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RO Winds, Reanalysis, PPE

RO Winds, Reanalysis, PPE. Stephen Leroy 1 , Chi Ao 2 , Olga Verkhoglyadova 2 CLARREO SDT Meeting, April 16-18, 2013 NASA Langley Research Center. 1 Harvard School of Engineering and Applied Sciences 2 Jet Propulsion Laboratory, California Institute of Technology. On-going activity.

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RO Winds, Reanalysis, PPE

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  1. RO Winds, Reanalysis, PPE Stephen Leroy1, Chi Ao2, Olga Verkhoglyadova2 CLARREO SDT Meeting, April 16-18, 2013 NASA Langley Research Center 1Harvard School of Engineering and Applied Sciences 2Jet Propulsion Laboratory, California Institute of Technology

  2. On-going activity • RO Winds: Balance winds? • Anchoring reanalysis: BAMS reviews • Developing a perturbed physics ensemble with climateprediction.net Leroy: RO Winds, Reanalysis, PPE

  3. Geostrophic Winds Leroy and Anderson, 2007: Geophys. Res. Lett., 34, doi:10.1029/2006GL028263. Leroy: RO Winds, Reanalysis, PPE

  4. COSMIC Geostrophic Winds At dry pressure 100, 125, 150, 175, 200, 225, 250, 275, 300 hPa. Leroy: RO Winds, Reanalysis, PPE

  5. Balance winds First order correction to geostrophic winds. In order to follow path of geostrophic winds, air parcels must accelerate. Include cyclostrophic acceleration terms. Randel, W.J., 1987: The evaluation of winds from geopotential height data in the stratosphere. J. Atmos. Sci., 44, 3097-3120. Leroy: RO Winds, Reanalysis, PPE

  6. Improvement with balance winds… 200 hPa Error, geostrophic winds from gridded ERA Interim Error, balance winds from gridded ERA Interim Leroy: RO Winds, Reanalysis, PPE

  7. Improvement with balance winds? 200 hPa Error, geostrophic winds after Bayesian mapping Error, balance winds after Bayesian mapping Leroy: RO Winds, Reanalysis, PPE

  8. Jet Stream Jet stream location and strength, January 2007 Actual wind Geostrophic wind Leroy: RO Winds, Reanalysis, PPE

  9. Jet Stream Strength Actual wind Geostrophic wind Leroy: RO Winds, Reanalysis, PPE

  10. RO Winds: Conclusions • No benefit at this point in computing balance winds rather than geostrophic winds • Does this change with denser RO sampling? • Is data assimilation absolutely necessary? What impact does RO provide on winds in assimilation? • Jet stream position seems well determined by geostrophic winds but strength is overestimated by ~10%. • Is accuracy in jet stream position sufficient for monitoring? • What influence does it have on North American weather? Leroy: RO Winds, Reanalysis, PPE

  11. Analysis Analysis Analysis Analysis Observation Observation Observation Observation + Bias adj. + Bias adj. + Bias adj. + Bias adj. = ‘Evolution’ = ‘Evolution’ = ‘Evolution’ = ‘Evolution’ Next Analysis Departure Next Analysis Next Analysis ‘First guess’ ‘First guess’ ‘First guess’ Next Analysis Departure Departure ‘First guess’ + Analysis Increment Departure + Analysis Increment + Analysis Increment (e.g.) Temperature (e.g.) Temperature + L.S. Precip + L.S. Precip + L.S. Precip Dynamics Dynamics Dynamics Dynamics + Analysis Increment + L.S. Precip + Other * numerics etc + Other * numerics etc + Other * numerics etc + Other * numerics etc + Convection + Convection + Convection + Radiation + Radiation + Radiation + Radiation + Vertical diffusion (&GWD) + Vertical diffusion (&GWD) + Vertical diffusion (&GWD) + Convection + Vertical diffusion (&GWD) * Deduced as a residual * Deduced as a residual * Deduced as a residual * Deduced as a residual Process order in each timestep Process order in each timestep Data Assimilation Diagnostics Leroy: RO Winds, Reanalysis, PPE

  12. Numerical experiments at ECMWF • Investigate upper tropospheric (specific) humidity • Four runs, 4 April – 31 May 2011, 37r2 T511, 91 levels, 15min • Control • Perturb HIRS channel 12 radiative transfer (q @ 300 hPa) • Perturb AIRS channel 1783 & IASI channel 3645 radiative transfer (q @ 350 hPa) • Perturb vertical diffusion • Monitor multiple data types • Conventional in situ data: radiosondes T, q, u, v; aircraft T, u, v; • Satellite water vapor: AIRS and IASI humidity channels (1556 cm-1), AMSU-B channel 3, HIRS channel 12 • Other satellite data: AMSU-A, HIRS channel 11, scatterometer winds, atmospheric motion winds, radio occultation bending angles, SSM/I channel 14 • Mistakes • AIRS and IASI passively assimilated • Bias correction remained dynamic Leroy: RO Winds, Reanalysis, PPE

  13. Reanalysis Perturbed HIRS channel 12 Perturbed vertical diffusion physics Leroy: RO Winds, Reanalysis, PPE

  14. BAMS Review • “In general the paper was well received by the reviewers, but …” • Improve “crispness” of the ideas in the introduction; • Strengthen the claim that RO is anchoring the bias correction. Perform two new runs: Control run without GPS RO Perturbed diffusion without GPS RO Leroy: RO Winds, Reanalysis, PPE

  15. Bayesian Information on Data Types Form joint PDFP(x,y) using an ensemble of climate models. For each model, need (1) observation kernel to simulate dataxfrom hindcast run, and (2) emissions scenario run to generate prediction variablesy. Internal variability inxandyand uncertain physics will both be accounted for. With datad, setx = dandP(y|x=d ) is the projection PDF with data incorporated.P(x) is a normalization constant that guarantees a unit integral ofP(y|x) overy. Leroy: RO Winds, Reanalysis, PPE

  16. Ranking Data Types Satellite Measurements In Situ Measurements Leroy: RO Winds, Reanalysis, PPE

  17. Toward a Climate OSSE • Use a perturbed physics ensemble (PPE) with a radiance and refractivity simulator • Consider atmospheric variable retrieval • Consider inference of radiative feedbacks and forcing • Take advantage of accumulated expertise • Knowledge base of model sensitivity to changing parameters • Knowledge base of calibration of ensemble • Gain access to massive computing • Collaboration with climateprediction.net • Based on HadAM3, Unified Model 4.5 of Met. Office • Legal agreement is in place • Embed PCRTM, specify sampling frequency • Specify initialization, boundary conditions Leroy: RO Winds, Reanalysis, PPE

  18. GPS RO Processing (1) • Tool developed by Gorbunov (NOAA, CLARREO SDT) • Use 2-parameter ionosphericfitting • Initialization at 100 km • Canonical transform type 2 • Truncate lower troposphere when canonical transform signal drops below 50% • Build on Harvard FAS cluster “odyssey” • 8.6 core-seconds per level1b calibration • 83% of CHAMP passes quality control • Begin research • Systematic error from precise orbit determination (?) • Detectible climate signals in UTLS, stratosphere Leroy: RO Winds, Reanalysis, PPE

  19. GPS RO Processing (2) 7,902,055 total occultations, ~83% of which pass quality control (CHAMP). Leroy: RO Winds, Reanalysis, PPE

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