Climatology of easterly wave disturbances over the tropical South Atlantic

Autor(es)

Gomes, Helber B. ^[1] ; Ambrizzi, Tercio ^[2] ; Pontes da Silva, Bruce F. ^[3] ; Hodges, Kevin ^[4] ; Silva Dias, Pedro L. ^[2] ; Herdies, Dirceu L. ^[5] ; Silva, Maria Cristina L. ^[1] ; Gomes, Heliofabio B. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Alagoas, Inst Atmospher Sci, Maceio - Brazil

^[2] Univ Sao Paulo, Dept Atmospher Sci, Sao Paulo - Brazil

^[3] Capixaba Inst Res Tech Assistance & Rural Extens, Vitoria, ES - Brazil

^[4] Univ Reading, Dept Meteorol, Reading, Berks - England

^[5] Natl Inst Space Res, Cachoeira Paulista - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Climate Dynamics; v. 53, n. 3-4, p. 1393-1411, AUG 2019.
• Citações Web of Science: 2

Resumo

A 21-year climatology of Easterly Waves Disturbances (EWDs) over the tropical South Atlantic (TSA) has been examined using data from the European Centers for Medium-Range Weather Forecasting interim reanalysis (ERAI) and satellite data. This includes the frequency distribution of EWDs and their interannual variability. The large-scale environment associated with EWDs has been investigated for the coastal region of Northeast Brazil (NEB) for the rainy (April-August) season using a composite analysis. EWDs were first identified in ERAI, resulting in 518 observed cases. These were found to show notable interannual variability with around 16-40 episodes each year and with an average lifetime of 4-6days. Of the identified EWDs, 97% reached the coast of NEB, of which 64% were convective in nature and 14% moved across the NEB region and reached the Amazon. The annual occurrence of EWDs seems to be lower (higher) during El Nino (La Nina). The monthly occurrence of EWDs shows higher activity in the rainy season. EWDs originate in association with four types of system: cold fronts, convective clusters from the west coast of Africa, Intertropical Convergence Zone and Tropical Upper Tropospheric Cyclonic Vortices. The composite analysis indicates strong relative vorticity and divergence anomalies at low levels, as well as in the vertical profiles of relative humidity and vertical velocity (omega). The precipitation composites show that the EWDs propagate between the TSA and NEB and contribute at least 60% of the total rainfall over the east coast of NEB throughout the rainy season. (AU)

• Processo FAPESP: 14/50848-9 - INCT 2014: INCT para Mudanças Climáticas (INCT-MC)
• Beneficiário: Jose Antonio Marengo Orsini
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático
• Processo FAPESP: 08/58101-9 - Impact of the Southwestern Atlantic Ocean on South American climate for the 20th and 21st centuries
• Beneficiário: Tercio Ambrizzi
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático