Playa soil moisture and evaporation dynamics during the MATERHORN field program

Chaoxun Hang, Daniel F. Nadeau, Derek D. Jensen, Sebastian W. Hoch, Eric R. Pardyjak

Research output: Contribution to journalArticleResearchpeer-review

12 Citations (Scopus)

Abstract

We present an analysis of field data collected over a desert playa in western Utah, USA in May 2013, the most synoptically active month of the year, as part of the Mountain Terrain Atmospheric Modeling and Observations (MATERHORN) program. The results show that decreasing surface albedo, decreasing Bowen ratio and increasing net radiation with increasing soil moisture sustained a powerful positive feedback mechanism promoting large evaporation rates immediately following rain events. Additionally, it was found that, while nocturnal evaporation was negligible during dry periods, it was quite significant (up to 30 % of the daily cumulative flux) during nights following rain events. Our results further show that the highest spatial variability in surface soil moisture is found under dry conditions. Finally, we report strong spatial heterogeneities in evaporation rates following a rain event. The cumulative evaporation for the different sampling sites over a five-day period varied from ≈ 0.1 to ≈ 6.6 mm. Overall, this study allows us to better understand the mechanisms underlying soil moisture dynamics of desert playas as well as evaporation following occasional rain events.

Original languageEnglish
Pages (from-to)521-538
Number of pages18
JournalBoundary-Layer Meteorology
Volume159
Issue number3
DOIs
Publication statusPublished - 1 Jun 2016
Externally publishedYes

Keywords

  • Bare soil evaporation
  • Dry lake
  • Gravimetric method
  • Nocturnal evaporation
  • Spatial heterogeneity
  • Surface energy balance

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