Document: HEN-3-66-17

ENSO effects on bulk precipitation and temperature, and their potential consequences for productivity in wet tropical ecosystems of Central America.

LOESCHER, H.W* ¹ and S.FOBERBAUER ^2,3

University of Florida at Gainesville, Gainesville FL 32611 ¹
Florida International University, Miami FL 33199 ²
Fairchild Tropical Garden, Miami, FL 33156 ³

Abstract:
ENSO events are purported to affect ecosystem productivity, but little is known about the magnitude at which climate can play a role. We examined differences between ENSO and non-ENSO events on regional patterns of bulk precipitation and temperature from three sites with contrasting seasonal circulations in the lower Central American isthmus. Bulk precipitation during the dry season at all three sites was negatively correlated to both the Southern Oscillation Index and the Sea-level Pressure Differential on a monthly timestep, while the wet season precipitation was positively correlated. There were marked qualitative seasonal differences in both magnitude and frequency of bulk precipitation between ENSO and non-ENSO events as examined through Fast-Fournier Transforms (FFT) on a daily timestep. Mean minimum temperature regimes showed similar patterns with FFT analyses. Model simulations show lower productivity during ENSO events in tropical wet forests. This suggests that during an ENSO, both higher minimum temperatures during dry season and greater rainfall in the wet are likely to have negative effects on productivity.

Keywords: El Nino, ENSO, southern oscillation, tropical forest productivity, climate change, general circulations, La Selva

This abstract is being presented at: 2:30 PM in session:
Oral Session #66: Large Scale Climate Change.