netcdf 20031001_chilbolton_iwc-Z-T-meteo-france-grid {
dimensions:
time = 24 ;
height = 41 ;
variables:
float horizontal_resolution ;
horizontal_resolution:units = "km" ;
horizontal_resolution:long_name = "Horizontal resolution of model" ;
float altitude ;
altitude:units = "m" ;
altitude:long_name = "Height of radar above mean sea level" ;
float forecast_time(time) ;
forecast_time:units = "hours" ;
forecast_time:long_name = "Time since initialization of forecast" ;
forecast_time:comments = "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." ;
forecast_time:missing_value = -999.f ;
forecast_time:_FillValue = -999.f ;
float time(time) ;
time:units = "hours since 2003-10-01 00:00:00 +00:00" ;
time:long_name = "Hours UTC" ;
time:standard_name = "time" ;
time:axis = "T" ;
float height(time, height) ;
height:units = "m" ;
height:long_name = "Height above ground" ;
height:standard_name = "height" ;
height:C_format = "%.3f" ;
height:_FillValue = -999.f ;
height:missing_value = -999.f ;
height:axis = "Z" ;
float iwc(time, height) ;
iwc:long_name = "Observed mean ice water content, 1 hour sampling" ;
iwc:units = "kg m-3" ;
iwc:units_html = "kg m-3" ;
iwc:missing_value = -999.f ;
iwc:_FillValue = -999.f ;
iwc:comment = "This variable is the observed mean ice water content derived from radar reflectivity factor and temperature using an empirical formula derived using aircraft\n",
"data, averaged onto the model grid with height, and 1 hour in time.\n",
"The formula has been applied where the \"categorization\" data has diagnosed that the radar echo is due to ice, but note that the phase of pixels is sometimes\n",
"misdiagnosed. Where microwave radiometer liquid water path was available it was used to correct the radar for liquid attenuation when liquid cloud\n",
"occurred below the ice, but there is some uncertainty in this prodedure.\n",
"This variable does not include ice water content retrievals in situations of uncorrected attenuation (due to liquid water clouds beneath the ice cloud but no\n",
"microwave radiometer data; rain and melting ice beneath the ice cloud; attenuation due to wetting of the radome when the rain reaches the surface); ice clouds\n",
"being detected only by the lidar. In these situations the ice water content will be assigned \"missing_value\"." ;
iwc:plot_range = 1.e-08f, 0.001f ;
iwc:plot_scale = "logarithmic" ;
float iwc_adv(time, height) ;
iwc_adv:long_name = "Observed mean ice water content, 23.4 km." ;
iwc_adv:units = "kg m-3" ;
iwc_adv:units_html = "kg m-3" ;
iwc_adv:missing_value = -999.f ;
iwc_adv:_FillValue = -999.f ;
iwc_adv:comment = "This variable is the same as the observed mean ice water content, iwc, except that model winds were used to estimate the time taken to advect the cloud\n",
"a distance equivalent to the model\'s horizontal resolution of 23.4 km (max 1 hour, min 10 minutes)." ;
iwc_adv:plot_range = 1.e-08f, 0.001f ;
iwc_adv:plot_scale = "logarithmic" ;
float iwc_inc_att(time, height) ;
iwc_inc_att:long_name = "Observed mean ice water content (including attenuated profiles), 1 hour sampling" ;
iwc_inc_att:units = "kg m-3" ;
iwc_inc_att:units_html = "kg m-3" ;
iwc_inc_att:missing_value = -999.f ;
iwc_inc_att:_FillValue = -999.f ;
iwc_inc_att:comment = "This variable is the same as the observed mean ice water content, iwc, except that profiles with uncorrected attenuation of the radar reflectivity were included\n",
"(although profiles with rain at the surface were still excluded) and should therefore only be used when the effect of attenuation is being studied." ;
iwc_inc_att:plot_range = 1.e-08f, 0.001f ;
iwc_inc_att:plot_scale = "logarithmic" ;
float iwc_adv_inc_att(time, height) ;
iwc_adv_inc_att:long_name = "Observed mean ice water content (including attenuated profiles), 23.4 km." ;
