Journal
HYDROLOGY AND EARTH SYSTEM SCIENCES
Volume 17, Issue 6, Pages 2147-2159Publisher
COPERNICUS GESELLSCHAFT MBH
DOI: 10.5194/hess-17-2147-2013
Keywords
-
Categories
Funding
- California Energy Commission
- CALFED Bay-Delta program
Ask authors/readers for more resources
When correcting for biases in general circulation model (GCM) output, for example when statistically down-scaling for regional and local impacts studies, a common assumption is that the GCM biases can be characterized by comparing model simulations and observations for a historical period. We demonstrate some complications in this assumption, with GCM biases varying between mean and extreme values and for different sets of historical years. Daily precipitation and maximum and minimum temperature from late 20th century simulations by four GCMs over the United States were compared to gridded observations. Using random years from the historical record we select a base set and a 10 yr independent projected set. We compare differences in biases between these sets at median and extreme percentiles. On average a base set with as few as 4 randomly-selected years is often adequate to characterize the biases in daily GCM precipitation and temperature, at both median and extreme values; 12 yr provided higher confidence that bias correction would be successful. This suggests that some of the GCM bias is time invariant. When characterizing bias with a set of consecutive years, the set must be long enough to accommodate regional low frequency variability, since the bias also exhibits this variability. Newer climate models included in the Intergovernmental Panel on Climate Change fifth assessment will allow extending this study for a longer observational period and to finer scales.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available