| Full text | |
| Author(s): |
José A. Marengo
[1]
;
Gilberto Fisch
[2]
;
Carlos Morales
[3]
;
Iria Vendrame
[4]
;
Paulo C. Dias
[5]
Total Authors: 5
|
| Affiliation: | [1] Centro de Previsão de Tempo e Estudos Climáticos - Brasil
[2] Universidade de São Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas. Departamento de Ciências Atmosféricas - Brasil
[3] Universidade de São Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas. Departamento de Ciências Atmosféricas - Brasil
[4] Universidade de São Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas. Departamento de Ciências Atmosféricas - Brasil
[5] Universidade de São Paulo. Instituto de Astronomia, Geofísica e Ciências Atmosféricas. Departamento de Ciências Atmosféricas - Brasil
Total Affiliations: 5
|
| Document type: | Journal article |
| Source: | Acta Amazonica; v. 34, n. 4, p. 593-603, 2004-12-00. |
| Abstract | |
The TRMM-LBA field campaign was held during the austral summer of 1999 in southwestern Amazonia. Among the major objectives, was the identification and description of the diurnal variability of rainfall in the region, associated with the different rain producing weather systems that occurred during the January-February season. By using a network of 40 digital rain gauges implemented in the state of Rondônia, and together with observations and analyses of circulation and convection, it was possible to identify details of the diurnal cycle of rainfall and the associated rainfall mechanisms. Rainfall episodes were characterized by regimes of "low-level easterly" and "westerly" winds in the context of the large-scale circulation. The westerly regime is related to an enhanced South Atlantic Convergence Zone (SACZ) and an intense and/or wide Low Level Jet (LLJ) east of the Andes, which can extend eastward towards Rondônia, even though some westerly regime episodes also show a LLJ that remains close to the foothill of the Andes. The easterly regime is related to easterly propagating systems (e.g. squall-lines) with possible weakened or less frequent LLJs and a suppressed SACZ. Diurnal variability of rainfall during westerly surface wind regime shows a characteristic maximum at late afternoon followed by a relatively weaker second maximum at early evening (2100 Local Standard Time LST). The easterly regime composite shows an early morning maximum followed by an even stronger maximum in the afternoon. (AU) | |
| FAPESP's process: | 01/13816-1 - Brazilian component of the South American low level jet east of the Andes field experiment: interaction in meso and large scale between the Amazon and La Plata River Basins |
| Grantee: | Jose Antonio Marengo Orsini |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 01/06908-7 - Radiation, cloud and climate interactions in the Amazon during the Dry-To-Wet transition season/LBA |
| Grantee: | Maria Assunção Faus da Silva Dias |
| Support Opportunities: | Research Projects - Thematic Grants |