Collaborative Research: Quantifying Feedbacks Affecting High Altitude Climate Change

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In many mountain regions there is evidence that temperatures are changing at different rates than the global average. Three questions arise: Are temperatures in mountain regions increasing faster than the global average? Within mountain regions are warming rates dependent on elevation? And if the answers to the above are yes, why do such differences occur? Several different feedbacks can contribute, including those related to snow-albedo, atmospheric water vapor, cloud cover, and cloud properties. These feedbacks are difficult to quantify because the relationship between two climate variables is invariably interconnected with other variables as well. Also, the sparsity of observations in high-altitude regions exacerbates this difficulty.This project will combine surface-based and satellite observations with climate model simulations and a neural network analysis scheme to (1) quantify some of the principal relationships that contribute to feedbacks on temperature in high altitude regions, and (2) investigate how these relationships and feedbacks might change through the 21st century in response to increasing atmospheric greenhouse gases. The focus will be on the Tibetan Plateau and the Rocky Mountains in southwestern Colorado. The neural network analysis calculates partial derivatives between pairs of climate variables (e.g., downward longwave radiation and cloud cover) so that the strength of the various links in a feedback loop can be determined. Broader impacts of this work include: (1) The neural network can be applied in other regions and can enable researchers to quantify important feedbacks in the climate system and analyze non-linear processes; (2) By combining surface-based and satellite observations, a new spatially and temporally expanded observational data base will be available to the research community; (3) A better understanding of climate change in mountain regions will benefit the public by improving management practices that affect the future of water resources, agriculture, tourism, and ecosystems in high altitude regions; (4) A high-school teacher will be supported to work with the investigators to help develop and implement podcasts on mountains and climate change; (5) There will be training for a postdoctoral fellow and undergraduates; and (6) Educational materials will be developed in collaboration with the Mountain Studies Institute in Colorado.