Project: 

  Implement an urban model in CLM3.

Mission:

  An implementation will be made in CLM3.0 of an offline urban model
  for the investigation of urban impacts on climate and that will
  ultimately be able to aid in urban planning.

Goals:

  - Using mulitple reflectances caused by the urban canyon, calculate
    solar fluxes absorbed and reflected by roof and canyon (walls,
    road), as well as net and upward longwave fluxes. The key is to capture
    the interactions between canyon surfaces. This will involve interactions
    between urban canyon columns.

  - Create the ability to easily modify the hydrologic and thermal
    properties of the urban walls, road and roof.

  - Modify CLM turbulent flux calculations to account for interactions 
    between the urban canyon columns.

  - Incorporate the ability to split up the canyon road into pervious and
    impervious components (i.e. columns).

  - Produce a high resolution urban dataset that can be used to produce 
    an urban surface dataset at the model resolution.

Motivation:

  The ability to have urban landunits in CLM3.

Authority:

  Gordon Bonan

Project Lead(s):

  Keith Oleson and Mariana Vertenstein 

Implementation Plan:

  Phase 1) Implement the following for a single purely urban gridcell:
          - calculation of solar and longwave radiation fluxes for 
            urban canyon and roof utilizing the multiple reflectances in
            the urban canon
          - determination of urban landunit component albedos
          - all calculations will be done for unit wall area - for history
            output must put in scaling to per unit ground area for gridcell or
            landunit output 

   Phase 2) Implement the pervious/impervious road components.

   Phase 3) Test that (1) and (2) have been implemented correctly for
            a variety of incident zenith angles and canyon height to width
            ratios.

   Phase 4) Develop parameterization for canyon surface -> canyon air resistances.

   Phase 5) Develop wind profile model.

   Phase 6) Incorporate (4) and (5) into turbulent flux calculations.

   Phase 7) Test (4)-(6). 

   Phase 8) Incorporate hydrological modifications for canyon components.
 
   Phase 9) Create urban dataset.

   Phase 10) Test implementation of global model using urban landunits.

Resources and Schedule:

   Phase (1) => (3) have been completed as of 10/1/2004.
   Phase (4) => (8) will be completed by 12/31/2004.

   Phase (4) SE work will be done by Mariana Vertenstein with a 
            .5 man-month effort