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Experiment will investigate the impact of ocean changes on atmosphere
Tuesday, October 09, 2012

Aboard the Polar ship Almirante Maximiano, staff of the National Institute for Space Research (Instituto Nacional de Pesquisas Espaciais - INPE) will held in October and November the INTERCONF experiment, aimed at assessing the impacts of the surface temperature of the sea water changes in the atmosphere. The mission, which extends from South America to Antarctica, will be important for studies of the region called Brazil-Malvinas Confluence.

In this region the Brazils warm current meet the Malvinas cold current causing atmospheric instabilities of synoptic characteristics and impacts in the climatic balance of ocean-atmosphere system, sayd Luciano Ponzi Pezzi, an INPEs researcher. This variability may cause effects in spatial scales up to 500 Kilometers and in time scales up to three months (oceanic mesoscale).

The atmosphere reacts differently above warm or cold water. This temperature variation causes impacts on the flows of heat, momentum and gases, especially CO2, between atmosphere and ocean, determining the stability at lower levels of the atmosphere above sea level (atmospheric boundary layer).

When the lower part of atmosphere is colder, and therefore heavier than the upper part, the atmosphere is stable. Otherwise, the atmosphere gets instable. So, over colder water there is a stable atmosphere: weak winds on sea surface and less intense heat fluxes from the ocean to the atmosphere. If there were a chance of passing weather fronts or cyclones in the region, that could all change, and would make the weather forecasting fail," explains Ronald Buss de Souza, head of Antarctic Project of INPE.

During the INTERCONF experiment, will be launched atmospheric radiosondes and oceanic probes, as well as conventional data collection performed by the ships weather station. The data will help determine the so-called horizontal thermal gradients of the seawater temperature under atmosphere in a synoptic scale. The radiosondes will measure up to 20 kilometers high, while bathythermographs will record water temperature at depths reaching two kilometers.

The meeting of cold and warm water produces the formation of oceanic eddies, which are the marine equivalent of atmospheric cyclones. It has been studied a system of eddies called "dipole", where there is a coupling of a warm-core vortex (turning counterclockwise in the southern hemisphere) and a cold-core vortex (turning clockwise in the southern hemisphere). This system has a unique dynamic and its impact on the atmosphere has never been investigated. Together, warm and cold vortex in this dipole may reach a 400 kilometers diameter.

The dipole system might last longer at sea than a single vortex system. Consequently, the impact in the atmosphere is greater, causing changes in patterns of stability, heat and gas flows, moisture, wind intensity, among other parameters. These instabilities are difficult to predict by weather forecasting models existing in the world nowadays.

Data collected during the INTERCONF may help improve prediction models. The INPEs researcher says that oceanographers and meteorologists around the world are interested in studies of ocean variability and its impacts on the atmosphere in the region of Brazil-Malvinas Confluence. "This kind of system with two eddies is rarely described in the literature. Due to the rarity of this phenomenon and the lack of vessels of any country in the region at the time of its existence, during this scientific mission we may become the first in situ observers of  these systems in this region," concludes Ronald Buss.

Another experiment

The INTERCONF experiment will take place between October 12 and November 30. After collecting data for studies on the Brazil-Malvinas Confluence, the INPEs team will be aboard the Polar ship Almirante Maximiano until the Deception Island, Antarctica, to conduct another scientific experiment, this one related to the INTERCEPTION project (Ocean-Atmosphere-Coast Micro Scale Interactions in Deception Island, Antarctica).

The ship itself, boats and a Brazils Navy helicopter will be used during the INTERCEPTION activities, and two camps will be installed to conduct experiments of meteorology and geological oceanography at the Bay Foster beach, in Deception Island. During the expedition to Antarctica, researchers will also pass through Ushuaia (the worlds most southern city), Argentina, and Punta Arenas, Chile.

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