Mapping the climate of Puerto Rico, Vieques and Culebra

Abstract

Spatially explicit climate data contribute to watershed resource management, mapping vegetation type with satellite imagery, mapping present and hypothetical future ecological zones, and predicting species distributions. The regressionbased parameter-elevation regressions on independent slopes model (PRISM) uses spatial data sets, a knowledge base and expert interaction to generate grids of climate variables that are compatible with geographical information systems. This study applied PRISM to generate maps of mean monthly and annual precipitation and minimum and maximum temperature for the Caribbean islands of Puerto Rico, Vieques and Culebra over the 1963-95 averaging period. PRISM was run under alternative parameterizations that simulated simpler interpolation methods as well as the full PRISM model. For temperature, the standard PRISM parameterization was compared with a hypsometric method (HYPS), in which the temperature-elevation slope was assumed to be −6.5°C/km. For precipitation, the standard PRISM parameterization was compared with an inverse-distance weighting interpolation (IDW). Spatial temperature patterns were linked closely to elevation, topographic position, and coastal proximity. Both PRISM and HYPS performed well for July maximum temperature, but HYPS performed relatively poorly for January minimum temperature, due primarily to lack of a spatially varying temperature-elevation slope, vertical atmospheric layer definition, and coastal proximity guidance. Mean monthly precipitation varied significantly throughout the year, reflecting seasonally differing moisture trajectories. Spatial precipitation patterns were associated most strongly with elevation, upslope exposure to predominant moisture-bearing winds, and proximity to the ocean. IDW performed poorly compared with PRISM, due largely to the lack of elevation and moisture-availability information. Overall, the full PRISM approach resulted in greatly improved performance over simpler methods for precipitation and January minimum temperature, but only a small improvement for July maximum temperature. Comparisons of PRISM mean annual temperature and precipitation maps with previously published handdrawn maps showed similar overall patterns and magnitudes, but the PRISM maps provided much more spatial detail.

The impact of forest regeneration on streamflow in 12 mesoscale humid tropical catchments

“…Soils developed in the volcanic substrates are largely clayey Ultisols with a rapidly diminishing saturated hydraulic conductivity (K s ) with depth (Schellekens et al, 2004) whereas the granodiorites produce less clayey Ultisols with a less pronounced K s profile (Kurtz et al, 2011). Islandwide mean precipitation (P ) is ∼ 1700 mm yr −1 (Daly et al, 1994(Daly et al, , 2003. There is a moderate P seasonality, with the three driest months of the year (January-March) receiving on average ∼ 300 mm in total and the three wettest months of the year (September-November) receiving on average ∼ 775 mm in total (Daly et al, 1994(Daly et al, , 2003.…”

Diameter growth performance of tree functional groups in Puerto Rican secondary tropical forests

“…The trade winds approach the island from the northeast and as a result of encountering the mountains create a distinct precipitation gradient with areas in the southwest receiving less than half the annual rainfall (~750 mm) than areas in the northeast (~1,500-2,000 mm). Mean annual temperatures range between 19.4 to 29.7°C with cooler temperatures occurring at higher elevations (Daly et al, 2003). The steep climate gradient, a large elevation range, and a complex geology have generated striking environmental variation within the island.…”

“…Puerto Rico contains six Holdridge life zones: Subtropical moist forests account for 62% of Puerto Rican forests, subtropical wet forests and rain forest combined covers 23%, subtropical dry forest 14%, and combined subtropical lower montane wet and rain forest slightly over 1% (Ewel and Whitmore, 1973;Holdridge, 1967). Vegetation ranges from dry, semi deciduous forests in patches and bands on the north and east coasts and in the southwest part of the island, to moist forests that cover the major proportion of the island, and wet and rain forests, including cloud forests, at higher elevations (Daly et al, 2003).…”

“…Climate variables values were assigned of the nearest weather station from 47 National Weather Service cooperative stations (Daly et al, 2003). Precipitation and elevation were used as drivers under the assumption that cooler temperatures and relatively high precipitation in the higher elevations may accelerate biomass accumulation relative to warmer areas (Daly et al, 2003).…”

“…Trees may grow faster on slopes facing moisture bearing wind, which in Puerto Rico tend to face northnortheast (Daly et al, 2003;Weaver, 1991). We used 30 × 30 m SRTM elevation data from USGS to calculate aspect.…”