Using the simple anomaly method (modifying a historical baseline
with differences or ratios projected by General Circulation
Models), scientists from the California Academy of Sciences
downscaled monthly total precipitation from 16 different global
circulation models (GCMs). The GCMs were described in the latest
Intergovernmental Panel for Climate Change (IPCC 2007) and
archived at the WCRP PCMDI (
http://www-pcmdi.llnl.gov/ipcc/about_ipcc.php).
Monthly total precipitation was downscaled using the ratio between
each 20 year-period in the future (e.g. 2040-2059) and the simulated
historical average (1950-2000) from each GCM. Each layer was then
interpolated to a spatial grain of 10x10 km2 using the regularized
spline function of Spatial Analyst tool in ArcGIS 9.3, and then
multiplied by the baseline historical climate (Wordclim 1.4) to
create future projected precipitation: Pdw=((Pf/Pc )*Pobs )
Monthly precipitation was averaged seasonally over 20 year
periods of GCM simulations from 2000 through 2099. Seasonal climate
means were generated by averaging values for three months (ex.
winter conditions correspond to the average climate for
December,
January,
February). Two
sets of future climate projections are available, corresponding to
either the regional economic A2 or the global environmental and
equitable B1 greenhouse gas emissions scenarios. Every data layer
has a corresponding layer representing the standard deviation
across GCMs, which gives an estimate of the variability of the
climate across the various GCMs (16 for precipitation) used to
calculate the average.
Related datasets and documentation can be found in the Databasin gallery at: http://app.databasin.org/app/pages/galleryPage.jsp?id=2a47360040364876b37a52657793faa6
I am a biodiversity scientist interested in understanding and conserving the diversity of life at multiple evolutionary and spatial scales. As Chief Scientist at Natureserve, I lead a talented and dedicated team of ecologists, taxonomists, and biodiversity information scientists in the application...