THE ASSESSMENT OF SOME HYDROMETEOROLOGICAL ARIDITY INDICES IN THE BEND SUBCARPATHIANS AND PERIPHERAL ZONES PUBLISHEDViorel Chendeş, Sorin Cheval, Sorina Dumitru
This study tackles an interdisciplinary water resources issue, comprising one of the joint researches in Meteorology, Hydrology, Soil Science and Agronomy. Thereby, the main hydrometeorological parameters for identifying areas affected by water deficit will be discussed. Drought is one of the major natural hazards that may cause great losses to the rural community each year, due to the dependence of agriculture on water resources, especially water scarcity, during different phenophases of crop growth. A climate with high evaporation and limited precipitation leads to limited yields. During the minimum runoff periods caused by meteorological droughts, stream channels are recharged exclusively from groundwater, their flow rate being dependent on the state of aquifers depletion, as well as on the manner in which river channels intercept the water table. The investigated area (Bend Subcarpathians and peripheral zones) is characterized by a greater frequency of dry autumn seasons starting north of Buzau, both in the internal and external Subcarpathians. A higher frequency has been identified along the Prahova Valley, too. North to Buzau, the summer seasons perform a similar trend. In some areas, the mean maximum ranges of the consecutive days with no rainfall exceed annually 20 days. A larger interval for average number of days with no rainfall is registered in autumn (more than 22 days). An analysis of minimum monthly mean discharge frequency highlights the same pattern with that of rainfall analysis: more than 50% occurrence in autumn season, especially for subcarpathian basins, with higher frequency in Prahova Subcarpathians (over 60%). In Vrancea Subcarpathians, these values recorded a large frequency in summer, too. To identify the water deficit areas, “Emm. The Martonne” aridity index has been used, expressing the relationship between climate, vegetation and water resources. This index was calculated and mapped both for multiannual values and for summer only. The frequency of minimum monthly mean discharge in summer is related mostly to this index, as well as to the catchment area in a smaller proportion. Therefore, a correlation between the frequency and a parameter which incorporate the aridity index for summer, catchment elevation and surface has been obtained.
drought indices; SPI; CDD; minimum runoff; monthly discharge; Bend Subcarpathians