Drought Assessment and Monitoring Techniques in Climate Variability

Drought assessment encompasses a suite of methodologies designed to quantify and monitor deficits in water availability arising from long‐term precipitation shortfalls and elevated evaporative demand under a changing climate. Key approaches include the application of standardised drought indices, remote sensing of land surface and vegetation stress, in-situ soil moisture networks and land-surface models for hydrological drought characterisation. Advances in sensor technology, data assimilation and high-resolution modelling have improved early warning capabilities and facilitated multi-sectoral impact assessments. Techniques now routinely integrate precipitation and temperature-based indices with satellite-derived soil-moisture and vegetation indicators, enabling more accurate delineation of drought onset, duration and severity across temporal scales from days to decades. The global significance of these methods lies in their capacity to inform water resource management, agricultural planning and ecosystem resilience strategies in an era of heightened climate variability.

Research from Nature Portfolio

Recent studies have advanced the spatial–temporal analysis of drought trends in complex terrains using combined precipitation and evapotranspiration indices. One investigation in a major Chinese province demonstrated differential trends in standardised precipitation and evapotranspiration indices across plains, hills, plateaux and mountains over six decades, revealing eastward shifts in drought hotspots and guiding regional water-management decisions. In another study of a high-elevation plateau, researchers employed long-term SPEI records from a dense station network to uncover elevation-dependent wetting and drying trends, identifying a critical threshold above which warming-driven moisture gains accelerate. These works underscore the value of high-density observational datasets and robust statistical trend tests for refining drought risk assessments in topographically diverse environments.

Drought Assessment and Monitoring Techniques in Climate Variability publication trend

The graph below shows the total number of articles in drought assessment and monitoring techniques in climate variability across all publications each year (not limited to Nature Index journals).

Technical terms

Standardised Precipitation Index (SPI): A dimensionless index that quantifies precipitation anomalies against a historical record over specified timescales to identify meteorological drought intensity.

Standardised Precipitation Evapotranspiration Index (SPEI): A drought index incorporating both precipitation and potential evapotranspiration, reflecting the climatic water balance and temperature‐driven moisture demand.

Eddy covariance: A micrometeorological technique that measures fluxes of water vapour, energy and trace gases between ecosystems and the atmosphere at high temporal resolution.

Mesoscale Hydrological Model (mHM): A distributed land‐surface model used to simulate soil moisture and evapotranspiration over large domains, aiding gap‐filling and long-term drought analyses.

References

1. Long-term daily hydrometeorological drought indices, soil moisture, and evapotranspiration for ICOS sites. Scientific Data (2023).
2. Spatiotemporal drought analysis by the standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI) in Sichuan Province, China. Scientific Reports (2021).
3. Drought characteristics and its elevation dependence in the Qinghai–Tibet plateau during the last half-century. Scientific Reports (2020).
4. A multi-scale daily SPEI dataset for drought characterization at observation stations over mainland China from 1961 to 2018. Earth System Science Data (2021).