RegCM3_25 RegCM3_10

Driving Field ECHAM5 Nested from 25km

Number of grid points 192 x 108 128x 144

Number of vertical levels 18 18

Integration time Jan 1, 1950 - Dec 31, 2000 Jan 1, 1950 - Dec 31, 2000

Time step 60 sec 30 sec

Terrain and landuse resolution 10 min 3 min

Cumulus Scheme Grell MIT-Emanuel

Convective Closure Scheme Fritsch & Chappell -

Planetary Boundary Layer Scheme Holtslag Holtslag

Acknowledgments: This research has been co-financed by the European Union (European Social Fund– ESF) and Greek national funds through the Operational Program "Education and Lifelong Learning" of the National Strategic Reference Framework (NSRF) - Research Funding Program: Thalis. Investing in knowledge society through the European Social Fun

“CCSEAWAVS: Estimating the effects of Climate Change on SEA level and WAve climate of the Greek seas, coastal Vulnerability and Safety of coastal and marine structures”www.thalis-ccseawavs.web.auth.gr

Climate ModelThe model used for the regional climate simulations in this work is RegCM3. RegCM was originally developed at the National Center for Atmospheric Research (NCAR) and has been mostly applied to studies of regional climate and seasonal predictability around the world. Two long term regional climate simulations were carried out, one over Europe (25x25km resolution) and one over the Greek Area (10x10km resolution). The model domains can be seen in Figure 1 and 2 and the model setup is presented in Table 1 .

Table 1: Model Setup

DiscussionThe RegCM3_10, as well as RegCM3_25 produce realistic monthly wind direction patterns (Wind Roses). The partitioning of the total variance of wind speed among different wind direction, separated in classes of 22.5 degree, are generally reproduced by the models while the mean wind speed is systematically overestimated for the majority of the wind directions. The RegCM3 projections show an overall agreement to extreme wind speed. The high-resolution simulations (RegCM3_10) of the 75th, 90th and 95th percentile of max and mean wind speed present the best results (Figure 4) and the higher R2 values.

Extreme values

Fig. 4a: Model vs Observation percentiles (75th - red, 90th - blue, 95th - green) for max wind speed

Fig. 4b: Model vs Observation percentiles (75th - red, 90th - blue, 95th - green) for mean wind speed

Aristotle University of Thessaloniki, Dept. of Meteorology and Climatology, Thessaloniki, Greece

Effects of regional climate model spatial resolutionon 10m wind field over the Aegean Sea

I. Tegoulias, Ch. Anagnostopoulou, K. Tolika, K. Velikou, and Ch. Vagenas

13th EMS Annual Meeting & 11th European Conference on Applications of Meteorology (ECAM) | 09 – 13 September 2013 | Reading, United Kingdom

Percentage (%) of Wind Direction

Mean Speed of Wind Directions

In order to evaluate RegCM3 and analyze the advantages of high resolution simulations over the Aegean Sea, the simulated values of 10 meter u and v components of wind speed are compared to the respective observed values at 15 Greek meteorological stations from the network of the Hellenic National Meteorological Service (Fig. 3).

Fig. 2: Simulation domain (10x10km)

Fig. 1: Simulation domain (25x25km)

Fig. 3: Location of the meteorological stations

MODELS vs OBSERVATION R2

MAX WIND SPEED JAN MAR JUN SEP

Percentile Mod10 Mod25 Mod10 Mod25 Mod10 Mod25 Mod10 Mod25

75th 0.30 0.15 0.30 0.15 0.37 0.22 0.58 0.2890th 0.14 0.05 0.31 0.17 0.36 0.22 0.56 0.24

95th 0.09 0.05 0.20 0.10 0.28 0.17 0.56 0.24

MODELS vs OBSERVATION R2

MEAN WIND SPEED JAN MAR JUN SEP

Percentile Mod10 Mod25 Mod10 Mod25 Mod10 Mod25 Mod10 Mod25

75th 0.29 0.28 0.55 0.44 0.68 0.55 0.76 0.5590th 0.24 0.17 0.52 0.37 0.67 0.59 0.79 0.53

95th 0.17 0.14 0.42 0.27 0.63 0.51 0.82 0.53