NOAA Climate Reanalysis Task Force Telecon
18 November 2015, 2-3 PM ET
Rapporteur: Arun Kumar
Recording: https://mapp.adobeconnect.com/p390wumtiks/
2:00 - 2:05 Welcome and introduction, NCRTF co-leads
2:05 - 2:30 Update on stratosphere improvement project, C. Long, NCEP/CPC
2:30 - 2:55 Progress on NOAA Climate Reanalyses development, J. Woollen, NCEP/CPC
2:55 - 3:15 Discussion of Technical Workshop draft report and BAMS article planning, NCRTF co-leads
Planning for BAMS article (CRTF, please review/provide your input here)
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Notes:
Update on stratosphere improvement project, C. Long, NCEP/CPC
- Provied an update on the CPO/MAPP funded project. Last report was in a CRTF telecon in 2013
- Discussed issues stratrospheric issues in the CFSR. Reasons included
- Discontinuities due to running CFSR in several streams
- Bias correction of SSU Channel 3
- No assimilations of AMSU channels
- Various reanalysis also treat TOVS and ATOVS channels differently and the differences in stratrosphere show up as a a consequence of this
- Compared the performance of QBO winds in various reanalyses
- Assimilation experiments as part of the project
- 3DVAR
- Hybrid EnKF
- Discussion about the vertical structure in various reanalysis and weighting functions for different channels
- Analysis of results from 3DVAR from 1998-2003 - Does a good job in matching results from MERRA
- QBO in EnKF assimilation experiments was better
- Results between 3DVAR and Hybrid EnKF different during the SSU period but were similar for AMSU; Don't know why?
- Need to Investigate transition from SSU to AMSU
- Have not yet looked at the performance of MERRA 2 in stratosphere
Progress on NOAA Climate Reanalyses development, J. Woollen, NCEP/CPC
- A progress report on the CPC component of the NOAA Climate Reanalysis (NCR) Project
- Summary of sequence of assimilation experiments from the start of the project
- Finally settled on the EnKF data assimilation without the assimilation of satellite data (NoSAT EnKF)
- Currently running NoSAT EnKF over the R1 period to test the perforamace of this system over periods with different observational data density and to compare against R1 (that after 1979 included assimilation of satellite radiances)
- About 40+ years of analysis between 1950-2010 is complete; Analysis is done in differert streams
- Gave and overview of EnKF assimilation system
- Discussed improvements in input data archives since R1
- Initial assessments of the performance of EnKF (based on a comparison of 5-day anomaly correlation for 500-mb results show very encouraging results. During the data sparse periods of 1950 AC for EnKF are better than for R1 (in NH) and continue to be so during 2000s (even though R1 includes assimilation of satellite radiances)
- Discussion of some further diagnostics on the performance of QBO over different periods; tropical winds etc. Different measures show that perforamce of NoSAT ENKF is at par with other reanalysis. In general, EnKF peformance much better during periods of sparse data
- Comment - Should be able to fill in the entire 1950-2010 period in about six months and at that point will spend time on doing a more comprehensinve assessment of the performance of NoSAT EnKF.
- When 1950-2010 period is complete, data can also be given to other reanalysis projects under the MAPP/CRTF for a broader assessment.