J. Kapsomenakis

Climatology of Upper Air Temperature in the Eastern Mediterranean Region

The goal of this study is to contribute to the climatology of upper air temperature in the Eastern Mediterranean region, during the period 1965–2007. For this purpose, both radiosonde station and NCEP/NCAR reanalysis gridded datasets of upper air temperature were used for seven barometric levels at 850, 700, 500, 300, 200, 150, and 100 hPa. The impact of atmospheric circulation, by means of correlation between upper air temperature at different barometric levels and specific climatic indices such as Mediterranean Oscillation Index (MOI), North Sea Caspian Pattern Index (NCPI) and North Atlantic Oscillation Index (NAOI), is also quantified.

Climatology of Upper Air Temperature Over the Mediterranean. Trends and Variability

This study shed light on the long term air temperature changes in the troposphere over the Mediterranean. For this purpose, we utilized the radiosonde datasets for the barometric levels at 850, 700, 500, 300, 200, 150, and 100 hPa from seventeen meteorological stations within the Mediterranean, for the period 1965–2015. Besides, the gridded reanalysis products of upper air temperature for the respective barometric pressure levels from the European Centre for Medium-Range Weather Forecasts (ECMWF, ERA-Interim) and the National Center for Environmental Prediction–National Center for Atmospheric Research (NCEP–NCAR) were used and compared to stations’ datasets. We analyzed the trends and variability of upper air temperature on seasonal and annual basis. The impact of atmospheric circulation, by means of specific climatic indices such as Mediterranean Oscillation Index (MOI), North Sea Caspian Pattern Index (NCPI) and North Atlantic Oscillation Index (NAOI), was also examined. The results of our analysis indicate the anthropogenic forcing to climate variability, especially in lower/middle troposphere against upper troposphere over the Mediterranean.

An Assessment of Near Surface Ozone Over Europe from the Global CAMS Interim Reanalysis

ECMWF-Copernicus Atmospheric Monitoring Service (CAMS) interim reanalysis (CAMSiRA) provides global atmospheric composition fields at a horizontal resolution of ~80 km and 60 hybrid sigma-pressure levels from the surface up to 0.1 hPa which can be further used to serve as boundary conditions for regional air quality models over Europe and world-wide. Here we present an evaluation of near surface ozone reanalysis for the period 2003–2013 based on measurements at rural locations from the European Monitoring and Evaluation Program (EMEP) and the European Air Quality Database (AirBase). The CAMS interim reanalysis is also compared to a control run in order to assess the impact of assimilation on near surface ozone. The evaluation results are discussed in terms of the physical processes (transport and deposition) and the chemical processes (photochemical production and destruction) that control near surface ozone variability.

Regional Climate Models’ Future Simulations of Mean Air Temperature in Greece

The future projections of mean air temperature in Greece for the near future 2021–2050 and distant future 2071–2100 relative to the reference period 1961–1990 are studied, analyzing the simulations from 12 Regional Climate Models (RCMs) within the ENSEMBLES European project. The simulations of the future climate were carried out on annual and seasonal basis under SRES A1B. The results showed that the mean annual air temperature in Greece will present an increase of 1.5°C and 3.2°C, for the periods 2021–2050 and 2071–2100 respectively, based on the average of the 12 climatic simulations. This increase is projected to be larger during summer and smaller during winter. Additionally, the projected warming varies among the different climatic simulations concerning the continental regions of the country especially during summer.

Future Projections of Heat Waves in Greece. Extreme or Common Events

The aim of this study is to analyze and quantify the future projections of heat waves in Greece. For this reason, specific climatic indices were used in the analysis, and concern percentile and absolute indices defined by the CCl/CLIVAR/JCOMM Expert Team (ET) on Climate Change Detection and Indices (ETCCDI). The future projections (SRES A1B) of these indices were carried out using six regional climate models from the ENSEMBLES project, concerning the near future 2031–2050 and the far future 2071–2100 compared to the reference period 1961–2000. The findings of this analysis are discussed against recent recorded heat waves in order to understand if such events are even more extreme or common in the future.

Estimation of precipitation change over Greece during the 21st century, using RCM simulations

In the present study, an estimation of the future change in precipitation within the 21st century was carried out for the 12 climatic zones of Greece. The estimation is based on the results of 12 Regional Climate Models (RCM) simulations of the ENSEMBLES Program. The precipitation is projected to decrease mildly in the near future (2021-2050) and moderately in the far future (2071-2100) by 5% and 20% respectively for the area of Greece. The decrease seems to be most prominent during spring and summer, less prominent during winter. The autumn precipitation is projected to increase mildly in the near future and to decrease mildly in the far future. The projected precipitation change in Greece is expected to result in drastic changes on the ground water balance and on several sectors of human activity and environment parameters, as well.