Improved near real time surface wind resolution over the Mediterranean Sea

Abstract

Abstract.Several scientific programs, including the Mediterranean Forecasting System Toward Environmental Predictions (MFSTEP project), request high space and time resolutions of surface wind speed and direction. The purpose of this paper is to focus on surface wind improvements over the global Mediterranean Sea, based on the blending near real time remotely sensed wind observations and ECMWF wind analysis. Ocean surface wind observations are retrieved from QuikSCAT scatterometer and from SSM/I radiometers available at near real time at Météo-France. Using synchronous satellite data, the number of remotely sensed data available for each analysis epoch (00:00 h; 06:00 h; 12:00 h; 18:00 h) is not uniformly distributed as a function of space and time. On average two satellite wind observations are available for each analysis time period. The analysis is performed by optimum interpolation (OI) based on the kriging approach. The needed covariance matrixes are estimated from the satellite wind speed, zonal and meridional component observations. The quality of the 6-hourly resulting blended wind fields on 0.25 • grid are investigated trough comparisons with the remotely sensed observations as well as with moored buoy wind averaged wind estimates. The blended wind data and remotely wind observations, occurring within 3 h and 0.25 • from the analysis estimates, compare well over the global basin as well as over the sub-basins. The correlation coefficients exceed 0.95 while the rms difference values are less than 0.30 m/s. Using measurements from moored buoys, the high-resolution wind fields are found to have similar accuracy as satellite wind retrievals. Blended wind estimates exhibit better comparisons with buoy moored in open sea than near shore.

Analysis of Wave Height Variability Using Altimeter Measurements: Application to the Mediterranean Sea

“…Highresolution wind fields were produced from atmospheric models (Sotillo et al 2005) within the Hindcast of Dynamic Processes of the Ocean and Coastal Areas of Europe (HIPOCAS) project. Blended wind products using both atmospheric model and satellite data are currently in development (Bentamy et al 2007) through the Mediterranean Forecasting System Toward Environmental Predictions (MFSTEP) project. An atlas of waves for the Mediterranean Sea is now available, using a 10-yr (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002) archive of ECMWF wind and wave model data (Medatlas Group 2004).…”

Matching ASCAT and QuikSCAT winds

“…[6] There have been numerous efforts to construct a combined multisatellite data set of winds [Milliff et al, 1999;Zhang et al, 2006;Bentamy et al, 2007, Atlas et al, 2011. These efforts generally rely on utilizing a third reference product such as passive microwave winds or reanalysis winds to which the individual scatterometer data sets can be calibrated.…”

Statistics of wind and wind power over the Mediterranean Sea

“…The surface wind vector is characterized by a large spatial and temporal variability. Even though the seasonal signal is quite common to several sub-basins of the Mediterranean Sea, significant regional changes in its amplitude and phase are depicted (BENTAMY et al, 2007). The highest mean winds are associated with the mistral event, while the lowest are located in eastern area.…”

“…The highest wind conditions (exceeding 10m/s) are mostly found in Gulf of Lion and at Gibraltar strait. There is a factor 4 between northern and southern regions and highly related to wind characteristics in the Mediterranean sea (BENTAMY et al, 2007). Their occurrences retrieved from remotely sensed data are 2447, 924, 216, and 937 during winter, spring, summer, and fall seasons, respectively.…”