Solar Backscatter Ultraviolet Spectral Radiometer Version 2 (SBUV/2)
Data Description for SBUV/2 and Product Master Files (PMFs)
The Solar Backscatter Ultraviolet Radiometer-2 (SBUV/2) is an operational remote sensor designed to map, on a global scale, total ozone concentrations and the vertical distribution of ozone in the earth's atmosphere. The 1b Capture Data Set contains (1) all SBUV/2 sensor data and support data necessary for the derivation of atmospheric ozone and solar flux; (2) instrument in-flight calibration data and housekeeping functions for monitoring post-launch instrument changes; and (3) prelaunch calibration factors, and computed current-day instrument calibration and albedo correction factors to adjust the ozone algorithm for actual instrument performance. The Product Master File (PMF) contains ozone information located in space and time, other meteorological information developed in support of the ozone computation, parameters indicating the validity of the individual ozone retrievals, and the radiance information derived from the SBUV/2 measurements.
The SBUV/2 instruments on the TIROS-N satellites are designed to measure the total ozone in a vertical column beneath the satellite and its distribution with height in the atmosphere. The SBUV/2 contains a scanning double monochromator and a cloud cover radiometer (CCR) designed to measure ultraviolet (UV) spectral intensities. In its primary mode of operation, the monochromator measures solar radiation backscatter by the atmosphere in 12 discrete wavelength bands in the near-UV, ranging from 252.0 to 339.8 nm, each with a bandpass of 1.1 nm. The total-ozone algorithm uses the four longest wavelength bands (312.5, 317.5, 331.1, and 339.8 nm), whereas the profiling algorithm uses the shorter wavelengths. The cloud cover radiometer operates at 379 nm (i.e. outside the ozone absorption band) with a 3.0-nm bandpass and was designed to measure the reflectivity of the surface in the instantaneous field of view (IFOV). The SBUV/2 also makes periodic measurements of the solar flux by deploying a diffuser plate into the field of view (FOV) to reflect sunlight into the instrument.
The monochromator and the cloud cover radiometer are mounted so that they look in the nadir direction with coincident nominal FOV =s of 11.3 by 11.3 degrees. As the satellite moves in a Sun-synchronous orbit, the FOV traces 160-km wide paths on the ground. The earth rotates approximately 26 o degrees during each orbit. The satellite footprint moves at a speed of about 6 km/sec. In discrete mode a set of 12 measurements, 1 for each discrete wavelength band, is taken every 32 seconds. The order of measurements is 252.0 to 339.8 and the integration time is 1.25 seconds per measurement. For each monochromator measurement there is a cloud cover radiometer measurement.
The SBUV/2 instrument can also measure the solar irradiance or the atmospheric radiance with a continuous spectral scan from 160 to 400 nm in increments of nominally 0.148nm.
Collection will include 1B and PMF products in monthly data formats for the entire length of the SBUV/2 life-cycle, beginning with NOAA-9 data in Dec 1984 and continuing through NOAA-N' data (launch estimated Dec 2007). Data will be held in the archive for perpetuity.
1B File Naming Convention
ozone.sbuv.YYYYMM.op1b.n SS
Where YYYY = year
MM = month
SS = satellite ID
PMF File Naming Convention
ozone.sbuv.YYYYMM.nSSv6.oper.tar
(the tar file contains daily files named ozone.sbuv.YYYYMMDD.nSSv6.oper )
Where YYYY = year
MM = month
DD = day
SS = satellite ID