Evaluation of Airborne X- and Ku-Band SAR Measurements over Snow Covered Tundra
Derksen, Chris1; Toose, Peter1; King, Joshua2; Lemmetyinen, Juha3; Marsh, Philip1; Royer, Alain4; Coccia, Alex5; Meta, Adriano5; Nagler, Thomas6; Rott, Helmut6; Schuettemeyer, Dirk7; Wang, Libo1
1Environment Canada, CANADA; 2University of Waterloo, CANADA; 3Finnish Meteorological Institute, FINLAND; 4Universite de Sherbrooke, CANADA; 5MetaSensing, NETHERLANDS; 6ENVEO, AUSTRIA; 7European Space Agency, NETHERLANDS
The proposed European Space Agency (ESA) Earth Explorer 7 CoReH20 mission has the primary objective of retrieving snow water equivalent (SWE) over land and glaciers at a high spatial resolution (200-500 metres) from spaceborne X- and Ku-band synthetic aperture radar (SAR) measurements. In order to evaluate the CoReH20 retrieval capability, airborne measurements with the SnowSAR instrument (X- and Ku-band SAR installed on a Cessna-208) will be acquired over the Trail Valley Creek (TVC) watershed near Inuvik, Northwest Territories in March and April 2013. The predominant land cover in TVC is open and shrub tundra, with some small tree stands in river valleys. Environment Canada led research on cold regions hydrological processes and modeling has been conducted in TVC over the past 2 decades.
Ground-based snow measurements were initially acquired during December 2012 in order to capture early season snow conditions across the study area, as a baseline to understand the evolution of physical snow characteristics (snow metamorphism; redistribution) by the time of airborne radar measurements in March 2013. Coincident to the March and April flights, long transects of georeferenced snow depth will be acquired along flight line segments; more broadly spaced snow core measurements will provide bulk snow density measurements needed to convert the snow depths to SWE. Snow stratigraphic measurements will be acquired from conventional manual observations and state of the art objective techniques, including snow specific surface area (SSA) estimates from 1300 nm laser measurements. A ground-based LiDAR system will be used to estimate the volume of snow stored in large snow drifts present along valley edges.
The airborne backscatter measurements at X- and Ku-bands will be used to retrieve SWE using the CoReH20 processing chain. This presentation will provide an initial assessment of backscatter behaviour and SWE retrieval sensitivity, determined using the in situ snow datasets. Looking forward, we aim to identify the potential use of CoReH20 SWE retrievals as observational inputs to various environmental prediction models, including land surface data assimilation systems.