Cloud Base Height
Measurement Instruments
Measurement Definition: Height of the bottom surface of the cloud - Physical unit: [ km ] - Accuracy unit: [ km ].
| Instrument | Status/
Accuracy | Instrument Description | Measurement Technology | Timeline |
| ATLID | Operational | Derivation of cloud and aerosol properties - Measurement of molecular and particle backscatter in Rayleigh, co-polar and cross-polar Mie channels. | n/a |  |
| CPR (EarthCARE) | Operational | Measurement of cloud properties, light precipitation, vertical motion. | Cloud and precipitation radar | |
| OLCI | Operational | Marine and land services. | n/a | |
| OLS | Operational | Used to monitor the global distribution of clouds and cloud top temperatures twice each day. The archive data set consists of low resolution global and high resolution regional, imagery recorded along a 3,000 km scan, satellite ephemeris and solar and lunar information. Infrared pixel values correspond to a temperature range of 190 to 310 Kelvins in 256 equally spaced steps. Onboard calibration is performed during each scan. Visible pixels are relative values ranging from 0 to 63 rather than absolute values in Watts per m^2. Instrumental gain levels are adjusted to maintain constant cloud reference values under varying conditions of solar and lunar illumination. Telescope pixel values are replaced by Photo Multiplier Tube (PMT) values at night. A telescope pixel is 0.55 km at high resolution (fine mode) and 2.7 km at low resolution(smooth mode). Low resolution values are the mean of the appropriate 25 high resolution values. | n/a | |
| VIIRS | Operational | Global observations of land, ocean, and atmosphere parameters: cloud/weather imagery, sea-surface temperature, ocean colour, land surface vegetation indices. | n/a | |
| Multiview Thermal-Infared | Approved | Observations of motion occurring at or near Earth’s surface. | n/a | |
| AOLCI | Proposed | Visible and near-infrared hyperspectral radiometer supporting a wide range of Marine, Land, Atmosphere and Climate Services. Provides enhanced continutity of ocean colour and land colour measurements from OLCI and enhanced synergy with ASLSTR | n/a | |