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Level 2b Cloudnet product:

Liquid water content (scaled adiabatic method) on Météo France model grid

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Summary

Designation
lwc-adiabatic-meteo-france-grid
Level
2b
Algorithm design/Product maintainer
Institute
University of Reading and Météo France
Description
This product consists of liquid water content calculated from the observations on grid of the Météo France model.
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 on Météo France model grid data, which was produced by the University of Reading and Météo France using measurements from [SITE].

Dataset contents

Sample NetCDF file: 20031001_chilbolton_lwc-adiabatic-meteo-france-grid.nc
Header of sample NetCDF file in ASCII: 20031001_chilbolton_lwc-adiabatic-meteo-france-grid.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 at Chilbolton, averaged to the Meteo-France ARPEGE grid.

This dataset contains liquid water content derived using radar/lidar cloud boundaries and liquid water path from dual-wavelength microwave radiometers, averaged on to the grid of a forecast model. It also contains the liquid water content and liquid water path from that model, so may be used to calculate statistics quantifying the model performance.

    Institution:Data processed at the Department of Meteorology, University of Reading.
    Software version:1.1

Dimensions and coordinate variables

time
Hours UTC
    Units:hours since 2003-10-01 00:00:00 +00:00
    Type:single-precision floating-point vector
height
Height above ground
    Units:m
    Type:single-precision floating-point array
num_lwp_var
(No coordinate variable)

Variables

horizontal_resolution
Horizontal resolution of model
    Units:km
    Type:single-precision floating-point scalar
altitude
Height of radar above mean sea level
    Units:m
    Type:single-precision floating-point scalar
forecast_time(time)
Time since initialization of forecast

    For each profile in the file this variable contains the time elapsed since the initialization time of the forecast from which it was taken. Note that the profiles in this file may be taken from more than one forecast.

    Units:hours
    Type:single-precision floating-point vector
rain_rate_threshold
Rain rate threshold

    Measurements above a surface rain rate of greater than this value were excluded due to the possibility of strong attenuation leading to an underestimate of cloud fraction.

    Units:mm hr-1
    Type:single-precision floating-point scalar
height(time, height)
Height above ground
    Units:m
    Type:single-precision floating-point array
lwc(time, height)
Observed mean liquid water content, 1 hour sampling

    This variable is the observed mean liquid water content estimated for pixels where the "categorization" data has diagnosed that liquid water is present, averaged onto the model grid with height, and 1 hour in time. The model temperature and pressure were used to estimate the theoretical adiabatic liquid water content gradient for each cloud base and the adiabatic liquid water content was scaled so that its integral matches the liquid water path obtained from a coincident microwave radiometer measurement. If the liquid layer is detected by the lidar only, there is the potential for cloud top height to be underestimated and if the integrated liquid water content is less than that measured by the microwave radiometer, the cloud top is extended until both agree. When microwave radiometer data were not available, liquid water content was not retrieved although the adiabatic value is still included in the lwc_adiabatic and lwc_adv_adiabatic variables. Rain present below the liquid is associated with an uncertain measurement of liquid water path and cloud boundaries so these profiles are not included.

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adv(time, height)
Observed mean liquid water content, 23.4 km.

    This variable is the same as the observed mean liquid water content, lwc, except that model winds were used to estimate the time taken to advect the model's horizontal resolution of 23.4 km (max 1 hour, min 10 minutes).

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adiabatic(time, height)
Observed mean adiabatic liquid water content, 1 hour sampling

    This variable is the liquid water content that would be present if the cloud conformed to adiabatic conditions, for periods where liquid water path was available from coincident dual-wavelength microwave radiometer data.

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adv_adiabatic(time, height)
Observed mean adiabatic liquid water content, 23.4 km.

    This variable is the same as the adiabatic mean liquid water content, lwc_adiabatic, except that model winds were used to estimate the time taken to advect the model's horizontal resolution of 23.4 km (max 1 hour, min 10 minutes).

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adiabatic_inc_nolwp(time, height)
Observed mean adiabatic liquid water content, 1 hour sampling

    This variable is the liquid water content that would be present if the cloud conformed to adiabatic conditions, including data where no liquid water path information was available.

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adv_adiabatic_inc_nolwp(time, height)
Observed mean adiabatic_inc_nolwp liquid water content, 23.4 km.

    This variable is the same as the adiabatic mean liquid water content, lwc_adiabatic_inc_nolwp, except that model winds were used to estimate the time taken to advect the model's horizontal resolution of 23.4 km (max 1 hour, min 10 minutes).

