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Addressing Climate Model Errors Through Observation Integration

Explore the impact of observational data on climate model accuracy. Discuss errors, spin-up, and observational proposals for better model performance in climate studies.

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Addressing Climate Model Errors Through Observation Integration

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  1. GPCI spin-up issues • Advertisement: CEOP cloud observations – coming up • Spin-up: Why interesting? • Errors: RMSE, bias, anomaly correlation, variabiltiy • 5day evolutions • Model errors: Hadley circulation, cirrus cloud, PBL height • Some observations: w, IWP • A very speculative fix of a low resolution bias in climate models. GCSS meeting 9-2006 Martin Köhler 1

  2. CEOP observation proposal(with Rachel Pinker, U. Maryland and Mike Bosilovich, GMAO, NASA) Linderberg lidar+radar conv. cloud high cloud med. cloud low cloud Dec 2004 • CEOP compares reference point and gridded data from observations and models • Yet, there are NO cloud observations in CEOP database • Add point data: TCC from ISCCP and cloud profiles form CLOUDNET lidar/radar • Add gridded data: 5km / 1hour resolution data from METEOSAT and GOES • Most interesting for diurnal cycle and Monsoon studies. GCSS meeting 9-2006 Martin Köhler 2

  3. Initial errors - Schematic state variable (e.g. TCWV) Forecast < 1kg/m2 1mm Analysis Observations True state 1day 5days Time Initial tendency reflects the errors of physical parameterizations assuming that analysis errors are small. Balance between analysis and forecast model: Both have identical biases. Makes it hard to detect any errors. GCSS meeting 9-2006 Martin Köhler 3

  4. History of spin-down: precip TCWV AN-FC48h(20N-20S) 29R2: Assim. Rain, limit q-incr 28R1: Conv. changes 24R3: Conv.+supersat 26R3: AIRS, New q-anal 23R4: 29R1: Moist BL, num. 1st step 25R3: Mult. Incr. 4DVAR, SSMI-rad, changes clds+cnv 28R3: num. cld+cnv, FG from 6+18, No SYNOP-q at night 25R1 28R2: Early delivery GCSS meeting 9-2006 Martin Köhler 4

  5. Spin-up Profile split into physical processesMark Rodwell, ECMWF Temperature tendencies over first 6h. Amazon, Jan 2005. GCSS meeting 9-2006 Martin Köhler 5

  6. Forecast setup • Analysis: JJA 2003 ECMWF (e-suite with AIRS) • Resolution: T42 (NCAR), T240 (UKMO), T399 (ECMWF) • UKMO: SST climatology instead of SST JJA2003 GCSS meeting 9-2006 Martin Köhler 6

  7. RMSE, anomaly correlation, BIAS, variability if ANC=1: variability2 ANC: anomaly correlation BIAS2 GCSS meeting 9-2006 Martin Köhler 7

  8. U 850hPa RMSE, BIAS, AC, variability GCSS meeting 9-2006 Martin Köhler 8

  9. W 500hPa RMSE, BIAS, AC, variability RMSE [Pa/s] GCSS meeting 9-2006 Martin Köhler 10

  10. RMSE 900hPa Q, PT, R, CC RMSE [K] GCSS meeting 9-2006 Martin Köhler 11

  11. BIAS 900hPa Q, PT, R, CC GCSS meeting 9-2006 Martin Köhler 12

  12. RMSE 800hPa Q, PT, R, CC GCSS meeting 9-2006 Martin Köhler 13

  13. BIAS 800hPa Q, PT, R, CC GCSS meeting 9-2006 Martin Köhler 14

  14. GPCI spinup: Precipitation NCAR ECMWF UKMO ITCZ precip spin-down: < factor 2 GCSS meeting 9-2006 Martin Köhler 15

  15. GPCI spinup: PBL height NCAR ECMWF UKMO UKMO, ECMWF: strcu zi spin-up: 100-200m NCAR: strcu zi spin-down: 80m GCSS meeting 9-2006 Martin Köhler 16

  16. GPCI spinup: LWP NCAR ECMWF UKMO UKMO, ECMWF: strcu LWP spin-up: 20-40 g/m2 GCSS meeting 9-2006 Martin Köhler 17

  17. GPCI spinup: IWP NCAR ECMWF ECMWF: IWP spin-down: 20 g/m2 NCAR: IWP only 10 g/m2 GCSS meeting 9-2006 Martin Köhler 18

