Evaluation of atmospheric instability indices in Greece

Abstract. The potential of instability indices in assessing atmospheric instability is examined for the areas of Attica, Thessaly and Central Aegean and Crete, Greece. Generally, many indices have been developed to estimate the troposphere's stability for forecasting purposes. At this study several instability indices, commonly used in Meteorology, are computed based on radiosonde data. Firstly, the indices are computed for several months based on the 00:00 and 12:00 UTC radiosonde data during the period 1981–2003. Statistical methods were used to compare and test the effectiveness of these indices in the described area using meteorological data from seventeen meteorological stations of Greece. Thus, the potential of monitoring the atmospheric instability conditions is examined. The next stage of this study is an effort to test the thresholds of the existing indices in order to improve the results of these indices. It seems that this effort can make a good simulation to the assessment of instability, contributing to local level weather forecasting.