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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Electrification of precipitating systems over the Amazon: Physical processes of thunderstorm development

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Author(s):
Albrecht, Rachel I. [1] ; Morales, Carlos A. [1] ; Silva Dias, Maria A. F. [1]
Total Authors: 3
Affiliation:
[1] Univ Sao Paulo, Dept Ciencias Atmosfer, BR-05508090 Sao Paulo - Brazil
Total Affiliations: 1
Document type: Journal article
Source: JOURNAL OF GEOPHYSICAL RESEARCH; v. 116, APR 23 2011.
Web of Science Citations: 17
Abstract

This study investigated the physical processes involved in the development of thunderstorms over southwestern Amazon by hypothesizing causalities for the observed cloud-to-ground lightning variability and the local environmental characteristics. Southwestern Amazon experiences every year a large variety of environmental factors, such as the gradual increase in atmospheric moisture, extremely high pollution due to biomass burning, and intense deforestation, which directly affects cloud development by differential surface energy partition. In the end of the dry period it was observed higher percentages of positive cloud-to-ground (+CG) lightning due to a relative increase in +CG dominated thunderstorms (positive thunderstorms). Positive (negative) thunderstorms initiated preferentially over deforested (forest) areas with higher (lower) cloud base heights, shallower (deeper) warm cloud depths, and higher (lower) convective potential available energy. These features characterized the positive (negative) thunderstorms as deeper (relatively shallower) clouds, stronger (relatively weaker) updrafts with enhanced (decreased) mixed and cold vertically integrated liquid. No significant difference between thunderstorms (negative and positive) and nonthunderstorms were observed in terms of atmospheric pollution, once the atmosphere was overwhelmed by pollution leading to an updraft-limited regime. However, in the wet season both negative and positive thunderstorms occurred during periods of relatively higher aerosol concentration and differentiated size distributions, suggesting an aerosol-limited regime where cloud electrification could be dependent on the aerosol concentration to suppress the warm and enhance the ice phase. The suggested causalities are consistent with the invoked hypotheses, but they are not observed facts; they are just hypotheses based on plausible physical mechanisms. (AU)

FAPESP's process: 04/09049-3 - Electrification of the precipitant systems in the Amazon region: physical and dynamic processes of development of storms
Grantee:Rachel Ifanger Albrecht
Support type: Scholarships in Brazil - Doctorate