Transcript Lowy_Rebecca_sol _sm

Impacts of Deforestation in
Central America on Regional
Precipitation Patterns
Summer 2013
Princeton Environmental Institute
Medvigy Group
Rebecca Lowy, PEI Summer Intern
Background
 Deforestation in the tropics has long been an issue. This study
focused on Central American rainforests.
 General Circulation Models (GCMs) predict a decrease in
precipitation over deforested rainforests, but observation has
indicated an increase in precipitation in deforested sections of the
Amazon (Baidya Roy).
 A 2005 study (Aguilar) showed for the years 1961-2003 no
significant change in
precipitation overall for
Central America, but
occasions of heavier
rainfall were identified as
becoming more intense.
Baida Roy
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Background Continued
 Andrea Beale conducted a study for her Spring 2013 JP to
further understand precipitation patterns from 2001-2011
 Satellite data was taken from NASA’s Tropical Rainfall Measuring
Mission (TRMM).
 Andrea’s areas of focus:
 all of Central America
 3 locations that had distinct situations of forestation: Previously
Deforested, Recently Deforested, and Forested
 For this project, I reexamined Andrea’s results, as well as
looking at seasonal precipitation
patterns to further
understand the
correlation between
deforestation and rainfall.
All data was accessed &
analyzed using MatLab.
Beale, land cover in selected
areas
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Central America Region
Total Central
American data
included
precipitation over
the ocean, which
gives an
incomplete sense
of the region as a
whole. This could
indicate erroneous
results. However, it
is interesting to
note that during
the wet season,
there is some
increase in
precipitation over
the decade.
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Forested Region
The Forested region
shows what the
undisturbed climate
would likely be. Overall
there is no increase in
precipitation for the
decade. The seasons
however – 3 and 4, in
particular – show
interesting trends.
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Previously Deforested Region
Overall there is no
significant
change, while
season 3 is
increasing rapidly
and season 4
decreasing in
precipitation.
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Recently Deforested Region
While the changes in
seasonal precipitation
here are less than that
of previously
deforested, both
seasons 3 and 4 show
similar trends. The
annual average
similarly shows no
significant change.
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Conclusions
 The lack of significant change over time in the three
distinct locations agrees with the results of various papers
stating that there has been no overall trend in
precipitation for Central America.
 The wet season has a marked increase across all
locations. This follows with Aguilar 2005 results that
observed an increase in amount of precipitation for the
occasions of heavier rainfall.
 What it means for us:
 Wetter wet seasons can lead to flooding and mudslides, while drier
dry seasons will result in drought. These have negative impacts on
agriculture (a main component of life in Central America) and can
endanger human life.
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Conclusions Continued
 Future Research
 Limit analysis of Central America to land for more valuable
results.
 Further analysis of the wet season, specifically on amount of
rainfall that would be considered a “wet day” to find if the
intensity of rainfall is indeed increasing over time.
 Other previously deforested locations should be investigated to
determine long-term impacts. Locations should be chosen on
the west coast as well.
 Since satellite data is not entirely reliable, comparison to ground
data observation would be required to verify the results.
 What I Learned
 A better understanding of the role of rainforests in regulating
local climate regions.
 New analysis skills, especially the use of MatLab and coding.
 That I absolutely want to continue to pursue and academic
course that involves understanding of the environment!
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Special Thanks to:
Professor David Medvigy
Jaya Khanna (graduate student)
PEI
References
Aguilar, E., et al. (2005), Changes in precipitation and temperature extremes
in Central America and northern South America, 1961–2003, J. Geophys.
Res., 110, D23107, doi:10.1029/2005JD006119.
Baidya Roy, S. (2009), Mesoscale vegetation-atmosphere feedbacks in
Amazonia, J. Geophys. Res., 114, D20111, doi:10.1029/2009JD012001.
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