engleski

Can regional climate models realistically reproduce the near-surface wind variability over broader Adriatic region?

Higher resolution of regional climate models (RCMs) is expected to contribute to a better representation of the small-scale variability than in global climate models (GCMs), especially in the coastal regions and over complex terrains, like the Adriatic region. Hence, the aim here is to identify if there is any added value in the near-surface wind when increasing horizontal resolution of RCMs using a multi-model ensemble composed of CORDEX RCM simulations at 50 km and 12.5 km resolution, COSMO-CLM convection-parametrizing model at 12.5 km and COSMO-CLM convection-resolving model at 2.2 km resolution. Surface station observation data and satellite QuikSCAT data have been compared against the (sub-)daily model output obtained from available simulations. The evaluation is carried out for both instantaneous wind speed and it's frequency distribution depending on the score elaborated. The standard scores for instantaneous wind speed are standard deviation, correlation coefficient and root-mean-square deviation summarized by the Taylor diagram. The frequency distribution is analyzed with Perkins skill score and wind rose. RCMs are also explored in terms of the skill in reproducing specific wind regimes over the Adriatic region (e.g. the bora wind) where large spread in the RCM ensemble is found. Yet, when considering the results of the EOF analysis, models frequently give the right angle of the bora flow, correctly reproducing the observed wind direction. The wind magnitude is overestimated, especially in strong wind cases. Moreover, the power spectrum is analysed when the sub-daily data is available. Power spectrum shows two large peaks at 12 h and 24 h period, also present in measurements, exposing the correct temporal variability of the simulated wind speed. Results of this work motivate the next steps where wind field from an ensemble of RCMs forced by the GCMs in historical and future climate runs will be examined.

Adriatic region ; CORDEX ; Regional climate models ; Convection-resolving models

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