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Land Cover Forcing from the SRES Scenarios in Climate Models
 

Project Abstract

The goal of this project is to extend future climate change scenarios by including human impacts on land cover and soils. This work has been initiated with LSM/PCM and will be expanded to use CLM/CCSM. Simulated changes are land cover, human impacts on soil, and urbanization. These experiments will address how human land use and land cover change are altering climate, water and carbon cycles, and biogeochemistry. In particular it will address:

  1. How have changes in land use and land cover altered present-day climate, and how are they likely to alter future climates?

  2. How important is the land use and land cover change forcing relative to other IPCC SRES forcings (e.g., greenhouse gases)?

The project is comprised of four main sub components. The progress of each to date is summarized below. Continued progress is expected during FY04.

 

LSM/PCM Land Cover Simulations

Three equilibrium model runs have been completed. These include:

  1. PCM run B07.09
    Standard 1870 atmospheric conditions with IMAGE2.2 potential vegetation as the underlying land cover (Image 2.2 biome classes are converted to LSM land cover types)

  2. PCM run B07.43
    Standard 1870 atmospheric conditions with IMAGE2.2 1970 land cover as the underlying land cover (Image 2.2 biome classes are converted to LSM land cover types)

  3. PCM run B07.46
    Standard 1870 atmospheric conditions with hybrid LSM/IMAGE 1970 land cover as the underlying land cover (IMAGE cropland superimposed on LSM natural vegetation)

Outcome:

For analyses of these experiments, see: www.cgd.ucar.edu/tss/clm/diagnostics/pcm/

Comparison between B07.43 with the existing B06.62 LSM land cover control run shows that there is considerable sensitivity in the model to the land cover datasets used in the simulations. Especially in the boreal biomes and tropical rainforest regions differences due to albedo and bowen ratio changes are apparent.

Comparison between B07.09 and B07.42 shows that anthropogenic land cover changes also are likely to affect the global climate, in this case the simulation suggest that replacing forest land cover with agricultural lands could induce a mid latitude cooling effect. In turn these changes appear to affect global circulation features through alteration of the Asian monsoon intensity.

Land cover data, converted from Image 2.2 to LSM land cover classes, for the transient A2 model run experiments have been completed (present day, 2050 and 2100), and simulations are in progress. One transient simulation has been completed PCM run B07.47/B07.48. This is a transient simulation through 2100 using the LSM/IMAGE hybrid 1970 land cover data. Preliminary analyses show the simulated climate is colder than a previous PCM control simulation using the LSM land cover. This is due to the greater extent of croplands in the IMAGE dataset compared to the LSM dataset. See: www.cgd.ucar.edu/tss/clm/diagnostics/pcm/

 

Agriculture

We propose, and are organizing efforts, to incorporate recently development of crop model for winter wheat, spring wheat, corn and soybeans in CLM. These models have specifically been designed for use in GCMs by Foley et al, and should be ready for incorporation into CLM in the spring of 2004. These crop models are accompanied by a present day crop distribution dataset developed by Ramankutty that will be incorporated into all past and future land cover change datasets for this project.

 

Soil Degradation

This project has not yet been initiated and will follow once current upgrades to the TOPMODEL component of CLM have been implemented (Z-L Yang, CCSM workshop 2003). The new parameterizations will greatly facilitate implementation of the soil degradation effects.

 

Urbanization

Work is in progress to develop an urban canyon type model into CLM. The radiation flux component of the model has been completed as have the ground and wall fluxes and energy storage simulations. Tests of these sub-models have been conducted and shown to produce results comparable to similar models in the literature. Current development is focusing on the aerodynamic fluxes and the coupling of the surface fluxes to the atmospheric model.

 

Regional Models

This topic will primarily be addressed in the planned workshop. However we are working on coordinating with a number of modeling groups within NCAR (ACD and the TSS, and CCR (Paleo and IPCC oriented group) of CGD) to ensure that the land cover datasets we develop will meet the needs of all of these groups.

 

More Information

 

Publications

Feddema J., Bonan G., Mearns L.O., Oleson K., Washington W., Meehl J. An evaluation of GCM sensitivity to land cover change experiments, and their potential importance to IPCC scenario simulations. (In preparation, manuscript draft 1/04).

 

Presentations

Feddema, J.J. 2004: GCM Simulations of the Impacts of Anthropogenic Land Cover Change on Climate, Department of Geography, University Delaware, Newark, DE, April 23.

Feddema, J.J. 2003: Simulating the impacts of anthropogenic land cover change on climate, Department of Geography, Kansas Sate University, Geography Awareness Week lecture, Manhattan KS, November 21.

Feddema, J.J. 2003: Simulating Anthropogenic Land Cover Change in Global Circulation Models, Terrestrial and Sciences Section, Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, CO, July 17.

Feddema, J.J. 2003: Developing a global urbanization database and its use for developing past, present and future surface change scenarios, CCSM workshop Land Surface modeling Group, Breckenridge, CO, June 27.

Feddema, J.J. 2002: Development of surface based anthropogenic climate change scenarios for GCMs, AAG annual meetings, March 23, Los Angeles, CA.

Feddema, J.J. 2002: Simulating Anthropogenic Land Cover Change in Global Circulation Models, Department of Geography, University of Iowa, Iowa City, September 19.

Feddema, J.J. 2002: Climate variability and change: from scenarios to adaptation, Presentation at the workshop on GIS in Weather, Climate and Impacts. National Center for Atmospheric Research, Boulder, Colorado, 12-14 August. www.gis.ucar.edu/02workshop/presentations/feddema/index.html

Feddema, J.J. 2002: Developing a global urbanization database and its use for developing past, present and future surface change scenarios, CCSM workshop Land Surface modeling Group, Breckenridge, CO, June 27.

Feddema, J.J. 2002: Status of Land Use Change Dataset Preparation and Experiments, CCSM workshop Land Surface modeling Group, Breckenridge, CO, June 26.

Feddema, J.J. 2002: The Value of GIS to Human Induced Surface Change Scenario Development," GIS seminar Series, National Center for Atmospheric Research, Boulder CO.

Feddema, J.J. 2002: Developing GCM surface change scenarios using GIS, a population model and soil degradation data," Department of Geography, University of Colorado, Boulder, CO, April 12.

 

Project PI, Leads, and Staff

  • Gordon Bonan, PI, Project Lead
    Climate & Global Dynamics Division, NCAR
  • Johan Feddema, Project Lead
    University of Kansas
  • Linda Mearns
    Environmental & Societal Impacts Group, NCAR
  • Keith Oleson
    Climate & Global Dynamics Division, NCAR

For more information about this project, please contact Gordon Bonan at: bonan@ucar.edu, or Johan Feddema at: feddema@ku.edu

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