Abstract
Hurricanes cause severe impacts on the ecosystem, which substantially
affects the carbon cycle at the local or regional scale. During the
hurricanes, the loss of many vegetation/trees in the forest and
agricultural lands causes more carbon to be released into the
atmosphere. Studying the effects of hurricanes on the terrestrial carbon
cycle, which includes gross primary product (GPP), net ecosystem
exchange (NEE), heterotrophic respiration (Rh), and their interactions
with land-use change, flood, and others are critical to understand the
effect on the terrestrial ecosystem. The main objective of this research
was to evaluate the impact of three hurricanes (Harvey, Irma, and Maria
in 2017) on the carbon cycle and study the interactions among the flood
events, land uses, and terrestrial carbon cycling in the state of Texas,
Florida, Puerto Rico using satellite measurements. This study analyzed
the GPP, NEE, and Rh distributions in the coastal climate zones in
Texas, Florida, and Puerto Rico during hurricane season using Soil
Moisture Active Passive (SMAP) carbon products. SMAP Carbon products
(Res=9 km) were evaluated using CO2 flux data measured at EC flux site
on the Prairie View A&M University Research Farm, Texas. Results showed
Florida (Irma) had higher carbon emissions and lower GPP during the
hurricane compared to Texas (Harvey), and Puerto Rico (Maria). For
example, hurricanes Harvey (08/26/2017), Irma (09/10/2017), and Maria
(09/20/2017) caused 2.6, 4.1, and 3.03 gC/m2, of carbon emissions when
the recorded daily precipitations were 162, 135, and 241 mm,
respectively. However, mostly carbon uptakes or low (<1 gC/m2)
carbon emissions were observed on the same day in 2016 and 2018. The
analysis showed that the amount of precipitation is not the only driving
factor causing increased carbon emission; the characteristics of the
drainage area also affect the carbon cycle and emission. Overall, the
results showed that hurricanes increase carbon emissions. This study
helps to understand the impact of hurricanes on the carbon cycle through
analyses of spatial and temporal variations of carbon emission and
uptake during the hurricane season.