Eco-hydrological controls on summertime convective rainfall triggers

Jehn Yih Juang, Gabriel G. Katul, Amilcare Porporato, Paul C. Stoy, Mario S. Siqueira, Matteo Detto, Hyun Seok Kim, Ram Oren

Research output: Contribution to journalArticle

46 Scopus citations

Abstract

Triggers of summertime convective rainfall depend on numerous interactions and feedbacks, often compounded by spatial variability in soil moisture and its impacts on vegetation function, vegetation composition, terrain, and all the complex turbulent entrainment processes near the capping inversion. To progress even within the most restricted and idealized framework, many of the governing processes must be simplified and parameterized. In this work, a zeroth - order representation of the dynamical processes that control convective rainfall triggers - namely land surface fluxes of heat and moisture -is proposed and used to develop a semianalytical model to explore how differential sensitivities of various ecosystems to soil moisture states modify convective rainfall triggers. The model is then applied to 4 years (2001-2004) of half-hourly precipitation, soil moisture, environmental, and eddy-covariance surface heat flux data collected at a mixed hardwood forest (HW), a maturing planted loblolly pine forest (PP), and an abandoned old field (OF) experiencing the same climatic and edaphic conditions. We found that the sensitivity of PP to soil moisture deficit enhances the trigger of convective rainfall relative to HW and OF, with enhancements of about 25% and 30% for dry moisture states, and 5% and 15% for moist soil moisture states, respectively. We discuss the broader implications of these findings on potential modulations of convective rainfall triggers induced by projected large-scale changes in timberland composition within the Southeastern United States.

Original languageEnglish (US)
Pages (from-to)887-896
Number of pages10
JournalGlobal Change Biology
Volume13
Issue number4
DOIs
StatePublished - Apr 2007

All Science Journal Classification (ASJC) codes

  • Global and Planetary Change
  • Environmental Chemistry
  • Ecology
  • Environmental Science(all)

Keywords

  • Atmospheric mixed-layer
  • Convective rainfall
  • Landcover change
  • Soil moisture

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    Juang, J. Y., Katul, G. G., Porporato, A., Stoy, P. C., Siqueira, M. S., Detto, M., Kim, H. S., & Oren, R. (2007). Eco-hydrological controls on summertime convective rainfall triggers. Global Change Biology, 13(4), 887-896. https://doi.org/10.1111/j.1365-2486.2007.01315.x