This retrospective study aims to search out the influence of temperature, atmospheric pressure and humidity on the frequency of epistaxis. The study includes 701 patients who have suffered from epistaxis and have been treated in the ENT department of the University of Ioannina Hospital, during the years 1995 and 1996. The statistical methods used are simple linear correlation and linear stepwise regression analysis. The results of simple correlation analysis showed that the daily number of epistaxes depends mainly on mean, maximum and minimum temperature and water vapour pressure. The corresponding correlation coefficients are statistically significant, indicating an influence of weather on epistaxis up to 9% of its total variance. By applying stepwise regression analysis, we managed to increase the linear correlation coefficient and the corresponding amount of variance of epistaxis explained by meteorological factors. This percentage was found to approach 20% for the cold period and 10% for the warm period of the year.

The intra-annual variation of precipitation amount and duration and their spatial distribution during the year are studied on a 10 day basis for the Greek region, using S-mode and T-mode factor analysis. (i) For the intra-annual variation of precipitation amount, two modes were revealed: the first shows one broad maximum during the conventional winter in stations affected by the sea; the second presents two maxima, the first during late autumn-early winter and the second during late spring, corresponding to the northern mainland stations. (ii) For the spatial distribution of precipitation, three main patterns were revealed: the first one is the 'winter' pattern, with the maximum over the west windward area; the second is the 'summer' pattern, with a maximum over the north inland region; and the third is the 'autumn' pattern, with the maximum over northwestern Greece. (iii) For precipitation duration, two types of intra-annual variation were revealed. The first one is similar to the first of the analysis for precipitation amount; the second presents two maxima, the first during the beginning of December and the second during the middle of February, corresponding to the areas of northwestern and northeastern Greece. (iv) For the spatial distribution of precipitation duration, three main patterns were revealed: the first is the 'summer' pattern, which is similar to the second of the analysis for precipitation amount; the second is the 'winter' pattern, with the spatial maximum located over the eastern mainland and western Crete; finally, the third one is the 'autumn' pattern, with the maximum in northwestern Greece. During the third 10 day period of October and the second 10 day period of February, precipitation seems to present singularities, possibly due to fluctuations in atmospheric circulation. The above intra-annual variations and spatial distribution patterns are connected to the seasonal variations of the depression trajectories, the atmospheric instability, the influence of sea-surface temperature as a cyclogenesis factor, and the windward or leeward character of the various areas (orographic effect).

The variability of sensible and latent heat fluxes in the Mediterranean Sea and their effect on precipitation in the Greek area during the winter months are investigated for the 39 year period 1959-97 by using multivariate statistical methods. First, factor analysis is applied, mainly as a data reduction tool, and then canonical correlation analysis is applied on the factor scores time series of the two pairs, i.e. sensible heat flux-precipitation and latent heat flux-precipitation, to reveal their interrelations. The results show there is a statistically significant relationship between sensible and latent heat fluxes over the western Mediterranean Sea and precipitation in the western windward areas of Greece. The sensible and latent heat fluxes in the western Mediterranean Sea contribute significantly to depression development. The depressions formed advect cold and dry air masses over the western Mediterranean, reinforcing these sensible and latent heat fluxes. Furthermore, these depressions lead to a southerly or southwesterly airflow over Greece. This flow, along with the existence of potential instability, significantly contributes to precipitation formation in the windward areas of western Greece and also in the islands of the eastern Aegean Sea.

BackgroundClimatic or meteorological condition changes have been implicated in the pathogenesis of Idiopathic Sudden Sensorineural Hearing Loss (ISSHL). We investigated the seasonal distribution of ISSHL and evaluated the influence of meteorological parameters (such as temperature, humidity, and atmospheric pressure), their variation and covariation on the incidence of the disease.MethodsA total of 82 cases of ISSHL, admitted to our department over a five-year period, were enrolled in the study. Seasonal distribution of the disease was investigated by dividing the year in four seasons. Meteorological data included daily values of 13 distinct parameters recorded at the meteorological station of the University of Ioannina during this period. A relationship between each meteorological variable and the incidence of ISSHL was investigated by applying (χ2) test on data from 13 contingency tables as well as by using logistic regression and t-test approaches. In addition, the influence of different weather types on the incidence of ISSHL was investigated using Cluster Analysis in order to create eight clusters (weather types) characteristic for the prefecture of Ioannina.ResultsThe results of the study could not indicate any seasonal distribution of the disease. The incidence of ISSHL could not be significantly correlated either to any distinct meteorological parameter or to any specific weather type.ConclusionsMeteorological conditions, such as those dominating in the Northwestern Greece, and/or their changes, have no proven effect on the incidence of ISSHL.

Cases of atmospheric circulation evolution favouring the occurrence of desert aerosol episodes (DAEs) over the broader Mediterranean region were investigated using an objective and dynamic algorithm, with daily satellite data for the period 2000-2013. After identifying strong and extreme DAEs, at a 1 • × 1 • geographical-cell level, 255 dust aerosol episode days (DAEDs) and 148 cases of consecutive DAEDs, namely desert aerosol episode cases (DAECs), are defined. For each DAEC, the evolution of the lower tropospheric circulation 1 and 2 days before, during the initiation and after the cessation of the DAEC, is considered. S-mode factor analysis and k-means cluster analysis are applied on mean sea-level pressure and 700 hPa geopotential height fields obtained from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis Project, classifying the 148 cases of atmospheric-circulation evolution into six homogeneous and discrete clusters. The mean intra-annual variation of the DAECs reveals a primary maximum in May (18.9%), and their mean annual number is equal to 11.4 DAECs. On a seasonal basis, the highest percentage of the DAECs is found in spring (51.4%). Maximum duration of the DAECs is 7 days, with 58.8% lasting 1 day. Annually, the mean monthly number of the DAEs varies from 35.8 (September) to 58.0 (April). The western parts of the Mediterranean are affected by the DAEs when cyclonic conditions prevail in the western Mediterranean and northwestern Africa. In contrast, the central and eastern parts of the study region are affected by dust storms when a low-pressure system in the central Mediterranean or central Europe and an anticyclone in the eastern Mediterranean prevail. As to the mean regional intensity (aerosol optical depth at 550 nm) the strong DAEs vary from 0.67 to 0.77, while the extremes vary from 1.14 to 2.06. Generally, strong DAEs are more frequent than extremes (in five out of six clusters).