    Units:kg m-3
    Type:single-precision floating-point array
lwc_th(time, height)
Observed mean liquid water content (tophat distribution), 1 hour sampling

    This variable is the liquid water content assuming a tophat distribution. I.e. the profile of liquid water content in each layer is constant.

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adv_th(time, height)
Observed mean liquid water content (tophat distribution), 23.4 km.

    This variable is the same as lwc_th, except that model winds were used to estimate the time taken to advect the model's horizontal resolution of 23.4 km (max 1 hour, min 10 minutes).

    Units:kg m-3
    Type:single-precision floating-point array
lwc_std(time, height)
Std. of observed liquid water content, 1 hour sampling

    This variable is the standard deviation of the liquid water content estimated for pixels where the "categorization" data has diagnosed that liquid water is present, averaged onto the model grid with height, and 1 hour in time. The model temperature and pressure were used to estimate the theoretical adiabatic liquid water content gradient for each cloud base and the adiabatic liquid water content was scaled so that its integral matches the liquid water path obtained from a coincident microwave radiometer measurement. If the liquid layer is detected by the lidar only, there is the potential for cloud top height to be underestimated and if the integrated liquid water content is less than that measured by the microwave radiometer, the cloud top is extended until both agree. When microwave radiometer data were not available, liquid water content was not retrieved although the adiabatic value is still included in the lwc_adiabatic and lwc_adv_adiabatic variables. Rain present below the liquid is associated with an uncertain measurement of liquid water path and cloud boundaries so these profiles are not included.

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adv_std(time, height)
Std. of observed liquid water content, 23.4 km.

    This variable is the same as the standard deviation of the observed liquid water content, lwc_std, except that model winds were used to estimate the time taken to advect the model's horizontal resolution of 23.4 km (max 1 hour, min 10 minutes).

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adiabatic_std(time, height)
Std. of observed adiabatic liquid water content, 1 hour sampling

    This variable is the standard deviation of the liquid water content that would be present if the cloud conformed to adiabatic conditions, for periods where liquid water path was available from coincident dual-wavelength microwave radiometer data.

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adv_adiabatic_std(time, height)
Std. of observed adiabatic liquid water content, 23.4 km.

    This variable is the same as the standard deviation of the adiabatic liquid water content, lwc_adiabatic_std, except that model winds were used to estimate the time taken to advect the model's horizontal resolution of 23.4 km (max 1 hour, min 10 minutes).

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adiabatic_inc_nolwp_std(time, height)
Std. of observed adiabatic liquid water content, 1 hour sampling

    This variable is the standard deviation of the liquid water content that would be present if the cloud conformed to adiabatic conditions, including data where no liquid water path information was available.

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adv_adiabatic_inc_nolwp_std(time, height)
Std. of log10(observed adiabatic_inc_nolwp liquid water content), 23.4 km.

    This variable is the same as the standard deviation of the adiabatic log10(liquid water content), lwc_adiabatic_inc_nolwp_std_log, except that model winds were used to estimate the time taken to advect the model's horizontal resolution of 23.4 km (max 1 hour, min 10 minutes).

    Units:kg m-3
    Type:single-precision floating-point array
lwc_th_std(time, height)
Std. of observed liquid water content (tophat distribution), 1 hour sampling

    This variable is the standard deviation of the liquid water content assuming a tophat distribution. I.e. the profile of liquid water content in each layer is constant.

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adv_th_std(time, height)
Std. of observed liquid water content (tophat distribution), 23.4 km.

    This variable is the same as lwc_th_std, except that model winds were used to estimate the time taken to advect the model's horizontal resolution of 23.4 km (max 1 hour, min 10 minutes).

    Units:kg m-3
    Type:single-precision floating-point array
lwc_std_log(time, height)
Std. of log10(observed liquid water content), 1 hour sampling

    This variable is the standard deviation of the log10(liquid water content) estimated for pixels where the "categorization" data has diagnosed that liquid water is present, averaged onto the model grid with height, and 1 hour in time. The model temperature and pressure were used to estimate the theoretical adiabatic liquid water content gradient for each cloud base and the adiabatic liquid water content was scaled so that its integral matches the liquid water path obtained from a coincident microwave radiometer measurement. If the liquid layer is detected by the lidar only, there is the potential for cloud top height to be underestimated and if the integrated liquid water content is less than that measured by the microwave radiometer, the cloud top is extended until both agree. When microwave radiometer data were not available, liquid water content was not retrieved although the adiabatic value is still included in the lwc_adiabatic and lwc_adv_adiabatic variables. Rain present below the liquid is associated with an uncertain measurement of liquid water path and cloud boundaries so these profiles are not included.

