On the identification of representative in situ soil moisture monitoring stations for the validation of SMAP soil moisture products in Australia

Mei Sun Yee, Jeffrey P. Walker, Alessandra Monerris, Christoph Rüdiger, Thomas J. Jackson

Research output: Contribution to journalArticleResearchpeer-review

36 Citations (Scopus)

Abstract

The high spatio-temporal variability of soil moisture complicates the validation of remotely sensed soil moisture products using in situ monitoring stations. Therefore, a standard methodology for selecting the most representative stations for the purpose of validating satellites and land surface models is essential. Based on temporal stability and geostatistical studies using long-term soil moisture records, intensive ground measurements and airborne soil moisture products, this study investigates the representativeness of soil moisture monitoring stations within the Yanco study area for the validation of NASA's Soil Moisture Active Passive (SMAP) products at 3 km for radar, 9 km for radar-radiometer and 36 km for radiometer pixels. This resulted in the identification of a number of representative stations according to the different scales. Although the temporal stability method was found to be suitable for identifying representative stations, stations based on the mean relative difference (MRD) were not necessarily the most representative of the areal average. Moreover, those identified from standard deviation of the relative difference (SDRD) may be dry-biased. It was also found that in the presence of heterogeneous land use, stations should be weighted based on proportions of agricultural land. Airborne soil moisture products were also shown to provide useful a priori information for identifying representative locations. Finally, recommendations are made regarding the design of future networks for satellite validation, and specifically the most representative stations for the Yanco area.

Original languageEnglish
Pages (from-to)367-381
Number of pages15
JournalJournal of Hydrology
Volume537
DOIs
Publication statusPublished - 1 Jun 2016

Keywords

  • Representativeness
  • Satellite validation
  • Soil Moisture Active Passive (SMAP)
  • Soil moisture measurement
  • Spatial stability
  • Temporal stability

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