Earthdata Forum

Hi?
We want to convert the OLCI SS aerosol reflectance to MS aerosol reflectance using the equation in aerosol.c as follows.
lnrhoas = log(rhoas[iw]*aeroob(sensorID,iw,cf,wv))
rhoa[iw] = exp(a + b*lnrhoas + c*lnrhoas*lnrhoas);
I have a few questions.
(1)  for the OLCI images, can I set aeroob(sensorID,iw,cf,wv) =1?
(2)  If aeroob(sensorID,iw,cf,wv)=1, I use aerosol_olci_r80f00v01.hdf to test this process. When solz=27.5, senz=7.66769, phi=15, and wavelength=400 nm, the values of acost?bcost and ccost are-0.838569,0.850478, and -0.0152793. Do the values of acost, bcost, and ccost represent a,b and c in the above equation?
(3)  If it is true. When rhoas_400 =0.01, the calculation result of rhoa_400 is 0.006225. The MS aerosol reflectance is lower than SS serosol reflectance. Where am I wrong?
Thank you very much.

> (1)  for the OLCI images, can I set aeroob(sensorID,iw,cf,wv) =1?

You could, or you could implement the correction from aerosol.c using the coefficients in $OCDATAROOT/olci/msl12_sensor_info.dat

> (2)  If aeroob(sensorID,iw,cf,wv)=1, I use aerosol_olci_r80f00v01.hdf to test this process. When solz=27.5, senz=7.66769, phi=15, and wavelength=400 nm, the values of acost?bcost and ccost are-0.838569,0.850478, and -0.0152793. Do the values of acost, bcost, and ccost represent a,b and c in the above equation?

Yes, acost, bcost and ccost are the coeffiicients for the MS->SS quadratic equation

> (3)  If it is true. When rhoas_400 =0.01, the calculation result of rhoa_400 is 0.006225. The MS aerosol reflectance is lower than SS serosol reflectance. Where am I wrong?

Don't know :sad:

Sean

Hi, Sean
     Thank you for your replying.  It really helps.

Best Wishes
Ge