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### The equation of SS aerosol reflectance to MS aerosol reflectance

Posted: **Sat Feb 02, 2019 11:49 pm America/New_York**

by **liugers11**

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.

### The equation of SS aerosol reflectance to MS aerosol reflectance

Posted: **Tue Feb 12, 2019 8:43 am America/New_York**

by **OB.DAAC - SeanBailey**

> (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

### The equation of SS aerosol reflectance to MS aerosol reflectance

Posted: **Wed Feb 13, 2019 7:19 am America/New_York**

by **liugers11**

Hi, Sean

Thank you for your replying. It really helps.

Best Wishes

Ge