aats-14 measurements during coast

AATS-14 measurements during COASTJ. LivingstonR. Johnson

M. KacenelenbogenC. ChangP. Russell

Data acquisition and analysis 14 data channels centered at wavelengths (l) 354 – 2139 nm Data sampled at 10 Hz and averaged over 2 sec during flights

2-sec voltage means and stds written to raw data file

September MLO sunrise calibration results used to calculate aerosol optical depth (AOD) at 13 l (using OMI columnar ozone data) and columnar water vapor (CWV) at 941 nm

AODs at 12 l, CWVs, estimated uncertainties archived with a/c latitude, longitude, GPS and P altitudes, static P, and spectral AOD fitting parameters in modified Gaines-Hipskind formatted files for 10/26, 10/27, and 10/28 flights

System performance issues

Tracking changes caused by reflection off wing during aircraft turns• Reflection of the sun off the higher wing occasionally led to a small

deviation in AATS-14 tracking that yielded slightly elevated or depressed signals in some science channels.

• These reflections occurred when the relative azimuth of the AATS-to-sun vector coincided with the azimuth of the vector defined by the Twin Otter fuselage/higher wing intersection and the higher wing tip.

• All affected data have NOT been removed from the archived files.

Computer clock timing uncertainties• Twin Otter computer, AATS can computer, AATS laptop

Anomalously high AODs in 1558-nm channel• These were observed during the MLO calibration and during COAST flights.

The source of this problem may have been a light leak in the 1558-nm filter. AODs in this channel have been excluded from the archived files.

System performance issues

Tracking changes caused by reflection off wing during aircraft turns• Reflection of the sun off the higher wing occasionally led to a small

deviation in AATS-14 tracking that yielded slightly elevated or depressed signals in some science channels.

• These reflections occurred when the relative azimuth of the AATS-to-sun vector coincided with the azimuth of the vector defined by the Twin Otter fuselage/higher wing intersection and the higher wing tip.

• All affected data have NOT been removed from the archived files.

Computer clock timing uncertainties• Twin Otter computer, AATS can computer, AATS laptop

Anomalously high AODs in 1558-nm channel• These were observed during the MLO calibration and during COAST flights.

The source of this problem may have been a light leak in the 1558-nm filter. AODs in this channel have been excluded from the archived files.

Data Examples

28 Oct

late

early

Bottom altitude

Top altitude

AOD latitudinal traces and spectra

Profiles

Bottom altitude

Top altitudelate

early

Comparison of AOD spectra on 10/26 and 10/28

26 Oct

Columnar water vapor increased with time

28 Oct

Columnar water vapor decreased with time