대기 (Atmosphere)

  • 제30권1호
  • /
  • Pages.75-89
  • /
  • 2020
  • /
  • 1598-3560(pISSN)
  • /
  • 2288-3266(eISSN)
한국기상학회 (Korean Meteorological Society)
권호 표지
DOI QR코드

DOI QR Code

항공기 구름 관측에 사용되는 전방산란 관측 기기의 정확도 향상을 위한 구름입자의 광학적 특성 계산

Calculations of Optical Properties of Cloud Particles to Improve the Accuracy of Forward Scattering Probes for In-Situ Aircraft Cloud Measurements

  • 엄준식 (부산대학교 대기환경과학과)
  • Um, Junshik (Department of Atmospheric Sciences, Pusan National University)
  • 투고 : 2020.01.29
  • 심사 : 2020.02.05
  • 발행 : 2020.03.31
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

Current in-situ airborne probes that measure the sizes of ice crystals smaller than 50 ㎛ are based on the concept that the measured intensity of light scattered by a particle in the forward and/or backward direction can be converted to particle size. The relationship between particle size and scattered light used in forward scattering probes is based on Mie theory, which assumes the refractive index of particle is known and all particles are spherical. Not only are small crystals not spherical, but also there are a wide variety of non-spherical shapes. Although it is well known that the scattering properties of non-spherical ice crystals differ from those of spherical shapes, the impacts of non-sphericity on derived in-situ particle size distributions are unknown. Thus, precise relationships between the intensity of scattered light and particle size and shape are required, as based on accurate calculations of scattering properties of ice crystals. In this study, single-scattering properties of ice crystals smaller than 50 ㎛ are calculated at a wavelength of 0.55 ㎛ using a numerically exact method (i.e., discrete dipole approximation). For these calculations, hexagonal ice crystals with varying aspect ratios are used to represent the shapes of natural small ice crystals to determine the errors caused by non-spherical ice crystals measured by forward scattering probes. It is shown that the calculated errors in sizing nonspherical ice crystals are at least 13% and 26% in forward (4~12°) and backward (168~176°) directions, respectively, and maximum errors are up to 120% and 132%.

