The Study of Climatic Variability on San Salvador: Challenges and Solutions to Isolation

This presentation describes a ten year effort to document and study climatic variability on San Salvador, Bahamas. First attempts focused upon assessment of cave microclimates and the integration of results with data from Guam and Puerto Rico to develop a microclimate model for tropical flank margin caves. Results indicate that tropical flank margin caves are much more variable than their temperate fluvio-karst counterparts and a two-zone model is more appropriate than the traditional three zone model. Building upon the study of cave microclimatology, research assessed and linked the impact of climatic variability upon inland pond levels and water in caves. Results of this phase of research indicate that short-term (day-week) variability dominates the dynamics of pond and karst hydrology. The final component of climatic variability research on San Salvador is the assessment of rainfall variability through time and space on the island. Results indicate that the early season maxima in precipitation was extremely wet during the period of study, non-synoptic storms occur frequently contributing the largest portion of rainfall on San Salvador, non-tropical storms, particularly stationary fronts, can contribute significantly to rain totals exceeding totals from the hurricane season, the entire island of San Salvador was completely covered by rainfall ~40% of observed rain days, and statistical hypothesis testing indicates no significant difference in rainfall totals across the island. Throughout the entire project, the greatest difficulty in conducting research on climatic variability is overcoming instrumentation problems that are exacerbated by the isolation of the island. Without the assistance and guidance of Kathy and Don Gerace this challenge would have not been overcome and the overall study of climatic variability on small carbonate islands would have been severally inhibited.