Carribean Islands: Experts Urging For Accurate Measures On Dry Conditions As Region Prone To Drought

Experts urged for accurate measures on dry conditions over Caribbean Islands as the region was found to be prone to drought.

Flash drought has recently gained momentum as a paradigm to describe rapid-onset drought events that develop due to the superposition of both high evaporative demand and insufficient rainfall.

While rapid-onset droughts have been observed over the US Central Plains in 2012, 2016, and 2017, conventional drought definitions based on months-long precipitation anomalies can either miss these events altogether, underestimate their severity, and/or truncate the length of the dry period following the rapid onset.

Flash Drought

Given these shortcomings, several methods of flash drought identification have been proposed that each attempt to capture instances of rapid landscape desiccation.

While most of the Caribbean experiences a dry season, normally from December to March, flash droughts are not confined to this period and can occur throughout the year.

Experts noted that while many flash droughts identified by the detection criteria used in the study were localized, there were several that initiated simultaneously across a large spatial domain.

These high-impact flash droughts tend to occur in discrete clusters in the Caribbean as shown by the evidence obtained from the study.

However, this requirement may also depress occurrences of flash drought in the Windward Islands, whose entire island may be represented by a single grid point.

In such cases, for flash droughts in these locations to be detected, they needed to be accompanied by larger flash drought onsets elsewhere in the domain.

The study indicated that many numerous studies have examined the flash drought paradigm across a wide range of midlatitude settings, noting that the transferability of flash drought to the world's tropics has been relatively unexplored.

Scientists said that because the cadence of precipitation in moist tropical regions differs substantially from the midlatitude testbeds where flash drought has received the most attention, there remains a need to critically examine the suitability of midlatitude-centric flash drought criteria to tropical environments.

Consequently, this study tested the flash drought definition proposed by Pendergrass et al. (2020), which is predicated on the evaporative demand drought index over the Caribbean basin.

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Complex Topography

Researchers said that the complex topography of the insular Caribbean as well as the Central and South American coasts can yield tight juxtapositions of large versus small return intervals, which is likely related to ERA5-Land's diminished performance in areas of high intra-gridcell landscape variability.

Beyond prediction, the prevalence of tropical flash drought in the Caribbean shown in the study necessitates future work in examining the agricultural and ecological impacts of the rapid drying events.

Specifically, in Puerto Rico and the US Virgin Islands, crop insurance policies may be tied to the drought category, if any, resolved by the US Drought Monitor.

However, the instrument may be slow to recognize the emergence of a flash drought event, placing the Puerto Rican agricultural industry in a difficult position.

Given the regularity of flash drought across the Caribbean, future work should seek to understand the extent to which flash droughts are associated with tangible economic losses, and by extension, how these events should be monitored and communicated to stakeholders in a timely fashion.

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