Online portal »Drought meter« for monitoring the drought situation in Slovenia

The frequency of droughts in Slovenia has been increasing in recent decades. In the last twenty years we have recorded 7 droughts that affected Slovenia on the scale of a natural disaster, with the most recent one in 2022 causing around 148 million euros of direct damage to agriculture. Droughts have been occurring with increasing intensity, and in areas and seasons where they have not been a problem in the past.

For the purpose of detecting drought conditions in near real time and informing the public about these, Slovenian Environment Agency has developed the »Drought meter« online portal where estimated drought conditions in three parts of the water cycle (topsoil layer, surface water, groundwater) are published on a weekly basis throughout the year. For each part of the water cycle, drought conditions are monitored at representative stations using a specific indicator; in case of topsoil layer, the surface water balance for the past 30 days is used. Regional estimation of drought conditions is then determined based on a percentile analysis of the indicator at representative stations, which gives information on how often in the past similar conditions have occurred in the selected time period.

In addition to drought conditions in the three parts of the water cycle, »Drought meter« also consists of a climate analysis of three basic variables influencing these conditions, namely temperature, precipitation and reference evapotranspiration over the last 7 and last 30 days. This is also done on a weekly basis, where for each variable we highlight the spatial distribution and meteorological stations that deviated the most. For the last 30 days, maps of deviations by percentile classes are shown. An outlook for the following week is also provided through a meteorological forecast, consisting of a description of the synoptic situation for the coming week and an estimate of expected precipitation amount and temperature range by the end of the selected period.

The »Drought meter« online portal represents a progress in providing information on drought conditions in Slovenia, since near real time drought information for all three parts of the water cycle is available in one place and on a uniform spatial and temporal scale. In our talk, we will provide an overview of the development of the drought in 2022. That year the estimated drought conditions in »Drought meter« also served as the basis for the competent authorities to determine the onset of the period for assessing damage to agricultural crops due to drought.