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SURFACE TEMPERATURE TRENDS IN THE CARIBBEAN SEA & THE EASTERN PACIFIC OCEAN


Emil A. Cherrington Betzy E. Hernández Bessy C. García Antonio H. Clemente Marcelo O. Oyuela Water Center for the Humid Tropics of Latin America & the Caribbean (CATHALAC) 111 City of Knowledge, Panama City, Panama TEL: (507) 317-3200 • servir@cathalac.org May 2011


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SURFACE TEMPERATURE TRENDS IN THE CARIBBEAN SEA & THE EASTERN PACIFIC OCEAN


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SEA SURFACE TEMPERATURE TRENDS IN THE CARIBBEAN SEA & THE EASTERN PACIFIC OCEAN

BACKGROUND Mesoamerica and the Caribbean represent global hotspots for biodiversity. In addition to Mesoamerica’s being home to some 9.4% of the world’s terrestrial species, the region’s marine environment is also of global importance. Coral reef ecosystems can be found across the Caribbean Sea, and the Mesoamerican Barrier Reef System (MBRS) located in the north of Mesoamerica’s territorial waters is the second most extensive in the world, after the Great Barrier Reef of Australia. A significant proportion of the inhabitants of mainland Mesoamerica and the insular Caribbean depend on the sea for their livelihoods. Those livelihoods, however, are threatened by a number of factors, the least of which is climate change and which is expected to lead to increased ocean temperatures. Warm ocean temperatures, year after year, feed recurring hurricanes and tropical storms which ravage the region.

A key gap, however, in understanding what is occurring in the waters off Mesoamerica and the Caribbean islands, is the lack of a comprehensive, widespread network of sensors for collecting information on the seas’ fluctuating temperatures. Satellite technology, however, has and continues to make important contributions in that arena. In 2005, for instance, the Regional Visualization & Monitoring System (SERVIR) was established at the Water Center for the Humid Tropics of Latin America & the Caribbean (CATHALAC), in partnership with NASA, the U.S. Agency for International Development (USAID), and other partner institutions. SERVIR serves as a virtual observatory of the region’s marine and terrestrial environment, and its atmosphere. The system’s information is provided freely to the region’s decision-makers, scientists, and the general public via the Internet at www.servir.net.


SEA SURFACE TEMPERATURE TRENDS IN THE CARIBBEAN SEA & THE EASTERN PACIFIC OCEAN

OBJECTIVES

METHODOLOGY

The objective of this study is to review the past decade’s worth of satellite data to understand how the temperature of the surface of the waters off Mesoamerica’s coasts (i.e. the eastern Pacific Ocean and the Caribbean Sea) have changed over the past decade. Since data from temperature gauges is lacking, this satellite-based data will also provide the first such perspective on the oceans’ temperature. Use is made of NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS), which flies some 705km above the earth’s surface on the Terra and Aqua satellites and which is used to study different processes in the world’s oceans (Lillesand et al 2007, UMD 2007). In terms of temperature readings, MODIS takes snapshots of Mesoamerica about four times daily.

MODIS sea surface temperature data was acquired from NASA, utilizing both daytime and nighttime data from MODIS Aqua. Analyses and visualizations used in this paper were produced with the Giovanni online data system, developed and maintained by the NASA GES DISC (Goddard Earth Sciences Data and Information Services Center), using the domain depicted in Figure 1. In addition to generating average monthly temperature maps for the period from July 2002 to December 2010, the system was also able to generate a time series of the mean, maximum, and minimum temperatures.

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SEA SURFACE TEMPERATURE TRENDS IN THE CARIBBEAN SEA & THE EASTERN PACIFIC OCEAN

Figure 1. Average daytime sea surface temperatures, based on MODIS Aqua data for the period February 2000 – December 2010 (data source: NASA Giovanni system)

RESULTS The satellite data reveal, for the first time, trends about the annual temperature fluctuations in the eastern Pacific and in the Caribbean Sea. Figure 2 and Figure 4, for instance, illustrate that February generally has the lowest average daytime temperatures, as well as the lowest average nighttime temperatures. From mid 2002 through the end of 2010, the highest average daytime temperature observed was above 29 degrees Celsius, usually in September of each year, while the highest average nighttime temperature was usually just below 29 degrees, Figure 2. Average daytime temperatures (source: NASA Giovanni system)


SEA SURFACE TEMPERATURE TRENDS IN THE CARIBBEAN SEA & THE EASTERN PACIFIC OCEAN

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Figure 3. Average nightime sea surface temperatures, based on MODIS Aqua data for the period February 2000 – December 2010 (data source: NASA Giovanni system)

and also observed in September of each year. The year 2006 had the highest average temperature of the decade. While average temperatures peak at 29 degrees, Figure 5-6 tell a different tale, from the perspective of maximum temperatures. For instance, maximum temperatures have generally been recorded during August. The maximum daylight temperature peaked at roughly 35.7 degrees in August 2004, while the maximum nighttime temperature peaked at roughly 33.3 degrees in August 2005.

Figure 4. Average nighttime temperatures (source: NASA Giovanni system)


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SEA SURFACE TEMPERATURE TRENDS IN THE CARIBBEAN SEA & THE EASTERN PACIFIC OCEAN

Where 2006 had the lowest maximum daylight sea surface temperature (in the month of February), that year also saw the lowest minimum daylight temperature (in April), and the lowest minimum nighttime temperature (in May). Minimum temperatures have generally fluctuated between 13 and 25 degrees during the daytime and 13 to 24 degrees during the nighttime.

