Gulf of Maine Alexandrium fundyense Model Results – 2013

 

Ruoying He1, Yizhen Li1, Dennis McGillicuddy2, Don Anderson2, Bruce Keafer2

1North Carolina State University

2Woods Hole Oceanographic Institution

 

 

Disclaimer: these simulations are for experimental purposes only.

 

Results here represent model solutions initiated from a cyst abundance map from October 2012, with germination, growth, and transport of Alexandrium fundyense cells driven by the factors listed below.

 

Physical circulation model

Multiple nested ROMS, ca. ~1km resolution in GOM

Tides (M2, S2, N2, K2, K1, O1, Q1)

6-hourly wind and heat fluxes from NOAA/NCEP NOMADS (35-km resolution)

River runoff data from USGS

Sea surface temperature from satellites

Initial conditions and open boundary conditions from large-scale parent model (HYCOM)

 

Alexandrium fundyense model

Population dynamics from Stock et al. (2005); McGillicuddy et al. (2005), He et al., (2008) and Li et al.(2009)

Cyst maps from Fall 2012 Survey in comparison with earlier years

(http://omglnx3.meas.ncsu.edu/yli/cystmap/cystmap_04_12_v2.png)

Solar radiation from NOAA/NCEP

Monthly climatological nutrient fields from University of Maine

The mortality rate of A. fundyense is now parameterized using the temperature dependent Q10 formulation (Durbin and Durbin, 1992)

 

Modeled A. fundyense bloom

          An animation showing surface wind fields and modeled bloom conditions from February 1, 2013 to August 04, 12:00, 2013

http://omglnx3.meas.ncsu.edu/GOMTOX/2013forecast/dino_13.htm
 
A 3-D animation showing modeled surface and subsurface cell abundance from February 1, 2013 to August 04, 12:00, 2013
           http://omglnx3.meas.ncsu.edu/GOMTOX/2013forecast_3d/dino_13.htm


Model-data comparisons







Figure 1. Comparison between observed (left) and modeled (right) surface cell concentration (unit: Cell#/L) on  April10th, 2013. (Thanks to MWRA for providing preliminary observations)





               Figure 2. Comparison between observed (left) and modeled (right) surface cell concentration (unit: Cell#/L) on  May17th, 2013. (Thanks to MWRA for providing preliminary observations)




             Figure 3. Comparison between observed (left) and modeled (right) surface cell concentration (unit: Cell#/L) during  May14-16th, 2013 Tioga survey.
Recent results from the ESP and R/V Tioga ground-truthing cruise (TI667, 14-16 May) indicate the model is overestimating the bloom in the western Gulf of Maine.  Hydrography collected during the R/V Tioga survey reveal a water mass anomaly reminiscent of that present in 2010, which suppressed the A. fundyense bloom as described in McGillicuddy et al. 2011 (Limnology and Oceanography, 56(6), 2411–2426).  Although the intermediate water is not quite as fresh as in 2010, it is significantly warmer, and quite distinct from the conditions present during the large bloom of 2008.  Continued analysis of these observations, together with the associated nutrient data, will help assess the degree to which these changes in water mass properties are affecting the growing conditions for A. fundyense populations in the region.



Figure 4. Comparison between ESP Chris and Don observed (black and blue dots) and model simulated (grey solid line) surface cell concentration (unit: Cells/L) at location [-70.443oW, 43.18oN]
and [-70.4406oW, 43.1726oN] .



Last update: August 02, 2013