Fiat Lux: Tarik Benmarhnia & Sasha Gershunov

More information on their combined work found here:

Drs. Gershunov and Benmarhnia are particular experts on the health impacts of wildfires. Their smoke-health research direction was initially started with Multicampus Research Programs and Initiatives (MRPI) University of California Office of the President funding (project ended in December 2020) and has been supported by the California Environmental Protection Agency and other sources. 

This involves understanding the climate drivers of wildfire as well. These prolific researchers collaborate with ecologists on understanding the weather-climate-ecosystem processes that prime fuels for catastrophic wildfire via precipitation, Santa Ana winds, and coastal marine layer clouds impacts on fuel moisture. In addition, Dr. Gershunov notes that “Coastal clouds (marine layer), their dynamics, and how they modulate coastal climate as well as extremes, e.g. expressions of heat waves along the coast, is another robust area of our research.”

These two researchers are also investigating compounded health impacts from wildfire and heatwaves, building on their research into California heatwaves and their heat-health impacts.

Relevant Research Articles:

Fire weather — The both of them study Santa Ana winds and other downslope wind systems (e.g. Diablo, etc.) – the dry gusty winds that drive our largest wildfires and partially determine the fire regime in coastal California.

Guzman Morales, J., A. Gershunov, J. Theiss, H. Li and D.R. Cayan, 2016: Santa Ana Winds of southern California: Their climatology, extremes, and behavior spanning six and a half decades. Geophysical Research Letters, 43, doi:10.1002/2016GL067887. 

Guzman Morales, J. and A. Gershunov, 2019: Climate change suppresses Santa Ana Winds of Southern California and sharpens their seasonality. Geophysical Research Letters, 46, 2772–2780, DOI: 10.1029/2018GL080261.

Gershunov, A., J. Guzman Morales, B. Hatchett, R. Aguilera, T. Shulgina, K. Guirguis, J. Abatzoglou, D. Cayan, D. Pierce, P. Williams, I. Small, R. Clemesha, L. Schwarz, T. Benmarhnia, A. Tardy, 2021: Hot and cold flavors of southern California’s Santa Ana winds: Their causes, trends, and links with wildfire. Climate Dynamics. In Press.

Fire climate — They study fire climate (mainly via precipitation) variability and change underpinning California’s wildfire regime and how the salient climate elements are pushing wildfire regimes to evolve into the future. These studies (mostly focused on precipitation regimes) are relevant for California and other Mediterranean climate regions around the globe. 

Polade, S.D., D.W. Pierce, D.R. Cayan, A. Gershunov and M.D. Dettinger, 2014: The key role of dry days in changing regional climate and precipitation regimes. Nature Scientific Reports 4, 4364; DOI:10.1038/srep04364.

Polade, S.D., A. Gershunov, D.R. Cayan, M.D. Dettinger and D.W. Pierce, 2017: Precipitation in a warming world: Assessing projected hydro-climate of California and other Mediterranean climate regions. Nature Scientific Reports, 7: 10783, DOI:10.1038/s41598-017-11285-y. Gershunov, A., T.M. Shulgina, R.E.S. Clemesha, K. Guirguis, D.W. Pierce, M.D. Dettinger, D.A. Lavers, D.R. Cayan, S.D. Polade, J. Kalansky and F.M. Ralph, 2019: Precipitation regime change in

They collaborate with ecologists to translate our results on fire weather and climate to understand California’s changing wildfire regimes:

Syphard, A.D., A. Gershunov, D.M. Lawson, H. Rivera Huerta, J. Guzman-Morales, and M.K. Jennings, 2018: San Diego Wildfires: Drivers of Change and Future Outlook. Pages 49 – 69 in: Jennings, M.K., D. Cayan, J. Kalansky, A.D. Pairis et al. San Diego County ecosystems: ecological impacts of climate change on a biodiversity hotspot. California’s Fourth Climate Change Assessment, California Energy Commission. Publication number: EXT-CCC4A- 2018-010 

Williams A.P., J.T. Abatzoglou, A. Gershunov  J. Guzman Morales, D.A. Bishop and D.P. Lettenmaier, 2019: The link between anthropogenic climate change and wildfire in California. Earth’s Future, 7. 10.1029/2019EF00121. 

Keeley, J.E., J. Guzman Morales, A. Gershunov, A.D. Syphard, D.R. Cayan, D.W. Pierce, M. Flannigan and T. Brown, 2021: Ignitions explain more than precipitation or temperature in driving Santa Ana Wind fires. PNAS. In Press.

Health impacts — Tarik and Sasha have been advising a postdoc to study the impacts of smoke from Santa Ana-fanned wildfires on air quality and health:  

Aguilera, R., A. Gershunov, S.D. Ilango, J. Guzman Morales and T. Benmarhnia, 2020: Santa Ana winds of Southern California impact PM2.5 with and without smoke from wildfires. GeoHealth, 4, e2019GH000225.

Leibel S., M. Nguyen, W. Brick, J. Parker, S. Ilango, R. Aguilera, A. Gershunov, T. Benmarhnia, 2020: Increase in Pediatric Respiratory Visits Associated With Santa Ana Wind-driven Wildfire and PM 2.5 levels in San Diego County. Annals of the American Thoracic Society, doi: 10.1513/AnnalsATS.201902-150OC.


Aguilera, R., K. Hansen, A. Gershunov, S. Ilango, P. Sheridan, and T. Benmarhnia, 2020: Respiratory Hospitalizations and Wildfire Smoke: A spatio-temporal analysis of an extreme firestorm in San Diego County, California. Environmental Epidemiology, 4, doi: 10.1097/EE9.0000000000000114. 

Aguilera, R., T. Corringham, A. Gershunov and T. Benmarhnia, 2021: Wildfire smoke impacts respiratory health much more than fine particles from other sources: observational evidence from Southern California. Nature Communications. 12:1493,