WINTERTIME CLIMATE TRENDS IN THE NORTHEASTERN UNITED STATES

Humans experience climate variability and climate change primarily through changes in weather at a local and regional scale. One of the most effective means to track these changes is through detailed analysis of meteorological records. In this paper, changes in the Northeastern United States winter climate are documented. Meteorological data were collected from the United States Historical Climate Network (USHCN) for: temperature, snowfall, snow depth, and precipitation. Snow depth data are used to derive the number of days with snow on the ground, monthly and seasonally. Daily meteorological data have undergone extensive quality assurance measures for completeness, reasonableness, and accuracy by the National Climatic Data Center (NCDC) and the Carbon Dioxide Information Analysis Center (CDIAC). However, the daily data have not been adjusted for station relocations, instrument changes, or time of observation biases. In this paper, daily station data are adjusted for these three factors to remove inhomogeneities. Station records are compared with the nearest neighboring records to evaluate spatial coherence, to fill in missing values, and to remove outliers where necessary. Analysis of these four meteorological variables indicates that Northeast US winter temperatures are warming at a rate significantly greater than the global trend. In addition, monthly and seasonal snowfall is decreasing, and the number of days with snow deeper than three inches has decreased substantially.