Overview - The 2021 SnowEx Time Series continues the multi-year effort to improve snow water equivalent (SWE) and snow-surface energy balance measurements and estimates.  The combination of remote sensing, ground observations, and modeling are to identify a pathway to accurate spaceborne snow measurements. Coincident airborne and ground observation were consistent with the 2020 Time Series sampling design, the difference being fewer regional sites and more frequent mid-winter ground data validation discussions to standardize data collection protocols.

The scientific objectives for the 2021 Time Series campaign:

1. UAVSAR

• Define the snow conditions where L-band InSAR is likely to work (maintain coherence) based on time series approach at seven sites, four states
• Quantify the accuracy of L-band InSAR retrievals of snow depth, density, SWE, and wetness 

2. Albedo 

• Evaluate the spatiotemporal variability in snow albedo, the controls on this variability
• Quantify uncertainty of remote sensing measurements from AVIRIS-NG relative to mountains, forests, and as snow albedo declines over time.

3. Prairie 

• Quantify the accuracy and uncertainty in SWE retrievals L-band InSAR in a Prairie environment, specifically assessing the impact of shallow, drifted snow, terrain with variability of soil temperature and moisture conditions, and wet snow 
• Characterize the spatial heterogeneity of snow characteristics due to soil conditions, wind redistribution, landscape, and sublimation, and assess the scales at which different processes dominate, as well as the ability of remote sensing techniques to characterize spatial distribution.

Learn more by reading the 2021 Experimental Plan