YEAR-TO-YEAR VARIABLITY IN HYDROMETEOROLOGY OF A TROPICAL
MONTANE
RAINFORESTM. Zapata1,2, G. Miller2, E. Gonzales3, K. Brumbelow4,
G. Moore5
1Lone Star College; 2,4Texas A&M University, Dept. of
Ecosystem Science & Management and Civil & Environmental
Engineering,3Soltis Center for Research and Education in San Isidro
de Peñas Blancas, Costa Rica, 5Texas A&M University, Dept. of
ESSM
Introduction
Methods and Instruments
• Total rainfall was approximately
1026 mm, or 40%, less than
average.
• Relative humidity was
approximately 3%, above
average.
• Solar radiation was
approximately 12 W/m2, or 9%,
above average.
• Temperature was 0.3°C, or 1%
below average.
Conclusion
Acknowledgments
Thank you to the Texas A&M Soltis Center Director, Eugenio
Gonzalez, and the
Soltis Center staff who made this research possible. I’d also
like to thank the rest
of the REU students for helping me take measurements and record
data for my
project. Funding for this Research Experiences for Undergraduate
program is
provided by the National Science Foundation’s Division of Earth
Sciences (EAR-
1659848).
Figure 1: Google Earth Satellite map of Costa Rica
with a marker showing the location of the Texas
A&M Soltis Center
Figure 2: Image captured by the high resolution phenocam
at the Texas A&M Soltis Center
(https://phenocam.sr.unh.edu/webcam/sites/soltis/).
Figure 6A: Cumulative rainfall at 456 m
Results –
Time Series 2018-2019
Results - Elevation Effect
Figure 3A: Headstream located
at the Texas A&M Soltis Center
Figure 3C: Datalogger CR100, Campbell Scientific
Figure 3B: On-site
Meteorological Station
recording precipitation in 5-
minute intervals
Results –
Year-to-year Variability (2010-2018)
• Average Greenness index slightly
increased by 0.63%
• Total precipitation decreased 449
mm or 29%
• In the span of July 2nd to 13th 2019,
average water level from second-
order stream in decreased by 85%
in comparison to 2018 results
From January to June, cumulative rainfall at 456 m in 2019
was
approximately 449 mm, or 29%, less than in 2018, while at 1122
m
cumulative rainfall decreased by approximately 25%, or 304
mm.
Methods:
Long-term meteorological
data was collected and
analyzed at the Soltis Center
site in the northern region of
Costa Rica to understand the
drought’s impact. Flow was
measured in two near-by
streams, one headwater and
one second-order.
Instruments:
▪ Datalogger: CR1000,
Campbell Scientific
▪ Wind: Wind Sentry, RM
Young
▪ Barometric pressure:
CS100, Campbell Scientific
▪ Solar Radiation: LI-200R,
LI-COR Biosciences
▪ Tipping Bucket: TE525,
Texas Electronics
▪ RH and T: HMP60,
Campbell Scientific
▪ Phenocam: StarDot
NetCam SC
▪ Weir and Chachagua
pressure transducer:
Levelloger Edge, Solinst
Instruments
Despite a 40%, or 1026 mm decrease in precipitation in 2019
compared to the
average of the previous eight years and decreased cumulative
rainfall in 2019
compared to 2018, the Green Chromatic Coordinate (GCC) slightly
increased
from 2018 to 2019. Temperature, solar radiation, and
precipitation were below
average and relative humidity was above average for 2019
compared to the
average of the previous eight years. These markers are opposite
of expected
during periods of reduced rainfall.
Figure 3D: Diagram of
a tipping bucket Figure 3D: Student recollecting
data from logger
From the figures above we can observe that although there was
a
decrease in precipitation and relative humidity, temperature and
solar
radiation stayed below average.
• Average Solar Radiation increased
27 W/m2 or 18%
• Average Soil Moisture decreased
by 29%
• Average streamflow from
headstream decreased by 0.001406
m^3/s or 45%
• 2019
Figure 6B: Cumulative rainfall at 1122 m
Future Research
Ongoing analysis of incoming solar radiation and fog frequency
will help us
further understand the relationship between precipitation and
forest health to
help us better assess forest response to severe drought.
Image captured by the high resolution phenocam at the Soltis
Center (https://phenocam.sr.unh.edu/webcam/sites/soltis/).Image
captured by the high resolution phenocam at the Soltis Center
(https://phenocam.sr.unh.edu/webcam/sites/soltis/)
The rainforests of Costa Rica
experienced a drought beginning
in November 2018 that has not
abated by July 2019. Although
there is considerable research on
the effects of drought and plant
health, few direct measurements
have been previously available to
characterize the effects of such a
severe drought on a tropical pre-
montane transitional forest.
We hypothesize that a decrease
in precipitation led to an increase
in light availability, enhancing the
greenness of the forest canopy
and decreasing flows in
headwater and second-order
streams. To test this hypothesis,
long-term meteorological data
was collected and analyzed at
the Texas A&M Soltis Center.
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