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Heat Flux Intercomparison. ▶ Focus on surface heat fluxes ▶ Timeseries comparison at buoy sites . Maria Valdivieso Department of Meteorology, University of Reading, UK . [email protected]. Monthly mean data regridded onto the WOA grid Common period 2004 – 2009 - PowerPoint PPT Presentation
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Heat Flux Intercomparison
Maria ValdiviesoDepartment of Meteorology,
University of Reading, UK
▶ Focus on surface heat fluxes▶ Timeseries comparison at buoy sites
Products Surface Heat Flux
Assimilation Heat Flux SST Time Frame
ECMWF-ORAS4 X X 1958- 2009JMA-MOVEG2 X X X 1993-2011
JMA-MOVECORE X X X 1993-2011Kiel-GECCO2 X X 1993-2010NCEP-GODAS X X 1985-2010
Reading-UR025.4 X X X 1989-2010Met Office-GloSea5 X X 1993-2010
Mercator-GLORYS2V1 X X X 1993-2009GFDL-ECDA (Coupled) X X 2004-2011
NCEP-CFSR (Coupled) X X 1985-2010
LEGI-MJM95 (Control) X X 1993-2009
Monthly mean data regridded onto the WOA grid Common period 2004 – 2009
▶Other flux data sets: ISCCP+OAFlux, NOC2.0, ERAI, NCEP –R2
Global Integrals
Surface heat fluxes from ocean reanalysis products averaged over the global ocean (common ocean-land mask). Fluxes are positive into the ocean. Units are in Wm-2
Products 1993 – 2009 2004 – 2009ECMWF-ORAS4 4.99 ± 0.95 5.38 ± 0.47JMA-MOVEG2 7.90 ± 2.68 10.16 ± 1.97
JMA-MOVECORE 8.60 ± 0.54 8.65 ± 0.50Kiel-GECCO2 0.74 ± 0.64 0.31 ± 0.37NCEP-GODAS 0.10 ± 1.51 1.51 ± 1.29
Reading-UR025.4 3.99 ± 4.84 -0.14 ± 1.35Met Office-GloSea5 8.95 ± 3.36 5.36 ± 2.01
Mercator-GLORYS2V1 2.87 ± 2.26 0.56 ± 1.62GFDL-ECDA (Coupled) − 14.60 ± 1.28NCEP-CFSR (Coupled) 13.96 ± 2.14 14.21 ± 1.06LEGI-MJM95 (Control) 0.30 ± 0.72 0.17 ± 0.56
ISCCP + OAFlux 25.04 ± 3.61 22.28 ± 0.67NOC2.0 16.80 ± 2.86 15.01 ± 2.63
ECMWF-ERAI 7.41± 1.27 7.32 ± 1.32NCEP-R2 1.66 ± 1.88 1.67 ± 1.77
Fluxes are positive into the ocean. Units are in Wm-2
◀◀◀
◀
Zonal IntegralsMean 2004 - 09
Zonal IntegralsEquatorial heating in the middle of the range span by other products
Warming pattern in the SH underestimated at all latitudes
Heat loss north of20N seems reasonable
Northward heat transport - global
Also shown are the zonal integrals from Ganachaud and Wunsch (2003) and Lumpkin and Speer (2007) obtained from inverse analysis of WOCE sections
MHT as inferred from estimated surface heat fluxes
The mean transport due to the net heat uptake is ~ 2 PW, representing a non-zero heat storage in these ocean reanalyses
Mean 2004 - 09
Differences in Qsw
ISCCP ERAI NOC2.0 ECDA168.28 ±
0.98168.65±
0.51164.61±
0.66168.59±
0.41
Global averages over 2004 –2009. Units in Wm-2
Mean 2004 - 09
Cloud estimation from ships
Satellite-based Atmos reanalysis
Coupled reanalysis
SST Diff MapsHadISST (Rayner et al., 2003) combines in situ + satellite-based data
Mean 2004 - 09
Using NCEP-R2 + relaxation to weekly OISST
Using NCEP surface fields
Using COREII surface fields JMA Reanalysis surface fields
Using corrected ERAI Qsw
Assimilating Reynolds SSTs
OSTIA + real time GHRSST after 2008
Coupled Reanalyses
SST Diff Maps(cont.)
