Historical Trend in the Ratio of Solid to Total Precipitation in New England in Recent Decades

• Main Authors: Thomas G. Huntington, Glenn A. Hodgkins, Barry D. Keim, W. Dudley
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: snow; ratio of snow to total precipitation; hydrologic indicator variable; climate change; North Atlantic; North Atlantic oscillation
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.581.3748; http://www.easternsnow.org/proceedings/2003/huntington_et_al.pdf

The ratio of snow to total precipitation (S/P) is a hydrologic indicator that is sensitive to climate variability and can be used to detect and monitor hydrologic responses to climatic change. Changes in S/P ratio over time could influence the magnitude and timing of spring runoff and recession to summer base flow. The S/P ratio for 21 United States Historical Climatology Network (USHCN) sites in New England were examined. Annual S/P ratio decreased significantly (p<0.05) from 1950 through 1999 over northernmost New England. Temporal trends in other parts of New England generally were not significant, but a majority of sites in the Upper Connecticut River Valley and Coastal areas had weak decreasing S/P ratios. The four sites in northern New England showing the strongest and most coherent trends showed an average decrease in annual S/P ratio from 30 % in 1950 to 22 % in 1999. Trends in winter S/P ratio were also variable. Five sites, two in northern New England, two in the Upper Connecticut River Valley and one in a coastal region had significantly decreasing S/P trends. When trends in S/P were analyzed on a monthly basis for the northernmost sites, it was evident that decreasing S/P trends were significant for March and December only. Weak but significant correlations were observed between S/P ratios and the timing of spring runoff, North Atlantic Oscillation (NAO) index, and Trough Axis Index (TAI).