Location: Soil and Water Management ResearchTitle: Past and future changes in frost day indices on Catskill Mountains region of New York) Author
Submitted to: Hydrological Processes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/21/2013
Publication Date: 8/6/2013
Citation: Aavudai, A., Zion, M.S., Gowda, P., Pierson, D.C., Lounsbury, D., Frei, A. 2013. Past and future changes in frost day indices on Catskill Mountains region of New York. Hydrological Processes. 27:3094-3104. Interpretive Summary: Predicted increases in the air temperature in the Catskill Mountains region by global simulation models is expected to increase the length of the summer growing season. Climate changes in reservoir watersheds have important implications on water availability. In this study, changes in numerous frost indices were investigated using historic and predicted climatic data for the Catskill Mountains region in New York. Results indicated that the length of the growing season is increasing by 2-4 days per decade. This may contribute to slight increases in the net primary productivity and evapotranspiration in the study region.
Technical Abstract: Changes in frost indices in New York's Catskill Mountains region, the location of water supply reservoirs for New York City, have potentially important implications. Frost day is defined as a day with Tmin < 0 deg C. The objective of this study was to investigate past and predicted changes in minimum temperature (Tmin) and six frost indices in the Catskill Mountains covering six reservoir watersheds. Studied frost indices included (1) number of frost days (nFDs), (2) number of months with frost (nFMs), (3) last spring freeze date (LSF), (4) first fall freeze date (FFF), (5) growing season length (GSL), and (6) frost season length (FSL). Past changes in the frost indices were studied using observed daily Tmin for each watershed for the period 1960–2008. Future scenarios of daily Tmin values were derived by downscaling global climate model (GCM) simulations using a 25 bin change factor methodology. GCM simulations at a daily time scale were obtained from the World Climate Research Program's Coupled Model Intercomparison Project Phase3 (WCRP-CMIP3) multi-model dataset. The GCM simulations were for baseline scenario (20C3M), future scenarios (A1B, A2, and B1), and two 21st-century periods (2045–2065 and 2080–2100). Results indicated a general increase in average Tmin and GSL and a decrease in nFDs and nFMs, shorter FSL, earlier LSF, and later FFF from the historical to the future periods. Increase in GSL is expected to affect hydrologic, ecosystem, and biogeochemical processes with increased net primary productivity, and a resulting increase in total annual evapotranspiration.