THE FOEHN WIND EAST OF THE ANDES IN A 20 ‑ YEAR CLIMATE SIMULATION

ANTICO, PABLO LUIS; CHOU, SIN CHAN; BRUNINI, CLAUDIO

Workshop; VII Worketa online - Workshop em Modelagem Numérica de Tempo, Clima e Mudancas Climáticas Utilizando o Modelo Eta: Aspectos Físicos e Numéricos; 2022

Instituto Nacional de Pesquisas Espaciais

p { margin-bottom: 0cm; direction: ltr; text-align: justify; }p.western { font-size: 12pt; }p.cjk { font-size: 12pt; }a:link { color: rgb(0, 0, 255); }Thisstudy investigates the spatial structure and the seasonal occurrenceof foehn wind to the east of the Andes using a flow blocking analysisin a 20-year climate simulation. The latter was performed by theEta-CPTEC regional model at 50-km horizontal resolution. This versionof the model includes a cut-cell scheme to represent topography and afinite-volume vertical advection scheme for dynamic variables. Theresults indicate that foehn wind more frequently blows during winterand spring on the eastern slopes of the Andes, except to the south of37° S where it blows at all seasons. Higher mountains of the CentralAndes (27° S–35° S) and the High Plateau (15° S–27° S) resultin blocked foehn events, with a weak adjustment to the geostrophicbalance. On the Central Andes, rain and snow on mountain tops mayalso contribute to generate foehn wind on the eastern slopes. Theresults show that a low pressure develops to the east of the CentralAndes, and also to the east of the High Plateau when foehn blows.Lower mountains in Patagonia (to the south of 37° S) result in morefrequent non-blocked foehn event, with better adjustment to thegeostrophic balance.