iwc_adv_inc_att:units = "kg m-3" ;
iwc_adv_inc_att:units_html = "kg m-3" ;
iwc_adv_inc_att:missing_value = -999.f ;
iwc_adv_inc_att:_FillValue = -999.f ;
iwc_adv_inc_att:comment = "This variable is the same as the advected observed mean ice water content, iwc_adv, except that profiles with uncorrected attenuation of the radar reflectivity\n",
"were included (although profiles with rain at the surface were still excluded) and should therefore only be used when the effect of attenuation is being studied." ;
iwc_adv_inc_att:plot_range = 1.e-08f, 0.001f ;
iwc_adv_inc_att:plot_scale = "logarithmic" ;
float iwc_inc_rain(time, height) ;
iwc_inc_rain:long_name = "Observed mean ice water content (including attenuated and raining profiles), 1 hour sampling" ;
iwc_inc_rain:units = "kg m-3" ;
iwc_inc_rain:units_html = "kg m-3" ;
iwc_inc_rain:missing_value = -999.f ;
iwc_inc_rain:_FillValue = -999.f ;
iwc_inc_rain:comment = "This variable is the same as the observed mean ice water content including attenuation, iwc_inc_att, except that profiles with rain at the surface were also included.\n",
"It should only be used when the effect of attenuation is being studied. Radome attenuation is a serious problem for some of these profiles." ;
iwc_inc_rain:plot_range = 1.e-08f, 0.001f ;
iwc_inc_rain:plot_scale = "logarithmic" ;
float iwc_adv_inc_rain(time, height) ;
iwc_adv_inc_rain:long_name = "Observed mean ice water content (including attenuated and raining profiles), 23.4 km." ;
iwc_adv_inc_rain:units = "kg m-3" ;
iwc_adv_inc_rain:units_html = "kg m-3" ;
iwc_adv_inc_rain:missing_value = -999.f ;
iwc_adv_inc_rain:_FillValue = -999.f ;
iwc_adv_inc_rain:comment = "This variable is the same as the advected observed mean ice water content including attenuation, iwc_adv_inc_att, except that profiles with rain at the surface\n",
"were also included. It should only be used when the effect of attenuation is being studied. Radome attenuation is a serious problem for some of these profiles." ;
iwc_adv_inc_rain:plot_range = 1.e-08f, 0.001f ;
iwc_adv_inc_rain:plot_scale = "logarithmic" ;
float model_iwc(time, height) ;
model_iwc:long_name = "Model ice water content" ;
model_iwc:units = "kg m-3" ;
model_iwc:units_html = "kg m-3" ;
model_iwc:missing_value = -999.f ;
model_iwc:_FillValue = -999.f ;
model_iwc:plot_range = 1.e-08f, 0.001f ;
model_iwc:plot_scale = "logarithmic" ;
float model_iwc_filtered(time, height) ;
model_iwc_filtered:long_name = "Model ice water content with undetectable cirrus removed using best guess of radar sensitivity" ;
model_iwc_filtered:units = "kg m-3" ;
model_iwc_filtered:units_html = "kg m-3" ;
model_iwc_filtered:missing_value = -999.f ;
model_iwc_filtered:_FillValue = -999.f ;
model_iwc_filtered:comment = "This variable is model ice water content, filtered to remove ice cloud deemed to be too tenuous to be detected by the radar.\n",
"The best guess of the radar sensitivity has been used, and the spread of IWC across the grid box assumed to be described by a gamma\n",
"distribution (Hogan and Illingworth, 2003, J. Atmos. Sci., 60, 756-767)." ;
model_iwc_filtered:plot_range = 1.e-08f, 0.001f ;
model_iwc_filtered:plot_scale = "logarithmic" ;
float model_iwc_filtered_min(time, height) ;
model_iwc_filtered_min:long_name = "Model ice water content with undetectable cirrus removed assuming radar 3 dB less sensitive than best guess" ;
model_iwc_filtered_min:units = "kg m-3" ;
model_iwc_filtered_min:units_html = "kg m-3" ;
model_iwc_filtered_min:missing_value = -999.f ;
model_iwc_filtered_min:_FillValue = -999.f ;
model_iwc_filtered_min:comment = "This variable is the same as \"model_iwc_filtered\" except that the sensitivity of the radar is taken to be 3 dB worse.\n",
