Summary
Results from in-cloud measurements with an instrumented aircraft from an icing research campaign in Southern Germany in March 1997 are presented. Measurements with conventional optical cloud probes and of the ice accretion on a cylinder exposed to the flow show the existence of supercooled large drops (SLD) in the size range up to 300 µm simultaneously with severe icing with ice-accretion rates of up to 3.5 mm min−1. Nearly all periods with icing, including the ones with severe icing, occurred in mixed-phase convective cells embedded in surrounding stratus clouds. The spatial scales of SLD occurrence, respectively severe icing, ranged between several hundred meters and some kilometers and correspond to the length of the transects through the embedded cells. SLD formed through the coalescence process and were found through the whole cloud depth pointing to a source region near cloud top, in line with the arguments of Rauber and Tokay (1991). No indication of ice-multiplication by the Hallet-Mossop process was found, despite of the favorable temperatures for that process. Comparisons of the measured amount of accreted ice with the observed cloud-particle size distributions quite surprisingly indicate that ice accretion is mostly caused by 10–30 µm sized drops rather than by SLD. The latter, therefore, appear to be a by-product of a hypothesized liquid water accumulation zone near cloud top which is also the primary cause of the observed severe ice accretion. The results confirm the importance of embedded convection and of mixed phase clouds with high amounts of liquid water and simultaneously occurring SLD.
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References
Amendola A, Mingione G, Cailhol D, Hauf T (1998) EURICE: An European effort for the improvement of in-flight aircraft icing safety. 36th Aerospace Sciences Meeting and Exhibition, January 12–15, 1998, Reno, NV
M Bain JF Gayet (1982) ArticleTitleAircraft measurements of icing in supercooled and water droplet/ice crystal clouds. J Appl Meteor 21 631–641 Occurrence Handle10.1175/1520-0450(1982)021<0631:AMOIIS>2.0.CO;2
CJ Biter JE Dye D Huffman WD King (1987) ArticleTitleThe drop-size response of the CSIRO liquid water content probe. J Atmos Ocean Tech 4 359–367
SG Cober GA Isaac JW Strapp (1995) ArticleTitleAircraft icing measurements in East Coast winter storms. J Appl Meteor 34 88–100 Occurrence Handle10.1175/1520-0450-34.1.88
SG Cober JW Strapp GA Isaac (1996a) ArticleTitleAn example of supercooled drizzle droplets formed through a collision coalescence process. J Appl Meteor 35 2250–2260
Cober SG, Isaac GA, Strapp JW, Marcotte D (1996b) Analysis of aircraft icing environments associated with supercooled drizzle. Proc. FAA Int. Conf. on Aircraft Inflight Icing, Springfield, Virginia, 6–8 May 1996, DOT/FAA/ AR-96/81, II, 1–11
SG Cober JW Strapp GA Isaac (2001a) ArticleTitleCharacterizations of aircraft icing environments that include supercooled large drops. J Appl Meteor 40 1984–2002
SG Cober GA Isaac AV Korolev JW Strapp (2001b) ArticleTitleAssessing cloud-phase conditions. J Appl Meteor 40 1967–1983
WA Cooper WR Sand MK Politovich LV Donald (1984) ArticleTitleEffects of icing on performance of a research airplane. J Aircraft 21 708–715
Federal Aviation Administration (1999) Appendix C. Airworthiness standard: Transport category airplanes, part 25. Aeronautics and Space, Vol. 14, U.S. Code of Regulations, Office of the Federal Register, National Archives and Records Administration (available from Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402-9328)
JF Gayet (1986) ArticleTitleCalibration of Johnson-Williams and PMS-FSSP probes in a wind tunnel. J Atmos Ocean Tech 3 381–390
