Summer Convective Precipitation Changes over the Great Lakes Region
under a Warming Scenario
Abstract
To understand the future summer precipitation changes over the Great
Lakes Region (GLR), we perform an ensemble of regional climate
simulations through the Pseudo-Global Warming (PGW) approach. We found
that different types of convective precipitation respond to the PGW
signal differently. Isolated deep convection (IDC), which is usually
concentrated in the southern domain, shows an increase in precipitation
to the north of the GLR. Mesoscale convective systems (MCSs), which are
usually concentrated upstream of the GLR, shows a shift to the
downstream region with increased precipitation. Thermodynamic variables
such as convective available potential energy (CAPE) and convective
inhibition energy (CIN) are found to be increased in almost the entire
studied domain, providing a potential environment more (less) favorable
for stronger (weaker) convection systems. Meanwhile, changes in lifting
condensation level (LCL) and level of free convection (LFC) show a
strong correlation with variations in convective precipitation,
underscoring the significance of these thermodynamic factors in
controlling precipitation over the domain. Results show that decreased
LCL and LCF over places where convective precipitation is increased, is
mainly contributed by the atmospheric moisture increase. In response to
the prescribed warming perturbation, MCSs show more frequent occurrences
downstream, while localized IDCs show more intense rain rate, longer
duration, and larger rainfall area.