W-band <i>S</i>–<i>Z</i> relationships for rimed snow particles: observational evidence from combined airborne and ground-based observations
<p>Values of undercatch-corrected liquid-equivalent snowfall rate (<span class="inline-formula"><i>S</i></span>) at a ground site and microwave reflectivity (<span class="inline-formula"><i>Z</i></span>) retrieved using an air...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-12-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://amt.copernicus.org/articles/16/6123/2023/amt-16-6123-2023.pdf |
| Summary: | <p>Values of undercatch-corrected liquid-equivalent snowfall rate (<span class="inline-formula"><i>S</i></span>) at a ground site and microwave reflectivity (<span class="inline-formula"><i>Z</i></span>) retrieved using an airborne W-band radar were acquired during overflights. The temperature at the ground site was between <span class="inline-formula">−</span>6 and <span class="inline-formula">−</span>15 <span class="inline-formula"><sup>∘</sup>C</span>. At flight level, within clouds containing ice and supercooled liquid water, the temperature was approximately 7 <span class="inline-formula"><sup>∘</sup>C</span> colder. Additionally, airborne measurements of snow particle imagery were acquired. The images demonstrate that most of the snow particles were rimed, at least at flight level. A relatively small set of <span class="inline-formula"><i>S</i></span>–<span class="inline-formula"><i>Z</i></span> pairs (four) is available from the overflights. Important distinctions between these measurements and those of Pokharel and Vali (2011), who reported <span class="inline-formula"><i>S</i></span>–<span class="inline-formula"><i>Z</i></span> pairs and an <span class="inline-formula"><i>S</i></span>–<span class="inline-formula"><i>Z</i></span> relationship for rimed snow particles, are (1) the fewer <span class="inline-formula"><i>S</i></span>–<span class="inline-formula"><i>Z</i></span> pairs, (2) the method used to acquire <span class="inline-formula"><i>S</i></span>, and (3) the altitude, relative to ground, of the W-band <span class="inline-formula"><i>Z</i></span> retrievals. This analysis corroborates the fact that the <span class="inline-formula"><i>S</i></span>–<span class="inline-formula"><i>Z</i></span> relationship reported in Pokharel and Vali (2011) yields an <span class="inline-formula"><i>S</i></span> – in scenarios with snowfall produced by riming – substantially larger than that derived using an <span class="inline-formula"><i>S</i></span>–<span class="inline-formula"><i>Z</i></span> relationship developed for unrimed snow particles.</p> |
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| ISSN: | 1867-1381 1867-8548 |