On the Hydrometeorological Changes of a Tropical Water Basin in the Caribbean and Its Sensitivity to Midterm Changes in Regional Climate

Abstract

lobal climate change manifests in the Caribbean basin as increased SSTs, precipitation anomalies, and changes in atmospheric moisture content, among other effects. These regional climate changes have a profound impact on the local human, flora, and fauna populations. Such is the case of the Enriquillo basin, a highly sensitive ecosystem located in the southwestern region of the Caribbean island of Hispaniola. The major bodies of water in the basin, Lake Enriquillo and Lake Azuéi, show a shrinking and expanding pattern since the early 1980s. The surface area of Lake Enriquillo was observed to reach minimum values in 2004 (170 km2), shifting to a rapid expansion to its current levels (>350 km2 as of late 2013). Lake Azuéi is observed to grow at similar rates. This lake expansion could be attributed to regional climate change. Long-term regional climate data reflect increasing SSTs (~1°C), air temperatures (~0.37°C decade?1), dewpoint (~0.66°C decade?1), and precipitation (~30%); no reliable local precipitation records were found. Furthermore, local governments are being forced to issue evacuations, prompting one of the first cases of environmental refugees not caused by an extreme event (e.g., a hurricane or tsunami). The hypothesis of lake expansion in the Enriquillo basin as a regional response to climate change is further investigated with the use of an integrated regional atmospheric modeling system. Model results from simulations performed for years during the lakes? lowest water levels (2003?04) and during their continued growth (2012?13) show increased total accumulated surface precipitation, atmospheric liquid water content, and an enhanced positive feedback system that produces orographic cloud cover in the surrounding tropical montane cloud forests as a consequence of the changing atmospheric and oceanic conditions.