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NOAA-19 AVHRR HRPT from 7 Sep 2019 - 19:37 UTC

NOAA-19 AVHRR HRPT from 7 Sep 2019 - 19:37 UTC

Animated gif of multiple CLAVR-x operational products

  1. False Color Image
  2. Cloud Mask
  3. Cloud Type
  4. Cloud-top Pressure
  5. Cloud Emissivity
  6. Cloud Optical Depth
  7. Cloud Effective Radius
  8. Cloud Water Path

Cloud Products

Algorithm Description

The Clouds from AVHRR Extended (CLAVR-x) System is a cloud product generation system that has run in OSPO since 2002. CLAVR-x generates a complete suite of cloud products from NOAA's and EUMETSAT's AVHRR sensors. The cloud product suite includes cloud mask, cloud probability, cloud type, cloud height/temperature/pressure, cloud emissivity, cloud IR microphysical index, cloud optical depth, cloud particle size and cloud water path. Products are generated at the pixel resolution of the input data (1 or 4 km).

CLAVR-x runs versions of the NOAA Enterprise Cloud Algorithms, which means they are the same algorithms run on other sensors, such as VIIRS and AHI. These algorithms include a naive Bayesian cloud detection scheme, threshold-based cloud typing algorithms and two Optimal Estimation (OE) physical retrievals for cloud height products and daytime cloud optical and microphysical products. For VIIRS, the Enterprise suite includes a nighttime optical properties algorithm and IR-only cloud typing approach. CLAVR-x is slated to be retired once the NDE Enterprise processing system for AVHRR is developed, which are also same algorithms CLAVR-x uses. CLAVR-x will remain as the processing system used in the generation of the NOAA/NESDIS Pathfinder Atmospheres Extended (PATMOS-x) climate data set.


The primary use of the AVHRR products is to support the Polar Winds Application by providing the cloud-top pressure for the pixels which comprise wind targets. Another important use of the cloud products is to help classify the cloudiness within IASI footprints for improved radiance assimilation. AVHRR products are also available in AWIPS and provide high latitude data missing from the geostationary data. Finally, CLAVR-x output is also used in by other NESDIS applications, such as CoastWatch and Radiation Budget.

Key Users

Used as an input to many other baseline products; NCEP (use of VIIRS cloud products for use in CrIS cloud characterization); Polar Winds Application; JPSS Hydro Initiative; NWS/AWC (Aviation Weather Center) and Boeing; Alaska NWS Region with GINA; NCEP/NWS to get VIIRS clouds in Real- Time Mesoscale Analysis (RTMA)

Algorithm PI

Principal Investigator
Andy Heidinger

Operational Product Access

Monitoring and Algorithm Support

Other Relevant Links

List of satellite/instruments for algorithm

  • To be supplied