MODIS_ACNDC: adiabatic cloud droplet number concentration
doi:10.1594/WDCC/MODIS_ACNDC
Quaas, Johannes; Boucher, Olivier
DatasetDOI
Summary
Cloud droplet number concentration [m-3] derived from the MODIS Terra dataset assuming adiabatic clouds. CDNC is computed from the joint histogram of cloud optical thickness (COD) and cloud-top droplet effective radius (CDR) for liquid water clouds as CDNC = 1.37 e-5 * COD^0.5 * CDR^-2.5 (CDR in m and CDNC in m-3; Brenguier et al., J. Atmos. Sci., 2000; Quaas et al., Atmos. Chem. Phys. Discuss., 2005). No vertical distribution, CDNC is considered vertically constant in each cloud.
Longitude -180
to 180
Latitude -90
to 90
Altitude: 0 m
Temporal Coverage
2000-03-01
to 2005-02-28
(calendrical)
Use constraints
unrestricted
Data Catalog
World Data Center for Climate
Access constraints
registered users
Size
452.88 MiB (474878840 Byte)
Format
NetCDF
Status
completely archived
Creation Date
Download Permission
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Cite as
Quaas, Johannes; Boucher, Olivier (2005). MODIS_ACNDC: adiabatic cloud droplet number concentration. World Data Center for Climate (WDCC) at DKRZ. https://doi.org/10.1594/WDCC/MODIS_ACNDC
CDNC data is derived from MODIS-retrieved cloud optical thickness and...
Description
CDNC data is derived from MODIS-retrieved cloud optical thickness and cloud-top droplet effective radius. Liquid water clouds only are used, and COD and CDR are restricted to their most reliable values (4um <= CDR <= 30um and 4 <= COD <= 70; Nakajima and King, J. Atmos. Sci., 1990). However, for MODIS-retrieved CDR, problems are known (Breon and Doutriaux-Boucher, IEEE Trans. Geosci. Remote Sens., 2005). The assumption of adiabacity may not necessarily be valid, even though large regions are considered. We recommend to use CDNC for statistical studies rather than to rely on absolute accuracy in single regions or short time-periods
Completeness report
Missing values occur due to entirely clear sky grid-boxes (where thus no cloud retrieval is possible) or due to other retrieval problems (e.g.,instrum...
Description
Missing values occur due to entirely clear sky grid-boxes (where thus no cloud retrieval is possible) or due to other retrieval problems (e.g.,instrument failure or unsuitable viewing geometries).
[1] DOIQuaas, J.; Boucher, O.; Lohmann, U. (2005). Constraining the total aerosol indirect effect in the LMDZ and ECHAM4 GCMs using MODIS satellite data. doi:10.5194/acpd-5-9669-2005
Parent
MODIS_ACDNC Adiabatic Cloud Droplet Number Concentration daily value