1 The Oceanic Component of CFSR Yan Xue 1, David Behringer 2, Boyin Huang 1,Caihong Wen 1,Arun Kumar 1 1 Climate Prediction Center, NCEP/NOAA, 2 Environmental Modeling Center, NCEP/NOAA, The 34 th Annual Climate Diagnostics and Prediction Workshop, Monterey, CA, October 26-30 2009
2 Use of CFSR Ocean Reanalysis Provide ocean memory for predictability of major climate modes (ENSO, PDO, IOD, TAV, AMOC) Provide historical and real time ocean surface fluxes, temperature, salinity and currents Delivery ocean climate information to society: monitoring ENSO and beyond ENSO
Current Global Ocean Monitoring Products (delivering information to society) http://www.cpc.ncep.noaa.gov/products/godas/ Synthesis of global ocean observations by NCEP s Global Ocean Data Assimilation System (GODAS) Climatology and anomaly plots for each month in 1979 present Synthesis of Ocean Observations Monthly Ocean Briefing Annual Ocean Review Intended for use by operational climate prediction centers, researchers, fishery managers, industries, news media, program managers, teachers and students Contact: Yan Xue, NOAA/CPC 3
4 Model and Data Assimilation System Model GFDL MOM4, 0.5 o x 0.5 o (0.25 o within 10 o S-10 o N) including an Arctic sea ice model Data input XBT, Argo temp/salinity, TAO/TRITON/PIRATA/RAMA temp, Altimetry SSH, NCDC daily SST Analysis system 3-D variational, 1979 present 6 hour coupled model forecast as first guess Hourly 2-D and daily/pentad/monthly 3-D outputs
5 Validation Data Sets Optimal Interpolation SST (OI SST) version 2 NCEP s Global Ocean Data Assimilation System Aviso Altimetry sea surface height Ocean Surface Current Analyses Realtime (OSCAR) NODC objective temperature analysis TAO/TRITON/PIRATA/RAMA mooring temperature, currents, winds NCEP Reanalysis 1 and 2 (R1 and R2) WHOI OAFlux (sensible and latent heat flux) ISCCP satellite data (short and long wave)
6 Divide Global Ocean into Sub-regions North Pacific North Atlantic Tropical Indian Tropical Pacific Tropical Atlantic South Indian South Pacific South Atlantic
Sea Surface Temperature ( o C) 7
Sea Surface Temperature 8
300m Ocean Heat Content ( o C) 9
300m Ocean Heat Content 10
Mean Surface Heat Fluxes (1984-2004, W/m 2 ) 11 Net Heat Fluxes Short Wave Latent Heat Fluxes
Correlation with OAFlux (1984-2004) 12 Net Heat Fluxes Short Wave Latent Heat Fluxes
13 165E 170W 140W 110W Flux Reference Sites along the equator at 165E, 170W, 140W, 110W were used to validate model temperature, currents and surface winds.
14 CFSR TAO Temp 165E 170W 140W 110W 1999
15 GODAS TAO Temp 165E 170W 140W 110W
Were the warm biases in the eastern Pacific after 1999 forced by errors in the zonal winds? 16
Mean 79-98 99-08 TAO = -0.74-2.5 CFSR = -2.1-2.8 R2 = -1.7-2.5 Trade winds strengthened by 1.8 m/s. TAO = -4.4-5.6 CFSR = -5.0-5.4 R2 = -4.0-5.2 Trade winds strengthened by 1.2 m/s. TAO = -5.6-5.6 CFSR = -5.7-5.5 R2 = -5.6-5.6 Trade winds changed little R2_10m TAO = -3.7-3.4 CFSR = -3.7-3.7 R2 = -3.9-3.5 Trade winds weakened slightly 17
TAO data suggested trade winds strengthened by 1-2 m/s near the Dateline from the period before 1999 to that after 1999. CFSR underestimated the strengthening of trades due to too strong trades before 1999. 18
19 TAUX (160E-160W, 5S-5N) Mean 79-98 99-08 CFSR = -0.37-0.37 R1 = -0.19-0.31 R2 = -0.29-0.36 Taux strengthened by about 1 dyn/cm 2 in R2 and R1, but it remains unchanged in CFSR.
Depth of 20C in CFSR in the equatorial eastern Pacific agreed well with that in TAO before 1999, but was about 10 m too deep after 1999. 20
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23 Summary Improvements in CFSR over GODAS 1. SST variability is much better simulated. 2. Ocean surface fluxes are generally superior to those in GODAS that were derived from R2. Improvements are largely due to short wave radiation that agrees with observations better in both the mean and variability. 3. Ocean surface fresh water fluxes are significantly improved over those in R1 and R2 (not shown). 4. Ocean heat content for upper 300m is generally improved except in the tropical and South Atlantic. Unsatisfactory features in CFSR 1. Trade winds in the equatorial Pacific are too strong before 1999. 2. Subsurface temperature in the eastern Pacific (140W, 110W) has significant warm biases from TAO temperature after 1999. 3. Both temperature and currents in CFSR have larger RMSE and smaller correlation with TAO data than those of GODAS. 4. Discontinuity in temperature (salinity) is apparent at depths below 600m (100m).
24 Thank you! For CFSR data access at NCDC: http://nomads.ncdc.noaa.gov/noaareanalysis/cfsrr
Backup Slides 25
Sea Surface Height 26
Sea Surface Height 27
CFSR has a lower correlation and higher RMSE with TAO temperature than GODAS does. 28
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