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Future precipitation characteristic change and mechanisms over the Great Lakes Region through the Pseudo-global warming approach

Presentation Date
Monday, December 11, 2023 at 8:30am - Monday, December 11, 2023 at 8:40am
Location
MC - 3006 - West
Authors

Author

Abstract

To understand how future precipitation will change over the Great Lakes region by the end of the century, we perform an ensemble of regional climate simulations through the Pseudo-Global Warming (PGW) approach. By adding the climate perturbations derived from a suit of global climate models to the baseline climate, the ERA-5 reanalysis data in this case, we generated the future forcing and used it to drive the regional climate model to represent the future scenario. We decompose precipitation into two types: isolated deep convection (IDC) and mesoscale convective systems (MCS). We found that different types of convective precipitation respond differently, with IDC increasing in the northern part of the Great Lakes Region (GLR), while MCS increasing in the eastern part of GLR. In general, thermodynamic variables such as convective available potential energy (CAPE) and convective inhibition energy (CIN) are found to be increased almost over the entire domain, whereas lifting condensation level (LCL) and level of free convection (LFC) are found to be the determining factors of precipitation changes. By dissecting the effect of temperature and moisture on these thermodynamic variables, we found that temperature perturbation (i.e., warmer temperature) increases LCL and LFC, not favorable for precipitation development; but more moisture reduces the LCL and LFC, which is more conducive for convection to occur. We also found that the changes in MCS/IDC precipitation over GLR align very well with their corresponding near surface relative humidity changes.

Category
Atmospheric Sciences
Funding Program Area(s)
Additional Resources:
NERSC (National Energy Research Scientific Computing Center)