Interplay of climate seasonality and soil moisture-rainfall feedback

Jun Yin, Amilcare Michele M. Porporato, John Albertson

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

The soil moisture-rainfall feedback (SMRF) may significantly impact hydro-climatic dynamics, inducing persistent weather conditions that are responsible for prolonged droughts or abnormally wet states. However, externally driven seasonal variability in rainfall and potential evapotranspiration, with the associated patterns of wet and dry conditions, may both interact with such an SMRF. In this study, seasonal variations in radiation and precipitation forcing are included in a stochastic SMRF model with the assumption of a soil moisture-dependent average rainfall frequency to explore their effects on the soil moisture probabilistic structure. The theoretical model results, based on a parameterization using data for soil moisture and climate in Illinois, show that average rainfall frequency peaks in late spring when both the soil condition and the SMRF strength favor convective rainfall triggering. Under such conditions, the soil moisture tends to exhibit bimodal behavior until the SMRF strength becomes weak again toward the end of the growing season. Such a behavior is reminiscent of the dynamics of a system undergoing a periodic, stochastically forced pitchfork bifurcation. The presence of bimodal soil moisture behavior is also verified using nonparametric statistical tests on soil moisture data. The analysis of wet-to-wet and dry-to-dry soil moisture transitions in the joint probability distribution of soil moisture further corroborates the presence of hydro-climatic persistence in the spring-to-summer transition. Key Points Stochastic soil moisture-rainfall feedback model and the role of seasonality Soil moisture distribution may exhibit bimodal behavior at the start of the warm season The results corroborate the hypothesis of soil moisture-rainfall feedback

Original languageEnglish (US)
Pages (from-to)6053-6066
Number of pages14
JournalWater Resources Research
Volume50
Issue number7
DOIs
StatePublished - Jan 1 2014
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Water Science and Technology

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