Mean 2004 - 09
Differences in the bulk
fluxesEddy-permitting +
Core bulk forcing using ERAI surface fields
Assimilating EN3 T/S profiles Assimilating SST + EN3 data
Assimilating SST + CORA dataNo data assimilation
Mean 2004 - 09
Comparison at buoy sitesCLIMODE: 38.5N, 65WKEO: 32.4N, 144.5EWHOTS: 22N, 158WNTAS: 15N, 51WTAO_w: 0, 165ETAO_e: 0, 110WSTRATUS: 25S, 85W
The underlying map is the annual mean (1993 – 2009) net surface heat flux from the OAFlux + ISCCP product (Wm-2, positive downward) available at http://oaflux.whoi.edu
CLIMODE [38.5N, 65.0W]
CLICLMODE ORAS4 MOVEC GECCO GODAS UR025.
4GloSea
5 GLORYS MJM95 CFSR ECDA ENSEMBLEemble
MEAN -95.10 -159.17 -70.66 -47.81 -193.11 -196.44 -194.30 -162.88 -207.57 -167.89 -149.49
MeanDIFF 111.30 47.23 135.74 158.59 13.29 9.96 12.10 43.52 -1.17 38.51 56.91
STD 59.52 46.91 85.68 72.39 29.83 20.67 17.18 30.08 12.76 47.69 24.31
Monthly Climatology 2004 -
2009
Mean (ISCCP+OAF) = -206.4 ±22.4 Wm-
2
Sea Surface Temperatures
Interestingly, GODAS net heat flux is much too weak here (only -47 Wm-2), yet the SST is reasonably well reproduced.
GECCO2 is systematically too cold; MOVECORE is too warm
warm winters in 2008 and 2009
Monthly Climatology 2004 -
2009
KEO [32.4N, 144.5E]
Mean (ISCCP+OAF) = -101.35 ±16.2
Wm-2
KEOS ORAS4 MOVEC GECCO GODAS UR025.4
GloSea5 GLORYS MJM95 CFSR ECDA ENSEMB
LE
MEAN -85.66 -125.97 -72.35 -124.23 -86.45 -82.62 -82.82 -76.60 -77.36 -116.83 -93.09
MeanDIFF 15.68 -24.62 29.00 -22.88 14.90 18.72 18.53 24.75 23.99 -15.48 8.26
STD 15.81 32.07 14.47 41.15 20.13 14.05 20.33 23.34 21.60 15.81 12.07
WHOTS [22.0N, 158.0W]Mean (ISCCP+OAF)
= +23.53 ± 9.96 Wm-2
WHOTS ORAS4 MOVEC GECCO GODAS UR025.4
GloSea5 GLORYS MJM95 CFSR ECDA Ensembl
e
MEAN +2.83 +9.22 -0.91 -0.98 +22.55 +15.33 +12.36 +0.08 -7.68 -8.60 +4.42
DIFF -20.70 -14.30 -24.44 -24.50 -0.98 -8.19 -11.17 -23.45 -31.21 -32.12 -19.11
STD 25.63 28.80 33.43 16.43 19.95 18.66 17.58 22.27 27.57 20.12 22.24
Sea Surface Temperatures
Surface Heat Fluxes
NTAS[15N, 51W]
Mean (ISCCP+OAF) = +40.25 ± 8.2 Wm-
2
NTAS ORAS4 MOVEC GECCO GODAS UR025.4
GloSea5 GLORYS MJM95 CFSR ECDA ENSEMB
LE
MEAN +10.48 +4.09 -0.43 -1.83 -0.89 +6.13 +5.85 +9.71 +26.54 -23.80 +3.58
DIFF -29.77 -36.16 -40.69 -42.09 -41.14 -34.13 -34.41 -30.54 -13.71 -64.05 -36.67
STD 12.86 23.98 22.85 19.22 10.21 11.82 16.03 14.53 17.27 18.59 +12.99
STRATUS[25S, 85W]Mean (ISCCP+OAF)
= +52.56 ±8.83 Wm-2
STRATUS ORAS4 MOVEC GECCO GODAS UR025.
