Diagnosing the Climatic Causes and Consequences of Snow Depth Variability

Columbia University, New York NY

Investigators

Abstract

The goal of the proposed work is to provide an improved understanding of snow depth ? climate relationships and the physical mechanisms involved. An extensive body of scientific literature describes the linkages between snow extent anomalies and climate, but snow extent alone does not tell the whole story. Variations in snow depth, which do not necessarily coincide with variations in snow extent, may have a distinct and considerable impact on climate over a range of spatial and temporal scales. Recently completed research by the PI clearly distinguishes the climatic significance of snow depth, and complements the somewhat limited existing literature on snow depth ? climate linkages. This serves as motivation for this proposal to identify the responsible mechanisms. The snow depth - climate relationship is likely to be very complicated, and involve different dynamic and thermodynamic processes across varying spatial domains and scales. Some facets of this overall relationship are better understood than others, while still other facets may benefit from updated analyses using more recent data and/or modeling resources. Therefore the proposed work will specifically target two aspects of the overall snow depth ? climate relationship where our current state of understanding is incomplete. Two hypotheses are investigated, the first involving a remote climatic cause for snow depth variability over North America, and the second involving a local climatic consequence of snow depth variability. A key resource for this proposal is a newly released, long-term, gridded, daily snow depth dataset covering all of North America (Dyer and Mote 2006). Its availability offers exciting new opportunities to study snow depth and its interactions with climate, especially in northern regions of North America where snow depth information has historically been lacking but is expected to vary considerably. Hence this frequently neglected parameter can be empirically evaluated over a broader domain than previously was possible. Furthermore, snow depth perturbation experiments will be performed using both a one-dimensional snowpack model and a regional climate model, to comprehensively evaluate the thermodynamic and near-surface dynamic processes associated with anomalous snow depth. Diagnosing specific climatic causes and consequences of snow depth variability, rather than an exploratory and unfocused study of the overall relationships, hold the strongest prospects for success and impact within the hydrologic and climate science communities. Recognition of snow depth as an important contributor to climate variations will promote continued improvements in the still relatively crude snow parameterizations in climate models, and also in snow depth remote sensing techniques. The concept of distinct snow depth and snow extent linkages will lead to a more comprehensive understanding of snow ? climate relationships, and provide new information to help identify additional regions/seasons which may hold some predictive capability for climate. This in turn would have far-reaching societal benefits for water resource management, hazard mitigation and anthropogenic climate change. The proposed research will be managed to maximize its broader impacts on education. Despite its focused scope and relatively modest budget, the project will support three students at dramatically different stages of their educational career. An existing doctoral candidate at the PI?s institution will complete her dissertation, and ensure a smooth and efficient transition to a new doctoral student for the duration of this project. Furthermore, one high school student at New York City?s prestigious Bronx High School of Science will be sponsored, whose research on this project will be entered in the Intel Science Talent Search competition (http://www.sciserv.org/Sts/). Such early exposure to research can inspire students to pursue careers in science and engineering, and foster the development of the next generation of researchers.