The Concordiasi Project in Antarctica

Abstract

International audienceThe Concordiasi project is making innovative observations of the atmosphere above Antarctica. The most important goals of the Concordiasi are as follows: 1. To enhance the accuracy of weather prediction and climate records in Antarctica through the assimilation of in situ and satellite data, with an emphasis on data provided by hyperspectral infrared sounders. The focus is on clouds, precipitation, and the mass budget of the ice sheets. The improvements in dynamical model analyses and forecasts will be used in chemical-transport models that describe the links between the polar vortex dynamics and ozone depletion, and to advance the understanding of the Earth system by examining the interactions between Antarctica and lower latitudes. 2. To improve our understanding of microphysical and dynamical processes controlling the polar ozone, by providing the first quasi-Lagrangian observations of stratospheric ozone and particles, in addition to an improved characterization of the 3D polar vortex dynamics. Techniques for assimilating these Lagrangian observations are being developed. A major Concordiasi component is a field experiment during the austral springs of 2008-10. The field activities in 2010 are based on a constellation of up to 18 long-duration stratospheric super-pressure balloons (SPBs) deployed from the McMurdo station. Six of these balloons will carry GPS receivers and in situ instruments measuring temperature, pressure, ozone, and particles. Twelve of the balloons will release drop-sondes on demand for measuring atmospheric parameters. Lastly, radiosounding measurements are collected at various sites, including the Concordia station

Effect of gravity wave temperature fluctuations on homogeneous ice nucleation in the tropical tropopause layer

“…The temperature time series used in this study are derived from data collected by two long-duration, superpressure balloons launched by the French Space Agency from Seychelles Islands (55.5 • E, 4.6 • N) in February 2010 in the framework of the pre-Concordiasi campaign (Rabier et al, 2010). The balloons flew at an altitude of about 19 km and achieved circumterrestrial flights, therefore sampling the whole equatorial circle.…”

Using MODIS land surface temperatures and the Crocus snow model to understand the warm bias of ERA-Interim reanalyses at the surface in Antarctica

“…Indeed, the latter is not produced by the analysis scheme but by a diagnosis from the surface temperature and the air temperature at the lowest atmospheric vertical level of IFS. Air temperature in the lowest atmospheric levels is constrained very weakly by the observations in the Antarctic Plateau because of both the scarcity in radiosoundings and the absence of low-level observations by satellite sounders (Rabier et al, 2010). Hence ERA-Interim T 2 m evolves almost freely under the combined influence of both surface temperature, derived from the surface energy budget, and temperature of higher levels in the atmosphere.…”

A simple kinematic model for the Lagrangian description of relevant nonlinear processes in the stratospheric polar vortex

“…We use in this work the ERA-Interim reanalysis data set produced by a weather forecast assimilation system developed by the European Centre for Medium-Range Weather Forecasts (ECMWF; Simmons et al, 2007). de la Cámara et al (2013) obtained encouraging results on the suitability of the ERA-Interim data set for Lagrangian studies of stratospheric motions in their comparison of parcel trajectories on the 475 K isentropic surface (around 20 km) using this data set and the trajectories of super-pressure balloons released from Antarctica by the VORCORE project during the spring of 2005 (Rabier et al, 2010).…”