Title
Tests of sequential data assimilation for retrieving profile soil moisture and temperature from observed L-band radiobrightness
Abstract
Sequential data assimilation (Kalman filter optimal estimation) techniques are applied to the problem of retrieving near-surface soil moisture and temperature state from periodic terrestrial radiobrightness observations that update soil heat and moisture diffusion models. The retrieval procedure uses a time-explicit numerical model to continuously propagate the soil state profile, its error of estimation, and its interdepth covariances through time. The model's coupled soil moisture and heat fluxes are constrained by micrometeorology boundary conditions drawn from observations or atmospheric modeling. When radiometer data are available, the Kalman filter updates the state profile estimate by weighing the propagated state, error, and covariance estimates against an a priori estimate of radiometric measurement error. The Kalman filter compares predicted and observed radiobrightnesses directly, so no inverse algorithm relating brightness to physical parameters is required. The authors demonstrate Kalman filter model effectiveness using field observations and a simulation study. An observed 1 m soil state profile is recovered over an eight-day period from daily L-band observations following an intentionally poor initial state estimate. In a four-month simulation study, they gauge the longer term behavior of the soil state retrieval and Kalman gain through multiple rain events, soil dry-downs, and updates from radiobrightnesses
Year
DOI
Venue
1999
10.1109/36.774699
Geoscience and Remote Sensing, IEEE Transactions
Keywords
Field
DocType
Kalman filters,geophysical signal processing,hydrological techniques,radiometry,remote sensing,soil,terrain mapping,Kalman filter optimal estimation,L-band,geophysical measurement technique,hydrology,land surface,microwave radiometry,radiobrightness,remote sensing,sequential data assimilation,soil moisture,temperature,terrain mapping
A priori estimate,Remote sensing,Optimal estimation,Atmospheric model,Kalman filter,Data assimilation,Observational error,Mathematics,Radiometer,Covariance
Journal
Volume
Issue
ISSN
37
4
0196-2892
Citations 
PageRank 
References 
15
5.12
3
Authors
3
Name
Order
Citations
PageRank
Galantowicz, J.F.12830.70
D. Entekhabi24012.57
E. G. Njoku350098.59