Analysis of the Snow Water Equivalent at the AEMet-Formigal Field Laboratory (Spanish Pyrenees) During the 2019/2020 Winter Season Using a Stepped-Frequency Continuous Wave Radar (SFCW)

Rafael Alonso,José María García Del Pozo,José Adolfo Álvarez,Samuel T Buisán

doi:10.3390/rs13040616

Rafael Alonso, José María García Del Pozo + Show 2 more

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https://doi.org/10.3390/rs13040616

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Abstract

Snow makes a great contribution to the hydrological cycle in cold regions. The parameter to characterize available the water from the snow cover is the well-known snow water equivalent (SWE). This paper presents a near-surface-based radar for determining the SWE from the measured complex spectral reflectance of the snowpack. The method is based in a stepped-frequency continuous wave radar (SFCW), implemented in a coherent software defined radio (SDR), in the range from 150 MHz to 6 GHz. An electromagnetic model to solve the electromagnetic reflectance of a snowpack, including the frequency and wetness dependence of the complex relative dielectric permittivity of snow layers, is shown. Using the previous model, an approximated method to calculate the SWE is proposed. The results are presented and compared with those provided by a cosmic-ray neutron SWE gauge over the 2019–2020 winter in the experimental AEMet Formigal-Sarrios test site. This experimental field is located in the Spanish Pyrenees at an elevation of 1800 m a.s.l. The results suggest the viability of the approximate method. Finally, the feasibility of an auxiliary snow height measurement sensor based on a 120 GHz frequency modulated continuous wave (FMCW) radar sensor, is shown.

Highlights

This paper presents a near-surface-based technique for determining the snow water equivalent (SWE) from the measured complex spectral reflectance, in the range from 150 MHz to 6 GHz, and an electromagnetic model for the analysis of the reflectance of the snowpack
The aim of this paper is to show the operation of an software defined radio (SDR)-stepped-frequency continuous wave radar (SFCW) radar, and the application of an electromagnetic model of the multilayer snowpack to analyze the SWE of snow cover
This work shows the validation of the proposed SFCW radar technique, based in a RDS system, and an electromagnetic model of snowpack, to obtain its SWE and depth, in real time, for hydrological purposes

Summary

Introduction

Snow makes a large contribution to the water balance, climate, and economy of many regions. The seasonal accumulation of snow acts as a form of natural regulation of great importance in the hydrological cycle. The parameter to characterize the available water from snow cover is the well-known snow water equivalent (SWE). The SWE is the equivalent depth of water available if the snowpack melted into liquid water. This paper presents a near-surface-based technique for determining the SWE from the measured complex spectral reflectance, in the range from 150 MHz to 6 GHz, and an electromagnetic model for the analysis of the reflectance of the snowpack

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