키워드

참고문헌

  1. Bailey, M., and J. Hallett, 2004: Growth rates and habits of ice crystals between $-20^{\circ}C$ and $-70^{\circ}C$. J. Atmos. Sci., 61, 514-544, doi:10.1175/1520-0469(2004)061<0514:GRAHOI>2.0.CO;2.
  2. Baumgardner, D., H. Jonsson, W. Dawson, D. O'Connor, and R. Newton, 2001: The cloud, aerosol and precipitation spectrometer: a new instrument for cloud investigations. Atmos. Res., 59-60, 251-264, doi:10.1016/S0169-8095(01)00119-3.
  3. Baumgardner, D., H. Chepfer, G. B. Raga, and G. L. Kok, 2005: The shapes of very small cirrus particles derived from in situ measurements. Geophys. Res. Lett., 32, L01806, doi:10.1029/2004GL021300.
  4. Baumgardner, D., and Coauthors, 2012: In situ, airborne instrumentation: Addressing and solving measurement problems in ice clouds. Bull. Amer. Meteor. Soc., 93, 29-34, doi:10.1175/BAMS-D-11-00123.1.
  5. Baumgardner, D., R. Newton, M. Kramer, J. Meyer, A. Beyer, M. Wendisch, and P. Vochezer, 2014: The Cloud Particle Spectrometer with Polarization Detection (CPSPD): A next generation open- path cloud probe for distinguishing liquid cloud droplets from ice crystals. Atmos. Res., 142, 2-14, doi:10.1016/j.atmosres.2013.12.010.
  6. Baumgardner, D., and Coauthors, 2017: Cloud ice properties: In situ measurement challenges. Meteor. Monogr., 58, 9.1-9.23, doi:10.1175/AMSMONOGRAPHS-D-16-0011.1.
  7. Bi, L., and P. Yang, 2014: Accurate simulation of the optical properties of atmospheric ice crystals with the invariant imbedding T-matrix method. J. Quant. Spectrosc. Radiat. Transfer, 138, 17-35, doi:10.1016/j.jqsrt.2014.01.013.
  8. Borrmann, S., L. Beiping, and M. Mishchenko, 2000: Application of the T-matrix method to the measurement of aspherical (ellipsoidal) particles with forward scattering optical particle counters. J. Aerosol Sci., 31, 789-799, doi:10.1016/S0021-8502(99)00563-7.
  9. Cha, J. W., and Coauthors, 2019: Analysis of results and techniques about precipitation enhancement by aircraft seeding in Korea. Atmosphere, 29, 481-499, doi:10.14191/Atmos.2019.29.4.481 (in Korean with English abstract).
  10. Cox, C. J., D. C. Noone, M. Berkelhammer, M. D. Shupe, W. D. Neff, N. B. Miller, V. P. Walden, and K. Steffen, 2019: Supercooled liquid fogs over the central Greenland Ice Sheet. Atmos. Chem. Phys., 19, 7467-7485, doi:10.5194/acp-19-7467-2019.
  11. Dye, J. E., and D. Baumgardner, 1984: Evaluation of the forward scattering spectrometer probe. Part I: Electronic and optical studies. J. Atmos. Ocean. Tech., 1, 329-344, doi:10.1175/1520-0426(1984)001<0329:EOTFSS>2.0.CO;2.
  12. Glen, A., and S. D. Brooks, 2013: A new method for measuring optical scattering properties of atmospherically relevant dusts using the Cloud and Aerosol Spectrometer with Polarization (CASPOL). Atmos. Chem. Phys., 13, 1345-1356, doi:10.5194/acp-13-1345-2013.
  13. Gonser, S. G., O. Klemm, F. Griessbaum, S.-C. Chang, H.-S. Chu, and Y.-J. Hsia, 2012: The relation between humidity and liquid water content in fog: An experimental approach. Pure Appl. Geophys., 169, 821-833, doi:10.1007/s00024-011-0270-x.
  14. Knollenberg, R. G., 1970: The optical array: An alternative to scattering or extinction for airborne particle size determination. J. Appl. Meteor., 9, 86-103, doi:10.1175/1520-0450(1970)009,0086: TOAAAT.2.0.CO;2.
  15. Knollenberg, R. G., 1976: Three new instruments for cloud physics measurements: The 2-D spectrometer probe, the forward scattering spectrometer probe, and the active scattering aerosol spectrometer. Preprints, Int. Conf. on Cloud Physics, Amer. Meteor. Soc., 554-561.
  16. Knollenberg, R. G., 1981: Techniques for probing cloud microstructure. In P. V. Hobbs and A. Deepak, Eds., Clouds - Their Formation, Optical Properties and Effects, Academic Press, 15-91.
  17. Lance, S., C. A. Brock, D. Rogers, and J. A. Gordon, 2010: Water droplet calibration of the cloud droplet probe (CDP) and in-flight performance in liquid, ice and mixed-phase clouds during ARCPAC. Atmos. Meas. Tech., 3, 1683-1706, doi:10.5194/ amt-3-1683-2010.
  18. Lawson, R. P., R. E. Stewart, and L. J. Angus, 1998: Observations and numerical simulations of the origin and development of very large snowflakes. J. Atmos. Sci., 55, 3209-3229, doi:10.1175/1520-0469(1998)055,3209:OANSOT.2.0.CO;2.
  19. Lawson, R. P., D. O'Connor, P. Zmarzly, K. Weaver, B. Baker, Q. Mo, and H. Jonsson, 2006: The 2DS (stereo) probe: Design and preliminary tests of a new airborne, high speed, high-resolution particle imaging probe. J. Atmos. Oceanic Technol., 23, 1462-1471, doi:10.1175/JTECH1927.1.