Hagen M, Meischner P (2000) Estimation of rainfall parameters from polarimetric radar measurements with POLDIRAD. Phys Chem Earth (B) 25: 10–12, 849–853
J Hallett SC Mossop (1974) ArticleTitleProduction of secondary particles during the riming process. Nature 249 26–28 Occurrence Handle10.1038/249026a0
PV Hobbs AL Rangno (1985) ArticleTitleIce particle concentrations in clouds. J Atmos Sci 42 2523–2549 Occurrence Handle10.1175/1520-0469(1985)042<2523:IPCIC>2.0.CO;2
Hoffmann HE, Demmel J (1992) Analysis of three icing test flights reaching the aircraft-referred icing degree “severe”. European Space Agency, Report ESA-TT-1254
AV Korolev JW Strapp GA Isaac (1998) ArticleTitleEvaluation of accuracy of PMS optical array probes. J Atmos Ocean Tech 15 708–720
MK Politovich (1989) ArticleTitleAircraft icing caused by large supercooled droplets. J Appl Meteor 28 856–868 Occurrence Handle10.1175/1520-0450(1989)028<0856:AICBLS>2.0.CO;2
MK Politovich (1996) ArticleTitleResponse of a research aircraft to icing conditions and evaluation of icing severity indices. J Aircraft 33 291–297 Occurrence Handle10.2514/3.46936
Pruppacher HR, Klett JD (1997) Microphysics of clouds and precipitation, 2nd ed. Dordrecht: Kluwer Academic Publishers, 954 pp
RM Rasmussen MK Politovich JD Marwitz J McGinley J Smart W Sand G Stossmeister B Bernstein R Pielke D Wesley S Rutledge K Elmore ER Westwater B Stankov D Burrows (1992) ArticleTitleWinter Icing and Storms Project (WISP). Bull Amer Meteor Soc 73 951–974 Occurrence Handle10.1175/1520-0477(1992)073<0951:WIASP>2.0.CO;2
Rasmussen RM, Geresdi I, Thompson G, Manning K, Karplus E (2000) Freezing drizzle and supercooled large droplet (SLD) formation in stably stratified layer clouds: Results from detailed microphysical simulations and implications for aircraft icing. 9th Conf. on Aviation, Range, and Aerospace Meteorology, Amer Meteor Soc, 11–15 September 2000, Orlando, FL
RM Rauber A Tokay (1991) ArticleTitleAn explanation for the existence of supercooled water at the top of cold clouds. J Atmos Sci 48 1005–1023
Riley JT (1998) Mixed-Phase Icing Conditions: A Review. Office of Aviation Research, Washington D.C., Final Report 20591DOT/FAA/AR-98/76, December 1998, National Technical Information Service (NTIS), Springfield, Virginia 22161
Sand WR, Biter CJ (2000) Meteorology surrounding the Roselawn accident. 9th Conf. on Aviation, Range, and Aerospace Meteorology, Amer Meteor Soc, 11–15 September 2000, Orlando, FL
Stingl S (1999) Das EURICE Flugmessexperiment – Experimentbeschreibung und Analyse eines Messfluges. Diploma thesis, Institut für Meteorologie und Klimatologie, Universität Hannover, Germany
Strapp JW, Stuart RA, Isaac GA (1996) Canadian climatology of freezing precipitation, and a detailed study using data from St. John’s, Newfoundland. Proc. FAA Int. Conf. on Aircraft Inflight Icing, Springfield, Virginia, Vol. II, DOT/FAA/AR-96/81: 45–55
Vali G (1997) Cloud properties measured from aircraft – an assessment. WMO Workshop on Measurement of Cloud Properties for Forecasts of Weather, Air Quality and Climate, June 23–27, 1997, Mexico City, Mexico
Vohl O (2000) An experimental investigation of the effects of turbulence on the scavenging of aerosol particles by rain drops, and on the growth of cloud drops by collision. Diss. Johannes-Gutenberg-Universität Mainz, 2000
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Hauf, T., Schröder, F. Aircraft icing research flights in embedded convection. Meteorol. Atmos. Phys. 91, 247–265 (2006). https://doi.org/10.1007/s00703-004-0082-y
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DOI: https://doi.org/10.1007/s00703-004-0082-y