The Yukon River basin encompasses 832,000 square-kilometers and is one of Earth's largest boreal-Arctic rivers. Characterized by a long, frozen winter season, the river demonstrates an abrupt ice breakup and spring snowmelt-driven flood pulse. Capabilities for regional monitoring and forecasting of the flood pulse and river ice breakup in the Yukon and other northern basins are limited but critical to informing flood-related risks to regional communities and impacts to natural resources.
NPS researchers used satellite multi-frequency daily microwave brightness temperatures to derive a consistent multi-year record (1988–2016) of key spring snow metrics, including the dates of river ice breakup and snowmelt onset, mapped to a consistent 6.25-kilometer grid resolution. The satellite data used were the 18.7 and 36.5 GHz reflectance bands from Special Sensor Microwave/Imager (SSM/I) and the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) instruments. The satellite retrievals showed good agreement with station observations of ice breakup (r = 0.61). The snowmelt onset date retrieval was also found to be an effective 14–27-day leading indicator for ice breakup within catchments.
These observations show the capability for all-weather satellite monitoring and forecasting of the spring flood pulse and ice breakup in the Yukon and other northern latitude basins where cloud cover inhibits optical forms of remote sensing. Details of this study can be found at https://doi.org/10.3390/rs13122284.
A new suite of passive microwave satellite-derived snow metrics, including Main Melt Onset Date (MMOD), snowoff date, and snowmelt duration from 1988–2016, is presented and validated using in situ observations and other complementary satellite data. The MMOD values represent Day of Year (DOY), with MMOD scaled from March 23* (DOY 82, red) and June 2 (DOY 153, blue). Researchers found Day of Year (DOY) correspondence between these satellite-derived snow metrics and measured streamflow quantiles and River Ice Breakup (RIB) observations, demonstrating their potential for regional monitoring and forecasting of hydrologic events. The RIB values represent DOY scaled from May 4 (DOY 124, light blue) and May 14 (DOY 134, dark blue). *Non-leap year DOY dates given.