Satellite Radiance Dataset
Overview
Description
The MADIS satellite radiance dataset consists of multiple products from different "providers" that are integrated into a single dataset. Currently, these products consist of radiances (also called brightness temperatures) from the NOAA Polar Orbital Environmental Satellites (POES). Through the use of various mathematical techniques the radiances can be used to calculate vertical profiles of temperature and moisture. Those users who are interested in acquiring radiances in order to perform these calculations are encouraged to get this dataset. On the other hand, users who are only interested in getting the temperature and moisture profiles that have been produced by the ATOVS (Advanced TIROS Operational Vertical Sounder) processing system should get the MADIS Satellite Sounding dataset.
The POES system offers the advantage of daily global coverage, by making nearly polar orbits roughly 14.1 times daily. Since the number of orbits per day is not an integer the suborbital tracks do not repeat on a daily basis, although the local solar time of each satellite's passage is essentially unchanged for any latitude. NOAA maintains a four satellite configuration (morning -- NOAA-15 primary, NOAA-17 secondary, and afternoon -- NOAA-19 primary, NOAA-16 and NOAA-18 secondary)*, allowing NOAA to obtain data five times daily in any one location. The brightness temperatures are from the Advanced Microwave Sounding Unit A (AMSU-A) and the High Resolution Infrared Radiation Sounders (HIRS/3 and HIRS/4). NOAA-15 and NOAA-16 have the HIRS/3 instrument. For the NOAA N-N' satellite series, starting with NOAA-18, the infrared sounder has been upgraded to HIRS/4. The AMSU-A is a multi-channel microwave radiometer that will be used for measuring global atmospheric temperature profiles under clear and cloudy conditions. AMSU-A measures in 15 spectral bands, where the temperature sounding mainly exploits the oxygen band at 50 GHz. The HIRS/3 and HIRS/4 instruments are infrared sounders that measure the incident radiation primarily in the infrared region of the spectrum in 19 channels. They also have one channel in the visible. Its purpose is to measure temperature and water vapour profiles under clear-sky conditions.
*Due to a failed AMSU-A instrument, MADIS doesn't carry data from NOAA-17.
MADIS has been collecting Satellite Radiance data since October 2005.
Geographic Coverage
The coverage is global (see first paragraph above). There are approximately 340,000 data points available per day. Here are graphics showing typical orbits for NOAA-15, NOAA-16, and NOAA-18.
Data Schedule
Newly arriving data are binned into hourly files, and between 3 and 10 files are produced (or updated) every 15 minutes or so. Because of the variance in the schedule, ldm is the preferred communications method. Ftp users should download data at minutes 13, 28, 43 and 58. Each download should get 10 files ranging from one hour back to 10 hours back. For example, at 13:15 you should get the 0300, 0400, ..., 1200 files.
Volume
Typical daily volume for all MADIS datasets can be seen here.
Restrictions
No restrictions. All observations are publicly accessible.
Variable Details
Related Links
- AMSU-A Characteristics and Specifications
- HIRS Characteristics and Specifications
- NOAA KLM User's Guide
Last updated 16 March 2017
