Aquarius: The Instrument and Initial Results

Aquarius was launched on June 10, 2011 aboard the Aquarius/SAC-D observatory and the instrument has been operating continuously since the initial turned-on was completed on August 25. The initial observed antenna temperatures were close to predicted and the first salinity map was released in September. In order to map the ocean salinity field, Aquarius includes several special features such as the inclusion of a scatterometer to provide a roughness correction, measurement of the third Stokes parameter to correct for Faraday rotation, and fast sampling to mitigate the effects of RFI. This paper provides an overview of the instrument and an example of initial results. Details are covered in subsequent papers in the session on Aquariu

Aquarius Radiometer Status

Aquarius was launched on June 10, 2011 as part of the Aquarius/SAC-D observatory and the instrument has been operating continuously since being turned on in August of the same year. The initial map of sea surface salinity was released one month later (September) and the quality of the retrieval has continuously improved since then. The Aquarius radiometers include several special features such as measurement of the third Stokes parameter, fast sampling, and careful thermal control, and a combined passive/active instrument. Aquarius is working well and in addition to helping measure salinity, the radiometer special features are generating new results

Interannual long equatorial waves in the tropical Atlantic from high-resolution ocean general circulation model experiment in 1981-2000

International audienceWe investigate the tropical Atlantic vertical structure variability (1981-2000) based on the CLIPPER ocean general circulation model (OGCM). We aim at determining to what extent the observed interannual variability can be explained by the low-frequency wave dynamics. The linear vertical modes of the OGCM climatological stratification are estimated along the equator. The baroclinic mode contributions to surface zonal current and sea level anomalies are calculated and analyzed at interannual timescales. The second baroclinic mode is the most energetic. The first (third) mode exhibits a variability peak in the west (east). The summed-up contribution of the high-order baroclinic modes (4-6) is as energetic as the gravest modes and is largest in the east. Wave components are then derived by projection onto the associated meridional structures. The effect of longitudinal boundaries near the equator is taken into consideration. Equatorial Kelvin and Rossby waves propagations, with phases speed close to the theory, are identified for the first three baroclinic modes. The comparison with a multimode linear simulation corroborates the propagating properties of the OGCM waves coefficients. An estimation of the meridional boundary reflection efficiency indicates that wave reflections take place at both boundaries. A 65% reflection efficiency is found at the eastern boundary. Our study suggests that low-frequency wave dynamics is to a large extent at work in the tropical Atlantic. On the basis of what is known on the Pacific El Niño-Southern Oscillation mode this may provide a guidance for investigating ocean-atmosphere mechanisms that can lead to the Atlantic zonal equatorial mode

State of the Climate in 2012

International audienceEditors note: For easy download the posted pdf of the State of the Climate for 2012 is a very low-resolution file. A high-resolution copy of the report is available by clicking here. Please be patient as it may take a few minutes for the high-resolution file to download