Parameters

HOAPS Parameters

Wind speed at 10m height [m/s]
Acronym: WIND
Reference: ››Andersson et al. (2010)
Comment: This new windspeed algorithm uses a neural network to derive the windspeed at 10m height above the sea surface from SSM/I measurements. It consists of 3 layers: an input layer with 5 neurons (19V, 19H, 22V, 37V, 37H), a hidden layer with 3 neurons and an output layer with one neuron (windspeed). The network was trained with a composite dataset of buoy measurements and radiative transfer simulations.
Near surface specific humidity [g/kg]
Acronym: HAIR
Reference: ››Bentamy et al. (2003)
Precipitation [mm/d]
Acronym: RAIN
Reference: ››Andersson et al. (2010)
Comment: From 04/1988 to 12/1991 the SSM/I on DMSP-F08 was defective, thus synthesized 85 GHz brightness temperatures are used to derive this paramter, resulting in limited accuracy for some values.
Vertically integrated water vapour [kg/m**2]
Acronym: WVPA
Reference: ››Schlüssel and Emery (1990)
Vertically integrated total (ice+liquid) water [kg/m**2]
Acronym: TWPA
Reference: ››Bauer and Schlüssel (1993)
Comment: From 04/1988 to 12/1991 the SSM/I on DMSP-F08 was defective, thus synthesized 85 GHz brightness temperatures are used to derive this paramter, resulting in limited accuracy for some values.
Sea surface temperature [deg C]
Acronym: ASST
Reference: ››Casey (2004)
Comment: At first daily maps of SST are created using data from the NODC/RSMAS AVHRR Oceans Pathfinder SST product. Afterwards the SST is sampled like all other SSM/I atmospheric parameters. This results in SST fields as would be seen by the SSM/I and therefore leading to an internal consistent dataset. This methodology may lead to differences compared to monthly means from the Pathfinder data within data sparse areas.
Sea surface saturation specific humidity [g/kg]
Acronym: HSEA
Reference: Magnus formula applied to the SST
Comment: Salinity correction is applied by scaling the value from pure water with a factor of 0.98.
Surface net longwave radiation [W/m**2]
Acronym: FNET
Reference: ››Schlüssel et al. (1995)
Comment: From 04/1988 to 12/1991 the SSM/I on DMSP-F08 was defective, thus synthesized 85 GHz brightness temperatures are used to derive this paramter, resulting in limited accuracy for some values.
Difference in humidity [g/kg]
Acronym: DHUM
Reference: sea surface saturation specific humidity - near surface specific humidity
Latent heat transfer coefficient (Dalton number) [-]
Acronym: TRCE
Reference: parameterisation: ››Fairall (1996/2003)
Latent heat flux at sea surface [W/m**2]
Acronym: LATE
Reference: bulk formula, parameterisation scheme: ››Fairall (1996/2003)
Sensible heat flux at sea surface [W/m**2]
Acronym: HEAT
Reference: bulk formula, parameterisation scheme: ››Fairall (1996/2003)
Comment: The air temperature is derived using the mean of two simple bulk approaches: From the near surface specific humidity assuming a constant relative humidity of 80% at any time and from the SST assuming a constant temperature difference of 1K. Therefore the quality of this parameter may be of limited accuracy under certain conditions.
Evaporation [mm/d]
Acronym: EVAP
Reference: bulk formula, parameterisation scheme: ››Fairall (1996/2003)
Freshwater flux [mm/d]
Acronym: BUDG
Reference: evaporation-precipitation
Comment: The freshwater flux of each grid box is computed as the difference between the averaged evaporation and the averaged precipitation, hence statistical variables (numo, numd, stdv) are not available.

References

A. Andersson, K. Fennig, C. Klepp, S. Bakan, H. Graßl, and J. Schulz, 2010:
The Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data - HOAPS-3, Earth Syst. Sci. Data, 2, 215-234, doi:10.5194/essd-2-215-2010.

Bauer, P, 1992:
Wasserdampf, Gesamtwasser und Niederschlagsrate aus Daten passiver Mikrowellenradiometer über dem Ozean., Forschungsbericht, ISSN 0939-2963, DLR, Köln, 122 pp.

Bauer, P. and P. Schlüssel, 1993:
Rainfall, Total Water, Ice Water, and Water Vapor Over Sea From Polarized Microwave Simulations and Special Sensor Microwave/Imager Data., J. Geophys. Res., 98, 20737-20759, doi:10.1029/93JD01577 .

Bentamy A., K. B. Katsaros, A. M. Mestas-Nuñez, W. M. Drennan, E. B. Forde, H. Roquet, 2003:
Satellite Estimates of Wind Speed and Latent Heat Flux over the Global Oceans., J. Climate, 16, 637-656, doi:10.1175/1520-0442(2003)016<0637:SEOWSA>2.0.CO;2 .

Fairall, C. W., E. F. Bradley, D. P. Rogers, J. B. Edson, G. S. Young, 1996:
Bulk parameterization of air-sea fluxes for Tropical Ocean-Global Atmosphere Coupled-Ocean Atmosphere Response Experiment., J. Geophys. Res., 101, 3747-3764, doi:10.1029/95JC03205 .

Fairall, C. W., E. F. Bradley, J. E. Hare, A. A. Grachev, J. B. Edson, 2003:
Bulk Parameterization of Air-Sea Fluxes: Updates and Verification for the COARE Algorithm, J. Climate, 16, 571-591, doi:10.1175/1520-0442(2003)016<0571:BPOASF>2.0.CO;2.

Casey, K. S., 2004:
Global AVHRR 4 km SST for 1985-2001, Pathfinder v5.0, NODC Accession Numbers 0001763-0001864: Pathfinder AVHRR Pathfinder AVHRR Version 5.0, NODC/RSMAS, NOAA National Oceanographic Data Center, Silver Spring, Maryland.

Kilpatrick, K. A., G. P. Podestá, R. Evans, 2001:
Overview of the NOAA/NASA advanced very high resolution radiometer Pathfinder algorithm for sea surface temperature and associated matchup database., J. Geophys. Res., 106, 9179-9197, doi:10.1029/1999JC000065.

Schlüssel, P., W. J. Emery, 1990:
Atmospheric water vapour over oceans from SSM/I measurements., Int. J. Remote Sensing, 11, 753-766, doi:10.1080/01431169008955055.

Schlüssel, P., L. Schanz, and G. Englisch, 1995:
Retrieval of latent heat fluxes and longwave irradiance at the sea surface from SSM/I and AVHRR measurements., Adv. Space Res., 16, 107-116, doi:10.1016/0273-1177(95)00389-V.

Schlüssel, P., 1996:
Satellite remote sensing of evaporation over sea. Radiation and Water in the Climate System: Remote measurements, edited by Erhard Raschke., NATO ASI Series, Vol. 145, Springer Verlag Heidelberg, 431-461.

Schulz, J., J. Meywerk, S. Ewald, P. Schlüssel, 1997:
Evaluation of Satellite-Derived Latent Heat Fluxes., Journal of Climate, 10, 2782-2795, doi:10.1175/1520-0442(1997)010<2782:EOSDLH>2.0.CO;2.