Evaluation of the NASA MEaSUREs Enhanced-Resolution Brightness Temperature Data in the Red River of the North Basin

A newly processed NASA MEaSUREs dataset, the Calibrated Enhanced-Resolution Passive Microwave Daily EASE-Grid 2.0 Brightness Temperature ESDR provides a long-term record of higher-resolution passive microwave data than previously available. The data are provided at frequencies used to observe snow allowing the potential for greater understanding of snow distribution and melt events as well as future predictive analysis for hydrology applications.

This project evaluates the enhanced resolution brightness temperature data in the Red River of the North Basin, U.S. The passive microwave snow products have been shown to provide reliable snow information in the Northern Plains. Comparisons of AMSR-E and SSMI with in-situ observations, gamma flights as well as the NOAA SNODAS modeled snow products have shown consistent results in the Northern Plains area. Here we compare the new MEaSUREs data to coarser resolution brightness temperature to validate improvement in SWE resolution. We use the regression-based algorithms (i.e., Chang et. al. 1987) to estimate SWE and compare basin-averaged SWE to in-situ observations and modeled data, providing direct same-algorithm comparison of SWE data between the two different available data-sets. SWE estimated from the enhanced-resolution data show a strong concurrence with other data measures including SSMI, NOAA, and AMSRE SWE products. However, higher SWE estimates occur in some mid-season periods. The enhanced SWE data also declines sharply at the beginning of the melt period in which other measures of SWE show a gentler decline.

The new MEaSUREs passive microwave data is also evaluated for detection of melt onset and rain-on-snow events. This offers potential to improve our understanding of the relationship of brightness temperature and conditions in the snowpack at a higher resolution than previously available. Results of the analysis indicate a very clear signal response which has been identified as a potential correlation to rain on snow and melt onset events. This work will continue, furthering the evaluation of this potential for brightness temperature to indicate melt events and determining the scope of its applicability to the Red River of the North Basin.

Plots of SWE data across the water year for the Red River of the North basin consistently show the features of the new MEaSUREs data, with a representative sample of the 2009-2010 Snow Year shown above. These features include higher SWE estimates in mid-season, sharp decline at the beginning of the melt period, and extreme mid-season declines. The extreme mid-season declines will be investigated to determine if they correlate to rain-on-snow events.