Performance of the Adriatic Sea and Coast (AdriSC) climate component – a COAWST V3.3-based coupled atmosphere-ocean modelling suite: atmospheric part 

Abstract

Abstract. In this evaluation study, the coupled atmosphere-ocean Adriatic Sea and Coast (AdriSC) climate model, which was implemented to carry out 31-year long evaluation and climate projection simulations in the Adriatic and northern Ionian seas, is briefly presented. The kilometre-scale AdriSC atmospheric results, derived with the Weather Research and Forecasting (WRF) 3-km model for the 1987–2017 period, are then thoroughly compared to a comprehensive publicly and freely available observational dataset. The evaluation shows that overall, except for the summer surface temperatures which are systematically underestimated, the AdriSC WRF 3-km model has a far better capacity to reproduce the surface climate variables (and particularly the rain) than the WRF regional climate models at 0.11° of resolution. In addition, several spurious data have been found in both gridded products and in situ measurements which thus should be used with care in the Adriatic region for climate studies at local and regional scales. Long-term simulations with the AdriSC climate model, which couples the WRF 3-km model with a 1-km ocean model, might thus be a new avenue to substantially improve the reproduction, at the climate scale, of the Adriatic Sea dynamics driving the Eastern Mediterranean thermohaline circulation. As such it may also provide new standards for climate studies of orographically-developed coastal regions in general.

Performance of the Adriatic Sea and Coast (AdriSC) climate component – a COAWST V3.3-based coupled atmosphere-ocean modelling suite: ocean part

“…(1) a deficit of solar radiation by the AdriSC atmospheric model which have shown a systematic temperature underestimation (up to 5 °C) during the summer (Denamiel et al, 2021b), (2) some intrinsic shortcomings of the AdriSC ocean model such as vertical mixing, turbidity, etc. or (3) the fact that the river temperatures are imposed by taking the ERA-Interim skin temperatures the closest to the river estuaries, which is a crude approximation particularly for the largest Adriatic rivers such as the Po or the Albanian rivers.…”

“…The Adriatic Sea and Coast (AdriSC; Denamiel et al, 2019) climate component is built around a modified version of the Coupled Ocean-Atmosphere-Wave-Sediment-Transport (COAWST V3.3) modelling system (Warner et al, 2010) in order to provide kilometre-scale hourly results for 31-year long simulations as described in Denamiel et al (2021b). In this study, the ocean results of the evaluation run for the 1987-2017 periodwhich can be easily accessed and retrieved via the web interface https://vrtlac.izor.hr/ords/adrisc/interface_form (Ivanković et al, 2019;Denamiel et al, 2021b) are presented in detail while the set-up of the AdriSC climate model is summarized in Table 1. Hereafter, the Adriatic atmospheric processes are simulated with the Weather Research and Forecasting (WRF v3.9.1.1) model (Skamarock et al, 2005) for a 3-km grid covering the entire Adriatic and northern Ionian Sea (Fig.…”

“…As described in Denamiel et al (2021b), the COAWST model is compiled with the Intel 17.0.3.053 compiler, the PNetCDF 1.8.0 library and the MPI library (mpich 7.5.3) on the European Centre for Middle-range Forecast's (ECMWF's) High Performance Computing Facility (HPCF). Furthermore, the ecFlow work flow package used by all ECMWF operational suites is set-up to automatically and efficiently run the AdriSC long-term simulations in a controlled environment.…”

“…[Table 1] For a complete presentation of the AdriSC climate component, a detailed description of the set-up of both atmospheric and oceanic models is necessary. Since the evaluation of the AdriSC climate model is done separately for the atmosphere (Denamiel et al, 2021b) and the ocean, only the set-up of the AdriSC ROMS 3-km and ROMS 1-km models is described below.…”

“…The high-resolution atmosphere-ocean Adriatic Sea and Coast (AdriSC) climate model (up to 3-km in the atmosphere and 1-km in the ocean) was thus implemented and a 31-year long evaluation simulation was performed for the 1987-2017 period. In this work, the performance of the AdriSC ocean coastal model is evaluated while the skill assessment of the AdriSC atmospheric kilometre-scale model is done in a separate study (Denamiel et al, 2021b). In general, a proper evaluation of a high-resolution climate model is not a trivial task and most often the biggest challenge turns out to be the availability, incompleteness and scarcity of observational data, as well as the imperfections of the observing systems which set further limits on the evaluation process (Horak et al, 2021).…”