1	Impacts of Climate and basin-scale variability on the seeding and production of Calanus finmarchicus in the Gulf of Maine and Georges Bank Avijit Gangopadhyay With Bisagni, Gifford and Batcheldar (PhD student: Ayan Chaudhuri) GLOBEC meeting, WHOI 29 October 2007
2	List of Investigators Avijit Gangopadhyay (PI – Basin-scale physical modeling) Jim Bisagni (UMass Dartmouth) – Satellite SST field, Hydrographic analysis Dian Gifford (URI) – Zooplankton data analysis Hal Batchelder (OSU) – IBM modeling
3	Goals and Objectives to probe the connections between Calanus finmarchicus distributions and the physical oceanographic properties, climate variability, and basin-scale circulation changes that are likely to affect the copepod’s transport onto Georges Bank. We will do this using a combination of numerical model simulations and observational data.
4	Methodology (1) Set up and run an individual based model (IBM) for the Northwest Atlantic, using the high-NAO (1980-1993) and low-NAO (1962-1971) forced physical fields from an ongoing eddy-resolving North Atlantic simulation. Perform a set of eddy-resolving basin-scale model simulations during 1988-1999 starting from already existing high-NAO simulations (from the ongoing NASA project) and run the IBM to study the interannual variability of C. finmarchicus seeding and production in this region.
5	Methodology (2) Analyze long-term in-situ physical and biological datasets and satellite-derived sea surface temperature (SST) along with in-situ physical, biological, and chemical data collected during the GLOBEC core-measurement period (1995-1999), and validate the basin-scale physical and biological fields to develop a broader understanding of C. finmarchicus seeding and production. Generate four-dimensional high-resolution (5-km) physical fields using basin-scale fields and available data during 1993-1999, and run a series of IBM simulations at higher resolution in order to address questions relating ecosystem variability on the Scotian Shelf, on Slope Sea and within the Gulf of Maine and on Georges Bank to the large-scale fluctuations of the NAO.
6	Current/Future Work The High NAO simulation will be used as initial condition to run the ROMS model for GLOBEC years (1995-1999) SOC forcing available from 1980-1999 will be used to force the model instead of the NCEP climatology Model output is used to track the 1998 event of southwestward inflow of Labrador Current Melding of ROMS with FORMS for 1995-1999 using 5-day SST fields Run IBM for sensitivity tests for different hypotheses
7	Basin-scale model -- ROMS
8	Validation Criterion The Gulf Stream position is northward (southward) during High (Low) NAO years. The model is spun-up using Levitus climatology for the North Atlantic Basin and subsequently forced with adjusted NCEP High and Low NAO fields. GS mean positions are computed at different depths for both High and Low NAO simulations for comparison
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10	Upper Layer Integrated Path Model simulation validates our hypothesis that GS is northward (southward) during High (Low) NAO years
11	Advection of LSW
12	Basin-Scale Physical Fields Are available from www.smast.umassd.edu/modeling/ROMS.htm Questions and Concerns: avijit@umassd.edu
13	Proposed Biological simulations Individual-based models (HPB) Lagrangian pathways Zooplankton data as initial and validation fields (DG) Seeding vs. production hypothesis testing Impact of Labrador water inflow on Slope sea and GOMGB regions
14	Creating high resolution fields Use Feature oriented regional modeling system (FORMS) for GOMGB (Gangopadhyay et al., 2003; Brown et al. 2007a-b) 270 non-dimensional structure functions for temperature and salinity along and across seven features in the Gulf/Bank Calibrate with SST 5-day composite (Bisagni’s lab) Use basin-scale simulations as background Multiscale Objective analysis will meld basin-to-regional scale fields Use these high-resolution fields for biological simulations
15	High-Res fields for GOM
16	On Pan-Regional Synthesis Current Basin-scale North Atlantic model will be nested within a CLIMATE-scale model Retrospective 50-year analysis Pan-Atlantic synthesis Atlantic-Pacific comparison when forced with large-scale atmospheric forcing
17	Summary Basin-scale simulations are complete Advection of LSW during 96-98 is realized in the model simulation Will use this set-up to start GLOBEC period high-resolution simulations and nowcasting Biological IBM towards understanding impact of climate and BSV on calfin seeding and production