This dataset is a
Basin Characterization Model (BCM) output using the GFDL A2 Scenario for Climatic Water Deficit (CWD) in central Sierra Nevada California, for 2070-2099.
The term climatic water deficit defined by Stephenson
(1998) is quantified as the amount of water by which potential
evapotranspiration (PET) exceeds actual evapotranspiration (AET). This term
effectively integrates the combined effects of solar radiation,
evapotranspiration, and air temperature on watershed conditions given available
soil moisture derived from precipitation. Climatic water deficit can be thought
of as the amount of additional water that would have evaporated or transpired
had it been present in the soils given the temperature forcing. This
calculation is an estimate of drought stress on soils and plants and recent studies
suggest it may serve as an effective control on vegetation cover types in the
Bay Area (Cornwell 2010). In a Mediterranean climate, climatic water deficit
can also be thought of as a surrogate for water demand based on irrigation
needs, and changes in climatic water deficit effectively quantify the
supplemental amount of water needed to maintain current vegetation cover,
whether natural vegetation or agricultural crops.
Climatic water deficit (CWD) quantifies evaporative demand exceeding
available soil moisture, where S = soil moisture, AET = actual
evapotranspiration, D =climatic water deficit.
The California Basin
Characterization Model (BCM) climate dataset provides historical and projected
climate surfaces for the state at a 270 meter resolution. The historical data
is based on 4 kilometer PRISM data, and the projected climate surfaces are based
on the A2 and B1 scenarios of the PCM and GFDL GCMs. The BCM approach uses a
regional water balance model based on high resolution downscaled precipitation
and temperature as well as elevation, geology, and soils to produce surfaces
for a wide range of variables. These variables include maximum temperature,
minimum temperature, precipitation, potential evapotranspiration, runoff,
recharge, climatic water deficit, actual evapotranspiration, sublimation, soil
water storage, snowfall, snowpack, snowmelt, and excess water. Data is
distributed as 30-year monthly summaries and 30-year water year summaries, with
month-by-month data for each year available by special request.
Creator: Flint, Lorraine E. and Flint, Alan
L.
Contributor: Thorne, James, and Boynton, Ryan
Publisher: Public Interest Energy Research Program (PIER),
California Energy Commission