Snowmelt-Related Hydrologic Changes in the Central and Eastern United States Resulting from Warmer Winter Temperatures
Abstract
Snow research has most commonly focused on polar and alpine regions where snowmelt is a large portion of the regional water budget. This has led to poor spatial coverage of snow data at sub-polar non-alpine areas such as the Central and Eastern United States. The winter and spring hydrology across these regions are also driven by snowmelt-dominated processes and will experience impacts from anthropogenic climate change. By identifying warmer winters using GHCN temperature station data that has good spatial coverage, changes in melt processes from the sparse available snow station data can then be related to streamflow changes across years. This research examines changes to snow hydrology in the non-mountainous regions of the US resulting from warmer winter temperatures from 1960-2019. This involved combining daily temperature data from 646 Global Historical Climatology Network (GHCN) stations in 27 states, daily snow data from 141 GHCN stations, and daily stream discharge data from 648 USGS stream gages. Warmer and cooler winters relative to the 60-year means were identified using metrics of average and minimum temperatures across seasonal scales. Warmer winters during this period have significantly less seasonal snow cover, which melts much earlier in the year. When averaged across warm winters, station data showed 44 less days per year with snow on the ground and these warm winters are 67 days shorter than cooler winters. This leads to earlier and lower spring peak flow. These changes could alter the timing and magnitude of Great Lakes levels and regional shallow groundwater storage dynamics. The temporal pattern of these hydrologic shifts show warmer winters are becoming more common as global temperatures continue to climb in response to anthropogenic drivers. As the climate continues to warm it is expected that warmer winters and their associated hydrologic effects will increase in frequency.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.H33I2045F
- Keywords:
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- 0736 Snow;
- CRYOSPHERE;
- 0740 Snowmelt;
- CRYOSPHERE;
- 1860 Streamflow;
- HYDROLOGY;
- 1863 Snow and ice;
- HYDROLOGY