DROUGHT POLICY
Trinidad and Tobago's Meteorological Drought Policy
A Science-Based Approach to Dry Spell Monitoring and Management
1. Statement of the Problem
The Trinidad and Tobago Meteorological Service (TTMS) has developed a comprehensive policy to monitor and assess mild to extreme dry spells. This initiative stems from the critical need to understand and mitigate the impacts of dry conditions on water resources, agricultural production, health, and the economy.
With projected climate change and an increasing population, establishing a robust dry spell and drought early warning system has become imperative. The policy aims to provide science-based monitoring and regular updates to key stakeholders and decision-makers.
2. Understanding Dry Spells and Drought
Dry Spell Definition
According to the World Meteorological Organization (WMO), a dry spell is a period of at least 15 consecutive days with less than 1 mm of rainfall, generally applied to less extensive and less severe conditions than drought.
Drought Definition
Drought is an extended climatic condition characterized by significantly decreased rainfall that fails to meet the demands of societal and environmental activities.
3. Types of Drought
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Meteorological Drought
Based solely on rainfall deficiency compared to expected average over a specific period.
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Agricultural Drought
Measures soil water availability to plants, occurring when rainfall and soil moisture cannot meet plant needs.
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Hydrological Drought
Refers to deficits in surface and sub-surface water supplies based on stream flow, lake, reservoir, and groundwater levels.
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Socio-Economic Drought
Occurs when demand for an economic good exceeds supply due to weather-related physical water shortages.
4. Monitoring Methodology
Standard Precipitation Index (SPI)
The TTMS adopts the SPI as its primary dry spell and drought monitoring index. The SPI compares rainfall over a specific period with historical rainfall totals, expressed in standard deviations from the mean.
| SPI Value | Drought Characterization |
|---|---|
| -1.0 to -1.24 | Dry Spell |
| -1.25 to -1.49 | Moderate Dry Spell |
| -1.50 to -1.99 (two consecutive periods) | Drought Event |
| -2.0 and below (two consecutive periods) | Severe Drought Event |
5. Conclusion
This policy represents a transformative approach from reactive crisis management to a proactive, science-based early warning system for dry spells and meteorological droughts in Trinidad and Tobago.
By establishing a comprehensive monitoring framework, the TTMS aims to improve climate resilience, support water-sensitive sectors, and provide timely, accurate information to stakeholders.
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