The relationship between soil emissivity and soil reflectance under the effects of soil water content. (April 2019)

• Record Type: Journal Article
• Authors: Tian, Jing; Song, Shangkun; He, Honglin
• Is Part Of: Physics and chemistry of the earth. Volume 110(2019)
• Page Start: 133
• Page End: 137
• Publication Date: 2019-04
• Subjects: Geophysics -- Periodicals; Geochemistry -- Periodicals; Earth sciences -- Periodicals; Geodesy -- Periodicals; Astrophysics -- Periodicals; 550
• DOI: 10.1016/j.pce.2018.11.006
• Languages: English
• ISSNs: 1474-7065

Abstract

Abstract: Significant changes of surface emissivity have taken place in cities with the rapid urbanization. Surface emissivity influences the radiation budget and the surface energy balance, thereby influences city climate. It is an important parameter in retrieving surface temperature and has close relationship with city heat island effect. This paper attempts to explore the possibility of using soil moisture index (SMI) to estimate soil emissivity (SE). The advantage of using SMI over soil moisture (SM) is that SMI is easily obtained with remotely sensed data. Its advantage over soil reflectance (SR) is that SMI can reflect soil water condition better. On the basis of the careful measurements of the variations of SE and SR with SM for four soil samples, the following results were obtained: (1) Logarithmic function is better than linear function in describing the relationship between SE and SM/SMI; (2) Similar correlation coefficient (R 2 ) and the Root Mean Square Error (RMSE) between SMI and SE were obtained in comparison with that between SM and SE. Therefore, SMI can replace SM to estimate SE. (3) The index of Water Index SOIL (WISOIL) is the best in the estimation of SE. (4) SE in MODIS 29 waveband is the most sensitive to the change of SM in comparison with SE in the other MODIS thermal wavebands regardless of soil texture. Highlights: Soil moisture index (SMI) can replace soil moisture (SM) to estimate SE in a large degree. The soil moisture index of WISOIL is recommended as the best in the estimation of soil emissivity (SE). SE in MODIS 29 waveband is the most sensitive to the change of SM regardless of soil texture. The advantage of using SMI over SM in estimating SE is that SMI is easily obtained with remotely sensed data. Its advantage over soil reflectance (SR) is that SMI can reflect soil water condition better.