Miguel F.Acevedo
ABSTRACTS
RELATIONS OF CLIMATE VARIABILITY IN VENEZUELA
TO TROPICAL PACIFIC SST ANOMALIES
Miguel F. Acevedo 1,2, Kent McGregor1, Rigoberto
Andressen2, Hirma Ramirez2 and Magdiel Ablan2.
1)University of North Texas, Denton, Texas, 2)Universidad de Los
Andes, Mérida, Venezuela
10th Symposium on Global
Change
Studies, American Meteorological Society, preprints pp:81-84,
Annual
Meeting, Dallas, TX. 1999
ABSTRACT
The precipitation response to the warm phase of ENSO in South America
corresponds to positive anomalies in western coastal areas, Perú
and Ecuador, and possibly negative anomalies for Northern and Eastern
South
America where effects of Sea Surface Temperature (SST) in the Atlantic
combine with the ENSO effect. The methodology used time series analysis
to explore statistical relationships of monthly SST anomalies, in the
tropical
Pacific and Atlantic, with monthly climate anomalies in two sites of
the
Llanos of Venezuela for the period 1951-1997. For contrast, one site is
continental and the other is located near the Atlantic coast. Climate
data
for the two sites consists of air temperature, precipitation and solar
radiation. Monthly water balances are calculated and used as an
indication
of the potential impact of negative rainfall anomalies on soil
moisture.
The ENSO monthly anomalies in the Niño 3.4 region are used to
classify
months of Pacific SST events as “Niño”, “Niña” and
“Neutral”.
Analysis of variance is employed to test the hypothesis that climate
monthly
anomalies at each site differ according to the above three Pacific
event
groups. The same tests are also conducted after dividing the climate
data
according to rainy and dry season at each site. These differences are
found
to be statistically significant for temperature at both sites, but only
for certain seasons and sites for precipitation and water balance. The
statistical relations are sought in order to provide scenarios of
climate
variability that could be used for the assessment of the impact of such
variability on terrestrial ecosystems by using site-specific models. As
an example, monthly climate data for the continental site are used as
input
to a forest ecosystem model to calculate soil moisture deficit.
Keywords: ENSO, El Niño, Sea Surface Temperature, SST,
Tropical Pacific, Tropical Atlantic, South America, Venezuela, Llanos,
Climate Variability, Soil Moisture, Forest Ecosystems.
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