Objective Definition of Climatologically Homogeneous Areas in the Southern Balkans Based on the ERA5 Data Set

Abstract

An objective definition of climatologically homogeneous areas in the southern Balkans is attempted with the use of daily 0.25° × 0.25° ERA5 meteorological data of air temperature, dew point, zonal and meridional wind components, Convective Available Potential Energy, Convective Inhibition, and total cloud cover. The classification of the various grid points into climatologically homogeneous areas is carried out by applying Principal Component Analysis and K-means Cluster Analysis on the mean spatial anomaly patterns of the above parameters for the 10-year period of 2008 to 2017. According to the results, 12 climatologically homogenous areas are found. From these areas, eight are mainly over the sea and four are mainly over the land. The mean intra-annual variations of the spatial anomalies of the above parameters reveal the main climatic characteristics of these areas for the above period. These characteristics refer, for example, to how much warmer or cloudy the climate of a specific area is in a specific season relatively to the rest of the geographical domain. The continentality, the latitude, the altitude, the orientation, and the seasonal variability of the thermal and dynamic factors affecting the Mediterranean region are responsible for the climate characteristics of the 12 areas and the differences among them.

Spatiotemporal variability of total cloud cover measured by visual observation stations and their comparison with ERA5 reanalysis over South Korea

“…The wind at any given location depends highly on the regional topographic features (Johansson and Chen, 2003). The hourly average wind speed and direction always show a wider difference than the instantaneous speed and direction (Lolis et al ., 2018). We took the average wind speed from 2010 to 2019 and recorded its approximate variation from 0.4 m/s to 2.6 m/s.…”

On the Influence of the Prevailing Weather Regime on the Atmospheric Pollution Levels in the City of Ioannina

“…In Greece, many studies have been conducted concerning the connection between air quality in the two biggest cities, i.e., Athens and Thessaloniki, and the local and/or large-scale meteorological conditions [1][2][3][4][5]. Furthermore, the classification of Weather Types (WTs) is a research subject which has been extensively studied by many researchers in the past [6][7][8]. A weather type (WT) corresponds to a specific meteorological condition prevailing over a geographical area, associated with a specific characteristic mode of large-scale atmospheric circulation.…”