Atmos. Chem. Phys. Discuss., 7, 14103-14137, 2007
www.atmos-chem-phys-discuss.net/7/14103/2007/
doi:10.5194/acpd-7-14103-2007
© Author(s) 2007. This work is licensed under the
Creative Commons Attribution-NonCommercial-ShareAlike 2.5 License.
Review Status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Cloud thermodynamic phase inferred from merged POLDER and MODIS data
J. Riedi1, B. Marchant1, S. Platnick2, B. Baum3, F. Thieuleux1, C. Oudard1, F. Parol1, J-M. Nicolas4, and P. Dubuisson1
1Laboratoire d'Optique Atmosphérique, Université des Sciences et Technologies de Lille, France
2NASA Goddard Space Flight Center, MD, USA
3SSEC, University of Wisconsin-Madison, WI, USA
4ICARE Data and Services Center, Université des Sciences et Technologies de Lille, France

Abstract. The global spatial and diurnal distribution of cloud properties is a key issue for understanding the hydrological cycle, and critical for advancing efforts to improve numerical weather models and general circulation models. Satellite data provides the best way of gaining insight into global cloud properties. In particular, the determination of cloud thermodynamic phase is a critical first step in the process of inferring cloud optical and microphysical properties from satellite measurements. It is important that cloud phase be derived together with an estimate of the confidence of this determination, so that this information can be included with subsequent retrievals (optical thickness, effective particle radius, and ice/liquid water content).

In this study, we combine three different and well documented approaches for inferring cloud phase into a single algorithm. The algorithm is applied to data obtained by the MODIS (MODerate resolution Imaging Spectroradiometer) and POLDER3 (Polarization and Directionality of the Earth Reflectance) instruments. It is shown that this synergistic algorithm can be used routinely to derive cloud phase along with an index that helps to discriminate ambiguous phase from confident phase cases.

The resulting product provides a semi-continuous confidence index ranging from confident liquid to confident ice instead of the usual discrete classification of liquid phase, ice phase, mixed phase (potential combination of ice and liquid particles), or simply unknown phase clouds. This approach is expected to be useful for cloud assimilation and modeling efforts while providing more insight into the global cloud properties derived from satellite data.


Citation: Riedi, J., Marchant, B., Platnick, S., Baum, B., Thieuleux, F., Oudard, C., Parol, F., Nicolas, J-M., and Dubuisson, P.: Cloud thermodynamic phase inferred from merged POLDER and MODIS data, Atmos. Chem. Phys. Discuss., 7, 14103-14137, doi:10.5194/acpd-7-14103-2007, 2007.
 
Search ACPD
Discussion Paper
    XML
    Citation
    Final Revised Paper
    Share