Comparison of 10-m Wind Forecasts from a Regional Area Model and QuikSCAT Scatterometer Wind Observations over the Mediterranean Sea

Abstract

Surface wind forecasts from a limited-area model [the Quadrics Bologna Limited-Area Model (QBOLAM)] covering the entire Mediterranean area at 0.1° grid spacing are verified against Quick Scatterometer (QuikSCAT) wind observations. Only forecasts within the first 24 h in coincidence with satellite overpasses are used. Two years of data, from 1 October 2000 to 31 October 2002, have been considered, allowing for an adequate statistical assessment under different wind conditions. This has been carried out by analyzing the fields of the mean wind vectors, wind speed bias, correlation, difference standard deviation, steadiness, gustiness, and mean wind direction difference, in order to investigate spatial variability. Statistics have been computed on a seasonal basis. A comparison of satellite and forecast winds with measurements from three buoys was also performed. Some critical areas of the Mediterranean Sea where wind forecast quality is lower than average have been identified. Such areas correspond to semienclosed basins surrounded by important orography and to small regions at the lee side of the main islands. In open-sea regions the model underestimates wind strength from about 0.5 m s−1 in spring and summer to 1.0 m s−1 in winter, as evidenced by the existing biases against scatterometer data. Also, a wind direction bias (scatterometer minus model) generally between 5° and 15° exists. A survey of the identified and likely sources of forecast error is performed, indicating that orography representation plays an important role. Numerical damping is identified as a likely factor reducing forecast wind strength. The need for a correction scheme is envisaged to provide more accurate forcing for numerical sea state forecasting models, wind energy evaluation, and latent and/or sensible heat exchanges.

Mistral and Tramontane wind speed and wind direction patterns in regional climate simulations

“…Accadia et al (2007) and Ruti et al (2008) found QuikSCAT to show higher wind speeds than observations from two buoys in the Gulf of Lion area. Therefore, part of the simulation bias could be explained by an overestimation of wind speed by QuikSCAT.…”

“…QuikSCAT has been used for wind speed analysis in the Mediterranean (e.g., Accadia et al 2007;Ruti et al 2008), as well as in many other regions (Dorman et al 2013;Risien and Chelton 2006). QuikSCAT data have been validated with buoy data in the Gulf of Lion for the period 2000(Accadia et al 2007Ruti et al 2008), showing a bias of about 0.4-0.9 m/s, and an RMSE of about 1.5 m/s. Ruti et al (2008) found the bias of QuikSCAT compared to buoys to be higher for high wind speeds.…”

Numerical models sea surface wind compared to scatterometer observations for a single Bora event in the Adriatic Sea

“…The interpolation method is pure Laplacian, to avoid excessive data smoothing: it has been demonstrated not to change the wind speed and direction statistics (Accadia et al, 2007). LAMs winds have been mapped to the same grid with the nearest neighbour algorithm.…”

“…Accadia et al (2007) analysed the seasonal fields of several statistics parameters, using two years of QuikSCAT L2B 25 km observations and the wind field forecasts produced by the Quadrics Bologna Limited-Area Model (QBOLAM) over the Mediterranean Sea on a 0.1…”

SIMM: An integrated forecasting system for the Mediterranean area

“…The first point has been investigated in a systematic comparison of QBOLAM 10 m winds against scatterometer observations (Accadia et al, 2007). It was found that in open sea regions the meteorological model underestimates wind strength from about 0.5 m s −1 in spring and summer to 1.0 m s −1 in winter.…”