Examining Remotely Sensed Products Used in Operational Decision Support Services and how they have improved operations.

Floods are the most frequent natural disasters globally, impacting human lives and properties. During the river breakup season in the Arctic, it is critical for forecasters and stakeholders to access and assess observations quickly in order to make accurate predictions and issue warnings in a timely manner. For many years, the Alaska Pacific River Forecast Center (APRFC) has relied on information gathered from community calls and observations along the river as well as aerial observations during Riverwatch flights performed by APRC and the Civil Air Patrol. However, such observations are limited to specific locations along the river. Remotely sensed data from satellites provides the ability to observe large areas multiple times a day. Optical satellite imagery from Low-Earth-Orbiting satellites (LEO) are especially advantageous in flood mapping because of their excellent data availability, large spatial coverage, and low cost. Optical imagery, such as data from Sentinel-2, provides high resolution, high refresh situational awareness. However, the primary disadvantage of optical imagery is that it cannot see through clouds, which often appear in the afternoon over the interior of Alaska. Synthetic Aperture Radar (SAR), on the other hand, is able to provide flood and ice mapping under all conditions. However, SAR is relatively infrequent over the Arctic region and rivers, such as the Sagavanirktok, have very mineral rich soil, along with the braided channels and moist ground from the snowmelt and already most tundra, make it more difficult to detect overbank flooding in Alaska.

One of the advantages of sensors such as Sentinel-2 and, to some extent Landsat, is that it is possible to compare imagery from previous days and years to see how full the river is, providing needed information to the river forecasters.

This presentation will focus on the development of the relationship between APRFC and NOAA LEO to provide observational data from satellite imagery to help enhance the ability to fill in the gaps in data holes during breakup season as well as some lessons learned, such as the need to invest in higher spatial resolution sensors, such as those found on Sentinel-2 and Landsat,to provide even better situational awareness.