Tool for Drought Monitoring in the Danube Region: – Methods and Preliminary Developments

Drought is a naturally recurring phenomenon of the climate system that affects virtually all regions of the world. During the past decades extreme droughts with extensive negative effects on ecosystems became evident also in the Danube region. At the moment regional capacity to monitor drought is still very diverse and not synchronised among different countries. In this is paper, we present a recently developed drought monitoring tool – the Drought User Service (DUS) for the Danube region using remote-sensing products which aims at offering a more accurate and in near-real-time monitoring via different drought indices. The DUS was created as the monitoring tool of the risk-based paradigm, which seeks to give information in near real-time about the location and severity of droughts throughout the Danube region. Satellite remote sensing products meet the requirements for operational monitoring because they are able to offer continuous and consistent measurements of variables, which can be used to assess the severity, spatial extent and impacts of drought. In the DUS three different variables – vegetation, soil moisture and precipitation – are monitored with earth observation products. The condition of vegetation and soil moisture is tracked with two simple indicators computed as long-term anomalies of the NDVI and SWI products made available through EU’s Copernicus Global Land Service. The importance of DUS and of the developed methods for faster detection of drought onset as useful foundation for establishing a better pro-active drought management in order to mitigate the negative effects of drought in the region is discussed

HIGH-RESOLUTION WIND CLIMATOLOGY FOR SLOVENIA: A SPATIO-TEMPORAL VERIFICATION

An NWP model AI.AD1N is applied for dynamical downscaling of ERA40. The purpose is to deduce the wind climatology of Slovenia at horizontal scales around ten kilometers and finer. Verification against MAP-SOP reanalyses indicates that the downscaling has been successful. However, MAP-SOP reanalysis data produce wind roses closer to the observations and contain more energy in the subdiurnal range. On the other hand, a 10-km ALADIN overestimates the amount of energy in longer than diurnal periods

DOWNSCALING OF ERA40 FOR THE WIND FIELD IN A COMPLEX TERRAIN

This study deals with the optima] strategy for setting up the ALADIN model for the purpose of dynamic downscaling of ERA40 over the Alpine region. The mesoscale model wind field is compared with MAP-SOP reanalysis data and with wind observations at eleven Slovenian stations. As expected, there is an improvement in the conventional statistics at a 10-km grid as compared to the 40-km analyses. However, the differences between the mesoscale model scores at various domains can be greater than the difference between the MAP-SOP reanalyses and a particular mesoscale simulation

Repository of drought event impacts across the danube catchment countries between 1981 and 2016 using publicly available sources

Drought directly and indirectly affects human society in a number of ways. In many regions of the world climate change will exasperate the effects of droughts, affect national economies more intensely. The main aim of this article was to catalogue and analyze the drought impacts in the 11 Central and South Eastern European states located in the Danube river basin. The identification of dry episodes was based on information from publicly available sources, namely, newspaper and journal articles that reported drought impacts. Information on drought impact occurrences was classified into one of five defined categories in which the drought impact report was most clearly manifested (i.e., agriculture, forestry, soil systems, wildfires and hydrology). In terms of the spatial distribution of drought impacts, individual recorded events were analyzed at the level of EU NUTS regions (or their equivalent in non-EU countries). The analysis highlights country-specific vulnerability to drought. Furthermore, gradual increases in drought events and the number of reported impacts were identified, which was particularly evident in the agricultural sector

Observed versus forecasted precipitation in the South East Alps

Intense precipitation events are common on the SE slopes of the Alps and the climatological maximum of precipitation is located in the area of the Julian and Carnic Alps. Mesoscale intensification of rainfall in the area is explained. Two cases of intense precipitation were studied with fine mesh mesometeorological modelling using the ALADIN-SI model and verifying its results with all available ground-based raingauge measurements. For the first case of 5-8 November 1997 mesoscale topographically induced direct lifting was the main reason for precipitation intensification in the area. For the second case of 3-5 November 1998 this forcing was further modified by a mesofront moving along the eastern edge of the Alps in the opposite direction to the flow at upper levels. In the predicted precipitation the most noticeable feature was the shift of the forecasted precipitation fields by some 20 km with respect to the measured one leading to overestimation at the SW side, and underestimation at the NE side of the mountain ridge. The role of discrepancy sources of differences between the forecasted and raingauge precipitation are evaluated

Frost risk assessment in Slovenia in the period of 1981–2020

As spring frost proves to be an increasing risk throughout Slovenia and Europe, a better assessment of frost risk is needed. The statistical approach presented in this article consists of the conditional probability that the last spring frost occurs before budburst or flowering. The analysis was conducted using two separate phenological models and phenological data of various grapevine (Vitis vinifera L.), apple (Malus domestica), and sweet cherry (Prunus avium L.) varieties in locations across Slovenia. The increase in risk of spring frost for grapevine ranged from 1 to 1980, from 0.06 to 12 for apple, and from 1 to 180 for sweet cherry. Overall, the varieties most prone to frost proved to be Refošk (Teran) and Merlot grapevine varieties as well as the Germersdorf sweet cherry variety. We have identified the location in the hilly region with moderate climate where the Bobovec apple variety is grown as the least exposed to frost. Although counterintuitive, the GDD generally proved somewhat more efficient than the two-phase phenological model BRIN, although not in all cases. For the purpose of the study, the phenological models were calibrated, and the model parameters can serve as invaluable information for further research of this topic