A prototype international network is proposed to measure snowfall and ground snow at 5 arctic sites concurrently in an effort to improve the ability to monitor. All of the sites have been identified as key locations in a pan-arctic monitoring network and will augment existing meteorological and snow measuring instrumentation with solid-state snow pillows, heated plate precipitation sensors, snow fences, and eddy correlation towers for computation of sublimation. Ground surveys will also be conducted for snow cover depth, water equivalent, and other properties using tools that allow rapid collection of extensive data. These will be augmented with aerial photography and airborne remote sensing from inexpensive platforms (kites and UAVs) to visualize drift and deposition patterns. The combined suite of instruments and measurements is designed to allow closure of the winter water balance at each site, for the first time balancing the precipitation with measured accumulation. Using a set of modeling tools (e.g., a melt model, and a transport model for blowing snow), the PI's will a) develop methods and algorithms for quality checking both meteorological and snow data by cross-comparison between sensors and instruments, b) close the water balance in a way that produces more accurate values of winter precipitation and snow on the ground than are currently being collected, and c) apply a methodology to historical data from the existing gauge network to produce better estimates of past trends.
Satellite observations and models show Arctic snow is changing. Unfortunately, due to wind and frequent blowing-snow events, long-term precipitation measurements in the Arctic are unreliable. In the sub-Arctic and Arctic, where snow lasts 6-10 months of the year, snow cover is a critical energy, water, and ecosystem component. We need more measurements in more places, for less money, with higher accuracy. We aggregated a number of measurement approaches into several select Arctic sites to examine their performance. In three Alaskan (Barrow, Imnavait Creek, Fox) and one Canadian location (Trail Valley Creek) we installed and operated a constellation of instruments that record precipitation, weather, blowing snow, snow on the ground, sublimation, and snow-drift volume. We found that gauge-based assessments of precipitation continued to fail. However, our ability to measure snow depths over time and space was outstanding, and we recommend that more attention be paid to this precipitation metric instead of traditional gauge-catch estimates. We also estimated snow movement using snow fences, reporting that relatively few windy storm events drift most of the snow. Importantly, we developed automated and more efficient field-based methods to measure snow quickly, safely, and accurately at our sites. We are now focusing on making them more economical so they become widespread.
