
Changes in the RTG_SST_HR analysis
Description of changes effective April 7, 2007 The RTG_SST_HR analysis state was replaced by the RTG_SST analysis at 1/2 deg. interpolated to 1/12 deg. in the Northern Hemisphere north of the continents. The sea ice SST observations, which had been at 1/12 deg. resolution, are now being superobbed to 1/2 deg. resolution. The observation errors for the sea ice were increased to those for surface ship observations. The QC criteria in the physical (JCSDA) SST retrieval were changed to allow the generation of warmer SST retrievals. Description of changes effective September 7, 2006 The RTG_SST_HR analysis state was replaced by the RTG_SST analysis at 1/2 deg. interpolated to 1/12 deg. in the Northern Hemisphere north of the continents. Cold conditions had persisted in Arctic regions of the RTG_SST_HR analysis since the melting of the ice in May. The palliative step was taken while investigation continues. Description of changes effective March 8, 2006 NOAA-16 physical retrievals were replaced by NOAA-18 physical retrievals. The land, ice, and coastal checks were removed from the physical retrieval algorithm. The lower limit of the correlation length scale was reduced from 100 km to 50 km. The land/sea mask was modified to removed small, isolated lakes. Description of changes effective September 27, 2005 The 1/12 deg. Real-Time Global SST (RTG_SST_HR) analysis was introduced. This new analysis uses physical SST retrieval data from both NOAA-16 and NOAA-17 satellites. It also uses sea ice at 1/12 deg. resolution. Description of changes effective May 6, 2004 The source of NAVY SST retrieval data was changed from NOAA-16 to NOAA-17. Description of changes effective May 8, 2002 Array sizes for one week of in situ data were doubled from 90,000 to 180,000 in the program which performs quality control of in situ data. The program in question was generating large numbers of messages indicating that buoy data were being dropped. This was due to insufficient array sizes. The effect was that up to 25% of buoy data were being dropped from the the most recent day's worth of data (i.e., the real-time buoy data). The buoys dropped were in the northern areas (off of Western Europe, the U. S. and Canadian East Coast, the Gulf of Alaska and the West Coast off the U. S. and Canada). The northernmost buoys started being lost around April 22. Description of changes effective April 23, 2002 Instituted a smoother to eliminate 2-delta grid length waves, while leaving larger scale phenomena unchanged. The reason for making this change is that small-scale noise in the RTG_SST analysis was growing noticeably with time. There was very little noise as of Febrary 2001, but it was increasing throughout the past year. The growth of the noise has been attributed to the growth of round-off error in the RTG_SST analysis. Description of changes effective October 23, 2001 Change in the operational run-time from 2045 UTC to 2240 UTC; and change the window for admitting data to the analysis system, in order to ingest all SST data received up to analysis run-time. The reasons for making these changes are: to synchronize the daily RTG_SST run-time with the 00 UTC EDAS and produce more timely SST fields for use by the 00 UTC Meso Eta model run. The previous operational run-time was 3 hours, 15 minutes before the 00 UTC EDAS, and most recent data in the previous operational RTG_SST was already 20 hours old. Description of changes effective June 5, 2001 Switch from NOAA-14 MUT SST retrievals to NOAA-16 SEATEMP SST retrievals. The reasons for making this change are: (1) switch to a high-resolution, higher quality SST retrieval from the Navy; (2) switch from the older satellite (NOAA-14) to the newer satellite (NOAA-16). For additional information about data-management and analysis techniques, contact William.Gemmill@noaa.gov. For information about the run cycle and digital data format, contact Bert.Katz@noaa.gov.

Changes in the RTG_SST_HR analysis

Description of changes effective April 7, 2007

The RTG_SST_HR analysis state was replaced by the RTG_SST analysis at 1/2 deg. interpolated to 1/12 deg. in the Northern Hemisphere north of the continents.
The sea ice SST observations, which had been at 1/12 deg. resolution, are now being superobbed to 1/2 deg. resolution. The observation errors for the sea ice were increased to those for surface ship observations.
The QC criteria in the physical (JCSDA) SST retrieval were changed to allow the generation of warmer SST retrievals.

Description of changes effective September 7, 2006

The RTG_SST_HR analysis state was replaced by the RTG_SST analysis at 1/2 deg. interpolated to 1/12 deg. in the Northern Hemisphere north of the continents.
Cold conditions had persisted in Arctic regions of the RTG_SST_HR analysis since the melting of the ice in May. The palliative step was taken while investigation continues.

Description of changes effective March 8, 2006

NOAA-16 physical retrievals were replaced by NOAA-18 physical retrievals. The land, ice, and coastal checks were removed from the physical retrieval algorithm. The lower limit of the correlation length scale was reduced from 100 km to 50 km. The land/sea mask was modified to removed small, isolated lakes.

Description of changes effective September 27, 2005

The 1/12 deg. Real-Time Global SST (RTG_SST_HR) analysis was introduced. This new analysis uses physical SST retrieval data from both NOAA-16 and NOAA-17 satellites. It also uses sea ice at 1/12 deg. resolution.

Description of changes effective May 6, 2004

The source of NAVY SST retrieval data was changed from NOAA-16 to NOAA-17.

Description of changes effective May 8, 2002

Array sizes for one week of in situ data were doubled from 90,000 to 180,000 in the program which performs quality control of in situ data.
The program in question was generating large numbers of messages indicating that buoy data were being dropped. This was due to insufficient array sizes. The effect was that up to 25% of buoy data were being dropped from the the most recent day's worth of data (i.e., the real-time buoy data). The buoys dropped were in the northern areas (off of Western Europe, the U. S. and Canadian East Coast, the Gulf of Alaska and the West Coast off the U. S. and Canada). The northernmost buoys started being lost around April 22.

Description of changes effective April 23, 2002

Instituted a smoother to eliminate 2-delta grid length waves, while leaving larger scale phenomena unchanged.
The reason for making this change is that small-scale noise in the RTG_SST analysis was growing noticeably with time. There was very little noise as of Febrary 2001, but it was increasing throughout the past year. The growth of the noise has been attributed to the growth of round-off error in the RTG_SST analysis.

Description of changes effective October 23, 2001

Change in the operational run-time from 2045 UTC to 2240 UTC; and change the window for admitting data to the analysis system, in order to ingest all SST data received up to analysis run-time.
The reasons for making these changes are: to synchronize the daily RTG_SST run-time with the 00 UTC EDAS and produce more timely SST fields for use by the 00 UTC Meso Eta model run. The previous operational run-time was 3 hours, 15 minutes before the 00 UTC EDAS, and most recent data in the previous operational RTG_SST was already 20 hours old.

Description of changes effective June 5, 2001

Switch from NOAA-14 MUT SST retrievals to NOAA-16 SEATEMP SST retrievals.
The reasons for making this change are: (1) switch to a high-resolution, higher quality SST retrieval from the Navy; (2) switch from the older satellite (NOAA-14) to the newer satellite (NOAA-16).

For additional information about data-management and analysis techniques, contact William.Gemmill@noaa.gov.

For information about the run cycle and digital data format, contact Bert.Katz@noaa.gov.

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Last updated November 14, 2002.