Figure 5. Maximum daytime temperatures (source: NASA Giovanni system)

Figure 6. Maximum nighttime temperatures (source: NASA Giovanni system)


SEA SURFACE TEMPERATURE TRENDS IN THE CARIBBEAN SEA & THE EASTERN PACIFIC OCEAN

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Figure 7. Minimum daytime temperatures (source: NASA Giovanni system)1

Figure 8. Minimum nighttime temperatures (source: NASA Giovanni system)2

1 The data values for the months December 2005, April 2006, and May 2006 appear to be anomalous. 2 The data values for the months December 2005, April 2006 and May 2006 appear to be anomalous


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SEA SURFACE TEMPERATURE TRENDS IN THE CARIBBEAN SEA & THE EASTERN PACIFIC OCEAN

DISCUSSION

CONCLUSIONS

Fluctuations in sea surface temperature can have many implications for marine species and marine ecosystems. Where the region is home to the world’s second largest barrier reef system, and where that coral reef has bleached in the past decade, it should be recognized that changes in the ocean’s surface temperature might have adverse changes on the reefs, and reef fisheries that the region’s inhabitants depend on.

It was demonstrated, through the use of NASA’s Giovanni system, that sea surface temperature across the eastern Pacific and the Caribbean exhibit a high degree of intraannual variation. For instance, temperatures are generally low at the end and the beginning of the year, and peak around September. Mean temperatures generally vary between 26 and 29 degrees during the day, and 25.5 and 28.5 during the night. Maximum temperatures, on the other hand, have reached above 35.5 degrees in 2004, a situation which, if exacerbated, will likely lead to bleaching of the region’s coral reefs.

In terms of follow-up studies, this research begs follow-up in the area of establishing statistical relationships between temperature and other factors, such as the incidence of harmful algal blooms or hurricanes. In the case of the former, there is likely a causal relationship between the proliferation of algal blooms and high water temperatures. In terms of the anticipated climate change question, it should be noted first that there is too little data to conclude whether or not the region’s oceans are indeed warming up. However, if they are indeed warming, this could prove disastrous. A study by the University of the West Indies on climate change’s potential impacts on the Caribbean cites how changing temperatures will likely cause the migration of fish species to cooler waters (Nurse 2008). Further analysis is nonetheless warranted in the areas of how temperature has been varying around the coral reefs, exploration of the relationship between temperature and harmful algal blooms, the relationship between temperature and hurricane strengthening, and the relationship between temperature and the productivity of regional fisheries.

While not comprehensive, this study is intended to be a first cut, cursory assessment of sea surface temperature change in the eastern Pacific Ocean and the Caribbean Sea. The satellite data have revealed trends in temperature changes which were previously unknown due to the lack of data. It is hoped that this type of research will pave the way for more in-depth studies of how sea surface temperature is indeed changing, and its relationships with other phenomena, such as hurricanes and harmful algal blooms.


SEA SURFACE TEMPERATURE TRENDS IN THE CARIBBEAN SEA & THE EASTERN PACIFIC OCEAN

ACKNOWLEDGEMENTS This work was supported under NASA Contract No. NNM07AB02C with CATHALAC, through the generous support of the U.S. Agency for International Development (USAID). In particular, Carrie Stokes, Orlando Altamirano, Ruben Aleman, and Michelle Jennings of USAID must be acknowledged. CATHALAC Director Emilio Sempris, NASA Earth Science Division Director Michael Freilich, NASA Program Scientist for Biological Diversity and Program Manager for Ecological Forecasting Woody Turner, NASA SERVIR Project Director Daniel Irwin, and NASA SERVIR International Programs Director Gwendolyn Artis must also be acknowledged for their support, as should Eric Anderson and Africa Flores of the University of Alabama-Huntsville.

REFERENCES Anderson, E.R., Cherrington, E.A., Tremblay-Boyer, L., Flores, A.I, and E. Sempris. 2008. “Identifying Critical Areas for Conservation using measures of Biodiversity and Climate Change in Central America, Mexico, and the Dominican Republic.” Biodiversity 9 (3 & 4): 89-99 Barry, P.L. 2003. “Mesoamerica Burning.” Science@NASA. National Aeronautics and Space Administration. Washington, DC. Available online: http://science.nasa.gov/headlines/ y2003/16may_biocorridors.htm Conservation International (CI). 2006. “Biodiversity Hotspots: Mesoamerica.” Center for Applied Biodiversity Science. Washington, DC. Available online: http://www.biodiversityhotspots.org/xp/hotspots/mesoamerica/Pages/biodiversity.aspx Lillesand, T.M., Kiefer, R.W., and J.W. Chipman. 2007. Remote Sensing & Image Interpretation. Sixth Edition. Wiley & Sons. 756 pp. Nurse, L. 2008. “Incorporating Climate Change Projections into Caribbean Fisheries Management.” Proceedings of the 61st Gulf and Caribbean Fisheries Institute. Gosier, Guadeloupe. Available online: http://procs.gcfi.org/pdf/GCFI_61-20.pdf

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CATHALAC 111 City of Knowledge Clayton, Panama Tel: +507-317-3200 Fax: +507-317-3299 servir@cathalac.org www.cathalac.org

Sea Surface Temperature Trends in the Caribbean Sea & the Eastern Pacific Ocean  

Reviewing the past decade's worth of satellite data, this regional assessment aims to understand how the temperatures of the surface of the...