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adv_std_log(time, height)
Std. of log10(observed liquid water content), 23.4 km.

    This variable is the same as the standard deviation of the log10(observed liquid water content), lwc_std_log, except that model winds were used to estimate the time taken to advect the model's horizontal resolution of 23.4 km (max 1 hour, min 10 minutes).

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adiabatic_std_log(time, height)
Std. of log10(observed adiabatic liquid water content), 1 hour sampling

    This variable is the standard deviation of the log10(liquid water content) that would be present if the cloud conformed to adiabatic conditions, for periods where liquid water path was available from coincident dual-wavelength microwave radiometer data.

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adv_adiabatic_std_log(time, height)
Std. of log10(observed adiabatic liquid water content), 23.4 km.

    This variable is the same as the standard deviation of the adiabatic log10(liquid water content), lwc_adiabatic_std_log, except that model winds were used to estimate the time taken to advect the model's horizontal resolution of 23.4 km (max 1 hour, min 10 minutes).

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adiabatic_inc_nolwp_std_log(time, height)
Std. of log10(observed adiabatic liquid water content), 1 hour sampling

    This variable is the standard deviation of the log10(liquid water content) that would be present if the cloud conformed to adiabatic conditions, including data where no liquid water path information was available.

    Units:kg m-3
    Type:single-precision floating-point array
lwc_th_std_log(time, height)
Std. of log10(observed liquid water content) (tophat distribution), 1 hour sampling

    This variable is the standard deviation of the log10(liquid water content) assuming a tophat distribution. I.e. the profile of liquid water content in each layer is constant.

    Units:kg m-3
    Type:single-precision floating-point array
lwc_adv_th_std_log(time, height)
Std. of log (observed liquid water content) (tophat distribution), 23.4 km.

    This variable is the same as lwc_th_std_log, except that model winds were used to estimate the time taken to advect the model's horizontal resolution of 23.4 km (max 1 hour, min 10 minutes).

    Units:kg m-3
    Type:single-precision floating-point array
lwp(time, num_lwp_var)
Observed mean liquid water path, 1 hour sampling

    This variable is the observed [mean, min, max, std] of liquid water path retrieved from dual-wavelength microwave radiometers, averaged 1 hour in time. Rain present below liquid layers is associated with an uncertain measurement of liquid water path and cloud boundaries so these profiles are not included.

    Units:kg m-2
    Type:single-precision floating-point array
lwp_adv(time, num_lwp_var)
Observed mean liquid water path, 23.4 km.

    This variable is the same as the observed liquid water path, lwp, except that model winds were used to estimate the time taken to advect the model's horizontal resolution of 23.4 km (max 1 hour, min 10 minutes). The mean wind, mean_wind_speed_adv, was calculated from the mean of model winds in the grid boxes in the profile that contain liquid water.

    Units:kg m-2
    Type:single-precision floating-point array
lwp_adv_3km(time, num_lwp_var)
Observed mean liquid water path, 23.4 km.

    This variable is the same as the observed liquid water path, lwp, except that model winds were used to estimate the time taken to advect the model's horizontal resolution of 23.4 km (max 1 hour, min 10 minutes). The mean wind, mean_wind_speed_adv_3km, was calculated from the mean of the magnitude of the model winds from 0 to 3 km in the vertical.

    Units:kg m-2
    Type:single-precision floating-point array
mean_wind_speed_adv(time)
Mean model winds where liquid water path is present in profile

    This variable is the mean model wind used to estimate the time taken to advect the model's horizontal resolution of 23.4 km. It was calulated from the mean of the magnitude of the model winds in the grid boxes that contain liquid water.

    Units:m s-1
    Type:single-precision floating-point vector
mean_wind_dir_adv(time)
Mean model wind direction where liquid water path is present in profile

    This variable is the mean of the model wind direction in the grid boxes that contain liquid water.

    Units:degrees
    Type:single-precision floating-point vector
mean_wind_speed_adv_3km(time)
Mean model winds from 0 to 3 km

    This variable is the mean model wind used to estimate the time taken to advect the model's horizontal resolution of 23.4 km. It was calulated from the mean of the model winds from 0 to 3 km in the vertical.

    Units:m s-1
    Type:single-precision floating-point vector
mean_wind_dir_adv_3km(time)
Mean model wind direction from 0 to 3 km

    This variable is the mean of the model wind direction from 0 to 3 km in the vertical.

    Units:degrees
    Type:single-precision floating-point vector
model_lwc(time, height)
Model liquid water content
    Units:kg m-3
    Type:single-precision floating-point array
model_lwp(time)
Model liquid water path
    Units:kg m-2
    Type:single-precision floating-point vector

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