Verification of a coupled atmosphere-ocean model using satellite observations over the Adriatic Sea

Abstract

Abstract.Verification of the EBU-POM regional atmosphere-ocean coupled model (RAOCM) was carried out using satellite observations of SST and surface winds over the Adriatic Sea. The atmospheric component has a horizontal resolution of 0.125 degree (approximately 10 km) and 32 vertical levels, while the ocean component has a horizontal resolution of approximately 4 km with 21 sigma vertical levels.Verification of the forecasted SST was performed for 15 forecasts during 2006, each of them seven days long. These forecasts coincide with the operating cycle of the Adriatic Regional Model (AREG), which provided the initial fields and boundary conditions for the ocean component of EBU-POM. Two sources of data were used for the initial and boundary conditions of the atmosphere: primary data were obtained from the European Center for Medium-Range Weather Forecasting (ECMWF), while data from National Centers for Environmental Prediction (NCEP) were used to test the sensitivity to boundary conditions. Forecast skill was expressed in terms of BIAS and root mean square error (RMSE). During most the of verification period, the model had a negative BIAS of approximately −0.3 • , while RMSE varied between 1.1 • and 1.2 • . Interestingly, these errors did not increase over time, which means that the forecast skill did not decline during the integrations.The 10-m wind verification was conducted for one period of 17 days in February 2007, during a strong bora episode, for which satellite estimates of surface winds were available. During the same period, SST measurements were conducted twice a day, which enabled us to verify diurnal variations of SST simulated by the RAOCM model. Since ECMWF's deterministic forecasts do not cover such a long period, we decided to use the ECMWF analysis, i.e. we ran the model in hindcast mode. The winds simulated in this analysis were Correspondence to: V. Djurdjevic (vdj@ff.bg.ac.yu) weaker than the satellite estimates, with a mean BIAS of −0.8 m/s.

Climate change impacts on marine water quality: The case study of the Northern Adriatic sea

“…Although these extremes may be affecting very small portions of each water body, we think that this representation is more adapt to convey the information pertinent to this work, and this caveat should be kept in mind when looking at the figure. For example, in agreement with other studies (see Djurdjevic and Rajkovic, 2008), sea temperature extremes are denoting a trend toward an increase in most of the considered water bodies during all seasons, with a lower rate of increment during spring. The distribution of the mean salinity extremes in the water bodies presents a general decrease in almost all water bodies and seasons.…”

“…The Regional Climate Models (RCMs) COSMO-CLM (Bucchignani et al, 2013) and EBU-POM (Djurdjevic and Rajkovic, 2008), nested in the SINTEX G and CMCC-CM models respectively, provided future projections of temperature, precipitation and wind variations at the Mediterranean scale that were successively used as input for a suite of hydrodynamic, wave and biogeochemical models running at the more detailed Adriatic and North Adriatic scale. Within the described chain, the input of water coming from rivers and lagoons was considered as constant and the current values were used for both the reference and future scenarios.…”

Prediction of the European beech (Fagus sylvatica L.) xeric limit using a regional climate model: An example from southeast Europe

“…The atmospheric module has been connected to a global model to make seasonal predictions (Fennessy and Shukla, 1999). In addition to a downscaling assessment in the Mediterranean and southern Europe (Djurdjević and Rajković, 2008), it has also been used for downscaling in the United States (Xue et al, 2007). To overcome the bias problem in addressing differences between the observed and modelled climate data, the so-called "delta change approach", was used (Graham et al, 2007;Ruml et al, 2012).…”

Assessment of meteorological climate models as inputs for coastal studies

“…The model is free surface, computes the complete thermodynamics, and has a secondorder Mellor-Yamada 2.5 turbulence closure scheme. The two models are coupled through the exchange of atmospheric surface fluxes and sea surface temperature (SST) (Djurdjevic and Rajkovic 2008).…”