The following conclusions were drawn from the simulations: 1. We found that in RCA3 simulations driven by eight GCMs (with one exception) the mean seasonal cycles of atmospheric variables, like 2 m air temperature, SLP, 10 m wind speed, 2 m specific humidity, total cloudiness and precipitation over the Baltic Sea, their variability and mean north-south
gradients, are qualitatively well simulated. However, a detailed, quantitative assessment showed that the biases are considerable. In most simulations 2 m air temperatures are underestimated during summer and overestimated during winter. During all seasons the 10 m wind speed is underestimated partly because of the horizontal resolution of the atmospheric
model RCA3 of 50 km, learn more which is too coarse for the Baltic Sea region. Although the positive precipitation bias is significantly selleck kinase inhibitor improved compared to earlier downscaling experiments when the latest versions of RCA3 and of the GCMs were used, the annual mean precipitation in most of the GCM driven simulations is still overestimated. Given the above-mentioned biases, and as RCA3 in dynamical downscaling experiments makes use of SST and sea ice data from the GCMs, which suffer from the coarse resolution, the results of the RCA3 scenario simulations should not be used as forcing for Baltic Sea models. In summary, it is important to develop fully coupled atmosphere-ice-ocean models with high quality in present climate simulations to avoid the impact of biases on model sensitivity in climate change simulations. We thank our colleagues at SMHI, Anders Ullerstig and Ulf Hansson, for their technical support in performing the RCA3 and RCAO simulations respectively. “
“The Advanced Scatterometer (ASCAT) on the Meteorological Operational (MetOp) satellite of the European Organization for
the Exploitation of until Meteorological Satellites (EUMETSAT) is a C band radar, whose primary objective is to determine the wind field at the ocean surface (Figa-Saldaña et al. 2002). Wind scatterometers are instruments that are used to infer data on wind speed and direction from radar measurements of the sea surface. They rely for their operation on the fact that winds blowing over the sea influence the radar backscattering properties of the surface in a manner that is related to wind speed and wind direction (Stoffelen 1998, Gelsthorpe et al. 2000, Portabella 2002, Chelton & Freilich 2005). The EUMETSAT ASCAT wind products provide the wind speed and direction measurements at 10 m above the sea surface. Data is provided either with a grid spacing of 12.5 km and a spatial resolution of 25 km or with a grid spacing of 25 km at a 50 km resolution across and along two 550-km wide swaths on either sides of the nadir track.