Percent change in the average annual amount of water contributed to the stream network between 1971-2000 and 2071-2000, as simulated by MC1 under MIROC medres A2 for the eastern Oregon study area, Oregon, USA

This map represents the percent change from 1971-2000 to 2071-2100 in the average annual amount of water contributed to the stream network, as simulated by the model MC1 under the MIROC medres future climate projection and A2 anthropogenic emissions scenario. The range of data values is from -92.2% to +67.3%.  The mean value is -16.6%.  Data values are calculated as (STREAMFLOW(2071-2100) minus STREAMFLOW(1971-2000)) divided by STREAMFLOW(1971-2000).  STREAMFLOW data is from MC1 version B60.
 
The dynamic global vegetation model MC1 (e.g. Bachelet et al. 2001) was used to simulate vegetation dynamics, associated carbon and nitrogen cycle, water budget, and wild fire impacts at two study sites in eastern Oregon (Deschutes and Fremont-Winema National Forests) and in Arizona (Apache Sitgreaves National Forest area) in the context of a project funded by the USDA Forest Service (PNW 09-JV-11261900-003).

Historical climate input data used to run the model were provided by the PRISM group (Chris Daly, Oregon State University) at a 30 arc-second (800m) spatial grain.

The model was also run using future climate change projections from two general circulation models, CSIRO Mk3 and MIROC 3.2 medres. Future climate change climate datasets were generated through statistical downscaling from general circulation model output using a simple anomaly method and the climatology (1971-2000) from the PRISM group at 30 arc-second spatial grain.

 The model was run assuming that nitrogen demand from the plants was always met so that the nitrogen concentrations in various plant parts never dropped below their minimum reported values. A CO2 enhancement effect increases productivity and water use efficiency as atmospheric CO2 concentration increases.