  18. Ice Content compared to Microwave Limb SounderLi, Jiang, Waliser, Tompkins GCSS meeting 9-2006 Martin Köhler 20

  19. GPCI cross-section: Omega GCSS meeting 9-2006 Martin Köhler 21

  20. GCSS Pacific Cross-section Project Omega Bias at 500hPa sfc vector wind: QuikSCAT vs ECMWF FG Equator ITCZ V-Bias: METEOSAT-8 vs ECMWF FG IWC and W decay in 10d FC 6.2 μm Thanks to Adrian Tompkins, Hans Herbach, Claire Delsol! GCSS meeting 9-2006 Martin Köhler 22

  21. Speculation on resolution dependent bias Thomas Jung (2005) half # cyclones in T95 vs T255 dxy=T399 - T159 T at 400hPa Peter Janssen (2005) surface KE missing in T95 vs Quickscat v`T` transient meridional sensible heat transport GCSS meeting 9-2006 Martin Köhler 23

  22. singular vector perturbation T511 T255 T159 GCSS meeting 9-2006 Martin Köhler 24

  23. Conclusions • Errors found (compared to ECMWF analysis): • NCAR: equatorial 850hPa westward wind bias • NCAR: stratus warm dry bias– but clouds OK • UKMO: trade cumulus cold moist bias – high CC • All models: precip spin-down by factor 2 • NCAR: PBL height down • UKMO, ECMWF: PBL height (and LWP) up • ECMWF: IWP reduces from 40g/m2 to 20g/m2 (fixed by CY31R1) • UKMO, ECMWF, NCAR: Hadley circulation slows down • Interpretation: • Surface scatterometer wind and cloud vector winds support Hadley circulation problem • Hypothesis: low resolution model misses pole-ward heat transport • Possible fix: use singular vector perturbations to amplify mid-latitude eddies. GCSS meeting 9-2006 Martin Köhler 25

  24. Extra Slides GCSS meeting 9-2006 Martin Köhler 26

  25. Temperature bias change due to resolution GCSS meeting 9-2006 Martin Köhler 27

  26. IWP in tropics: CY31R1 versus CY30R1 GCSS meeting 9-2006 Martin Köhler 28

  27. GCSS meeting 9-2006 Martin Köhler 29

  28. Validation of model against Meteosat 8 (IR channel) 1 July - 31 August 2006 / 24h FC from 00Z GCSS meeting 9-2006 Martin Köhler 30

  29. 150 hPa 480 hPa 150 hPa 480 hPa Qice OPER CY30R1 Qice esuite CY31R1 Validation of model against Meteosat 8 (IR channel) 1 July / 24h FC from 00Z GCSS meeting 9-2006 Martin Köhler 31

  30. Validation of model against Meteosat 8 1 July / 24h FC from 00Z: CCOV and Qliq. esuite CY31R1 OPER CY30R1 GCSS meeting 9-2006 Martin Köhler 32

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  45. History of spin-up (20N-20S) GCSS meeting 9-2006 Martin Köhler 47

  46. History of spin-up (20N-20S) 29R2: Assim. Rain, limit q-incr List with selection of model changes. In addition there were many changes to the use of satellite data. 24R3: Conv.+supersat 28R1: Conv. changes 23R4: 26R3: AIRS, New q-anal 29R1: Moist BL, num. 1st step 25R3: Mult. Incr. 4DVAR, SSMI-rad, clds+cnv changes 28R3: num. cld+cnv, FG from 6+18, No SYNOP-q at night 25R1 28R2: Early delivery GCSS meeting 9-2006 Martin Köhler 48

  47. History of spin-up (20N-20S) GCSS meeting 9-2006 Martin Köhler 49

  48. Conclusions on spin-up • Spin-up has improved with: • A modest reduction in precipitation spindown • A substantial reduction in TCWV spindown • A change from increase of evaporation during the forecast to a decrease of evaporation. (BL has become more dry in analysis). • It is difficult to make a precise link between model changes and impact on spin-up • Model changes and data assimilation changes (including use of satellite data) have contributed • It is impossible to verify TCWV within 1 kg/m2 using radio sonde data. GCSS meeting 9-2006 Martin Köhler 50

  49. End – Extra Slides GCSS meeting 9-2006 Martin Köhler 52

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