Retrieving soil physical properties by assimilating SMAP brightness temperature observations into the community land model

Hong Zhao, Yijian Zeng, Xujun Han, Zhongbo Su*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

1 Citation (Scopus)
37 Downloads (Pure)

Abstract

This paper coupled a unified passive and active microwave observation operator—namely, an enhanced, physically-based, discrete emission-scattering model—with the community land model (CLM) in a data assimilation (DA) system. By implementing the system default local ensemble transform Kalman filter (LETKF) algorithm, the Soil Moisture Active and Passive (SMAP) brightness temperature (Formula presented.) ((Formula presented.) = Horizontal or Vertical polarization) assimilations for only soil property retrieval and both soil properties and soil moisture estimates were investigated with the aid of in situ observations at the Maqu site. The results indicate improved estimates of soil properties of the topmost layer in comparison to measurements, as well as of the profile. Specifically, both assimilations of (Formula presented.) lead to over a 48% reduction in root mean square errors (RMSEs) for the retrieved clay fraction from the background compared to the top layer measurements. Both assimilations of (Formula presented.) reduce RMSEs by 36% for the sand fraction and by 28% for the clay fraction. However, the DA estimated soil moisture and land surface fluxes still exhibit discrepancies when compared to the measurements. The retrieved accurate soil properties alone are inadequate to improve those estimates. The discussed uncertainties (e.g., fixed PTF structures) in the CLM model structures should be mitigated.

Original languageEnglish
Article number2620
JournalSensors
Volume23
Issue number5
DOIs
Publication statusPublished - 27 Feb 2023

Keywords

  • brightness temperature
  • CLM
  • data assimilation
  • SMAP
  • soil properties
  • uncertainties
  • unified passive and active microwave observation operator
  • ITC-ISI-JOURNAL-ARTICLE
  • ITC-GOLD

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