Dürremaße

Dürremaße are quantitative indicators used to describe and monitor drought conditions in meteorology, hydrology and agriculture. The term, common in German-speaking literature, refers to measures that express the severity, duration and spatial extent of drought by comparing current conditions to long-term normals. Dürremaße can be based on precipitation deficits, soil moisture status, evapotranspiration, or streamflow, and are often designed to be comparable across regions and time.

There are several families of Dürremaße. Precipitation-based indices include standardized measures such as the Standardized Precipitation Index (SPI) and related forms like the SPEI, which also account for evapotranspiration. Hydrological measures use rainfall and runoff data to assess drought in the water cycle, while soil-moisture indicators rely on observations or modeled estimates of moisture in the root zone. These indices are typically calculated over multiple timescales (for example 1, 3, 6, 12 months) to reflect short-term moisture stress and longer-term drought persistence. Values are commonly standardized, allowing categorization into normal, moderate, severe, or extreme drought.

Applications of Dürremaße include drought monitoring, early warning, agricultural planning, water resource management, and policy decision support. National and regional agencies may publish drought bulletins and risk maps based on these measures. In Germany and other German-speaking regions, Dürremaße are part of integrated drought surveillance alongside meteorological and hydrological observations.

Limitations include data quality and spatial coverage, regional calibration needs, and the sensitivity of indices to chosen variables and timescales. Different definitions and methods can complicate cross-regional comparability, particularly under changing climate conditions.