Influence of soil moisture content on surface albedo and soil thermal parameters at a tropical station

Abstract

Half hourly data of soil moisture content, soil temperature, solar irradiance, and reflectance are measured during April 2010 to March 2011 at a tropical station, viz., Astronomical Observatory, Thiruvananthapuram, Kerala, India (76 • 59'E longitude and 8 • 29'N latitude). The monthly, seasonal and seasonal mean diurnal variation of soil moisture content is analyzed in detail and is correlated with the rainfall measured at the same site during the period of study. The large variability in the soil moisture content is attributed to the rainfall during all the seasons and also to the evaporation/movement of water to deeper layers. The relationship of surface albedo on soil moisture content on different time scales are studied and the influence of solar elevation angle and cloud cover are also investigated. Surface albedo is found to fall exponentially with increase in soil moisture content. Soil thermal diffusivity and soil thermal conductivity are also estimated from the subsoil temperature profile. Log normal dependence of thermal diffusivity and power law dependence of thermal conductivity on soil moisture content are confirmed.

Estimation of the advection effects induced by surface heterogeneities in the surface energy budget

“…The moisture contents at the upper part of the soil may modulate these variations, but in general there was good availability of water in the upper part of the soil due to recent rain events. Albedo may also change significantly with the changes of SM, decreasing as SM increases (Sugathan et al, 2014). during the evening of the same day, the numbers in white are minutes from the start of measurements, those made after minute 33 were after sunset (right).…”

The Sensitivity of North American Terrestrial Carbon Fluxes to Spatial and Temporal Variation in Soil Moisture: An Analysis Using Radar‐Derived Estimates of Root‐Zone Soil Moisture

“…Soil moisture is a key variable of the earth system influencing terrestrial water, carbon and nutrient cycling, and the exchange of carbon, water, and energy between the land‐surface and atmosphere. In particular, it impacts meteorological, hydrological, and ecological processes and properties including surface energy balance (Berg et al, ; Ford et al, ; Gallego‐Elvira et al, ; Lin & Cheng, ; Suarez et al, ), land surface albedo (Liu et al, ; Zhang et al, ), soil thermal properties (Juszak et al, ; Sugathan et al, ), runoff (Crow & Ryu, ; Morbidelli et al, ), plant water stress (He et al, ), and resulting vegetation productivity and ecosystem carbon fluxes (Huang et al, ; Jia et al, ; McInerney & Helton, ; Xu et al, ; Xu & Zhou, ).…”

“…Soil moisture is a key variable of the earth system influencing terrestrial water, carbon and nutrient cycling, and the exchange of carbon, water, and energy between the land-surface and atmosphere. In particular, it impacts meteorological, hydrological, and ecological processes and properties including surface energy balance (Berg et al, 2014;Ford et al, 2015;Gallego-Elvira et al, 2016;Lin & Cheng, 2016;Suarez et al, 2014), land surface albedo Zhang et al, 2014), soil thermal properties (Juszak et al, 2016;Sugathan et al, 2014), runoff (Crow & Ryu, 2009;Morbidelli et al, 2016), plant water stress (He et al, 2016), and resulting vegetation productivity and ecosystem carbon fluxes (Huang et al, 2016;Jia et al, 2016;McInerney & Helton, 2016;Xu et al, 2004;Xu & Zhou, 2005). Improved measurements of spatial and temporal patterns of variation in soil moisture are therefore essential for improved characterization of meteorological, hydrological, and ecological processes for hydrological forecasting, weather prediction, and estimates of terrestrial carbon, water, and energy fluxes.…”

Quantification of the Scale Effect in Downscaling Remotely Sensed Land Surface Temperature

“…The second type of descriptor was the surface broadband shortwave albedo. The surface albedo was selected because it influences the surface radiation balance and is mostly negatively related to the soil moisture over barren agricultural areas [50], two determinants that directly affect the surface energy balance and therefore the LSTs, especially during the daytime. The surface albedo was calculated based on the spectral reflectance of the ASTER VNIR channels, with an empirical equation developed by comprehensive radiative transfer simulation for snow/ice free surfaces [51].…”