Mechanistic Drivers Of The North American Monsoon
Presenter: Gigi Giralte P51
Co-Author(s): Marcus Lofverstrom
Advisor(s): Dr. Lofverstrom in the Geosciences Department
1Hydrology & Atmospheric Sciences
The North American Monsoon (NAM) is defined as a seasonal shift in the wind pattern from a dry, westerly flow across northwestern Mexico, Arizona, and New Mexico to a moist, southerly flow. The NAM season occurs between June 15th and September 30th but typically peaks near the end of July through mid-August. The NAM extends along the Sierra Madre Occidental in western Mexico through the Desert Southwest of the United States, including parts of Arizona, New Mexico, and California. Understanding how the NAM is fueled can help improve weather forecasts and messaging for high-impact events. Analysis of climate model simulations shows that the southern part of the NAM region, mainly western/northwestern Mexico, is fueled differently than the northern half, which primarily includes the Desert Southwest of the United States. This is partly caused by various jet influences and their flow, such as the California Low Level Jet. From this, it has been determined that a weaker California Low Level Jet correlates to a stronger monsoon. In addition, it has been determined that the southern NAM is connected to a tropical circulation, predominantly ENSO (El Niño-Southern Oscillation) variability. These varying influences help explain how precipitation values differ between the two halves of the region.