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Final Report: Modeling the Impacts of Climate Change on Wetland Ecosystems

EPA Grant Number: R829420E04
Title: Modeling the Impacts of Climate Change on Wetland Ecosystems
Investigators: Aravamuthan, Vibhas , Koppelman, David , Ramanujam, Jagannathan , Singh, Vijay P. , Suhayda, Joseph N. , Thiagarajan, Ganesh , Twilley, Robert
Institution: Louisiana State University - Baton Rouge , University of Missouri - Kansas City
EPA Project Officer: Winner, Darrell
Project Period: June 10, 2002 through June 9, 2004 (Extended to June 9, 2006)
Project Amount: $129,210
RFA: EPSCoR (Experimental Program to Stimulate Competitive Research) (2001)
Research Category: EPSCoR (The Experimental Program to Stimulate Competitive Research)

Description:

Objective:

The overall goal of this project was to develop a coupled global climate model and hydrologic/landscape ecology model for assessing the impact of climate change on the hydrology and ecology of Louisiana wetlands. Due to the complex interaction between the climatologic, hydrologic, and ecologic processes, an integrated approach to study these processes was proposed. The work involved the integration of a Global Climate Model (GCM), a coastal hydrodynamic model, and a landscape ecology model. The model addresses the issue of integrating processes occurring at widely varying spatial and temporal scales. Although the model would be applied to Louisiana wetlands, it would not be site-specific and should be applicable to other regions with minimal effort. Special attention was paid to algorithmic development so that the model would be architecture independent. This would be achieved by developing the model code using the Fortran 90 language with message passing interface (MPI) extensions, so that the model could be run on both uniprocessor and multiprocessor shared memory or distributed memory systems.

A stochastic weather generation model was developed. The hydrodynamic components of the model were calibrated and verified using river stage and tide gauge data collected by the U.S. Geological Survey and the National Oceanic and Atmospheric Administration.

The model would be used to study the climatological impacts on the hydrology and ecology of coastal Louisiana in the future. The results of this study should be of interest to a broad spectrum of agencies and individual researchers who are involved in making scientific and management decisions regarding the protection, planning and restoration of wetlands. This is a first step towards the development of an effective tool for the management and restoration of ecosystems.

The overall goal of the project was to develop a coupled hydrologic and ecologic model for assessing the impact of climate change on the hydrology and ecology of Louisiana wetlands. To accomplish the project, the following specific objectives are defined:

  1. Develop a stochastic weather generation model to obtain daily climatological data from monthly means forecasted by a GCM.
  2. Develop a coastal hydrodynamic model with sub-grid scale features, such as rivers and barriers, for predicting tidal circulation in the wetlands.
  3. Develop a landscape ecology model to predict landscape changes due to changes in climatology and hydrology.
  4. Develop a rational methodology for coupling the various models, which have diverse time and spatial scales.

Summary/Accomplishments (Outputs/Outcomes):

A two-dimensional, vertically integrated hydrodynamic model was developed for simulating coastal processes. The model has the capability of simulating flooding and drying processes. The model was applied to coastal Louisiana and was able to simulate the hydrodynamic processes effectively.

A two dimensional, vertically integrated transport model for sediments was developed. The model can simulate suspended load and bed load transport separately. The model is sensitive to the non-equilibrium adaptation length, which is used as a parameter in suspended load transport simulation. As a result, this value should be assigned with great care. Use of different settling velocity formulas leads to different simulated suspended sediment concentrations, so the settling velocity formula should be chosen based on the sediment type. The model is sensitive to the non-equilibrium adaptation length Lt, which is used as a parameter in bed load transport simulation. Bed load transport simulation is sensitive to different bed load transport capacity formulas. Great care should be taken in choosing the bed load transport capacity formula.

