The Polar Ozone and Aerosol Measurement instrument

1996 ◽  
Vol 101 (D9) ◽  
pp. 14479-14487 ◽  
Author(s):  
W. Glaccum ◽  
R. L. Lucke ◽  
R. M. Bevilacqua ◽  
E. P. Shettle ◽  
J. S. Hornstein ◽  
...  
2005 ◽  
Vol 5 (5) ◽  
pp. 1311-1339 ◽  
Author(s):  
P. Russell ◽  
J. Livingston ◽  
B. Schmid ◽  
J. Eilers ◽  
R. Kolyer ◽  
...  

Abstract. The 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) measured solar- beam transmission on the NASA DC-8 during the second SAGE III Ozone Loss and Validation Experiment (SOLVE II). This paper presents AATS-14 results for multiwavelength aerosol optical depth (AOD), including comparisons to results from two satellite sensors and another DC-8 instrument, namely the Stratospheric Aerosol and Gas Experiment III (SAGE III), the Polar Ozone and Aerosol Measurement III (POAM III) and the Direct-beam Irradiance Airborne Spectrometer (DIAS). AATS-14 provides aerosol results at 13 wavelengths λ spanning the range of SAGE III and POAM III aerosol wavelengths. Because most AATS measurements were made at solar zenith angles (SZA) near 90°, retrieved AODs are strongly affected by uncertainties in the relative optical airmass of the aerosols and other constituents along the line of sight (LOS) between instrument and sun. To reduce dependence of the AATS-satellite comparisons on airmass, we perform the comparisons in LOS transmission and LOS optical thickness (OT) as well as in vertical OT (i.e., optical depth, OD). We also use a new airmass algorithm that validates the algorithm we previously used to within 2% for SZA<90°, and in addition provides results for SZA≥90°. For 6 DC-8 flights, 19 January-2 February 2003, AATS and DIAS results for LOS aerosol OT at λ=400nm agree to ≤12% of the AATS value. Mean and root-mean-square (RMS) differences, (DIAS-AATS)/AATS, are -2.3% and 7.7%, respectively. For DC-8 altitudes, AATS-satellite comparisons are possible only for λ>440nm, because of signal depletion for shorter λ on the satellite full-limb LOS. For the 4 AATS-SAGE and 4 AATS-POAM near-coincidences conducted 19-31 January 2003, AATS-satellite AOD differences were ≤0.0041 for all λ>440nm. RMS differences were ≤0.0022 for SAGE-AATS and ≤0.0026 for POAM-AATS. RMS relative differences in AOD ([SAGE-AATS]/AATS) were ≤33% for λ<~755nm, but grew to 59% for 1020nm and 66% at 1545nm. For λ>~755nm, AATS-POAM differences were less than AATS-SAGE differences, and RMS relative differences in AOD ([AATS-POAM]/AATS) were ≤31% for all λ between 440 and 1020nm. Unexplained differences that remain are associated with transmission differences, rather than differences in gas subtraction or conversion from LOS to vertical quantities. The very small stratospheric AOD values that occurred during SOLVE II added to the challenge of the comparisons, but do not explain all the differences.


2009 ◽  
Vol 26 (11) ◽  
pp. 2340-2352 ◽  
Author(s):  
Anu-Maija Sundström ◽  
Timo Nousiainen ◽  
Tuukka Petäjä

Abstract The objective of this work is to investigate whether a commercial ceilometer-type lidar can be used as a quantitative aerosol measurement instrument. To this end, lidar backscattering measurements are compared with exact theoretical calculations of backscattering, which are based on in situ–measured size distributions and account for uncertainties in particle composition and shape. The results show that the differences between simulated and measured backscattering remain nearly constant and within the uncertainties involved. The differences are most plausibly explained by an error in the overlap function of the lidar and/or errors in the calibration of either the lidar or the in situ instruments used to measure the aerosol size distribution. Occasionally, large differences occur that are obviously connected to the unrepresentativeness of the in situ and lidar measurement volumes because of insufficient atmospheric mixing. The results imply that the absolute accuracy of the instrument investigated might be sufficient for quantitative aerosol measurements in some applications. A fix for the overlap function, however, would be desirable.


1999 ◽  
Vol 104 (D20) ◽  
pp. 24341-24357 ◽  
Author(s):  
Michael D. Fromm ◽  
Richard M. Bevilacqua ◽  
John Hornstein ◽  
Eric Shettle ◽  
Karl Hoppel ◽  
...  

2000 ◽  
Vol 105 (D3) ◽  
pp. 3929-3942 ◽  
Author(s):  
C. E. Randall ◽  
R. M. Bevilacqua ◽  
J. D. Lumpe ◽  
K. W. Hoppel ◽  
D. W. Rusch ◽  
...  

1998 ◽  
Vol 103 (D21) ◽  
pp. 28361-28371 ◽  
Author(s):  
C. E. Randall ◽  
D. W. Rusch ◽  
R. M. Bevilacqua ◽  
K. W. Hoppel ◽  
J. D. Lumpe

1994 ◽  
Author(s):  
Richard M. Bevilacqua ◽  
Eric P. Shettle ◽  
John S. Hornstein ◽  
Philip R. Schwartz ◽  
Davidson T. Chen ◽  
...  

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