Surveys in Geophysics

, Volume 35, Issue 3, pp 577–606

Connecting Satellite Observations with Water Cycle Variables Through Land Data Assimilation: Examples Using the NASA GEOS-5 LDAS

  • Rolf H. Reichle
  • Gabriëlle J. M. De Lannoy
  • Barton A. Forman
  • Clara S. Draper
  • Qing Liu
Article

DOI: 10.1007/s10712-013-9220-8

Cite this article as:
Reichle, R.H., De Lannoy, G.J.M., Forman, B.A. et al. Surv Geophys (2014) 35: 577. doi:10.1007/s10712-013-9220-8

Abstract

A land data assimilation system (LDAS) can merge satellite observations (or retrievals) of land surface hydrological conditions, including soil moisture, snow, and terrestrial water storage (TWS), into a numerical model of land surface processes. In theory, the output from such a system is superior to estimates based on the observations or the model alone, thereby enhancing our ability to understand, monitor, and predict key elements of the terrestrial water cycle. In practice, however, satellite observations do not correspond directly to the water cycle variables of interest. The present paper addresses various aspects of this seeming mismatch using examples drawn from recent research with the ensemble-based NASA GEOS-5 LDAS. These aspects include (1) the assimilation of coarse-scale observations into higher-resolution land surface models, (2) the partitioning of satellite observations (such as TWS retrievals) into their constituent water cycle components, (3) the forward modeling of microwave brightness temperatures over land for radiance-based soil moisture and snow assimilation, and (4) the selection of the most relevant types of observations for the analysis of a specific water cycle variable that is not observed (such as root zone soil moisture). The solution to these challenges involves the careful construction of an observation operator that maps from the land surface model variables of interest to the space of the assimilated observations.

Keywords

Land data assimilation Land surface modeling Satellite remote sensing Soil moisture Snow Terrestrial water storage Ensemble Kalman filter 

Copyright information

© Springer Science+Business Media Dordrecht (outside the USA) 2013

Authors and Affiliations

  • Rolf H. Reichle
    • 1
  • Gabriëlle J. M. De Lannoy
    • 1
    • 2
  • Barton A. Forman
    • 3
  • Clara S. Draper
    • 1
    • 2
  • Qing Liu
    • 1
    • 4
  1. 1.Global Modeling and Assimilation Office (Code 610.1)NASA Goddard Space Flight CenterGreenbeltUSA
  2. 2.Universities Space Research AssociationColumbiaUSA
  3. 3.Department of Civil and Environmental EngineeringUniversity of MarylandCollege ParkUSA
  4. 4.Science Systems and Applications, Inc.LanhamUSA

Personalised recommendations