1 / 13

Outline

Application of a Coupled Physical-Biogeochemical Model to Simulate and Forecast the Ecological Variability of Chesapeake Bay. Outline. ChesROMS Community Model Biogeochemical Model Implementation & Waypoints Assessment of Ecosystem Model Solutions Concluding Remarks.

saki
Download Presentation

Outline

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Application of a Coupled Physical-Biogeochemical Model to Simulate and Forecast the Ecological Variability of Chesapeake Bay

  2. Outline • ChesROMS Community Model • Biogeochemical Model Implementation & Waypoints • Assessment of Ecosystem Model Solutions • Concluding Remarks MODIS Image from Kemp et al. 2005

  3. ChesROMS Community Model • ROMS 3.0 • Curvilinear Horizontally • σ-coordinate Vertically • Includes major tributaries • Coarse mesh for model development (100*150*20) • Forcing: Tides, Winds, Heat Fluxes and Rivers • Validated Physical Model w/ 15-Year Hindcast (Xu et al., accepted) • Currently expanding the biogeochemical model • Goal: Improved Simulation of BGC processes & Water Quality Fields • Use Output to inform Ecological Models (HABs, pathogens, etc.) • Open Source Available at: http://sourceforge.net/projects/chesroms/ ChesROMS Team: Chris Brown, Tom Gross, Brooke Denton, Raleigh Hood, Mohan Karyampudi, Lyon Lanerolle, Wen Long, Raghu Murtugudde, Dave Potsiadlo, M. Bala Krishna Prasad, Jerry Wiggert, Jiangtao Xu

  4. CBP Sampling Sites • Chesapeake Bay Program • (http://chesapeakebay.net/) • Data Used For: • Initial Conditions • River Boundary Conditions • Solution Validation Sites (following Xu & Hood, 2006) • CB3.3C (Upper Bay) • CB5.3 (Mid-bay) • C6.3 (Lower Bay) • Chlorophyll • Dissolved Oxygen • DON, PON • Freshwater Flux • NO3/NO2/NH4 • TSS CB4.1C (upper bay) CB5.3 (middle bay) CB6.3 (lower bay) Map Courtesy of Chesapeake Bay Program

  5. Chesapeake Bay Ecological Prediction System (CBEPS) • Ocean Quality Control System (OQCS) • Automatic retrieval of historical and real-time data for validation and model forcing • Ocean Hydrodynamic Modeling System (OHMS) • ChesROMS and Empirical Habitat Models • Ocean Model Assessment System (OMAS) • Skill assessment of model predictions against data acquired by OQCS • Ocean Model Dissemination System (OMDS) • Data archive and forecast dissemination • Utilizes data interoperability techniques to facilitate efficient provision of model results to end users Brown, et al., J. Mar. Sys., 2013.

  6. BGC Modeling Targets & Implementation Goals • Phytoplankton Bloom Dynamics • Capture Spatio-temporal Physical-Biogeochemical Interactions Associated with Estuarine Circulation • Particulate and Dissolved Constituents • N-cycling Linkage of Water Column & Benthos • Dissolved Oxygen Evolution • Denitrification Onset - Offers Insight into N Balances & Budget Improved ChesROMS BGC Realism -> More Robust Ecological Forecast System (CBEPS) Hindcast Year Chosen for Model Implementation is 1999 (“Typical” Conditions; Model Physics Validated) Xu, et al., Est. and Coasts., 2011.

  7. ChesROMS Biogeochemical Flows Aspects of Implementation 1) Benthic NH4 Efflux & NO3 Uptake ramp up as overlying DO decreases 2) Reduce POM sinking in bottom layer i) Promote O2 Demand in Water Column ii) Promote BGC link to Estuarine Circulation Sensitivity Explorations • 1) Reduce DL Sinking Velocity • 2) Particle Aggregation (Stickiness) • i) Regulates Bloom Dynamics, POM Loads & Sinking/Export of Organic Matter • ii) Tends to Degrade O2 Evolution (WC DO Increases) Overall Goals Overcome “Tension” in BGC Mechanisms Bloom Dynamics <-> Hypoxia Realism <-> DIN Concentrations <-> Bloom Dynamics DO is Indicated by the Light Blue Background

  8. Nitrate Index Station DO Test 64 -> 85: ⬇ DL Sink Velocity (0.5 x); ⬆ Max Nitrification Rate (4x) Test 64 -> 91: Constant Phytoplankton Growth Rate Test 91 -> 96: ⬇ Non-Dim Zooplankton Growth Rate (0.8x) Test 96 -> 100: ⬆ Coagulation Param (1.5x) Test 91 -> 104: Zooplankton Grazing ≠ f(Temperature) Test 100 -> 105: ⬇ DL Sink Velocity (0.5 x) Chlorophyll Ammonium Summary of Sensitivity Studies

  9. Extension of Hypoxic Volume Envelope for Model Overall, the 4 mg/ml threshold is a closer fit to the CBP-based Hypoxic Volume Seasonal variability consisting of onset and dissipation timing are reasonable Initial Baseline Solution (Test 64) Test 64 -> 85: ⬇ DL Sink Velocity (0.5 x); ⬆ Max Nitrification Rate (4x) Test 91 -> 96: ⬇ Non-Dim Zooplankton Growth Rate (0.8x) New Baseline Solution (Test 105) Hypoxic Volume (km3) Comparisons

  10. Dissolved Oxygen Chlorophyll Baseline Solution Upper Bay (4.1C) Mid-Bay (5.3) Lower Bay (6.3) Upper Bay Mid-Bay Lower Bay

  11. Extending the Model Ideally, Phys-BGC Model Will Naturally Capture Interannual Variability or Model Provides Additional Insights into the Chesapeake System

  12. Retain Organic Matter in Water Column Promotes Water Column Oxygen Demand (to a point) BUT! Oxic N-cycling Promotes O2 Production Model Suggests a “Pulsing” of low DO conditions in bottom waters through the summer Linkage to variability in modeled phytoplankton biomass Bottom Dissolved Oxygen Summary • Refining Hypoxic Fidelity in the Model • How to Amplify Denitrification in the Water Column and Anoxia Establishment? • Adjust the Nitrification - Denitrification Transition Chesapeake Bay System and Availability of CBP Data Provide an Ideal Proving Ground for Development of the Biogeochemical Module

  13. Thank You!

More Related