EAGER: Collaborative Research: Monitoring Nearshore Ice and Closing the Arctic Tide-gauge Gap with GNSS-Reflectometry (MONICA)

Accurate and seamless monitoring of water levels along the coast can lead to economic and societal benefits by improving storm-surge forecasting, informing emergency responses, promoting safe navigation, and improving mapping and charting efforts. However, only a limited number of tide gauges are located along Alaska’s western and northern coastline. This scarcity of tide gauges is primarily attributed to the challenging weather conditions for installation and maintenance, as well as the seasonal presence of sea ice. Simultaneously, routine monitoring of coastal sea ice is also insufficient, despite its crucial role among coastal communities for harvesting marine wildlife and for safe navigation. The aim of the project is to develop an efficient and effective strategy for continuously monitoring the Arctic coastal marine environment by detecting the presence of sea ice, the onset and detachment of landfast ice, and measuring the water level throughout the year. To achieve this goal, the project intends to develop a novel technology to monitor water level and sea ice year-round by building technical innovations on the state-of-the-art Global Navigation Satellite System (GNSS) Reflectometry, referred to as a GNSS-R Water-Ice observation System (GRWIS). GNSS-R, which utilizes GNSS multipath signals, has become widely employed for monitoring water levels by measuring the geometric variation of reflecting surfaces. However, relatively few studies to date have explored the use of GNSS-R for monitoring sea ice. This project will leverage the capabilities of GNSS-R technique, which not only enables measurements of the reflector heights but also calculates the roughness of the reflector, e.g., the confidence level of retrieval (CLR). This project will investigate an optimized use of CLR to determine the presence of sea ice and landfast ice. The detected ice will be differentiated between landfast from open ocean or drifting ice by cross validating them against field observations and other data collected by sea ice radar systems and satellite imagery. Moreover, the GRWIS will monitor both the vertical and horizontal motion of the sea ice and this ice monitoring method will be facilitated by another novel ice monitoring technology, the Gamma portable radar interferometer (GPRI). The GPRI will assess and validate the sensitivity of GRWIS measurements to horizontal motion of sea ice that will aid in understanding the potential impact on water level measurements and determining the feasibility of GNSS-based observations for assessing the stability of landfast ice. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.