Aspects of the physical and physical-biogeochemical dynamics of Massachusetts Bay and Stellwagen Bank Pierre F.J. Lermusiaux Division of Engineering and Applied Sciences Harvard University Sand Lance Workshop, November 24, The Harvard Ocean Prediction System -Predictions, data collection and data assimilation -Recent applications relevant to fisheries and society (*) 2.Massachusetts Bay and Stellwagen Bank processes 3.Some Directions for Sand Lance Research (physics-biology)

HOPS – Harvard Ocean Prediction System (A. R. Robinson et al.) Internal Weather of the Sea (most energetic motions) Applications: e.g. AFMIS (G. Bank), EgyptAir Flight 990, Prestige Oil Spill

Multi-Variate Coupled Physical-Acoustical-Biological System DATA ASSIMILATION: Combines model and data for best ocean estimate Error Subspace Statistical Estimation – ESSE

R/V Alliance (NATO) in Massachusetts Bay (June 2001) Dr. Pat Haley and Wayne Leslie

Physical Observations AUV WHOI Gliders SIO Gliders Dorado NPS REMUS Cal Poly REMUS Moored/Fixed CODAR M1/M2 NPS ADCP MBARI Profiler Aircraft Twin Otter P3 / AXBT/ SST Ships Pt. Sur John Martin Drifting Surface Drifters Profilers Satellite SST SeaWiFS

FOOD WEB: Multiple trophic relations, e.g. leading to adult herring (arrows show energy flow). Notice the Sand Lance!

Cartoon of horizontal circulation patterns for stratified conditions in Massachusetts Bay, overlying topography in meters (thin lines). Patterns are not present at all times Most common patterns (solid), less common (dashed) Patterns drawn correspond to main currents in the upper layers of the pycnocline where the buoyancy driven component of the horizontal flow is often the largest HORIZONTAL CIRCULATION PATTERNS IN MASSACHUSETTS BAY

ASCOT-01 (6-26 June 2001) : Positions of data collected and fed into models

ASCOT-01: Sample Real-Time Forecast Products Massachusetts BayGulf of Maine 2m Temp.10m Temp.3m Temp. 25m Temp. 5m Chlorophyll15m Nitrate

Coupled bio-physical sub- regions of Massachusetts Bay in late summer: Dominant dynamics for trophic enrichment and accumulation

Chlorophyll at 5m, from June 14 to June 28, 2001

Chlorophyll cross-section, from June 14 to June 28, 2001 Scituate Stellwagen Bank

Sub-surface wind-forced upwelling/downwelling at Stellwagen Bank: sustained impacts on Sand Lance?

Internal tides, waves and bores and their effects on plankton distribution: impacts on Sand Lance? Left: Interpolated backscatter (top panel) and velocity magnitude (bottom panel) with depth (m) and time (s) obtained from the shipboard Doppler current meter. Bin size is 1 m. Boat steaming towards Stellwagen bank (Massachusetts) at about 3-4 knots. Patterns in backscatter and velocity magnitude reveal an internal bore followed by internal solitary waves s is about 9:11 EDT, 18 Sep Jesus Pineda and Scott Gallager Woods Hole Oceanographic Institution; Alberto Scotti, University of North Carolina Right: a surface slick associated to the leading edge of the bore (see left panels) observed from the bow of the RV Connecticut. The photo was taken 91 minutes after 09:11 EDT, 18 Sep The boat was steaming onshore, in the direction of propagation of the wave.

Ship Radar screen The three parallel clouds of green points are the surface manifestation of a train of internal waves. Jesus Pineda and Scott Gallager Woods Hole Oceanographic Institution; Alberto Scotti, University of North Carolina

Directions for Sand Lance Research (physics-biology) What are the impacts of physical forcing on the Sand Lance? (either directly due to temperature and currents, or indirectly through plankton) –Meanders of the Gulf of Maine coastal current –Mesoscale gyres and eddies –Sub-surface wind-induced upwelling/downwelling –Tides (barotropic and internal) –Internal waves, bores and solitons (mainly summer/fall) Is the Sand Lance behavior modified by these physical forcings? If yes, how? What about predators behavior? What is the seasonal and inter-annual variability of the Sand Lance population? Are the Sand Lance larvae and juvenile locally maintained or advected from elsewhere (Jeffreys Ledge, GOM, etc) Is the Sand-Lance population predictable? –Weather of the Sea: 2-3 days because of winds (internal ecosystem: at least 2 weeks) –Seasonal predictions How can we best help fishermen and local Mass. Bay communities/management?

EXTRA VUGRAFS

Integrated Ocean Observing and Prediction Systems Platforms, sensors and integrative models

Surface standard deviations error forecasts for Oct. 1 overlaid with the sampling tracks carried out on Sep. 30 and Oct. 1, 1998 Objective Adaptive Sampling