TITLE: Investigating the 2009 Red River of the North snowmelt flood using enhanced resolution passive microwave data
PRESENTER: Marissa Torres, Research general engineer, U.S. Corps of Engineers R&D Center - CRREL
ABSTRACT: A newly processed NASA MEaSUREs dataset, the Calibrated Enhanced-Resolution Passive Microwave Brightness Temperature (CETB) provides higher-resolution passive microwave data at frequencies used to observe snow. These data were developed for SMMR, SSM/I-SSMIs and AMSR-E passive microwave observations, potentially providing a high-resolution record of snow mass and snowmelt indicators in the Red River of the North (RRN) basin. This work presents a case study for the RRN focusing on the March 2009 snowmelt-driven flood. The CETB data were evaluated along with hydro-meteorological data for the event to assess potential for identifying snowpack ripeness and melt onset. SWE was estimated from the CETB data using a simple empirically-based algorithm, and compared to coarser-resolution passive microwave SWE products and SNODAS modeled SWE estimates.
Results from the March 2009 analysis show clear signal changes in the passive microwave data in the days preceding the flood, characteristic of the effects of snowpack ripening on the microwave signal. This signal change is particularly evident along the valley of the RRN mainstem and some of the south-eastern subbasins. Further, there is a distinct spatial relationship between air temperature and loss of passive microwave SWE estimates. Discharge data in several unregulated RRN subbasins were used to independently evaluate the timing of snow-melt as indicated by the sharp decrease in the CETB data. River discharge is shown to increase significantly prior to rainfall precipitation over the basin, most likely as a result of snowmelt runoff.
An initial observation is that despite the extreme flatness of the Red River of the North basin and lack of significant elevation change, the CETB data indicates heterogeneous behavior in the spatial distribution of the initial melt onset which may provide valuable hydrologic information.
PRESENTATION