APPLICATION OF REGIONAL DOWNSCALING TO THE FORECASTING OF Pseudonitzschia AND DOMOIC ACID EVENTS
Clarissa Anderson1, Mathew Sapiano2, Bala Prasad2, Christopher Brown3, Yi Chao4, David
Siegel5, Raphael Kudela1, Raghu Murtugudde2
1
University of California, Santa Cruz, CA
2
University of Maryland, College Park, MD
3
NOAA-NESDIS, College Park, MD
4
JPL-Caltech, University of California, Los Angeles, CA
5
University of California, Santa Barbara, CA
Toxigenic blooms of the domoic-acid producing diatom group Pseudo-nitzschia have been
widely reported for the west coast over the last decade and have recently been discovered to be a
potential threat to the nation’s largest estuary, the Chesapeake Bay. Recent downscaling efforts
for the Chesapeake Bay and the California Current System have led to robust hydrodynamic
models currently being applied to empirical habitat suitability models for various harmful algal
bloom taxa. I will discuss the development of these statistical habitat models for predicting
potentially toxigenic Pseudo-nitzschia spp. blooms in both regions and present hindcasts of
bloom probabilities using Regional Ocean Model System (ROMS) and satellite products.
Environmental parameters significantly associated with toxigenic diatom blooms in the
Chesapeake Bay have also been shown to be important for these blooms off the coast of central
California, suggesting certain commonalities across ecosystems, including the possibility of
nutrient limitation as a factor for bloom initiation. Lead times for the forecasts will be extended
by downscaling seasonal climate forecasts and IPCC projections in the context of land use
change. Future work will focus on validating near real-time estimates of the probability of
Pseudo-nitzschia bloom occurrence from ROMS and habitat model predictions as well as
working with end-users and managers to assess practical needs and verify results.