
Level 1b Cloudnet product:Liquid water path (radiometer/lidar/model method)Data Home  Overview of Cloudnet products  Product list  Quicklooks  Conditions of useSummary
Dataset contentsSample NetCDF file: 20030602_palaiseau_microwaveradiometerlwp.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 and vapour vater path from the palaiseauMicrowave Radiometers
Data processed at the University of Reading,UK : http://www.met.reading.ac.uk References:Documentation may be found at: http://www.met.reading.ac.uk/radar/cloudnet/documentation/ For further any further information about the retrieval technique using model and lidar, please contact Nicolas Gaussiat Dimensions and coordinate variablestimeTime UTC
Type:singleprecision floatingpoint vector Radiometer frequency
Type:singleprecision floatingpoint vector VariablesaltitudeHeight of ground level above mean sea level (Ordonance Survey Great Britain)
Type:singleprecision floatingpoint scalar
Type:singleprecision floatingpoint scalar
Type:singleprecision floatingpoint scalar Microwave radiometer brightness temperature
Type:singleprecision floatingpoint array Liquid water path This variable is the vertically integrated liquid water content, or liquid water path (lwp), obtained using dualwavelength microwave radiometer, lidar and information from a forecast model. The lwp is assumed to be proportional to microwave optical depth, and the coefficients used to derive it are obtained as follows. For the liquid water coefficients, the lidar is used to locate the cloud and the model to diagnose cloud base temperature. The water vapour coefficients are derived from model temperature and vertical humidity distribution. Note that humidity is not used in an absolute sense but only in the sense of determining the effective emission temperature of a given water vapour path. Finally, periods of clear sky identified by lidar are used to estimate calibration errors in the radiometers using the fact that lwp retrieved in these regions should be zero. Units:g m2Type:singleprecision floatingpoint vector Vapour water path This variable is the vertically integrated vapour water content, or vapour water path obtained using dualwavelength microwave radiometer, lidar and information from a forecast model. The vwp is assumed to be proportional to microwave optical depth, and the coefficients used to derive it are obtained as follows. For the liquid water coefficients, the lidar is used to locate the cloud and the model to diagnose cloud base temperature. The water vapour coefficients are derived from model temperature and vertical humidity distribution. Note that humidity is not used in an absolute sense but only in the sense of determining the effective emission temperature of a given water vapour path. Finally, periods of clear sky identified by lidar are used to estimate calibration errors in the radiometers using the fact that lwp retrieved in these regions should be zero. Units:g m2Type:singleprecision floatingpoint vector Liquid water path using fixed coefficients This variable is the vertically integrated liquid water content, or liquid water path obtained using dualwavelength microwave radiometer. The lwp is assumed to be lineary related to the brightness temperatures. Fixed coefficients are determined by appling a bilinear fit over 2 years of model data Units:g m2Type:singleprecision floatingpoint vector Vapour water path using fixed coefficients This variable is the vertically integrated vapour water content, or vapour water path (vwp), obtained using dualwavelength microwave radiometer. The vwp is assumed to be lineary related to the brightness temperatures. Fixed coefficients are determined using a 2year radiosonde ascent data set Units:g m2Type:singleprecision floatingpoint vector These pages are maintained by . 