Information on GOES image display from the NOAA/NESDIS/StAR/RAMM Branch
The following information is provided about GOES imagery to help satellite data users understand image calibration/scaling and differences between GOES images on RAMSDIS and AWIPS display systems. Information is also available on image noise and on a unique transformation of multi-spectral GOES imagery into image products via principal component analysis.
GOES image calibration/scaling and display
Whereas GOES Imager data are collected in 10-bit values called GVAR counts, image display systems use 8-bit displays. The process of converting from 10-bit GVAR counts into temperatures and into 8-bit display counts are both non-linear process. Information is also provided here about differences between GOES imagery displayed on RAMSDIS and AWIPS display systems, in particular on the differences for the GOES water vapor band and the GOES fog product.
GOES image noise characteristics
In the process of converting between different unit scales, satellite data users must be aware of how noise is manifest in GOES data. Noise in GOES data is a function of temperature and is therefore not constant over the 8-bit count range normally used for display of GOES data.
- Characteristics of GOES noise in different unit scales
- Bit depth (1-byte vs. 2-byte) has an effect on the quality of GOES imagery and on the quality of image products derived from GOES data.
- Effect of bit depth (8-bit vs. 10-bit) on the noise level of GOES images and image products
- Effect of bit depth (8-bit vs. 13-bit) on the noise level of GOES Sounder data
GOES Principal Component Image (PCI) transformation
It is possible to transform GOES imagery into image products which are statistically independent. Principal Component Images (PCIs) can be created to help explain the observed features in GOES imagery, such a differing cloud types and heights and variations in earth-surface features.
- A Principal Component Image (PCI) transformation of GOES imager bands
- At night the principal component image transformation changes as the visible band and the reflected component of GOES (shortwave) band-2 disappear.
- A PCI transformation of GOES imagery into new image products at night
The following acronyms are used throughout the Web pages linked to this page.
- AWIPS = Advanced Weather Interactive Processing System
- GOES = Geostationary Operational Environmental Satellite
- GVAR = GOES VARiable
- GINI = GOES Ingest NOAA-Port Interface
- LUT = Look Up Table
- McIDAS = Man Computer Interactive Data Analysis System
- NOAA = National Oceanic and Atmospheric Administration
- NESDIS = National Environmental Satellite, Data, and Information Service
- ORA = Office of Research and Applications
- PCI = Principal Component Image(s)
- RAMMB = Regional And Mesoscale Meteorology Branch
- RAMSDIS = RAMM Advanced Meteorological Satellite Demonstration and Interpretation System
Go to RAMM Branch home page.
- This Web page maintained by Don Hillger, PhD
- Web site courtesy of CIRA/Colorado State University.
- Copyright © 1998-2006, NOAA/NESDIS/StAR/RAMM Branch. All rights reserved.
- Updated: 2006-08-07