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Level 2a Cloudnet product:

Ice cloud parameters (radar/lidar method)

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Summary

Designation
ice-radar-lidar-method
Level
2a
Algorithm design
Product maintainer
Institute
Royal Dutch Meteorological Institute (KNMI)
Description
Ice cloud parameters such as water content and effective radius, derived by combining radar and lidar. This product is expected to be more accurate than the ice water content derived from radar and temperature, but it only operates in a subset of the ice clouds that the lidar was able to detect.
Documentation
See relevant publication
Relevant publication(s)
Donovan, D. P., and A. C. A. P. van Lammeren, 2001: Cloud effective particle size and water content profile retrievals using combined lidar and radar observations - 1. Theory and examples. J. Geophys. Res., 106(D21), 27425-27448.
Quicklooks
http://www.met.rdg.ac.uk/radar/cloudnet/quicklooks/
Suggested acknowledgement
We acknowledge the Cloudnet project (European Union contract EVK2-2000-00611) for providing the radar/lidar ice cloud retrieval, which was produced by the Royal Dutch Meteorological Institute (KNMI) using measurements from [SITE].

Dataset contents

Sample NetCDF file: 20031001_chilbolton_ice-radar-lidar-method.nc
Header of sample NetCDF file in ASCII: 20031001_chilbolton_ice-radar-lidar-method.cdl

The following is a description of the variables in this product, produced automatically from the metadata in the sample file (using the nc2html unix utility):

Dataset title: Ice cloud properties derived using combined radar and lidar

    Institution:Data processed at the Royal Dutch Meteorological Institute (KNMI)
    References:Donovan and Van Lammeren 2000, Donovan 2003
    Software version:Lidrad 1.04

Dimensions and coordinate variables

time
Time UTC
    Units:hours since 2003-10-01 00:00:00+0:00
    Type:single-precision floating-point vector
height
Height above mean sea level
    Units:m
    Type:single-precision floating-point vector

Variables

rpeff(time, height)
Effective radius prime

    This variable is the lidar-radar effective radius which \n is an invariant function of the ratio between the optical \n extinction and the radar reflectivity.

    Units:μm
    Type:single-precision floating-point array
    Variable containing the random error in rpeff:rpeff_error
rpeff_error(time, height)
Random error in rpeff, one standard deviation

    This variable is an estimate of the one-standard-deviation random error in \n effective radius prime calculated by propagating the errors in the \n lidar and radar signal

    Units:um
    Type:single-precision floating-point array
reff(time, height)
Effective radius

    Units:&um;m
    Type:single-precision floating-point array
    Variable containing the random error in reff:reff_error
reff_error(time, height)
Random error in effective radius, one standard deviation

    This variable is an estimate of the one-standard-deviation random error in \n effective radius taken from rpeff_error

    Units:um
    Type:single-precision floating-point array
alpha(time, height)
Extinction

    Units:(m)-1
    Type:single-precision floating-point array
    Variable containing the random error in alpha:alpha_error
alpha_error(time, height)
std deviation Extinction

    Units:m-1
    Type:single-precision floating-point array
iwc(time, height)
Ice water content

    This variable is the ice water content which \n is calculated from IWC-prime addopting an ice habit and particles size distribution

    Units:g m-3
    Type:single-precision floating-point array
    Variable containing the random error in iwc:iwc_error
iwc_error(time, height)
Random error in Ice water content, one standard deviation

    This variable is an estimate of the one-standard-deviation random error in \n effective ice water content calculated using the error in ice water content prime

    Units:g m-3
    Type:single-precision floating-point array
iwcp(time, height)
Ice water content prime

    This variable is the lidar-radar effective ice water content which \n is an invariant function of the ratio between the optical \n extinction and the radar reflectivity.

    Units:g m-3
    Type:single-precision floating-point array
    Variable containing the random error in iwcp:iwcp_error
iwcp_error(time, height)
Random error in Ice water content prime, one standard deviation

    This variable is an estimate of the one-standard-deviation random error in \n effective ice water content prime calculated by propagating the errors in the \n lidar and radar signal

    Units:g m-3
    Type:single-precision floating-point array
ice(time, height)
ice determination; ice=1 --> ice; ice=0 --> water or nothing
    Units:-
    Type:single-precision floating-point array
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