University:
Boston University
Course:
CAS EE 144 | Introduction to Oceanography
Academic year:

2022
Views:

448

Pages:

17
Author:

pubicswprv

A Global-Regional-Estuarine Nested FVCOM System: A Unstructured-grid Ocean Model With Aim at Simulating the Multi-scale Oceanic Response to Climate Change Outline 1. Review of critical needs for a model to resolve multi-scale processes over global-basin-coastal-estuarine-watershed scales; 2. Updated development of unstructured grid Finite-Volume Coastal Ocean Model (FVCOM) system; 3. Examples of applications of FVCOM to multi-scale problems; The northeast US coast and China Seas 4. Summary Examples of Multi-Scale Physical Processes Global: ~10,000 km High-frequency waves: ~ 1 m Basin: ~1,000 km Convection: ~ 1 km Coastal: ~10 km From Emily F Keiley and Brian Rothschild (SMAST) BIOMASS INDEX PRINCIPLE GROUNDFISH 1968 - 2004 BIOMASS INDEX (KG/TOW) S. RED HAKE 120.000 100.000 N. RED HAKE S. SILVER HAKE 80.000 N. SILVER HAKE ACADIAN REDFISH POLLOCK 60.000 40.000 GB HADDOCK GOM HADDOCK GB COD 20.000 0.000 GOM COD YEAR Impact of the Arctic Ocean to the western coastal region of the North Atlantic Ocean Spawning Site Local via Remote Forcing Local heat flux Flux From the remote upstream region Geostrophic Water Transport on Sections 1, 2 and 6 From D. K. Perovich and J. A. Richter-Menge Arctic Sea ice in summer 2007 From Don Anderson (WHOI) (Presentation at the MWRA meeting) May 27-29, 2008 From Joe DelliCarpini (National Weather Service at Taunton) Challenges We Are Facing to • Lack of the observation 4-dimensional (x,y,z,t) network that is capable of resolving the multi-scale physical and ecosystem processes; • Lack of the systematic understanding of impacts of global climate change on the coastal physical and ecosystem processes. Key Issues Multi-Scale (global-basin-coastal-estuarine-wetland) Interaction ! Two Critical Issues: Basin-shelf interaction Basin scale 1. Multi-scale dynamics: Basinshelf interaction, convection via advection, etc. 2. Open boundary connected to the North Atlantic Ocean and Pacific Ocean Coastal process Ocean Model Dynamics ~ a few meters ~1 ~1000 km Non-hydrostatic Hydrostatic Surface elevation " = ~1 Local water depth H Surface elevation " = <<1 Local water depth H ! Large-scale motion in which the vertical motion is at least one order of magnitude smaller than the horizontal motion. Vertical convection, over-turning, and high frequency internal waves are not resolved. ! Small-scale motion in which vertical motion is the same order of the horizontal motion. Vertical convection, over-turning, and high frequency internal waves can be resolved. In the ocean, Numerical error speed * s c = ± gH sin2 k"x s + sin2 l"y s 2 (k"x s ) + (l"y s ) 2 * L c = ± gH ! Small Domain! sin2 k"x L + sin2 l"y L 2 (k"x L ) + (l"y L ) 2 Large Domain Because Δxs ≠ ΔxL; Δys ≠ ΔyL; The surface gravity wave speed propagating from the small domain is not equal at the nesting boundary. Energy accumulation at the boundary ! Unstructured grid Common boundary Non-hydrostatic process Unstructured nesting approach: Mass conservation