A stochastic weather model was developed and data from various GCMs were used. The average maximum value of precipitation for 100 years (1991-2090) from control integration of the Canadian Centre for Climate Modeling and Analysis (CCCma) GCM is 27.368 millimeters. The average maximum value of precipitation for 100 years (1991-2090) from greenhouse gas integration of CCCma is 22.442 millimeters. The average maximum value of precipitation for 100 years (1991-2090) from greenhouse gas plus sulphate integration of CCCma is 24.11 millimeters. The average maximum value of maximum temperature for 100 years (1991-2090) from control integration of CCCma is 37.273 degrees centigrade. The average maximum value of maximum temperature for 100 years (1991-2090) from greenhouse gas integration of CCCma is 45.309 degrees centigrade. The average maximum value of maximum temperature for 100 years (1991-2090) from greenhouse gas plus sulphate integration of CCCma is 41.594 degrees centigrade. The average maximum value of solar radiation for 100 years (1991-2090) from control integration of CCCma is 781.24 langley. The average maximum value of solar radiation for 100 years (1991-2090) from greenhouse gas integration of CCCma is 780.76 langley. The average maximum value of solar radiation for 100 years (1991-2090) from greenhouse gas plus sulphate integration of CCCma is 781.9 langley. The average maximum value of precipitation for 100 years (1991-2090) from control integration of CSIRO is 35.26 millimeters. The average maximum value of precipitation for 100 years (1991-2090) from greenhouse gas integration of CSIRO is 37.915 millimeters. The average maximum value of precipitation for 100 years (1991-2090) from greenhouse gas plus sulphate integration of CSIRO is 37.437 millimeters. The average maximum value of maximum temperature for 100 years (1991-2090) from control integration of CSIRO is 36.117 degrees centigrade. The average maximum value of maximum temperature for 100 years (1991-2090) from greenhouse gas integration of CSIRO is 38.769 degrees centigrade. The average maximum value of maximum temperature for 100 years (1991-2090) from greenhouse gas plus sulphate integration of CSIRO is 38.381 degrees centigrade. The average maximum value of solar radiation for 100 years (1991-2090) from control integration of CSIRO is 724.75 langley. The average maximum value of solar radiation for 100 years (1991-2090) from greenhouse gas integration of CSIRO is 727.26 langley. The average maximum value of solar radiation for 100 years (1991-2090) from greenhouse gas plus sulphate integration of CSIRO is 731.03 langley.

A Landscape Ecology model was developed and the model’s sensitivity to different parameters was studied. It was found that the model was sensitive to monthly average salinity and the monthly average depth and duration of flooding; growth was limited by ambient temperature.

Conclusions:

An integrated framework was developed for predicting the influence of climate impacts on coastal hydrology and hydraulics of Louisiana. This was accomplished by developing four separate components. These were a 2-dimensional vertically integrated coastal hydrodynamic model, a 2-dimensional vertically integrated generic transport model with sources and sinks for predicting spatial and temporal distributions of conserved substances, a stochastic weather model for providing climatological scenarios, and a landscape ecology model. All the models were parallelized using the MPI library so that they can run on a variety of computing platforms. Although we have finished the model development and all individual modules were tested, we were unable to run real world scenarios due to lack of time. The development process was extremely time-consuming and we encountered numerous difficulties in terms of model code debugging. Model application to real world scenarios would be the subject of future studies. Specifically, we plan to: (1) use the model to quantify hydrological and ecological changes due to changes in climate that include an increase in CO2 and an increase in sea level; and (2) perform a 30-year model simulation to understand the impacts of changes in climate on wetland ecosystems.

Journal Articles:

No journal articles submitted with this report: View all 4 publications for this project

Supplemental Keywords:

global climate, coastal ecosystems, ecological modeling, regional climate model, hydrodynamic model, stochastic weather model, , Air, Geographic Area, Scientific Discipline, RFA, climate change, Ecology, Ecological Risk Assessment, Atmospheric Sciences, Hydrology, State, genetic diversity, Global Climate Change, watershed, coastal ecosystems, fish habitat, wetlands, Louisiana (LA), environmental monitoring, climate models, climate variability, land and water resources, global change, aquatic ecology

Progress and Final Reports:
2002 Progress Report
2003 Progress Report
2004 Progress Report
Original Abstract

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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