Reanalysis Needs for Climate Monitoring Craig S Long Arun Kumar and Wesley Ebisuzaki CPC NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

Reanalysis Needs for Climate Monitoring Outcomes from the May 2015 NCRTF Workshop. Topics to cover: –What are the differences between: reanalysis for monitoring and reforecast initializations? –What reanalysis research advances can be transitioned to improve operational climate-reanalysis? –How to coordinate the two reanalysis efforts in a resource- constrained environments? NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

Why the Need for Climate Reanalysis Monitoring: –Monitoring real-time climate anomalies requires placing them in a historical context, and hence, the need for a climate reanalysis Attribution: –and an increasing demand to provide explanations for extreme climate events requires access to physically consistent climate reanalysis data sets Applications: –Climate reanalysis data sets are used in a wide array of societal applications, e.g., decision making in the context of infrastructure development NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

Why the Need for Climate Reanalysis Climate reanalysis data sets: –provide base climatology relative to which climate forecasts are issued –are needed to verify hindcasts and real-time forecasts and provide skill information to the users –are needed to bias correct and calibrate real-time forecasts –provide initial conditions for hindcasts and real-time climate forecasts – ocean, land, sea ice NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

Review Review of what we’ve got: –R1, R2, CFSR, 20CR What are key attributes / inadequacies of the above? What’s being done to improve things? NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

NCEP/NCAR Reanalysis (R1) Circa 1995 model and data assimilation system Atmospheric model – T62/L present; maintained in real-time by CPC Still widely used for the analysis of climate variability NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

R1 Issues Relies on data assimilation system that is 20 years old Portability and maintenance Uses satellite retrievals (that are under constant threat to be discontinued) Replacement for R1 preferably should : –Extend over the same period –Not have climate trends & discontinuities worse than R1 NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

Climate Forecast System Reanalysis Coupled: Atmosphere, Land, Ocean, Sea Ice Atmosphere: T382/L64 : Upgraded to T574/L64 in 2010 with other changes Six Streams One year spin-up for atmosphere, land and ocean Used as IC for hindcasts and CFS forecasts Time constrained development and testing – was completed in limited time of available computer –No time to go back and rerun. –Only had R1 and ERA40 to compare against NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

CFSR Issues Analysis during earlier period is an outlier Multiple Streams – Zonal Avg.Resolution Change in 2010 NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

As a consequence… Continued CPC’s reliance for climate monitoring products using R1 Developed a research effort to understand some of the issues with climate reanalysis efforts, result of which is… The NOAA Climate Reanalysis (NCR) effort –Develop a hierarchical approach for climate reanalysis –Investigate the impact to the time-varying quality and density of the observing system and determine ways to reduce this impact –Deliverable: develop a prototype climate reanalysis as a potential candidate for replacing R1 NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

NOAA Reanalysis Projects Continuing: –R1 –CFSR Current and Future: –AMIP (1850-present) –20CRv3 (1850-present) –Conventional (1948-present) SFC + Radiosonde Test results are promising –Better analyses than R1 Overlap of reanalyses should reveal biases –Increase certainty of trends Use common data assimilation infrastructure (EnkF) shared across NOAA NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

Some Outstanding Research Issues Understanding reasons for discontinuities when new observational platforms come in NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

Discontinuities due to changes in observational platforms NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

No Trend Data Source Change How to deal with transitions? NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

No Trend Data Source Change No Trend Transition How to deal with transitions? NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

Thoughts I Old and New sensors are looking at the same Earth! Model reacts differently to new data versus old data sources. –Why? More / sharper channels Smaller errors Higher density Schemes developed for new data, not old data –Solution? Assuming new data is better…. Can we use new to bias adjust (train) the old –How does this affect the Historical Context? TOVS vs ATOVS NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

Thoughts II What will model improvements provide? –Higher Horizontal –Higher/more vertical –SL vs Eularian –Model climatology –New Physics –New Parameterizations How to transition from density poor to density rich? Is assimilation of more data sources better? Or is fewer, but higher quality better? Above requires lots of testing! –Testing on same model version to be used for next reanalysis? –Any benefit of testing on older model version? NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

What still needs to be done? What are barriers to getting things done: –Model architecture NEMS, NGGPS to the rescue? –Funding for: Manpower Computers –Testing –Running –Archive –Coordination between centers Assemble Test Evaluate NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP

Discussion?! NOAA Climate Test Bed (CTB) Meeting – November 9-10, NCWCP