An inter-comparison of six latent and sensible heat flux products over the Southern Ocean

Figures & data

Table 1 Overview of the six data sets compared in this study: the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40).

	GSSTF-2	HOAPS-3	J-OFURO	OAFlux	NCEP-2	ERA-40
Time extent	7/87–12/00	7/87–12/05	1/88–12/06	1/58–12/08	1/79–present	9/57–8/02
Spatial sampling	1×1	0.5×0.5°	1×1°	1×1	2.5×2.5°	2.5×2.5°
Sea surface temperature	NCEP^a	National Oceanographic Data Centre/Rosenstiel School of Marine and Atmospheric Science Pathfinder V5	NCEP^a and Metop global data	National Oceanic and Atmospheric Administration Optimum, Interpolation and numerical weather prediction models
Specific humidity	SSM/I ^b (Chou et al. 1997)	SSM/I^b (Bentamy et al. 2003)	SSM/I^b (Schlussel et al. 1995)	Satellites and numerical weather prediction models
Wind speed	SSM/I^b (Wentz 1997)	SSM/I^b	SSM/I^b, European Remote-Sensing Satellite 1/2, QuikSCAT, MSR-E^c and Tropical Rainfall Measuring Mission Microwave Imager (Kubota & Tomita 2007)	SSM/I^b, AMSR-E^c, Quick Scatterometer satellite and numerical weather prediction models (Yu et al. 2008)
Air temperature	NCEP ^a	SSM/I^b	NCEP^a	Satellites and numerical weather prediction models
Bulk algorithm	Chou (1993)	Fairall et al. (1996); Fairall et al. (2003)	Fairall et al. (2003)		unknown	Beljaars ( 1994, 1995)

^aNational Centres for Environmental Prediction.

^bSpecial Sensor Microwave/Imager.

^cAdvanced Microwave Scanning Radiometer–Earth Observing System.

Fig. 1  Annual mean latent heat flux over the Southern Ocean for the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40).

Fig. 2  Annual mean sensible heat flux over the Southern Ocean for the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40).

Fig. 3  The meridional distribution of the zonal mean (a) latent heat flux and (b) sensible heat flux from the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40). Also shown in (b) is the meridional distribution of the sea surface temperature (SST) and 2-m air temperature difference from OAFlux.

Fig. 4  Seasonal cycle of values averaged over regions south of 35°S for (a) latent heat flux and (b) sensible heat flux from the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from SatelliteData (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40).

Fig. 5  Standard deviation of annual mean latent heat flux over the Southern Ocean for the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40).

Fig. 6  Standard deviation of annual mean sensible heat flux over the Southern Ocean for the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40).

Fig. 7  Winter season correlation coefficients between the Antarctic Oscillation index and latent heat flux for the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Reanalysis (ERA-40). Thin black lines indicate regions with correlation coefficients above the 95% confidence level.

Fig. 8  Winter season correlation coefficients between the Antarctic Oscillation index and sensible heat flux for the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40). Thin black lines indicate regions with correlation coefficients above the 95% confidence level.

Fig. 9  Winter season correlations of Pacific-South American index and latent heat flux for the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40). Thin black lines indicate regions with correlation coefficients above the 95% confidence level.

Fig. 10  Winter season correlations of Pacific-South American index and sensible heat flux for the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40). Thin black lines indicate regions with correlation coefficients above the 95% confidence level.

Fig. 11  The linear trends of annual mean latent heat flux over the Southern Ocean for the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40). Thin black lines indicate regions with correlation coefficients above the 90% confidence level.

Fig. 12  The linear trends of annual mean sensible heat flux over the Southern Ocean for the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40). Thin black lines indicate regions with correlation coefficients above the 90% confidence level.

Fig. 13  Standard deviation of annual mean wind speed over the Southern Ocean for the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40).

Fig. 14  The standard deviations of the annual mean sea-air specific humidity difference over the Southern Ocean for the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40).

Fig. 15  The linear trends of the annual mean wind speed over the Southern Ocean for the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40).

Fig. 16  The linear trends of annual mean sea-air specific humidity difference over the Southern Ocean for the second version of the Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF-2), the third version of the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data (HOAPS-3), Japanese Ocean Fluxes Data Sets with Use of Remote Sensing Observations (J-OFURO), Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40). Thin black lines indicate regions with correlation coefficients above the 90% confidence level.

Fig. 17  Standard deviation (left column) and trend (right column) of sea-air temperature difference for Objectively Analyzed Air–Sea Fluxes for the Global Oceans (OAFlux), National Centers for Environmental Prediction Reanalysis 2 (NCEP-2) and the European Centre for Medium-Range Weather Forecasts 40 Year Re-analysis (ERA-40). Thin black lines indicate regions with correlation coefficients above the 90% confidence level.

Schlussel P. Schanz L. Englisch G. Retrieval of latent heat flux and longwave irradiance at the sea-surface from SSM/I and AVHRR measurements. Advances in Space Research. 1995; 16: 107–116.

 Web of Science ®Google Scholar

Beljaars A.C.M. The parameterization of surface fluxes in large scale models under free convection. Quarterly Journal of the Royal Meteorological Society. 1994; 121: 255–270.

 Web of Science ®Google Scholar

Beljaars A.C.M. 1995. The impact of some aspects of the boundary layer scheme in the ECMWF model. In: Seminar proceedings on parameterization of sub-grid scale physical processess. Pp. 125–161. ReadingMA: European Centre for Medium-Range Weather Forecasts.

 Google Scholar