NOAA 15,16,17,and18, All Instruments, Processing converter change, Implementation Date TBA- Issued: Date issued 13 December 2005; time issued 1530 UTC

Processing converter change for 1B data

*Date/Time(UTC) Message Issued:*
13 December 2005 1530 UTC

*Satellite(s) Involved:*
NOAA-15,16,17,and 18

*Instrument(s) Involved:*

*Product(s) Involved/Affected:*
NO products affected...test data only.

*Date/Time(UTC) of Initial Implementation:*

*Details/Specifics of Change:*
The following gives a description of the changes to the converter:

A problem with certain data values in 1b data sets has been reported by users. This problem involves 1-, 2-byte or 4-byte data fields where a valid data value has the most significant bit set, with all other bits 0. Therefore, values affected are 1-byte fields with a valid signed integer value of 128, 2-byte fields with a valid signed integer value of 32768, or 4-byte fields with a valid signed integer value of 2147483648. These values may be erroneously stored as 0 in the 1b. The 1b fields which have been reported as occasionally erroneous are AMSU-B and MHS radiometry values and HIRS minor frame bit flags and minor frame header elements. Specifically, the affected 1b data fields are:

AMSU-B 1b Field Beginning Byte Offset
Scene Data 1481
Space View Data 2569
Target View Data 2617

MHS 1b Field Beginning Byte Offset
Scene (Earth View) Data 1481
Space View Data 2569
OBCT View Data 2617

HIRS 1b Field Beginning Byte Offset
Header for Element 0 1457
Bit Flags for Element 0 1501
Header for Element 1 1505
Bit Flags for Element 1 1549

Please find test data available with the converter changes. This change
should not impact user processing of the 1B data. However, we would like
to provide test data prior to implementing the change operationally (
operational date to be announced). Please take some time to process this
test data and provide us with your feedback. The data is located at the
following website:

Again there is data for all satelliltes available at the above website..

This fix will be place into operations shortly after 9 January 2006

*Contact Person(s) Name/Email/Phone Number for Questions:*

Cecil A. Paris
Physical Scientist
301-457-5247 ext 129

Emily Harrod
Physical Scientist
301=457-5247 ext 117

*Web site(s) that contain other relevant information (where applicable):* - History of level 1B
notices - All user notices - SOCC polar satellites status - SOCC morning reports