Microphysical Properties of Ice Crystal Precipitation and Surface-Generated Ice Crystals in a High Alpine Environment in Switzerland
| Autor: | Oliver Schlenczek, Stephan Borrmann, Jonathan Crosier, Keith Bower, Michael Flynn, Jacob P. Fugal, Gary Lloyd, Thomas Choularton |
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| Rok vydání: | 2017 |
| Předmět: |
Atmospheric Science
010504 meteorology & atmospheric sciences Atmospheric sciences 01 natural sciences Physics::Geophysics 010309 optics Diamond dust Sea ice growth processes Cloud microphysics 0103 physical sciences Ice fog Precipitation Crystal habit Complex terrain Physics::Atmospheric and Oceanic Physics 0105 earth and related environmental sciences Ice crystals Ice particles Surface observations 13. Climate action In situ atmospheric observations Ice nucleus Particle Astrophysics::Earth and Planetary Astrophysics Geology |
| Zdroj: | Schlenczek, O, Fugal, J P, Lloyd, G, Bower, K N, Choularton, T W, Flynn, M, Crosier, J & Borrmann, S 2017, ' Microphysical Properties of Ice Crystal Precipitation and Surface-Generated Ice Crystals in a High Alpine Environment in Switzerland ', Journal of Applied Meteorology and Climatology, vol. 56, no. 2, pp. 433-453 . https://doi.org/10.1175/JAMC-D-16-0060.1 |
| ISSN: | 1558-8432 1558-8424 |
| DOI: | 10.1175/jamc-d-16-0060.1 |
| Popis: | During the Cloud and Aerosol Characterization Experiment (CLACE) 2013 field campaign at the High Altitude Research Station Jungfraujoch, Switzerland, optically thin pure ice clouds and ice crystal precipitation were measured using holographic and other in situ particle instruments. For cloud particles, particle images, positions in space, concentrations, and size distributions were obtained, allowing one to extract size distributions classified by ice crystal habit. Small ice crystals occurring under conditions with a vertically thin cloud layer above and a stratocumulus layer approximately 1 km below exhibit similar properties in size and crystal habits as Antarctic/Arctic diamond dust. Also, ice crystal precipitation stemming from midlevel clouds subsequent to the diamond dust event was observed with a larger fraction of ice crystal aggregates when compared with the diamond dust. In another event, particle size distributions could be derived from mostly irregular ice crystals and aggregates, which likely originated from surface processes. These particles show a high spatial and temporal variability, and it is noted that size and habit distributions have only a weak dependence on the particle number concentration. Larger ice crystal aggregates and rosette shapes of some hundred microns in maximum dimension could be sampled as a precipitating cirrostratus cloud passed the site. The individual size distributions for each habit agree well with lognormal distributions. Fitted parameters to the size distributions are presented along with the area-derived ice water content, and the size distributions are compared with other measurements of pure ice clouds made in the Arctic and Antarctic. |
| Databáze: | OpenAIRE |
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