scholarly journals Comparison of Polar Ozone and Aerosol Measurement (POAM) II and Stratospheric Aerosol and Gas Experiment (SAGE) II aerosol measurements from 1994 to 1996

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

scholarly journals Aerosol optical depth measurements by airborne sun photometer in SOLVE II: Comparisons to SAGE III, POAM III and airborne spectrometer measurements

2005 ◽  
Vol 5 (5) ◽  
pp. 1311-1339 ◽  
Author(s):  
P. Russell ◽  
J. Livingston ◽  
B. Schmid ◽  
J. Eilers ◽  
R. Kolyer ◽  
...  
Keyword(s):  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Stratospheric Aerosol ◽  
Line Of Sight ◽  
Aerosol Measurement ◽  
Validation Experiment ◽  
Satellite Sensors ◽  
Beam Transmission ◽  
Relative Differences ◽  
Polar Ozone

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.

scholarly journals An evaluation of the SAGE III Version 4 aerosol extinction coefficient and water vapor data products

2009 ◽  
Vol 9 (5) ◽  
pp. 22177-22222
Author(s):  
L. W. Thomason ◽  
J. R. Moore ◽  
M. C. Pitts ◽  
J. M. Zawodny ◽  
E.-W. Chiou
Keyword(s):  
Water Vapor ◽  
Extinction Coefficient ◽  
Stratospheric Aerosol ◽  
Data Sets ◽  
Aerosol Extinction ◽  
Data Products ◽  
Mean Differences ◽  
Aerosol Extinction Coefficient ◽  
Polar Ozone

Abstract. Herein, we provide an assessment of the data quality of Stratospheric Aerosol and Gas Experiment (SAGE III) Version 4 aerosol extinction coefficient and water vapor data products. The evaluation is based on comparisons with data from four instruments: SAGE II, the Polar Ozone and Aerosol Measurement (POAM III), the Halogen Occultation Experiment (HALOE), and the Microwave Limb Sounder (MLS). Since only about half of the SAGE III channels have a direct comparison with measurements by other instruments, we have employed some empirical techniques to evaluate measurements at some wavelengths. We find that the aerosol extinction coefficient measurements at 449, 520, 755, 869, and 1021 nm are reliable with accuracies and precisions on the order of 10% in the primary aerosol range of 15 to 25 km. We also believe this to be true of the aerosol measurements at 1545 nm though we cannot exclude some positive bias below 15 km. We recommend use of the 385 nm measurements above 16 km where the accuracy is on par with other aerosol channels. The 601 nm measurement is much noisier (~20%) than other channels and we suggest caution in the use of these data. We believe that the 676 nm data are clearly defective particularly above 20 km (accuracy as poor as 50%) and the precision is also low (~30%). We suggest excluding this channel under most circumstances. The SAGE III Version 4 water vapor data product appears to be high quality and is recommended for science applications in the stratosphere below 45 km. In this altitude range, the mean differences with all four corroborative data sets are no bigger than 15% and often less than 10% with exceptional agreement with POAM III and MLS. Above 45 km, it seems likely that SAGE III water vapor values are increasingly too large and should be used cautiously or avoided. We believe that SAGE III meets its preflight goal of 15% accuracy and 10% precision between 15 and 45 km. We do not currently recommend limiting the SAGE III water vapor data utility in the stratosphere by aerosol loading.

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 ◽  
...  
Keyword(s):  
Measurement Instrument ◽  
Aerosol Measurement ◽  
Polar Ozone

scholarly journals An analysis of Polar Ozone and Aerosol Measurement (POAM) II Arctic polar stratospheric cloud observations, 1993-1996

1999 ◽  
Vol 104 (D20) ◽  
pp. 24341-24357 ◽  
Author(s):  
Michael D. Fromm ◽  
Richard M. Bevilacqua ◽  
John Hornstein ◽  
Eric Shettle ◽  
Karl Hoppel ◽  
...  
Keyword(s):  
Aerosol Measurement ◽  
Polar Stratospheric Cloud ◽  
Polar Ozone
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