Abstract ID: 110

Analysis of Variation of Precipitation and Available Potential Energy for Convection During the Experiment COBRA-PA

The data used in this work (radiosoundings and precipitation) were obtained during the experiment COBRA-PARA (Biosphere, Rivers and Atmosphere Observations in the Pará). They were done in the region of Caxiuanã-PA (01° 42'30''S, 051° 31'45''W) in the period from 10/31/2006 to 11/15/2006. During the period from 11/06/2006 to 11/13/2006 were launched 8 daily radiosoudings, with intervals of about 3 hours between them, in times of 00, 03, 06, 09, 12, 15, 18, 21 UTC, using the system Väisälä RS 80-15. The analysis of temporal variability of convective available potential energy (CAPE) and the possible relationship between precipitation and the parcel (plot) energy was verified. During this experiment the results show that the CAPE presented a well-defined diurnal cycle, Characterizing with the values of CAPE increasing during the day, with a maximum between 18 and 21 UTC on the most of days, and reducing the in the nocturnal period. It was found that the thermodynamic factors not necessarily started the precipitation, because sometimes there were large amounts of CAPE and no precipitation was observed in the region. Then, in the most of times when there was precipitation, the highest values of precipitation were not directly related to the great values of CAPE, or contrary. This means that the rainfall was not due only to local thermodynamics effects, associated with surface warning that allows the formation of convective cells, but dynamic factors also contributed for the precipitations occurrence in the region.

Session:  Feedbacks to Climate - Land cover, surface hydrology, and atmospheric feedbacks.

Presentation Type:  Poster