602
Drummond C, Spinhirne JD, Hart WD: Case study: contrail microphysics from aircraft
remote sensing analysis
Mace GG, Ackerman T: Examination of observed radiative forcing during the 94-95 winter
Okamoto H, Mukai S, Sano I: Aerosol retrieval algorithms from ADEOS/ILAS measurements
Seker S: Stochastic propagation of model clouds
Raison F: ScaRaB Scanner for radiation budget
3 Group C: Cloud Precipitation Characterisations
Our studies concern liquid water, solid ice and snow in the atmosphere. The projects were
organised in terms of their scale, to show that they (almost!) covered the full range of cloud
and precipitation phenomena, from the molecular to the global.
Okamoto explains in his poster the modeling of 94 Ghz radar backscatter from hexagonal ice
crystals, using the Discrete Dipole Aproximation (DDA). Lemke and Oldag's poster analyses
94 Ghz radar observatons of cirrus, in which the DDA computed backscatter from hexagonal
column and plate crystals eliminates the errors arising from the spherical particle assumption
of Mie theory.
Fiig's poster is concerned with the problem of different spatial resolutions at different frequencies used in microwave radiometry. Using the high correlation between the different frequencies,
a method is developed on the basis of multiple regression to increase the poorer resolution of
the lower SSM/I frequency channels to that of the 85 Ghz channel. Taking into acount spatial
and temporal restrictions with this method, it is possible to use the SSM/I data unaffected by
land up to 15 km off the coast.
The following group members presented their work to the audience at a poster session, in
ascending order of atmospheric scale.
Simpson: Analysis of 3 Ghz and 35 Ghz radar signals can measure particle size distributions
in stratiform cloud, by exploiting Mie scatter from the larger particles at 35 Ghz. Results
demonstrated truly astonishing agreement with simultaneous sampling by aircraft. The size
distributions obtained can be used to compute essential cloud parameters such as Effective
Radius, Liquid Water Content, and Ice Water Content.
Oury et al.: X band radar beams are deeply attenuated when passing through rain cells.
The "Stereoradar Analysis" allows us to retrieve non-attenuated reflectivity fields and the corresponding attenuation fields from the apparent reflectivities. Obtaining boundary conditions
and a sampling of the cells from two viewing angles, the "Stereoradar Analysis" is currently
able to retrieve the cells in coplan and cartesian co-ordinates.
Bennartz: In the 1990s, satellites with improved remote sensing capabilities will be launched.
In preparation for these, a method to derive semi-statistical algorithms based on a systematic
use of data from different sensors was developed and tested for combined SSM/I and SSM/T2
datasets. First intercomparisons with classical algorithms showed the reliability and improvement of this method.
Dioszeghy and Fejes: For operational purposes, satellite based cloud classifications should be
done on datasets with high time resolution, such as Meteosat. This method determines the main
cloud classes on the two-dimensional histogram of the infrared and visible brightness values by
a dynamic cluster analysis, according to cloud heights and thicknesses. The cumuliform and
Drummond C, Spinhirne JD, Hart WD: Case study: contrail microphysics from aircraft
remote sensing analysis
Mace GG, Ackerman T: Examination of observed radiative forcing during the 94-95 winter
Okamoto H, Mukai S, Sano I: Aerosol retrieval algorithms from ADEOS/ILAS measurements
Seker S: Stochastic propagation of model clouds
Raison F: ScaRaB Scanner for radiation budget
3 Group C: Cloud Precipitation Characterisations
Our studies concern liquid water, solid ice and snow in the atmosphere. The projects were
organised in terms of their scale, to show that they (almost!) covered the full range of cloud
and precipitation phenomena, from the molecular to the global.
Okamoto explains in his poster the modeling of 94 Ghz radar backscatter from hexagonal ice
crystals, using the Discrete Dipole Aproximation (DDA). Lemke and Oldag's poster analyses
94 Ghz radar observatons of cirrus, in which the DDA computed backscatter from hexagonal
column and plate crystals eliminates the errors arising from the spherical particle assumption
of Mie theory.
Fiig's poster is concerned with the problem of different spatial resolutions at different frequencies used in microwave radiometry. Using the high correlation between the different frequencies,
a method is developed on the basis of multiple regression to increase the poorer resolution of
the lower SSM/I frequency channels to that of the 85 Ghz channel. Taking into acount spatial
and temporal restrictions with this method, it is possible to use the SSM/I data unaffected by
land up to 15 km off the coast.
The following group members presented their work to the audience at a poster session, in
ascending order of atmospheric scale.
Simpson: Analysis of 3 Ghz and 35 Ghz radar signals can measure particle size distributions
in stratiform cloud, by exploiting Mie scatter from the larger particles at 35 Ghz. Results
demonstrated truly astonishing agreement with simultaneous sampling by aircraft. The size
distributions obtained can be used to compute essential cloud parameters such as Effective
Radius, Liquid Water Content, and Ice Water Content.
Oury et al.: X band radar beams are deeply attenuated when passing through rain cells.
The "Stereoradar Analysis" allows us to retrieve non-attenuated reflectivity fields and the corresponding attenuation fields from the apparent reflectivities. Obtaining boundary conditions
and a sampling of the cells from two viewing angles, the "Stereoradar Analysis" is currently
able to retrieve the cells in coplan and cartesian co-ordinates.
Bennartz: In the 1990s, satellites with improved remote sensing capabilities will be launched.
In preparation for these, a method to derive semi-statistical algorithms based on a systematic
use of data from different sensors was developed and tested for combined SSM/I and SSM/T2
datasets. First intercomparisons with classical algorithms showed the reliability and improvement of this method.
Dioszeghy and Fejes: For operational purposes, satellite based cloud classifications should be
done on datasets with high time resolution, such as Meteosat. This method determines the main
cloud classes on the two-dimensional histogram of the infrared and visible brightness values by
a dynamic cluster analysis, according to cloud heights and thicknesses. The cumuliform and