Continuous secondary-ice production initiated by updrafts through the melting layer in mountainous regions

نویسندگان

چکیده

Abstract. An accurate prediction of the ice crystal number concentration in clouds is important to determine radiation budget, lifetime, and precipitation formation clouds. Secondary-ice production thought be responsible for observed discrepancies between ice-nucleating particle The Hallett–Mossop process active ?3 ?8 ?C has been implemented into several models, while all other secondary-ice processes are poorly constrained lack a well-founded quantification. During 2 h measurements taken on mountain slope just above melting layer at temperatures warmer than ?C, continuously high small plates identified as secondary was observed. presence drizzle drops suggests droplet fragmentation upon freezing mechanism. constant supply can explained by recirculation theory, suggesting that melted snowflakes, which sedimented through layer, were reintroduced cloud orographically forced updrafts. Here we introduce parametrization slightly sub-zero temperatures, where primary-ice nucleation basically absent, first initiated collision with aged crystals sedimenting from higher altitudes. Based previous measurements, estimate 200 µm diameter produces 18 when it fragments freezing. application our actual splinters produced fragmenting may up an order magnitude higher.

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ژورنال

عنوان ژورنال: Atmospheric Chemistry and Physics

سال: 2021

ISSN: ['1680-7316', '1680-7324']

DOI: https://doi.org/10.5194/acp-21-3855-2021