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

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

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.

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.

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.

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

Basin-scale model -- ROMS

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

Slide 9

Upper Layer Integrated Path

Model simulation validates our hypothesis that GS is northward (southward) during High (Low) NAO years

Advection of LSW

Basin-Scale Physical Fields

Are available from

www.smast.umassd.edu/modeling/ROMS.htm

Questions and Concerns: avijit@umassd.edu

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

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

High-Res fields for GOM

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

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


	Avijit Gangopadhyay
	With Bisagni, Gifford and Batcheldar
	(PhD student: Ayan Chaudhuri)
	GLOBEC meeting, WHOI
	29 October 2007


	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


	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.


	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.


	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.


	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


	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


	Model simulation validates our hypothesis that GS is northward (southward) during High (Low) NAO years


	Are available from
	www.smast.umassd.edu/modeling/ROMS.htm
	Questions and Concerns: avijit@umassd.edu


	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


	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


	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


	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