Review article: Performance assessment of radiation-based field sensors for monitoring the water equivalent of snow cover (SWE)
<p>Continuous and spatially distributed data of snow mass (water equivalent of snow cover, SWE) from automatic ground-based measurements are increasingly required for climate change studies and for hydrological applications (snow hydrological-model improvement and data assimilation). We presen...
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| Autores principales: | , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Copernicus Publications
2021
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/f321eb4bdd9f4e26a1d2b7c1376ba531 |
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| Sumario: | <p>Continuous and spatially distributed data of snow mass (water equivalent of
snow cover, SWE) from automatic ground-based measurements are increasingly
required for climate change studies and for hydrological applications (snow
hydrological-model improvement and data assimilation). We present and
compare four new-generation sensors, now commercialized, that are
non-invasive and based on different radiations that interact with snow for SWE
monitoring: cosmic-ray neutron probe (CRNP), gamma ray monitoring (GMON)
scintillator, frequency-modulated continuous-wave radar (FMCW radar) at 24 GHz and global navigation satellite system (GNSS) receivers (GNSSr). All
four techniques have relatively low power requirements, provide continuous
and autonomous SWE measurements, and can be easily installed in remote
areas. A performance assessment of their advantages, drawbacks and
uncertainties is discussed from experimental comparisons and a literature
review. Relative uncertainties are estimated to range between 9 % and 15 %
when compared to manual in situ snow surveys that are also discussed.
Results show the following. (1) CRNP can be operated in two modes of functioning:
beneath the snow, it is the only system able to measure very deep snowpacks
(<span class="inline-formula"><i>></i></span> 2000 mm w.e.) with reasonable uncertainty across a wide range
of measurements; CRNP placed above the snow allows for SWE measurements over a
large footprint (<span class="inline-formula">∼</span> 20 ha) above a shallow snowpack. In both cases, CRNP
needs ancillary atmospheric measurements for SWE retrieval. (2) GMON
is the most mature instrument for snowpacks that are typically up to 800 mm w.e. Both CRNP (above snow) and GMON are sensitive to surface
soil moisture. (3) FMCW radar needs auxiliary snow-depth
measurements for SWE retrieval and is not recommended for automatic SWE
monitoring (limited to dry snow). FMCW radar is very sensitive to wet snow,
making it a very useful sensor for melt detection (e.g., wet avalanche
forecasts). (4) GNSSr allows three key snowpack parameters to be
estimated simultaneously: SWE (range: 0–1000 mm w.e.), snow depth and
liquid water content, according to the retrieval algorithm that is used. Its
low cost, compactness and low mass suggest a strong potential for GNSSr
application in remote areas.</p> |
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