Topographic Enhancement of Tropical Cyclone Precipitation (TCP) in
Eastern Mexico
Abstract
Tropical Cyclone Precipitation (TCP) is one of the major triggers of
flash flooding and landslide in eastern Mexico. The interactions between
the topography of the Sierra Madre Occidental and the TCP of storms from
the Gulf of Mexico are still poorly understood. We apply multiple
statistical techniques to a 99 year daily TCP record and an elevation
data with high spatial resolution. Correlation analysis for the whole
dataset is dominated by the strong inland-to-ocean gradient of both TCP
and topography. Clusters defined by grids’ distances to the coast show
significant positive correlations between TCP variables and topographic
complexity variables (Range, Standard Deviation, and Slope). The
quantile analysis demonstrates that the most extreme TCPs are more
likely to locate in grids with higher amounts of topographic complexity
(Range and Standard Deviation) than the median and the trivial TCPs. The
Random Forest (RF) model is an excellent tool to disentangle complex
relationships between TCP and topography. The models show that the
grid’s location and aspect of the slope aspect are the two most
important variables that affect the TCP statistics. TCP in eastern
Mexico is sensitive within two zones: (1) Low lying coastal regions with
lower elevation and less topographic complexity. (2) The mountainous
region with higher elevation and topographic complexity, especially with
the slope facing the windward direction to the Gulf. All results support
that the topography in eastern Mexico has an enhancing effect on the
TCP.