Evaluation of Gridded Snow Water Equivalent Products Using Cloudsat-Cpr Snowfall Estimates

Arctic snow is a critical contributor to the global water and energy budget with important connections to cold region flooding and water resource management practices. Snow water equivalent (SWE) is the amount of liquid water contained within a snowpack. Measuring Arctic SWE through traditional ground-based techniques is challenging due to the vast size and remote nature of the region. Remote sensing applications offer new perspectives towards SWE accumulation estimates across the Arctic. The cloud profiling radar (CPR) instrument installed on the NASA CloudSat satellite observes snapshots of falling snow in clouds and has been effectively used in previous work for estimating monthly surface SWE accumulation across high latitude regions. By comparing consecutive month-pair estimates of accumulated SWE from CloudS at $(\overline{SWE}_{C})$ with the positive difference in SWE on ground over the same period in gridded SWE products $(\Delta SWE_{B})$, we gain new insights into areas and locations of statistically inconsistent accumulation estimates. Applying this technique to the Blended-4 gridded SWE product from 60° to 82° N allows us to generate a quality flag which automatically highlights areas of inconsistent accumulation. This technique has flagged 4885 outliers over 107 month-pairs spanning 2007–2015 across the Northern Hemisphere when applied to the Blended-4 dataset. CPR snowfall data acts as an independent observational constraint for accumulated SWE in a region which is both difficult and expensive to traditionally observe. This comparison process can be used to further enhance the accuracy and robustness of future gridded SWE products across high latitude regions.