Abstract
Abstract. The effect of coastal upwelling on the evolution of the atmospheric boundary layer (ABL) in Cabo Frio (Brazil) is investigated. For this purpose, radiosounding data collected in two experiments made during the austral summer (upwelling case) and austral winter (no upwelling case) are analysed. The results show that during the austral summer, cold waters that crop up near the Cabo Frio coast favour the formation of an atmospheric stable layer, which persists during the upwelling episode. Due to the low SSTs, the descending branch of the sea-breeze circulation is located close to the coast, inhibiting the development of a mixed layer mainly during the day. At night, with the reduction of the land-sea thermal contrast the descending motion is weaker, allowing a vertical mixing. The stable ABL favours the formation of a low level jet, which may also contribute to the development of a nocturnal atmospheric mixed layer. During the austral winter, due to the higher SSTs observed near the coast, the ABL is less stable compared with that in the austral summer. Due to warming, a mixed layer is observed during the day. The observed vertical profiles of the zonal winds show that the easterlies at low levels are stronger in the austral summer, indicating that the upwelling modulates the sea-breeze signal, thus confirming model simulations.
Highlights
During the austral summer and spring seasons, negative sea surface temperature (SST) anomalies caused by winddriven coastal upwelling are present along part of the Brazilian southeast continental shelf, near Cabo Frio (22◦59 S, 42◦02 W)
The purpose of the present paper is to analyse the vertical profiles of temperature, humidity, and wind, in order to investigate the effects of the coastal upwelling on the evolution of the atmospheric boundary layer (ABL) in the Cabo Frio region
This work investigates the influence of the coastal upwelling on the evolution of the ABL in the Cabo Frio region
Summary
During the austral summer and spring seasons, negative sea surface temperature (SST) anomalies caused by winddriven coastal upwelling are present along part of the Brazilian southeast continental shelf, near Cabo Frio. From early September through late April the atmospheric circulation over the Cabo Frio region is strongly influenced by the large-scale South Atlantic high pressure center which makes the prevailing winds blow from the northeast with a large component parallel to the coast. Dourado and Oliveira (2000) examined the evolution of the marine ABL during an event of cold front passage They noted a typical inversion of the wind from northeast to southwest, followed by the warming of the ocean surface due to the subsidence of SACW and the southwest wind advection of a deep atmospheric mixed layer from the continent towards the ocean. The purpose of the present paper is to analyse the vertical profiles of temperature, humidity, and wind, in order to investigate the effects of the coastal upwelling on the evolution of the ABL in the Cabo Frio region
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
