Download sea surface temperature trends in the caribbean

SEA
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 • [email protected]
May 2011
SEA
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
[email protected]
www.cathalac.org