Vízügyi Közlemények, 2004 (86. évfolyam)
1-2. füzet - Szalai Sándor-Bella Szabolcs: Az aszályos 2003. év
Az aszályos 2003. év IRODALOM 215 McKee, T. B.-Doesken, N. J.-Kleist, J .: The Relationship of Drought Frequency and Duration to Time Scales. Proceedings of the 8th Conference on Allpied Climatology. Anaheim, CA, USA. 1993. Pálfai I.: A 2003. évi aszály értékelése. Vízpart, 2003. Szalai. S.-Szinell, Cs.-Zoboki, J.: Drought Monitoring in Hungary. Proceedings of the Expert meeting of WMO on Drought Early Warning System, WMO, Geneva. 2000. * * * The drought of the year 2003 by Dr. Sándor SZALAI and Szabolcs BELLA, meteorologists At the National Meteorological Service of Hungary (OMSZ) the drought is characterised by indices SPI and PDSI and by the relative evaporation. Since there is no perfect index of drought it is favourable to use several indices. In this study the map of the index PAI for 2003 (Figure 1) is used on the basis of SPI and PDSI investigations. The analysis was carried out in four directions: First the drought was followed for four stations in the period August 2002 and August 2003. Next the 1, 2, 6, 12, 18 and 24 month periods, closing in August, were analysed for the past decade. The next step was to study the spatial variation of the large droughts. In order to be able to interpret and apply SPI for various periods, the relationship between SPI and the upper half metre dept of the soil was investigated. Finally the time series of various drought indices were analysed for the period starting in the beginning of the last century. The history of the drought of 2003 was studied on the basis of the data of the stations at Szeged, Debrecen, Mosonmagyaróvár and Pécs. These stations were selected because the 2003 map of Index PAI was available for such regions, and these cities also represent different geographic situations and they are located at considerable distances apart from each other. The month March was dry in the whole country, but extreme precipitation was measured in the western part. In the summer, however, the eastern part of the country was drier, and the western part wetter. We have shown the ways how the precipitation distribution affects various characteristic processes (Tables 2-5). The essence of these tables is that a month with higher precipitation relieves the drought partially only, but does not have effect on the lasting long-term process of drying out. The short-term drought of 2003 did not occur in all places of the country and not in all times. However, there is a long-term drought process over the whole Country. Monthly precipitation maps (Figures 2, 3) were used to elucidate the drying processes of various time scales. Next, the 1, 2, 6, 12, 18 and 24 month periods, closing in August, were analysed for the past decade, in which there were several larger droughts. The analysis was made for the above-mentioned four stations (Tables 6-9). It can be generally stated
