Paper Info
Title
Impact of Moisture Distribution Within the Sensing Depth on L- and C-Band Emission in Sandy Soils
Abstract
The performances of the soil moisture retrieval and assimilation algorithms using microwave observations rely on realistic estimates of brightness temperatures (TB) from microwave emission models. This study identifies circumstances when current models fail to reliably relate near-surface soil moisture to an observed TB at L-band; offers a plausible explanation of the physical cause of these failures; and recommends improvements needed so that L-band observations can provide reliable estimates of soil moisture, more universally. Physically consistent soil parameters and moisture at the surface were estimated by using dual-polarized C-band observations during an intensive field experiment, for an irrigation event and subsequent drydown. These derived parameters were used in conjunction with the in situ moisture in deeper layers and different moisture profiles within the moisture sensing depth to obtain estimates of H-pol TB at L-band, that provided best matches with the observed TB. The general assumptions of linear moisture distribution, with uniform or exponentially decaying weighting functions provided realistic TB during the later stages of the drydown. However, the RMSDs of the TBs were up to 10.37 K during the wet period. In addition, the use of one value of moisture representing the entire moisture sensing depth during this highly dynamic stage of the drydown provides unrealistic estimates of emissivity, and hence, TB at L-band. This study recommends use of a hydrological model to provide dynamic, realistic soil moisture profiles within the sensing depth and also an improved emissivity model that utilizes these detailed profiles for estimating TB.
Year
DOI
Venue
2013
10.1109/JSTARS.2012.2213239
Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of
Keywords
Field
DocType
hydrological techniques,microwave measurement,moisture,remote sensing,soil,c-band emission,l-band emission,brightness temperatures estimates,dual polarized c-band observations,hydrological model,irrigation event,linear moisture distribution,microwave emission models,microwave observations,moisture distribution effects,moisture sensing depth,near surface soil moisture,physically consistent soil parameters,post irrigation drydown event,sandy soils,soil moisture assimilation algorithms,soil moisture retrieval algorithms,soil surface moisture,emission models,passive microwave remote sensing,rough surface emissivity,soil moisture profile,l band,soil moisture,rough surfaces
Soil science,Moisture,Weighting,C band,Field experiment,Remote sensing,Water content,Emissivity,Brightness,Mathematics,Soil water
Journal
Volume
Issue
ISSN
6
2
1939-1404
Citations 
PageRank 
References 
5
0.59
13
Authors
4
Name
Order
Citations
PageRank
Pang-Wei Liu1275.51
De Roo, R.D.28011.99
Anthony W. England36211.39
Judge, J.450.59