Collaborative Research 

Atlantic Air-Sea fluxes from satellites, their variability and analysis of ocean models
Department of Atmospheric and Oceanic Science
University of Maryland, College Park

Examples of Radiative Flux Products


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Surface downward shortwave radiation derived from ISCCP DX

SW↓ Radiative fluxes were produced over the Atlantic Ocean for about ten years based on ISCCP DX at 0.5░ spatial resolution at daily time scale (Figure 1). They are produced by UMD/SRB model Ver3.3.3 from Jan 1, 2003 to Dec 31, 2005.

Figure 1. Annual mean surface downward shortwave flux from UMD/SW_DX for 2004



A preliminary evaluation was conducted against buoys from the Prediction and Research Moored Array in the Atlantic (PIRATA) array (Servain et al., 1998) (Figure 2).

Figure 2.  Evaluation of UMD/SW_DX product against ground observations using about 30 BSRN stations distributed globally. Period: monthly means for 2003-2005



Surface downward shortwave radiation derived from MODIS

The MODIS data are at 10 spatial resolution at daily time scale. The Moderate Resolution Imaging Spectro-radiometer (MODIS) instrument onboard the Terra and Aqua satellites is a sensor with 36 spectral bands with an onboard calibration of both solar and infrared bands. The wide spectral range (0.41-14.24 Ám), frequent global coverage (one to two days revisit), and high spatial resolution permit global monitoring of atmospheric profiles, column water vapor amount, aerosol properties, and clouds, at higher accuracy and consistency (King et al., 1993) allowing to derive radiative fluxes at global scale from the same instrument. An inference scheme (Wang and Pinker, 2009) to estimate surface, TOA, and atmospheric shortwave radiative fluxes has been developed and implemented with MODIS products as available at 10 spatial resolution twice a day (Terra and Aqua). Results have been evaluated over the Atlantic ocean (Figure 3) (Pinker et al., 2009).

Figure 3. Daily mean surface SW flux estimated by UMD/SW_MODIS against PIRATA buoys from January 1, 2003  to December 31, 2005 (cases eliminated: 1.1%).



Evaluation of various SW radiative fluxes


 
Figure 4. Evaluation of daily surface downward SW radiative fluxes from satellite estimates against PIRATA buoys for 2004: a) WHOI; b): UMD/SW_DX; c): UMD/SW_MODIS); d): UMD/SW_DX bias corrected  (black line is the best fit line).


Surface Downward Longwave Radiation derived from ISCCP DX

Figure 5. Left: downward LW; Right: LW net for the period of January 3-9, 2005 from UMD/LW_DX.


To compute upwelling LW, initially, SST from available sources (such as Reynolds et al. (2007)) have been used to be subsequently replaced by a newly developed algorithm for SEVIRI to be implemented at high resolution and represent the diurnal cycle.

Longwave Radiation derived from MODIS

  
Figure 6. Left: downward LW; Right: LW net for the period of January 3-9, 2005 from UMD/LW_MODIS.
 

Evaluation of LW radiative fluxes

Evaluation of the LW fluxes as derived from MODIS, ISCCP_DX/UMD, ISCCP-FD and ERA Interim for the year 2004 is shown in Figure 9. Evaluation against ocean observations was not possible due to lack of data.

  

Figure 7. Evaluation of the LW fluxes as derived from: 1) MODIS, 2) ISCCP_DX/UMD, 3) ISCCP-FD and 4) ERA interim for the year 2004.



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Please send questions or comments to srb@atmos.umd.edu.
 Chuan Li cli-at-atmos.umd.edu
Last Modified on 2014-03-05