keywords:
ESA ECV SM, Live fuel moisture content, Microwave, SMAP Level-4, Soil moisture
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Local EPrints ID: 448429
URI: http://eprints.soton.ac.uk/id/eprint/448429
ISSN: 0048-9697
PURE UUID: 8feec271-7163-4f7e-932c-4c06aa5b25a2
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Date deposited: 22 Apr 2021 16:31
Last modified: 29 Oct 2023 13:04
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Author:
Chunzhu Wei
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