Documents
Algorithm Theorical Basis Document ( ATBD )
This document contains a detailed description of the algorithm
varcloud – algorithm_description – v1.0
Products
Description
The ice cloud properties are retrieved :
- at a 60m vertical resolution between [ -1.02 km , 25.08 km ]
- at CLOUDSAT horizontal footprint resolution i.e. 1.4 km.
Naming convention
DARDAR-CLOUD_v<Version>_<Timestamp>_<Granule>.hdf
| <Version> | A 3 digits dot separated version number as X.X.X |
| <Timestamp> | The timestamp of the orbit, using the CLOUDSAT format YYYYJJJHHMMSS, Year, Julian day, hour, minute, second of the first data contained in the file (UTC) |
| <Granule> | The granule number, on 5 digits |
Examples
| Product | Parametres | Download |
|---|---|---|
| DARDAR-CLOUD | – Ice Water Content – Effective particle radius – Extinction |
DARDAR-CLOUD_v2.1.1_2009001021530_14253.hdf |
| Browse Images | Ice Water Content | DARDAR-CLOUD_v2.1.1_2009001021530_14253_iwc.png |
| Effective Radius | DARDAR-CLOUD_v2.1.1_2009001021530_14253_effective_radius.png | |
| Extinction Coefficient | DARDAR-CLOUD_v2.1.1_2009001021530_14253_extinction.png |
Variables
Description
| Name | Description | Unit | Type | Fill |
|---|---|---|---|---|
| time | UTC time | s | float32 | -999.0 |
| latitude | Latitude | degree | float32 | -999.0 |
| longitude | Longitude | degree | float32 | -999.0 |
| CALIOP_Profile_Time | Profile time of the first and the last LIDAR shot averaged in the RADAR footprint (TAI93 time convention) | secs | float64 | -9999.0 |
| vis_optical_depth | Optical Thickness forwad model | None | float32 | -999.0 |
| vis_optical_depth_error | Error in optical thickness forwad model | None | float32 | -999.0 |
| height | Height | m | float32 | -999.0 |
| n_iterations | Number of iteration to converge | None | int16 | -999 |
| wavelength | Wavelength of the centre of radiance channel (infrared) | m | float32 | -999.0 |
| chi2 | Value of chi squared for each iteration | None | float32 | 1000000000.0 |
| chi2_split | Value of chi squared for each iteration and for each instrument (lidar mie, lidar ray, Z, radiance, dradiance) | None | float32 | 1000000000.0 |
| radiance | Radiance Forward model | W m-2 um-1 sr-1 | float32 | -999.0 |
| radiance_sat | Radiance Forward model | W m-2 um-1 sr-1 | float32 | -999.0 |
| radiance_flag | Radiance flag (0 = radiance not used, 1 = radiance used) | None | int16 | -999 |
| radiance_difference_flag | Radiance difference flag (0 = radiance not used, 1 = radiance used (first radiance), 2 = radiance used (second radiance)) | None | int16 | -999 |
| Z | Radar reflectivity | mm6 m-3 | float32 | -999.0 |
| bscat | Lidar attenuated backscatter | m-1 sr-1 | float32 | -999.0 |
| DARMASK_Simplified_Categorization | -9 -> ground -1 -> don’t know 0 -> clear 1 -> ice 2 -> ice + supercooled 3 ->liquid warm 4 -> supercooled 5 -> rain 6 ->aerosol 7 -> maybe insects 8 -> stratospheric feature | None | int16 | -9 |
| instrument_flag | Instrument flag (0==nothing/1==lidar/2==radar/3==radar+lidar) | None | int16 | -999 |
| Z_fwd | Radar reflectivity forward model | mm6 m-3 | float32 | -999.0 |
| bscat_fwd | Lidar attenuated backscatter forward model | m-1 sr-1 | float32 | -999.0 |
| extinction | Retrieved visible extinction coefficient | m-1 | float32 | -999.0 |
| lidar_ratio | Retrieved extinction-to-backscatter ratio | sr | float32 | -999.0 |
| iwc | Retrieved Ice Water Content | kg m-3 | float32 | -999.0 |
| effective_radius | Retrieved effective radius | m | float32 | -999.0 |
| N0star | Retrieved normalized number concentration parameter | m-4 | float32 | -999.0 |
| ln_extinction_error | Fractional error in visible extinction coefficient | ln(m-1) | float32 | -999.0 |
| ln_lidar_ratio_error | Fractional error in extinction-to-backscatter ratio | ln(sr) | float32 | -999.0 |
| ln_iwc_error | Fractional error in IWC | ln(kg m-3) | float32 | -999.0 |
| ln_effective_radius_error | Fractional error in effective radius | ln(m) | float32 | -999.0 |
| ln_N0_error | Fractional error in normalized number concentration parameter | ln(m-4) | float32 | -999.0 |
| temperature | Temperature from ECMWF | K | float32 | -999.0 |
| day_night_flag | Day Night Flag for lidar Night (1) Day (0) | None | int16 | -999 |
| land_water_mask | Land Water Mask from Calipso files | None | int16 | -999 |
