Abstract[Drought indicators are proliferating, but with little consideration of which are most meaningful for describing drought impacts. A number of recent reviews compare different drought indicators, but none assess which indicators are actually used in the many operational drought monitoring and early warning efforts, why they were selected, or whether they have been 'ground-truthed', i.e., compared with information representing local drought conditions and/or impacts. Also lacking is a comprehensive assessment of the state of monitoring of drought impacts. To help fill this gap, we combine a review of drought indicators and impacts with a survey of 33 providers of operational drought monitoring and early warning systems from global to regional scales. Despite considerable variety in the indicators used operationally, certain patterns emerge. Both the literature review and the survey reveal that impact monitoring does exist but has rarely been systematized. Efforts to test drought indicators have mostly focused on agricultural drought. Our review points to a current trend towards the design and use of composite indicators, but with limited evaluation of the links between indicators and drought impacts. Overall, we find that much progress has been made both in research and practice on drought indicators, but monitoring and early warning systems are not yet strongly linked with the assessment of wider impacts on the environment and society. To understand drought impacts fully requires a better framing of drought as a coupled dynamic between the environment and society.]

Note to the reader: This publication is part of the 'Integrated Drought Management Tools and Guidelines Series', compiled by the Integrated Drought Management Programme (IDMP). This Handbook of Drought Indicators and Indices is based on available literature and draws findings from relevant works wherever possible. The handbook addresses the needs of practitioners and policymakers. The publication is considered as a resource guide/material for practitioners and not an academic paper. This publication is a 'living document' and will be updated based on the experiences of its readers. The indicators and indices detailed in chapter 7 of the handbook are also available online at www. droughtmanagement.info. IDMP encourages water managers and related experts engaged in the management of drought around the globe to participate in the enrichment of this publication. For this purpose, comments and other inputs are cordially invited. Authorship and contributions will be appropriately acknowledged.

ABSTRACT:Soil moisture dynamics and their temporal trends in the Czech Republic are forced by various drivers. The methodology of applying remotely sensed data with both high temporal and spatial resolutions provides detailed insight and objective quantification of the causes of changes in soil moisture patterns. Our analysis of temporal trends indicates that shifts in drought severity between 1961 and 2012 (especially in the April, May, and June period, which displayed a 50% increase in drought probability between 1961-1980 and 2001-2012) are alarming. We found that increased global radiation and air temperature together with decreased relative humidity (all statistically significant at the 0.05 level) led to increases in the reference evapotranspiration in all months of the growing season; this trend was particularly evident in April, May, and August, when more than 80% of the territory displayed an increased demand for soil water. This finding was shown to be consistent with the measured pan evaporation that was characterized by increasing trends, particularly during the April-June period. These changes, in combination with the earlier end of snow cover and the earlier start of growing season (up to 20 days in some regions), led to an increased actual evapotranspiration at the start of growing season that tends to deplete the soil moisture earlier, leaving the soil more exposed to the impacts of rainfall variability. These results support concerns related to the potentially increased severity of drought events in Central Europe. The reported trend patterns are of particular importance with respect to the expected climate change, given the robustness and consistency of the trends shown and the fact that they can be aligned with the existing climate model projections.

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