Characterizing the Galapagos terrestrial climate in the face of global climate change
The position of Galapagos in the Eastern Pacific gives it a unique seasonal climate that is atypical of other equatorial oceanic islands. Conditions are influenced by the interaction of ocean currents and winds, governed by the movement of the Inter-Tropical Convergence Zone, and by the periodic Pacific-wide El Niño Southern Oscillation. Weather data from 1959 to 2009 on Santa Cruz Island show that the hot season prevails from January to May, characterized by elevated sea and air temperatures and highly variable rainfall. During the cool season, from June to December, cooler temperatures and a stratus cloud layer persist, resulting in relatively consistent precipitation in the humid highlands and almost none in the dry lowlands. Hot season rainfall totals are strongly correlated with sea surface temperature, whereas cool season rainfall totals are consistent from year to year, and not so closely correlated with sea surface temperature. Seasonal rainfall totals from ten locations on six islands show correlations among the majority of sites for the hot season but fewer for the cool season, one exception being the correlation between sites on Santa Cruz Island, all of which receive at least some cool-season precipitation. Biological productivity in the dry lowlands is primarily influenced by the variable hot-season rainfall. The humid highlands are maintained by more consistent precipitation every year in the cool season, but are also affected by conditions during the hot season. We suggest that the dry zone is vulnerable to a warmer, wetter climate which would favour invasive species and thereby doubly threaten aridadapted endemic species. Potential climate change impacts on the already-invaded and more species-rich humid highlands are harder to predict due to our lack of understanding of cool-season precipitation patterns. In order to understand spatial climate variability in Galapagos better, there remains a need for meteorological data with a greater spatial spread throughout the islands, especially at higher altitudes.
| Main Authors: | , |
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| Format: | article biblioteca |
| Language: | English |
| Published: |
2010-10
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| Subjects: | Atmospheric Sciences, Earth Sciences, Ecology, Environment, |
| Online Access: | http://hdl.handle.net/1834/36285 |
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