4GloSea
5 GLORYS MJM95 CFSR ECDA ENSEMBLE
MEAN +13.44 +41.11 +19.64 +28.53 +16.10 +19.01 +3.85 +18.29 -4.92 +37.71 +19.28
MeanDIFF -39.12 -11.45 -32.92 -24.03 -36.46 -33.55 -48.71 -34.27 -57.48 -14.86 -33.28
STD 9.04 12.03 11.51 12.53 6.79 7.02 10.50 16.45 17.79 11.27 7.32
Sea Surface Temperatures
Surface Heat Fluxes
TAO_w[0, 165E]
Mean (ISCCP+OAF) = +56.68 ±21.62
Wm-2
STRATUS ORAS4 MOVEC GECCO GODAS UR025.
4GloSea
5 GLORYS MJM95 CFSR ECDA ENSEMBLE
MEAN +51.60 +28.91 +44.32 +52.20 +30.44 +42.95 +41.28 +27.99 +100.17 +44.47 +46.43
DIFF -5.08 -27.77 -12.36 -4.48 -26.24 -13.73 -15.40 -28.69 43.49 -12.21 -10.25
STD 7.06 7.34 8.10 12.12 9.70 8.03 7.74 11.19 7.23 7.55 6.06
TAO_e[0, 110W]
Mean (ISCCP+OAF) = +157.8 ± 9.86
Wm-2STRATU
S ORAS4 MOVEC GECCO GODAS UR025.4
GloSea5 GLORYS MJM95 CFSR ECDA Ense
mble
MEAN +171.24 +125.87 +142.71 +99.82 +137.69 +132.59 +120.19 +108.99 +130.01 +155.24 +132.43
DIFF 13.44 -31.94 -15.09 -57.99 -20.11 -25.21 -37.61 -48.81 -27.79 -2.57 -25.37
STD 15.49 22.71 28.86 18.48 8.10 3.96 7.36 6.72 22.47 6.62 5.37
Mean (2004 -09) differences at buoy sites
ISCCP + OAFlux versus
Ocean Reanalyses
Ocean Reana Based minus
ISCCP+OAFlux
For CLIMODE, the overall biases (less cooling) result primarily from the winter months. Here, fluxes are sensitive to the model resolution.
In the central tropical Pacific (WHOTS) and tropical Atlantic (NTAS), fluxes show less warming during spring and summer.
In the south east Pac (STRATUS), fluxes show less warming in the summer months and more cooling in the winter.
For TAO locations, fluxes provide less warming all year round.
KEO, for the Kuroshio region, and TAO_w have the smallest differences.
Comparing with other flux products
Mean DifferencesProduct - (ISCCP + OAFlux)
Ocean Reana Based minus
ISCCP+OAFlux
Most ocean reanalysis show a positive imbalance in global surface heating (ensemble mean of ~ 4 Wm-2 over 1993-2009). This can be as large as 14 Wm-2 in coupled reanalyses. Generally, the imbalance is reduced as more observations become available after 2004.
Ocean reanalysis-based fluxes are biased low compared to ISCCP+OAFlux data at all buoy locations. Variability is generally well reproduced.
The result that the reanalysis SSTs compare reasonably well with HadISST data while the reanalysis-based fluxes are systematically too low compared to ISCCP+OAFlux data suggests that the models stratify the upper ocean too strongly. This may be a result of inadequate vertical mixing, weak advection, ...
Direct flux measurements are needed for further validation.
Summary