
Level 2b Cloudnet product:Liquid water content (scaled adiabatic method) on Met Office Global model gridData Home  Overview of Cloudnet products  Product list  Quicklooks  Conditions of useSummary
Dataset contentsSample NetCDF file: 20030801_chilbolton_lwcadiabaticmetofficeglobalgrid.nc 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 UK Met Office Unified Model (Global) grid.This dataset contains liquid water content derived using radar/lidar cloud boundaries and liquid water path from dualwavelength 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.
Software version:1.1 Dimensions and coordinate variablestimeHours UTC
Type:singleprecision floatingpoint vector Height above ground
Type:singleprecision floatingpoint array (No coordinate variable) Variableshorizontal_resolutionHorizontal resolution of model
Type:singleprecision floatingpoint scalar Height of radar above mean sea level
Type:singleprecision floatingpoint scalar 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:hoursType:singleprecision floatingpoint vector 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 hr1Type:singleprecision floatingpoint scalar Height above ground
Type:singleprecision floatingpoint array 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:singleprecision floatingpoint array Observed mean liquid water content, 60 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 60 km (max 1 hour, min 10 minutes). Units:kg m^{3}Type:singleprecision floatingpoint array 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 dualwavelength microwave radiometer data. Units:kg m^{3}Type:singleprecision floatingpoint array Observed mean adiabatic liquid water content, 60 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 60 km (max 1 hour, min 10 minutes). Units:kg m^{3}Type:singleprecision floatingpoint array 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:singleprecision floatingpoint array Observed mean adiabatic_inc_nolwp liquid water content, 60 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 60 km (max 1 hour, min 10 minutes). Units:kg m^{3}Type:singleprecision floatingpoint array 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:singleprecision floatingpoint array Observed mean liquid water content (tophat distribution), 60 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 60 km (max 1 hour, min 10 minutes). Units:kg m^{3}Type:singleprecision floatingpoint array 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:singleprecision floatingpoint array Std. of observed liquid water content, 60 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 60 km (max 1 hour, min 10 minutes). Units:kg m^{3}Type:singleprecision floatingpoint array 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 dualwavelength microwave radiometer data. Units:kg m^{3}Type:singleprecision floatingpoint array Std. of observed adiabatic liquid water content, 60 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 60 km (max 1 hour, min 10 minutes). Units:kg m^{3}Type:singleprecision floatingpoint array 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:singleprecision floatingpoint array Std. of log10(observed adiabatic_inc_nolwp liquid water content), 60 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 60 km (max 1 hour, min 10 minutes). Units:kg m^{3}Type:singleprecision floatingpoint array 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:singleprecision floatingpoint array Std. of observed liquid water content (tophat distribution), 60 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 60 km (max 1 hour, min 10 minutes). Units:kg m^{3}Type:singleprecision floatingpoint array 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:singleprecision floatingpoint array Std. of log10(observed liquid water content), 60 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 60 km (max 1 hour, min 10 minutes). Units:kg m^{3}Type:singleprecision floatingpoint array 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 dualwavelength microwave radiometer data. Units:kg m^{3}Type:singleprecision floatingpoint array Std. of log10(observed adiabatic liquid water content), 60 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 60 km (max 1 hour, min 10 minutes). Units:kg m^{3}Type:singleprecision floatingpoint array 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:singleprecision floatingpoint array 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:singleprecision floatingpoint array Std. of log (observed liquid water content) (tophat distribution), 60 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 60 km (max 1 hour, min 10 minutes). Units:kg m^{3}Type:singleprecision floatingpoint array Observed mean liquid water path, 1 hour sampling This variable is the observed [mean, min, max, std] of liquid water path retrieved from dualwavelength 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:singleprecision floatingpoint array Observed mean liquid water path, 60 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 60 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:singleprecision floatingpoint array Observed mean liquid water path, 60 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 60 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:singleprecision floatingpoint array 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 60 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:singleprecision floatingpoint vector 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:degreesType:singleprecision floatingpoint vector 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 60 km. It was calulated from the mean of the model winds from 0 to 3 km in the vertical. Units:m s^{1}Type:singleprecision floatingpoint vector 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:degreesType:singleprecision floatingpoint vector Model liquid water content
Type:singleprecision floatingpoint array Model liquid water path
Type:singleprecision floatingpoint vector These pages are maintained by . 