Radar altimeter waveform simulations in Antarctica with the Snow Microwave Radiative Transfer Model (SMRT)

• Published in: Remote Sensing of Environment
• Main Authors: Larue, Fanny, Picard, Ghislain, Aublanc, Jérémie, Arnaud, Laurent, Robledano-Perez, Alvaro, Le Meur, Emmanuel, Favier, Vincent, Jourdain, Bruno, Savarino, Joel, Thibaut, Pierre
• Other Authors: Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Collecte Localisation Satellites (CLS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: Antarctic ice sheet; SMRT; remote sensing; radar altimetry; waveform; modeling; field measurements; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Antarctic; The Antarctic; Antarc*; Antarctica; Ice Sheet
• Online Access: https://hal.science/hal-03402150; https://hal.science/hal-03402150/document; https://hal.science/hal-03402150/file/altimetry_RSE_Fanny_Larue_11042021.pdf; https://doi.org/10.1016/j.rse.2021.112534

International audience Radar altimeters are important tools to monitor the volume of the ice sheets. The penetration of radar waves in the snowpack is a major source of uncertainty to retrieve surface elevation. To correct this effect, a better understanding of the sensitivity of the radar waveforms to snow properties is needed. Here, we present an extension of the Snow Model Radiative Transfer (SMRT) to compute radar waveforms and conduct a series of simulations on the Antarctic ice sheet. SMRT is driven by snow and surface roughness properties measured over a large latitudinal range during two field campaigns on the Antarctic Plateau. These measurements show that the snowpack is rougher, denser, less stratified, warmer, and has smaller snow grains near the coast than on the central Plateau. These simulations are compared to satellite observations in the Ka, Ku, and S bands. SMRT reproduces the observed waveforms well. For all sites and all sensors, the main contribution comes from the surface echo. The echo from snow grains (volume scattering) represents up to 40% of the amplitude of the total waveform power in the Ka band, and less at the lower frequencies. The highest amplitude is observed on the central Plateau due to the combination