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Level 2a Cloudnet product:

Liquid water content (Delft radar-lidar method)

Data Home | Overview of Cloudnet products | Product list | Quicklooks | Conditions of use

Summary

Designation
lwc-delft
Level
2a
Algorithm design/Product maintainer
Institute
International Research Centre for Telecommunications-transmission and Radar (IRCTR), TU Delft
Description
Liquid water content derived from Z-lwc relationships corresponding to three different classes of liquid water clouds (drizzle-free, light drizzle, heavy drizzle) diagnosed using radar and lidar.
Documentation
None yet available
Relevant publication(s)
Pending
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 liquid water content data, which was produced by the International Research Centre for Telecommunications-transmission and Radar (IRCTR), TU Delft using measurements from [SITE].

Dataset contents

Sample NetCDF file: 20031231_chilbolton_lwc-delft.nc
Header of sample NetCDF file in ASCII: 20031231_chilbolton_lwc-delft.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: Liquid Water Content from Radar/Lidar algorithm

March 2006 - all LWC radar/lidar products in one netCDF file.

    Institution:Data processed at IRCTR, TU Delft
    Software version:v. 0.5.4, March 2006 (MATLAB)

Dimensions and coordinate variables

time
Time UTC
    Units:hours since 2003-12-31 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

latitude
Latitude of site
    Units:degrees_north
    Type:single-precision floating-point scalar
longitude
Longitude of site
    Units:degrees_east
    Type:single-precision floating-point scalar
altitude
Height of radar above mean sea level
    Units:m
    Type:single-precision floating-point scalar
radar_frequency
Radar frequency
    Units:GHz
    Type:single-precision floating-point scalar
sigma(time, height)
Optical extinction

    Klett' inversion

    Units:1/m
    Type:single-precision floating-point array
Z(time, height)
Radar Reflectivity Factor
    Units:dBz
    Type:single-precision floating-point array
Tau(time)
Optical Depth

    This parameter calculated from lidar extinction profile

    Units:n/a
    Type:single-precision floating-point vector
ZA_threshold_1
First threshold value of the radar reflectivity to optical extinction ratio

    This value is using for the detection of "clouds without drizzle" (the ratio between radar reflectivity and optical extinction for such clouds has to be less than ZA_threshold_1)

    Units:log10([mm^6/m^3]/[1/m])
    Type:single-precision floating-point scalar
ZA_threshold_2
Second threshold value of the radar reflectivity to optical extinction ratio

    This value is using for the detection of "clouds with heavy drizzle" (the ratio between radar reflectivity and optical extinction for such clouds has to be greater than ZA_threshold_2). Clouds with radar reflectivity to optical extinction ratio values between ZA_threshold_1 and ZA_threshold_2 are categorized as "clouds with light drizzle"

    Units:log10([mm^6/m^3]/[1/m])
    Type:single-precision floating-point scalar
ZA(time, height)
Radar-to-Lidar Ratio

    no comments

    Units:log10( (mm^6/m^3) / (1/m) )
    Type:single-precision floating-point array
Z_threshold_1_1
First threshold value of the radar reflectivity

    This value is using for the detection of "clouds without drizzle" in cases when the ratio between radar reflectivity and optical extinction is not defined (radar reflectivity for such clouds has to be less than Z_threshold_1)

    Units:dBZ
    Type:single-precision floating-point scalar
Z_threshold_1_2
Second threshold value of the radar reflectivity

    This value is using for the detection of "clouds with heavy drizzle" in cases when the ratio between radar reflectivity and optical extinction is not defined (radar reflectivity for such clouds has to be greater than Z_threshold_2). Clouds with radar reflectivity values between Z_threshold_1 and Z_threshold_2 are categorized as "clouds with light drizzle"

    Units:dBZ
    Type:single-precision floating-point scalar
liquid_water_map_bits_1(time, height)
radar/lidar Liquid water categorization bits

    This variable contains information on the presence and nature of the liquid water at each pixel. The information is in the form of an array of bits, each of which states either whether a certain type of data or categorized water clouds is presented The definitions of each bit are given in the definition attribute. Bit 0 is the least significant.

    Units:n/a
    Type:byte array
    Definition:
    • Bit 0 - Reading's categorization product recognized pixel as water ((small droplets OR water precipitation) AND Temperature > 0C])
    • Bit 1 - radar signal presented
    • Bit 2 - lidar signal (extinction) presented
    • Bit 3 - radar reflectivity to lidar extinction presented
    • Bit 4 - atmospheric water, class 1 - "water cloud without drizzle"
    • Bit 5 - atmospheric water, class 2 - "water cloud with light drizzle"
    • Bit 6 - atmospheric water, class 3 - "water cloud with heavy drizzle"
LWC_Radar_Lidar_1(time, height)
radar/lidar LWC from Fox-Baedi-Drizzle Z-LWC relationship
    Units:g/m^3
    Type:single-precision floating-point array
LWP_Radar_Lidar_1(time)
radar/lidar LWP from Fox-Baedi-Drizzle Z-LWC relationship
    Units:g/m^2
    Type:single-precision floating-point vector
Z_threshold_2_1
First threshold value of the radar reflectivity

