Authors: Elizabeth Burakowski*, University of New Hampshire, Danielle Grogan, University of New Hampshire, Cameron Wake, University of New Hampshire
Topics: Climatology and Meteorology, Water Resources and Hydrology, Environmental Science
Keywords: climate, northeastern US, snow, climate change, hydrology
Session Type: Paper
Start / End Time: 8:00 AM / 9:40 AM
Room: Stones Throw 1 - Granite, Marriott, Lobby Level
Presentation File: No File Uploaded
Over the past century, the northeastern United States has warmed significantly, with an acceleration in the rate of warming since 1970. A wide range of regional indicators, including increases in temperature (especially in winter), in overall precipitation, in the number of extreme precipitation events, and in the proportion of winter precipitation falling as rain (as opposed to snow). Here, we present historical simulations and future projections of regional climate from a 29-member, high-resolution (4 km) statistically downscaled Coupled Model Intercomparison Project (CMIP5) ensemble under lower (4.5 W m-2) and higher (8.5 W m-2) representative concentration pathway (RCP) scenarios. Future hydroclimatic trends in snow and streamflow were generated by forcing the University of New Hampshire Water Balance Model (WBM) with daily temperature and precipitation fields. Relative to the ensemble 1980-2005 mean (12.4 3.3C), end of century (2070-2099) annual maximum temperatures warm +3.00.9C under the lower scenario and +5.31.3C under the higher scenario. The modeled ensemble mean annual precipitation agrees well with observations, with large variability among the models and weak influence of scenario on future increasing precipitation trends. During the cold season, the number of nights below freezing decreases by about three weeks under RCP4.5 and by nearly a month under RCP8.5. Seasonal snow cover declines dramatically under RCP8.5, with elimination of persistent snow pack in coastal and southern parts of the northeastern United States and flattening of the spring hydrograph.