Overview: Precipitation characteristics and sensitivities to environmental conditions during GoAmazon2014/5 and ACRIDICON-CHUVA

Author(s):Show less -

Machado, Luiz A. T. ^[1] ; Calheiros, Alan J. P. ^[1] ; Biscaro, Thiago ^[1] ; Giangrande, Scott ^[2] ; Silva Dias, Maria A. F. ^[3] ; Cecchini, Micael A. ^[3] ; Albrecht, Rachel ^[3] ; Andreae, Meinrat O. ^{[4, 5]} ; Araujo, Wagner F. ^[1] ; Artaxo, Paulo ^[6] ; Borrmann, Stephan ^[4] ; Braga, Ramon ^[1] ; Burleyson, Casey ^[7] ; Eichholz, Cristiano W. ^[1] ; Fan, Jiwen ^[7] ; Feng, Zhe ^[7] ; Fisch, Gilberto F. ^[8] ; Jensen, Michael P. ^[2] ; Martin, Scot T. ^[9] ; Poeschl, Ulrich ^[4] ; Poehlker, Christopher ^[4] ; Poehlker, Mira L. ^[4] ; Ribaud, Jean-Francois ^[1] ; Rosenfeld, Daniel ^[10] ; Saraiva, Jaci M. B. ^[11] ; Schumacher, Courtney ^[12] ; Thalman, Ryan ^[13] ; Walter, David ^[4] ; Wendisch, Manfred ^[14]

Affiliation:Show less -

^[1] Natl Inst Space Res INPE, Sao Jose Dos Campos - Brazil

^[2] Brookhaven Natl Lab, Upton, NY 11973 - USA

^[3] Univ Sao Paulo, Inst Astron Geophys & Atmospher Sci, Sao Paulo - Brazil

^[4] Max Planck Inst Chem, Mainz - Germany

^[5] Univ Calif San Diego, Scripps Inst Oceanog, La Jolla, CA 92037 - USA

^[6] Univ Sao Paulo, Inst Phys, Sao Paulo - Brazil

^[7] Pacific Northwest Natl Lab, Richland, WA - USA

^[8] Dept Aerosp Sci & Technol, Sao Jose Dos Campos - Brazil

^[9] Harvard Univ, Cambridge, MA 02138 - USA

^[10] Hebrew Univ Jerusalem, Jerusalem - Israel

^[11] Amazon Protect Syst SIPAM, Manaus, Amazonas - Brazil

^[12] Texas A&M Univ, College Stn, TX - USA

^[13] Snow Coll, Richfield, UT - USA

^[14] Univ Leipzig, Leipzig Inst Meteorol, Leipzig - Germany

• Document type: Journal article
• Source: Atmospheric Chemistry and Physics; v. 18, n. 9, p. 6461-6482, MAY 7 2018.
• Web of Science Citations: 5

Abstract

This study provides an overview of precipitation processes and their sensitivities to environmental conditions in the Central Amazon Basin near Manaus during the GoAmazon2014/5 and ACRIDICON-CHUVA experiments. This study takes advantage of the numerous measurement platforms and instrument systems operating during both campaigns to sample cloud structure and environmental conditions during 2014 and 2015; the rainfall variability among seasons, aerosol loading, land surface type, and topography has been carefully characterized using these data. Differences between the wet and dry seasons were examined from a variety of perspectives. The rainfall rates distribution, total amount of rainfall, and raindrop size distribution (the mass-weighted mean diameter) were quantified over both seasons. The dry season generally exhibited higher rainfall rates than the wet season and included more intense rainfall periods. However, the cumulative rainfall during the wet season was 4 times greater than that during the total dry season rainfall, as shown in the total rainfall accumulation data. The typical size and life cycle of Amazon cloud clusters (observed by satellite) and rain cells (observed by radar) were examined, as were differences in these systems between the seasons. Moreover, monthly mean thermodynamic and dynamic variables were analysed using radiosondes to elucidate the differences in rainfall characteristics during the wet and dry seasons. The sensitivity of rainfall to atmospheric aerosol loading was discussed with regard to mass-weighted mean diameter and rain rate. This topic was evaluated only dur- ing the wet season due to the insignificant statistics of rainfall events for different aerosol loading ranges and the low frequency of precipitation events during the dry season. The impacts of aerosols on cloud droplet diameter varied based on droplet size. For the wet season, we observed no dependence between land surface type and rain rate. However, during the dry season, urban areas exhibited the largest rainfall rate tail distribution, and deforested regions exhibited the lowest mean rainfall rate. Airplane measurements were taken to characterize and contrast cloud microphysical properties and processes over forested and deforested regions. Vertical motion was not correlated with cloud droplet sizes, but cloud droplet concentration correlated linearly with vertical motion. Clouds over forested areas contained larger droplets than clouds over pastures at all altitudes. Finally, the connections between topography and rain rate were evaluated, with higher rainfall rates identified at higher elevations during the dry season. (AU)

• FAPESP's process: 15/14497-0 - Nowcasting of intense thunderstorms and understanding of the physical processes inside clouds: the SOS-CHUVA (Severe Weather Observation System)
• Grantee: Luiz Augusto Toledo Machado
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants
• FAPESP's process: 14/08615-7 - Precipitation formation processes: a study about microphysics, aerosols interactions and cloud life cycle using radar and airplane data
• Grantee: Micael Amore Cecchini
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 09/15235-8 - Cloud processes of the main precipitation systems in Brazil: a contribution to cloud resolving modeling and to the GPM (Global Precipitation Measurement)
• Grantee: Luiz Augusto Toledo Machado
• Support Opportunities: Research Projects - Thematic Grants