Question: How much error will be induced if a climatology-based correction is used when real-time data is not available?

Note: the inherent atmospheric correction error is about 0.001 in reflectance at 443 nm (Gordon, 1997), corresponding to about 5% error in Lw(443) for clear, blue water.

This sets a limit for our goal.

Effect of Gaseous Absorption

January mean

Ozone Climatology (1998-2007)

January stdev

July mean

Ozone Climatology (1998-2007)

July stdev

Assuming 0=45o, =45o, if a monthly climatology ozone is used instead of real-time ozone, there is a 95% chance that the error in the “corrected” Lt(551 nm) is smaller than the value below. A 1% error in Lt(551 nm) is corresponding to about 10% error in Lw(551 nm) [Lt,typical 3 mW cm-2 m-1 sr-1, while Lw, typical0.3]. Errors for the blue wavelengths are much smaller. Note that the error has both signs.

Error in Lt (551 nm) and Lw (551 nm)

Error in Lt (551 nm) and Lw (551 nm)

How about NO2?

Effect of Gaseous Absorption

NO2 Climatology (2004-2008) Total NO2 climatology used in SeaDAS. Units: 1015 cm-2

Jan – Dec Mean

NO2 Climatology (2004-2008)

Jan – Dec Stdev

Units: 1015 cm-2

Question: How much error will be induced if a climatology-based NO2 correction is used when real-time NO2 data is not available?

Effect of Gaseous Absorption