Using snowflake surface-area-to-volume ratio to model and interpret snowfall triple-frequency radar signatures
The snowflake microstructure determines the microwave scattering properties of individual snowflakes and has a strong impact on snowfall radar signatures. In this study, individual snowflakes are represented by collections of randomly distributed ice spheres where the size and number of the cons...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-10-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/17/12011/2017/acp-17-12011-2017.pdf |
| Summary: | The snowflake microstructure determines the microwave scattering properties
of individual snowflakes and has a strong impact on snowfall radar
signatures. In this study, individual snowflakes are represented by
collections of randomly distributed ice spheres where the size and number of
the constituent ice spheres are specified by the snowflake mass and
surface-area-to-volume ratio (SAV) and the bounding volume of each ice sphere
collection is given by the snowflake maximum dimension. Radar backscatter
cross sections for the ice sphere collections are calculated at X-, Ku-, Ka-,
and W-band frequencies and then used to model triple-frequency radar
signatures for exponential snowflake size distributions (SSDs). Additionally,
snowflake complexity values obtained from high-resolution multi-view
snowflake images are used as an indicator of snowflake SAV to derive snowfall
triple-frequency radar signatures. The modeled snowfall triple-frequency
radar signatures cover a wide range of triple-frequency signatures that were
previously determined from radar reflectivity measurements and illustrate
characteristic differences related to snow type, quantified through snowflake
SAV, and snowflake size. The results show high sensitivity to snowflake SAV
and SSD maximum size but are generally less affected by uncertainties in the
parameterization of snowflake mass, indicating the importance of snowflake
SAV for the interpretation of snowfall triple-frequency radar signatures. |
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| ISSN: | 1680-7316 1680-7324 |