"It therefore provides an approximate estimate of the uncertainty associated with the removal of undetectable ice clouds from the model." ;
model_iwc_filtered_min:plot_range = 1.e-08f, 0.001f ;
model_iwc_filtered_min:plot_scale = "logarithmic" ;
float model_iwc_filtered_max(time, height) ;
model_iwc_filtered_max:long_name = "Model ice water content with undetectable cirrus removed assuming radar 3 dB more sensitive than best guess" ;
model_iwc_filtered_max:units = "kg m-3" ;
model_iwc_filtered_max:units_html = "kg m-3" ;
model_iwc_filtered_max:missing_value = -999.f ;
model_iwc_filtered_max:_FillValue = -999.f ;
model_iwc_filtered_max:comment = "This variable is the same as \"model_iwc_filtered\" except that the sensitivity of the radar is taken to be 3 dB better.\n",
"It therefore provides an approximate estimate of the uncertainty associated with the removal of undetectable ice clouds from the model." ;
model_iwc_filtered_max:plot_range = 1.e-08f, 0.001f ;
model_iwc_filtered_max:plot_scale = "logarithmic" ;
// global attributes:
:Conventions = "CF-1.0" ;
:title = "Ice water content at Chilbolton averaged to the Meteo-France ARPEGE grid" ;
:location = "Chilbolton" ;
:day = 1s ;
:month = 10s ;
:year = 2003s ;
:history = "07 May 2005 15:49:23 - Generated from categorization data and Meteo-France ARPEGE data by Ewan O\'Connor on anvil2\n",
"Ice water content history: 06 May 2005 20:47:08 - Generated from categorization data by Ewan O\'Connor \n",
"Categorization history: 19 Jan 2005 17:18:42 - Generated from level 1 data by Ewan O\'Connor \n",
"Radar history: Wed Feb 25 01:51:03 2004 - NetCDF generated from original data by Nicolas Gaussiat on hogwarts\n",
"Wed May 12 10:08:04 2004 - Recalibrated (-5.8 dB) by Nicolas Gaussiat on hogwarts\n",
"Wed May 12 11:31:20 2004 - Inserted incoherent reflectivity factor by radar on hogwarts\n",
"(Incoherent processing history: Wed Feb 25 00:54:30 2004 - NetCDF generated from original data by Nicolas Gaussiat on hogwarts\n",
"Wed May 12 10:34:18 2004 - Recalibrated (+0.5 dB) by Nicolas Gaussiat on hogwarts)\n",
"Lidar history: Thu Oct 2 04:24:21 2003 - NetCDF generated from original data by Ewan O\'Connor on hogwarts\n",
"Model history: Fri Sep 24 11:05:08 BST 2004 - NetCDF generated from original data by Ewan O\'Connor using cnmodel2nc on hogwarts\n",
"Fri Nov 12 17:36:14 2004 - Comments added by radar on hogwarts\n",
"Gauge history: Recorded using Microlink 3000 series DAQ\n",
"2003-11-10 13:53:59 : converted to netCDF from FORMAT5 using Matlab 6.5.0.180913a (R13) running on GLNX86\n",
"Microwave radiometer history: \n",
"2005-01-13 14:36:18 : Liquid and vapour vater path produced by Nicolas Gaussiat on hagrid\n",
"" ;
:source = "Meteo-France ARPEGE\n",
"CloudNet categorization product (software version 0.9.2)\n",
"Meteo-France ARPEGE\n",
"CloudNet categorization product (software version 0.9.2) comprising:\n",
"Chilbolton 94-GHz Cloud Radar (Galileo)\n",
"Frequency: 94.00 GHz\n",
"Antenna diameter: 0.46 m\n",
"Axis separation of transmit and receive antennas: 0.66 m\n",
"Peak power: 1.6 kW\n",
"Pulse width: 0.5 us\n",
"Pulse repetition frequency: 6250 Hz\n",
"Beam width: 0.5 degrees;\n",
"Chilbolton Vaisala 905-nm CT75K lidar ceilometer\n",
"Wavelength: 905 nm\n",
"Half-angle beam divergence: 0.75 mrad\n",
"Half-angle field of view: 0.66 mrad;\n",
"ECMWF Integrated Forecast System (IFS);\n",
"meteorological sensors;\n",
"Microwave radiometers" ;
:institution = "Data processed at the Department of Meteorology, University of Reading." ;
:software_version = "1.1" ;
:comment = "This dataset contains ice water content derived using radar reflectivity and temperature, averaged on to the grid of a forecast model.\n",
"It also contains the ice water content from that model, so may be used to calculate statistics quantifying the model performance." ;
}