Temperature Trend Biases in Gridded Climate Products and the SNOTEL Network

In the mountainous western U.S., temperatures from high-resolution gridded climate products are often used to assess climate impacts on local hydrology and ecosystem processes. However, there has been little formal analysis on the ability of these products to accurately capture temporal variability and trends in climate. Here, we summarize and expand upon recent assessments of trend biases in the widely used PRISM and Daymet data products (Oyler et al., 2014, 2015). Throughout the western U.S., we find that PRISM and Daymet contain systematic cold and warm trend biases. Most notably, we show that the products have propagated an extreme warm bias from the SNOTEL station network across large areas of mountainous terrain.

Presentation slides (PDF) - Artificial Amplification of Warming Trends Across the Mountains of the Western United States