The following are currently generated daily from RARS (Regional ATOVS Retransmission Service) and global NOAA-15, NOAA-16, NOAA-17 and NOAA-18 data.

The comparisons are made with HIRS level 1d data (HIRS, AMSU-A and AMSU-B/MHS on the HIRS grid). The level 1d files are generated using AAPP from the incoming level 1c RARS data.

Explanation of monitoring files generated:

• Warnings are text files generated if differences between RARS and global data are above a defined tolerance. The navigation differences of the RARS data are recorded, together with the brightness temperature differences for each channel - standard deviation and bias. Navigation differences of a few km are to be expected for NOAA-16 and NOAA-17, because AAPP and NESDIS use different assumptions with regard to the nominal pointing of the HIRS instrument. Channels 1-20 are HIRS, channels 21-35 are AMSU-A and channels 35-40 are AMSU-B/MHS.
• Mapping contains a plot of the RARS navigated HIRS fields of view superimposed upon the Global, providing a graphical display of the navigation error.
• All Channels shows the difference in brightness temperature for each instrument channel, plotted against the global brightness temperatures.
• AMSU Channel 15 is a map of the brightness temperature difference between RARS and global data for AMSU-A channel 15 (89.0 GHz). For NOAA-17, AMSU-B channel 1 (also 89 GHz) is used instead of AMSU-A.

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