    This value is using for the detection of "clouds without drizzle" in cases when the ratio between radar reflectivity and optical extinction is not defined (radar reflectivity for such clouds has to be less than Z_threshold_1)

    Units:dBZ
    Type:single-precision floating-point scalar
Z_threshold_2_2
Second threshold value of the radar reflectivity

    This value is using for the detection of "clouds with heavy drizzle" in cases when the ratio between radar reflectivity and optical extinction is not defined (radar reflectivity for such clouds has to be greater than Z_threshold_2). Clouds with radar reflectivity values between Z_threshold_1 and Z_threshold_2 are categorized as "clouds with light drizzle"

    Units:dBZ
    Type:single-precision floating-point scalar
liquid_water_map_bits_2(time, height)
radar/lidar Liquid water categorization bits

    This variable contains information on the presence and nature of the liquid water at each pixel. The information is in the form of an array of bits, each of which states either whether a certain type of data or categorized water clouds is presented The definitions of each bit are given in the definition attribute. Bit 0 is the least significant.

    Units:n/a
    Type:byte array
    Definition:
    • Bit 0 - Reading's categorization product recognized pixel as water ((small droplets OR water precipitation) AND Temperature > 0C])
    • Bit 1 - radar signal presented
    • Bit 2 - lidar signal (extinction) presented
    • Bit 3 - radar reflectivity to lidar extinction presented
    • Bit 4 - atmospheric water, class 1 - "water cloud without drizzle"
    • Bit 5 - atmospheric water, class 2 - "water cloud with light drizzle"
    • Bit 6 - atmospheric water, class 3 - "water cloud with heavy drizzle"
LWC_Radar_Lidar_2(time, height)
radar/lidar LWC from Fox-Baedi-Drizzle Z-LWC relationship
    Units:g/m^3
    Type:single-precision floating-point array
LWP_Radar_Lidar_2(time)
radar/lidar LWP from Fox-Baedi-Drizzle Z-LWC relationship
    Units:g/m^2
    Type:single-precision floating-point vector
Z_corr(time, height)
Radar Reflectivity Factor, corrected for the radar discrepancy
    Units:dBz
    Type:single-precision floating-point array
ZA_corr(time, height)
Radar-to-Lidar Ratio, corrected for the radar discrepancy

    no comments

    Units:log10( (mm^6/m^3) / (1/m) )
    Type:single-precision floating-point array
liquid_water_map_bits_1c(time, height)
radar/lidar Liquid water categorization bits

    This variable contains information on the presence and nature of the liquid water at each pixel. The information is in the form of an array of bits, each of which states either whether a certain type of data or categorized water clouds is presented The definitions of each bit are given in the definition attribute. Bit 0 is the least significant.

    Units:n/a
    Type:byte array
    Definition:
    • Bit 0 - Reading's categorization product recognized pixel as water ((small droplets OR water precipitation) AND Temperature > 0C])
    • Bit 1 - radar signal presented
    • Bit 2 - lidar signal (extinction) presented
    • Bit 3 - radar reflectivity to lidar extinction presented
    • Bit 4 - atmospheric water, class 1 - "water cloud without drizzle"
    • Bit 5 - atmospheric water, class 2 - "water cloud with light drizzle"
    • Bit 6 - atmospheric water, class 3 - "water cloud with heavy drizzle"
LWC_Radar_Lidar_1c(time, height)
radar/lidar LWC from Fox-Baedi-Drizzle Z-LWC relationship
    Units:g/m^3
    Type:single-precision floating-point array
LWP_Radar_Lidar_1c(time)
radar/lidar LWP from Fox-Baedi-Drizzle Z-LWC relationship
    Units:g/m^2
    Type:single-precision floating-point vector
liquid_water_map_bits_2c(time, height)
radar/lidar Liquid water categorization bits

    This variable contains information on the presence and nature of the liquid water at each pixel. The information is in the form of an array of bits, each of which states either whether a certain type of data or categorized water clouds is presented The definitions of each bit are given in the definition attribute. Bit 0 is the least significant.

    Units:n/a
    Type:byte array
    Definition:
    • Bit 0 - Reading's categorization product recognized pixel as water ((small droplets OR water precipitation) AND Temperature > 0C])
    • Bit 1 - radar signal presented
    • Bit 2 - lidar signal (extinction) presented
    • Bit 3 - radar reflectivity to lidar extinction presented
    • Bit 4 - atmospheric water, class 1 - "water cloud without drizzle"
    • Bit 5 - atmospheric water, class 2 - "water cloud with light drizzle"
    • Bit 6 - atmospheric water, class 3 - "water cloud with heavy drizzle"
LWC_Radar_Lidar_2c(time, height)
radar/lidar LWC from Fox-Baedi-Drizzle Z-LWC relationship
    Units:g/m^3
    Type:single-precision floating-point array
LWP_Radar_Lidar_2c(time)
radar/lidar LWP from Fox-Baedi-Drizzle Z-LWC relationship
    Units:g/m^2
    Type:single-precision floating-point vector
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