Interplay of drought and tropical cyclone activity in SE U.S. gross primary productivity

Lauren E.L. Lowman, Ana P. Barros

Research output: Contribution to journalArticlepeer-review

Abstract

Tropical cyclones (TCs), often associated with massive flooding and landslides in the Southeast U.S. (SE U.S.), provide a significant input of freshwater to the hydrologic system, and their timing and trajectory significantly impact drought severity and persistence. This manuscript investigates the sensitivity of gross primary productivity (GPP) in the SE U.S. to TC activity using the 1-D column implementation of the Duke Coupled Hydrology Model with Vegetation (DCHM-V) including coupled water and energy cycles and a biochemical representation of photosynthesis. Decadal-scale simulations of water, energy, and carbon fluxes were conducted at high temporal (30 min) and spatial (4 km) resolution over the period 2002–2012. At local scales, model results without calibration compare well against AmeriFlux tower data. At regional scales, differences between the DCHM-V estimates and the Moderate Resolution Imaging Spectroradiometer GPP product reflect the spatial organization of soil hydraulic properties and soil moisture dynamics by physiographic region, highlighting the links between the water and carbon cycles. To isolate the contribution of TC precipitation to SE U.S. productivity, control forcing simulations are contrasted with simulations where periods of TC activity in the atmospheric forcing data were replaced with climatology. During wet years, TC activity impacts productivity in 40–50% of the SE U.S. domain and explains a regional GPP increase of 3–5 Mg C/m2 that is 9% of the warm season total. In dry years, 23–34% of the domain exhibits a smaller positive response that corresponds to 4–8% of the seasonal carbon uptake, depending on TC timing and trajectory.

Original languageEnglish (US)
Pages (from-to)1540-1567
Number of pages28
JournalJournal of Geophysical Research: Biogeosciences
Volume121
Issue number6
DOIs
StatePublished - Jun 1 2016
Externally publishedYes

Keywords

  • carbon cycle
  • GPP
  • soil moisture
  • tropical cyclones
  • water uptake

ASJC Scopus subject areas

  • Geophysics
  • Forestry
  • Oceanography
  • Aquatic Science
  • Ecology
  • Water Science and Technology
  • Soil Science
  • Geochemistry and Petrology
  • Earth-Surface Processes
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Palaeontology

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