  20. Lawson, R. P., and Coauthors, 2019: A review of ice particle shapes in cirrus formed in situ and in anvils. J. Geophys. Res., 124, 10049-10090, doi:10.1029/2018JD030122.
  21. Macke, A., J. Mueller, and E. Raschke, 1996: Single scattering properties of atmospheric ice crystals. J. Atmos. Sci., 53, 2813-2825. doi:10.1175/1520-0469(1996)053<2813:SSPOAI>2.0.CO;2.
  22. McFarquhar, G. M., J. Um, M. Freer, D. Baumgardner, G. L. Kok, and G. Mace, 2007: Importance of small ice crystals to cirrus properties: Observations from the Tropical Warm Pool International Cloud Experiment (TWP-ICE). Geophys. Res. Lett., 34, L13803, doi:10.1029/2007GL029865.
  23. McFarquhar, G. M., and Coauthors, 2017: Processing of Ice Cloud In Situ Data Collected by Bulk Water, Scattering, and Imaging Probes: Fundamentals, Uncertainties, and Efforts toward Consistency. Meteor. Monogr., 58, 11.1-11.33, doi:10.1175/AMSMONOGRAPHS-D-16-0007.1.
  24. Meyer, J., 2012: Ice Crystal Measurements with the New Particle Spectrometer NIXE-CAPS. Forschungszentrum Julich GmbH, Institute for Energy and Climate Research, 132 pp.
  25. Mishchenko, M. I., and L. D. Travis, 1998: Capabilities and limitations of a current Fortran implementation of the T-matrix method for randomly oriented, rotationally symmetric scatterers. J. Quant. Spectrosc. Radiat. Transfer, 60, 309-324.
  26. Mishchenko, M. I., L. D. Travis, and D. W. Mackowski, 1996: T-matrix computations of light scattering by nonspherical particles: A review. J. Quant. Spectrosc. Radiat. Transfer, 55, 535-575.
  27. Pinnick, R. G., and H. J. Auvermann, 1979: Response characteristics of Knollenberg light-scattering aerosol counters. J. Aerosol Sci., 10, 55-74, doi:10.1016/0021-8502(79)90136-8.
  28. Pinnick, R. G., D. M. Garvey, and L. D. Duncan, 1981: Calibration of Knollenberg FSSP light-scattering counters for measurement of cloud droplets. J. Appl. Meteor. Climatol., 20, 1049-1057, doi:10.1175/1520-0450(1981)020<1049:COKFLS>2.0.CO;2.
  29. Sassen, K., Z. Wang, and D. Liu, 2008: Global distribution of cirrus clouds from CloudSat/Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) measurements. J. Geophys. Res., 113, D00A12, doi:10.1029/2008JD009972.
  30. Schnaiter, M., S. Buttner, O. Mohler, J. Skrotzki, M. Vragel, and R. Wagner, 2012: Influence of particle size and shape on the backscattering linear depolarisation ratio of small ice crystals - Cloud chamber measurements in the context of contrail and cirrus microphysics. Atmos. Chem. Phys., 12, 10465-10484, doi:10.5194/acp-12-10465-2012.
  31. Spiegel, J. K., P. Zieger, N. Bukowiecki, E. Hammer, E. Weingartner, and W. Eugster, 2012: Evaluating the capabilities and uncertainties of droplet measurements for the fog droplet spectrometer (FM-100). Atmos. Meas. Tech., 5, 2237-2260, doi:10.5194/amt-5-2237-2012.
  32. Um, J., and G. M. McFarquhar, 2007: Single-scattering properties of aggregates of bullet rosettes in cirrus. J. Appl. Meteor. Climatol., 46, 757-775, doi:10.1175/JAM2501.1.
  33. Um, J., and G. M. McFarquhar, 2009: Single-scattering properties of aggregates plates, Q. J. Roy. Meteor. Soc., 135, 291-304, doi:10.1002/qj.378.
  34. Um, J., and G. M. McFarquhar, 2011: Dependence of the single-scattering properties of small ice crystals on idealized shape models, Atmos. Chem. Phys., 11, 3159-3171, doi:10.5194/acp-11-3159-2011.
  35. Um, J., and G. M. McFarquhar, 2013: Optimal numerical methods for determining the orientation averages of single-scattering properties of atmospheric ice crystals. J. Quant. Spectrosc. Radiat. Transfer, 127, 207-223, doi:10.1016/j.jqsrt.2013.05.020.
  36. Um, J., and G. M. McFarquhar, 2015: Formation of atmospheric halos and applicability of geometric optics for calculating single-scattering properties of hexagonal ice crystals: Impacts of aspect ratio and ice crystal size. J. Quant. Spectrosc. Radiat. Transfer, 165, 134-152, doi:10.1016/j.jqsrt.2015.07.001.
  37. Um, J., and G. M. McFarquhar, Y. P. Hong, S.-S. Lee, C. H. Jung, R. P. Lawson, and Q. Mo, 2015: Dimensions and aspect ratios of natural ice crystals. Atmos. Chem. Phys., 15, 3933-3956, doi:10.5194/acp-15-3933-2015.
  38. Wendisch, M., and J.-L. Brenguier, 2013: Airborne Measurements for Environmental Research: Methods and Instruments. Wiley and Sons, 641 pp.
  39. Yurkin, M. A., and A. G. Hoekstra, 2007: The discrete dipole approximation: an overview and recent developments. J. Quant. Spectrosc. Radiat. Transfer, 106, 558-589, doi:10.1016/j.jqsrt.2007.01.034.
  40. Yurkin, M. A., and A. G. Hoekstra, 2011: The discrete-dipole-approximation code ADDA: capabilities and known limitations. J. Quant. Spectrosc. Radiat. Transfer, 112, 2234-2247, doi:10.1016/j.jqsrt.2011.01.031.