TRO-PICO: A SMALL BALLOON CAMPAIGN TO STUDY THE IMPACT OF TROPICAL CONVECTIVE OVERSHOOTING ON STRATOSPHERIC WATER BUDGET

摘要

The entry of water vapour in the tropical stratosphere is still a highly debated issue but is crucial for the radiative and the chemical balance of the stratosphere. This entry is due to two competing processes, ⅰ) The slow ascent leading to dehydration at the global scale (so-called the cold trap) is said to mainly drive the water concentration at the tropical tropopause. ⅱ) Overshooting convection, inject ice in the lower stratosphere leading to a potential hydration. It is a fast and local process, difficult to capture by global scale model. TRO-pico is a project funded by the French ANR dedicated to study the impact of tropical convective overshooting on stratospheric water budget from the local to wider scales. It is based on a small balloon campaign from Bauru, SP, Brazil at two timescales (overall wet season, and intense convective season), followed by the campaign data analysis with a wide set of modeling tools. Here we describe the scientific context of TRO-pico, the objectives of the project, the campaign planned to start in November 2011, as well as the instruments to be flown in Brazil, which have recently participated in the Kiruna 2011 campaign with preliminary results from this campaign.