HR: 13:55h
AN: A53B-02    [Abstracts]
TI: An Observational Study of East Pacific Intraseasonal Variability During Boreal Summer
AU: * Maloney, E D
EM: maloney@coas.oregonstate.edu
AF: COAS/Oregon State University, 104 Ocean Admin Bldg, Corvallis, OR 97331-5503
AU: Esbensen, S K
A53B-02 AF: COAS/Oregon State University, 104 Ocean Admin Bldg, Corvallis, OR 97331-5503
AB: The TAO array and satellite observations are used to examine the influence of the tropical intraseasonal oscillation in the east Pacific warm pool during boreal summer. Data during June-September of 2000-2003 are used, when the TAO array was augmented at 95° W with enhanced observations and buoys at 10° N and 12° N. Satellite products used include TRMM precipitation, QuikSCAT ocean vector winds, and column precipitable water from SSM/I. A strong correlation is found between intraseasonal latent heat flux and precipitation anomalies along the 95° W buoy line. Enhanced surface latent heat fluxes accompany anomalous surface southwesterly flow, consistent with enhancement of surface fluxes by wind-evaporation feedback, as hypothesized by Maloney and Esbensen (2003) using reanalysis data and Raymond et al (2003, 2005) using EPIC2001 field data. However, the correlation between latent heat flux and precipitation at 110° W, 8° N is negative. This location is characterized by anomalously low column water vapor during periods of enhanced southwesterly flow and fluxes. This tropospheric dryness may help suppress convection in the presence of enhanced surface fluxes, consistent with the hypothesis of Back and Bretherton (2005). Further examination of large-scale fields during east Pacific intraseasonal oscillation events is conducted using satellite data. Sensitivity of east Pacific intraseasonal variability in a general circulation model to wind-evaporation feedback is also described.
DE: 3314 Convective processes
DE: 3339 Ocean/atmosphere interactions (0312, 4504)
DE: 3374 Tropical meteorology
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005