RECENT EXTENSIONS OF THE SNOW MICROWAVE RADIATIVE TRANSFER (SMRT) MODEL ENABLING MULTI-MODAL ACTIVE/PASSIVE SIMULATIONS

G. Picard¹, M. Sandells², C. Prigent³, J. Murfitt⁴, C. Duguay^4,5

¹Univ. Grenoble Alpes, CNRS, Institut des Géosciences de l’Environnement (IGE), UMR 5001, Grenoble, France , ²Department of Geography and Environmental Sciences, Northumbria University, Newcastle upon Tyne, UK, ³LIRA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, Univ. Paris Cité, F-75014 Paris, France, ⁴H2O Geomatics Inc. Kitchener ON, Canada, ⁵Department of Geography and Environmental Management, University of Waterloo, Waterloo, Ontario, Canada

The Snow Microwave Radiative Transfer (SMRT) model is now 10 years old. Originally developed to address theoretical questions about the role of snow microstructure in microwave scattering, it has been widely used for the interpretation of radiometric measurements. Over time, it has evolved into a versatile, general-purpose radiative transfer model with applications across various cryospheric environments, sensor types, and satellite missions.

While most previous studies have focused on individual sensor types (e.g., radiometers, imaging radars, and altimeters), SMRT enables a consistent treatment of scattering and radiative transfer processes. This makes it possible to simulate multiple observables simultaneously, such as brightness temperature, radar backscatter, altimetric waveforms, and delay-Doppler maps, from a single physical configuration (e.g., a specific snowpack or sea-ice layer).

In this presentation, we first provide an overview of SMRT and highlight recent extensions that broaden its applicability to a wider range of sensors. We then illustrate the synergistic use of SMRT for active/passive microwave simulations in Antarctica through two examples. First, we investigate the frequency-dependent behaviour of brightness temperature and radar backscatter in a highly scattering region of the Antarctic continent. This study aims to improve our understanding of the extremely radar-bright surfaces observed on Saturn’s icy moons. Second, by combining passive microwave and altimetric simulations over Antarctica, we demonstrate how this approach enables us to constrain the simulations better and achieve an accurate balance between surface and volume scattering contributions, which is critical for altimetry.

We conclude this presentation with a discussion of potential future applications of SMRT, particularly in the context of recently launched or upcoming satellite missions.