Official drought monitoring services only concentrate on recent data, failing to take into account accumulating moisture trends

Official drought monitoring services, such as the U.S. Drought Monitor and similar systems globally, often emphasize recent or short-term data, which can lead to gaps in understanding the full scope of drought conditions. This approach has several implications and recognized limitations:

• Most operational drought indices and monitoring services rely on short-term meteorological data (e.g., precipitation, temperature, and soil moisture over weeks or months).

• These indices are designed to detect the onset, intensity, and end of droughts, but they may not fully account for long-term moisture deficits or surpluses that accumulate over multiple seasons or years12.

• —the long-term buildup or depletion of water in soils, aquifers, and reservoirs—are critical for understanding drought vulnerability and resilience, especially in regions prone to multi-year droughts.

• Many drought monitoring products struggle to integrate these long-term trends, often due to:

  • Limited historical records and in situ measurements.

  • The complexity of modeling deep soil moisture and groundwater changes.

  • Inconsistencies between different remote sensing and modeled datasets345.

• Recent research highlights that while some advanced soil moisture models and reanalysis products can provide near-real-time data, only a subset effectively captures long-term dry-season trends and accumulated deficits324.

• There are often mismatches between what is officially monitored and the actual, cumulative impacts experienced by communities, especially when drought indices are not tailored to local or long-term realities6.

• Combining multiple data sources (e.g., merging remote sensing with modeled soil moisture) can improve the spatial and temporal consistency of monitoring, but operational services still tend to prioritize pragmatic, short-term indices for decision-making45.

• Official monitoring systems may miss “blind spots,” such as:

  • Slow-developing, multi-year droughts.

  • Deep soil and groundwater depletion.

  • Local-scale impacts that are not reflected in broad regional indices6.

• These gaps can result in a monitoring “misalignment” between official data and the lived experiences of affected communities, particularly when accumulated moisture deficits are a key driver of impacts6.

• There is ongoing research to better integrate long-term hydrological and soil moisture trends into drought monitoring, using advanced satellite data, reanalysis products, and merged indices347.

• Some monitoring frameworks are beginning to incorporate longer-term averages and anomaly tracking, but widespread operational adoption remains limited18.

:
While official drought monitoring services provide valuable real-time and short-term assessments, they often underrepresent the importance of accumulating moisture trends and long-term deficits. This limitation can hinder effective drought management, especially for regions and communities vulnerable to prolonged or recurring droughts. Integrating long-term soil moisture, groundwater, and cumulative hydrological data remains a key frontier for improving drought monitoring and early warning systems134.

1. https://www.drought.gov/news/emerging-climate-trends-make-monitoring-drought-more-complex-2024-05-28
2. https://www.fs.usda.gov/rm/pubs_journals/2024/rmrs_2024_hoylman_z001.pdf
3. https://egusphere.copernicus.org/preprints/2023/egusphere-2023-2499/
4. https://hess.copernicus.org/preprints/hess-2024-182/
5. https://journals.ametsoc.org/view/journals/bams/98/9/bams-d-15-00149.1.xml
6. https://nhess.copernicus.org/articles/25/893/2025/
7. https://hess.copernicus.org/articles/29/397/2025/
8. https://www.epa.gov/climate-indicators/climate-change-indicators-drought
9. https://www.drought.gov/topics/soil-moisture
10. https://pmc.ncbi.nlm.nih.gov/articles/PMC4322588/
11. https://natural-resources.canada.ca/climate-change/climate-change-impacts-forests/drought
12. https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1095&context=droughtfacpub
13. https://www.drought.gov/sites/default/files/2022-08/Flash-Drought-Monitoring-and-Prediction-Tools.pdf
14. https://www.sciencedirect.com/science/article/pii/S2405844024171927
15. https://rmets.onlinelibrary.wiley.com/doi/10.1002/cli2.7
16. https://www.drought.gov/what-is-drought/monitoring-drought
17. https://www.sciencedirect.com/science/article/abs/pii/S0168192317300655
18. https://www.nature.com/articles/s41893-019-0326-y
19. https://www.oecd.org/en/publications/global-drought-outlook_d492583a-en/full-report/towards-a-drier-world_6f10e2e5.html
20. http://www.copernicus.eu/en/news/news/observer-how-eu-space-programme-helps-us-monitor-drought-around-world