Summary
Remotely sensed scanning radiometer and lidar data on cirrus clouds were obtained during the cirrus FIRE IFO experiment in November 1986 from the ER-2 aircraft plat-form.
Data were examined particularly on 2 November for an area in the vicinity of Wausau, Wisconsin where unusual effects were noticed in bispectral histograms from various channels in the scanner data.
After calibration of the data in spectral channels of both the Scan Cloud Radiometer (SCR) and Multichannel Cloud Radiometer (MCR) instruments, including direct comparison between compatible channels in the two instruments, it was found that the 0.856 µm SCR channel gave good data, whereas the 0.665 µm and 0.74 µm SCR channels gave large offsets, when compared with the MCR 0.754 µm data. The latter channel was found to compare well in a second comparison with coincident AVHRR channel satellite data. Similarly, the SCR 11.17 µm data gave consistent results and the SCR 3.74 µm data were carefully calibrated.
Bispectral histograms formed between 0.856 µm, 3.74 µm and 11.17 µm SCR channel data indicated that some coherent layers of cirrus clouds were giving enhanced solar reflectance at 3.74 µm, indicative of small (~ <25 µm radius) particles, whereas other neighbouring layers gave little reflectance.
A comparison of 0.856 µm reflections with 11.17 µm absorption optical depth indicated that the small particles where probably ice crystals. A comparison of 3.74 µm solar albedo and 11.17 µm absorption optical depths of these layers with theoretical calculations for ice spheres indicated a mode radius of about 8 µm for the cloud particle size distribution. An estimate from similar recent calculations on hexagonal ice crystals indicated that the retrieved effective radius would be increased to 25 µm. The difference between the two retrieved radii was a measure of the uncertainty in the retrievals, considering also differences in the assumed size distributions.
Qualitative comparison with ER-2 lidar data gave a tentative identification of the reflecting layers.
The results demonstrate the power of the 3.74 µm channel for identification of small-particle layers in cirrus.
Similar content being viewed by others
References
Ackerman, S. A., Smith, W. L., Spinhirne, J. D., Revercomb, H. E., 1990: The 27–28 October 1986 FIRE IFO Cirrus Case Study: spectral properties of cirrus clouds in the 8–12 µm window.Mon. Wea. Rev. 118, 2377–2388.
Arking, A., 1990: The radiative effects of clouds and their impact on climate.World Climate Programme Research, Report WCRP-52, WMO/TD-No. 399, WMO, Geneva, 39 pp.
Arking, A., Childs, J. D., 1985: Retrieval of cloud cover parameters from multispectral satellite images.J. Appl. Meteor. 24, 322–333.
Curran, R. J., Kyle, H. L., Blaine, L. R., Smith, J., Clem, T. D., 1981: Multichannel scanning radiometer for remote sensing cloud microphysical parameters.Rev. Sci. Instrum 52, 1546–1555.
Harshvardhan, 1991: Atmospheric Radiation.Rev. Geophys. Sci. [Suppl. 56–58.
Heymsfield, A. J., 1977: Precipitation development in stratiform ice clouds: a microphysical and dynamical study.J. Atmos. Sci. 34, 367–381.
Heymsfield, A. J., Platt, C. M. R., 1984: A parameterisation of the particle size spectrum of ice clouds in terms of the ambient temperature and the ice water content.J. Atmos. Sci. 41, 846–855.
Heymsfield, A. J., Miller, K. M., Spinhirne, J. D., 1990: The 27–28 October 1986 FIRE IFO Cirrus Case Study: cloud microstructure.Mon. Wea. Rev. 118, 2313–2328.
Liou, K. N., 1973: Transfer of solar irradiance through cirrus cloud layers.J. Geophys. Res. 78, 1409–1418.
Platt, C. M. R., 1983: On the bispectral method for cloud parameter determination from satellite VISSR data: separating broken cloud and semitransparent cloud.J. Climate Appl. Meteor. 22, 429–439.
Platt, C. M. R., 1989: The role of cloud microphysics in high-cloud feedback effects on climate change.Nature 341, 428–429.
Platt, C. M. R., Stephens, G. L., 1980: The interpretation of remotely sensed high cloud emittances.J. Atmos. Sci. 37, 2314–2322.
Platt, C. M. R., Reynolds, D. W., Abshire, N. L., 1980: Satellite and lidar observations of the albedo, emittance and optical depth of cirrus compared to model calculations.Mon. Wea. Rev. 108, 195–204, 1980.
Platt, C. M. R., Spinhirne, J., Hart, W. D., 1989: Optical and microphysical properties of a cold cirrus cloud: Evidence for regions of small ice particles.J. Geophys. Res. 94, 11, 151–11, 164.
Ramanathan, V., Cess, R. D., Harrison, E. F., Minnis, P., Barkstrom, B. R., Ahmad, E., Hartmann, D., 1989: Cloudradiative forcing and climate: results from the earth radiation budget experiment.Science 243, 57–63.
Rangno, A., Hobbs, P. V., 1986: Deficits in ice particle concentrations in stratiform clouds with top temperatures < − 30°C? Paper presented at the 23rd Conference on Radar Meteorology and the Conference on Cloud Physics.Amer. Meteorol. Soc., Snowmass, Col, 22–26 September 1986.
Roeckner, E., 1988: Cloud-radiation feedbacks in a climate model.Atmos. Res. 21, 293–303.
Sassen, K., Grund, C. J., Spinhirne, J. D., Hardesty, R. M., Alvarez, J. M., 1990: The 27–28 October FIRE IFO Cirrus Case Study: five-lidar overview of cloud structure and evolution.Mon. Wea. Rev. 118, 2288–2311.
Spinhirne, J. D., Hansen, M. Z., Caudill, L. O., 1982: Cloud top remote sensing by airborne lidar.Appl. Opt. 22, 1564–1571.
Spinhirne, J. D., Hart, W. D., 1990: Cirrus structure and radiative parameters from airborne lidar and spectral radiometer observations. The 28 October FIRE Study.Mon. Wea. Rev. 118, 2329–2343.
Starr, D. O'C, Wylie, D. P., 1990: The 27–28 October 1986 FIRE IFO cirrus cloud study: Meteorology and clouds.Mon. Wea. Rev. 118, 2259–2287.
Stone, R. S., Stephens, G. L., Platt, C. M. R., Banks, S., 1989: The remote sensing of thin cirrus cloud using satellites, lidar and radiative transfer theory.J. Appl. Meteor. 29, 353–366.
Wielicki, B. A., Suttles, J. T., Heymsfield, A. J., Welch, R. M., Spinhirne, J. D., Wu, M-li C., Starr, D.O'C., Parker, L., Arduini, R. F., 1990: The 27–28 October 1986 FIRE IFO Cirrus Case Study: comparison of radiative transfer theory with observations by satellite and aircraft.Mon. Wea. Rev. 118, 2356–2376.
Author information
Authors and Affiliations
Additional information
With 9 Figures
Rights and permissions
About this article
Cite this article
Platt, C.M.R., Arking, A. A case study of cirrus layers with variable 3.74 µm reflection properties in the first FIRE experiment, 2 November 1986. Theor Appl Climatol 56, 137–152 (1997). https://doi.org/10.1007/BF00866423
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00866423