Summer Midlatitude Stationary Wave Patterns Synchronize Northern Hemisphere Wildfire Occurence/Assessing the soil moisture-precipitation feedback in Australia: CYGNSS Observations

Hien Bui

seminar
Mar. 19, 2024

11:10 am – 12:00 pm MDT

Webcast

Main content

The presenter has two topics:

Summer Midlatitude Stationary Wave Patterns Synchronize Northern Hemisphere Wildfire Occurrence  

In this study, we analyze new large-ensemble simulations conducted with the Community Earth System Model, version 2 (CESM2-LE) in 1 degree resolution to elucidate the linkage between atmospheric stationary waves and clustered Northern Hemisphere wildfire occurrences, as well as the potential changes in this relationship in a warmer climate. Our analysis shows that wildfire occurrences tend to be clustered regionally by a zonal wavenumber 5–6 stationary wave pattern. More persistent regional high-pressure conditions further increase wildfire probabilities. This relationship can be largely explained by the quasi-stationary moisture and relative humidity conditions which are associated with the summer midlatitude wave trains. More persistent regional high-pressure conditions further increase likelihood of wildfire occurrences.  

Assessing the soil moisture-precipitation feedback in Australia: CYGNSS observations

This study investigates the relationship between soil moisture and next-day precipitation in Australia. Analyzing the 5-year soil moisture data from the NASA Cyclone Global Navigation Satellite System (CYGNSS), we find that soil moisture anomalies influence next-day precipitation probability where higher soil moisture is associated with a higher probability of precipitation, even allowing for precipitation persistence. We also find that this feedback is generally positive in northern Australia but slightly negative in the southern regions, suggesting regional dependence. Linkages between the persistence of dry/wet soil moisture days and the possibility of wildfires and floods are also discussed.

Hien Bui

Monash Univerity