Droughts, also identified as a moisture deficiency, has adverse effects on a community usually by reducing food production or surface water supplies.
Droughts can be highly destructive and it is thought that climate change fuels a rise in the intensity and frequency of its occurrence around the world. Droughts are sometimes called a “creeping phenomenon” because it moves slowly but steadily into an entire region and lingering for long periods of time.
To deal with the phenomenon effectively, it is crucial to determine when it started, how severe it is and when it is likely to end.
The long-term mean annual rainfall of Jamaica indicates a pattern of two distinct wet months, October and May. The drier months are January, February, March and July. This pattern may vary annually. It is recognised that human activity could influence the global climate system through global warming and this could alter the rainfall patterns of tropical countries like Jamaica.
Types of Drought
Drought is defined as a long period of weather without rain. There are more precise definitions for specific types of drought. The most commonly used are:
|Types of Drought||Description|
|Agricultural Drought||A period when soil moisture is inadequate to meet the demands for crops to initiate and sustain plant growth. In areas experiencing drought, plant life is severely damaged.|
|Hydrological Drought||A period of below-average or normal stream-flow and/or depleted reservoir storage. Hydrological drought occurs out of phase with meteorological and agricultural drought because it takes longer for the deficiencies to show up in lakes and streams.|
|Meteorological Drought||A period of well-below average or normal precipitation (rainfall) that spans from a few months to a few years.|
Who monitors rainfall and droughts in Jamaica?
The Meteorological Service is responsible for monitoring, analyzing and archiving the rainfall records of Jamaica. Its Climate Branch maintains a rainfall network of nearly four hundred rain gauges and rainfall recorders located strategically across the island. From the information collected the values for the island’s drought Index are computed. This index is used to determine the onset, intensity, and end of a drought in Jamaica.
Drought conditions can affect specific sections of parishes or widespread over most of the island.