Connecting the level of cloud organization to the hydrologic and aerosol cycles in the Amazon (CLOUDORG)

• Grant number: 22/13257-9
• Support Opportunities: Research Program on Global Climate Change - Young Investigators
• Start date: June 01, 2023
• End date: May 31, 2028
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Meteorology
• Agreement: Serrapilheira Institute
• Principal Investigator: Micael Amore Cecchini
• Grantee: Micael Amore Cecchini
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: André Seiji Wakate Teruya ; Carlos Frederico de Angelis ; Carlos Frederico Mendonça Raupp ; Edmilson Dias de Freitas ; Henrique de Melo Jorge Barbosa ; Luiz Augusto Toledo Machado ; Márcia Akemi Yamasoe ; Maria Assunção Faus da Silva Dias ; Paulo Eduardo Artaxo Netto ; Pedro Leite da Silva Dias ; Rachel Ifanger Albrecht ; Thiago Souza Biscaro
• Associated scholarship(s): 24/17448-9 - Correlating cloud organization with precipitation efficiency in the Amazon, BP.PD; 24/15111-7 - Network integration and automation of data collection and transfer at the ATTO-Campina site, BP.TT; 24/04763-3 - Analyzing the effects of aerosols and moisture on the organization of shallow cloud fields in the Amazon, BP.MS; 24/07198-5 - Data management during the CLOUDORG project, BP.TT

Abstract

The physical aspects of clouds, such as their horizontal and vertical extents, largely determine their role in the water and energy cycles in the Amazon. In this region, the locally driven diurnal convection cycle has a pulsating aspect, with the formation of the so-called shallow cumulus cloud field in the late morning, followed by a peak of activity in the afternoon due to deep convective cloud formation that then dissipates in the late afternoon. Historically, climate models fail to reproduce the growth of shallow convective clouds into deeper systems (i.e., the shallow-to-deep convective transition), triggering deep convection too early. This results in too early (2-3 hours) rainfall peaks within the daily cycle. Additionally, recent studies have shown that deep convective clouds play a major role in the new particle formation process in the Amazon. It has been proposed that clouds transport biogenic gases to the upper troposphere where they grow by condensation and are later transported to the boundary layer by downdrafts, replenishing the aerosol population that was removed by washout. In a context of a changing climate, it is essential that we achieve accurate reproduction of Amazonian cloud field evolution in order to better predict the future rainfall and aerosol regimes in the region. In this context, we propose an objective analysis to quantify the shallow-to-deep convective transition using high-resolution models and new observations at the ATTO (Amazon Tall Tower Observatory) tower region. The quantification will involve the determination of the level of cloud aggregation in the cloud fields, which dictates whether it is dominated by many small clouds (low level of aggregation) or by a few large clusters (high level of aggregation). The typical convective daily cycle in the Amazon is expected to evolve from the former towards the latter. Therefore, we propose a novel way to quantify the shallow-to-deep transition by tracking the evolution of the cloud aggregation levels. This information is intrinsically linked to the rainfall spatiotemporal variability and aerosol cycle because larger clusters produce more rainfall and transport more mass vertically than shallower and spread-out clouds. We propose that an index of cloud aggregation is an important factor to transition high-resolution model and observational results into parameterizations in climate models. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

HEYMSFIELD, ANDREW J.; CECCHINI, MICAEL A.; DETWILER, ANDREW; HONEYAGER, RYAN; FIELD, PAUL. Exploring the Composited T-28 Hailstorm Penetration Dataset to Characterize Hail Properties within the Updraft and Downdraft Regions. Journal of Applied Meteorology and Climatology, v. 62, n. 12, p. 24-pg., 2023-12-01. (22/13257-9)

CURTIUS, JOACHIM; HEINRITZI, MARTIN; BECK, LISA J.; POEHLKER, MIRA L.; TRIPATHI, NIDHI; KRUMM, BIANCA E.; HOLZBECK, PHILIP; NUSSBAUMER, CLARA M.; PARDO, LIANET HERNANDEZ; KLIMACH, THOMAS; et al. Isoprene nitrates drive new particle formation in Amazon's upper troposphere. Nature, v. 636, n. 8041, p. 23-pg., 2024-12-05. (22/01780-9, 21/03547-7, 22/13257-9)