HR: 1340h
AN: A33D-0089    [Abstracts]
TI: Validation of ILAS-II Aerosol Extinction Coefficients at 780 nm: Comparison with SAGE II, SAGE III, POAM III, and OPC/LPC measurements
AU: * Saitoh, N
EM: saitoh.naoko@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 onogawa, Tsukuba, 305-8506 Japan
AU: Hayashida, S
EM: sachiko@ics.nara-wu.ac.jp
AF: Faculty of Science, Nara Women_fs University, Kita-uoya Nishi-machi, Nara, 630-8506 Japan
AU: Sugita, T
EM: tsugita@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 onogawa, Tsukuba, 305-8506 Japan
AU: Nakajima, H
EM: hide@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 onogawa, Tsukuba, 305-8506 Japan
AU: Yokota, T
EM: yoko@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 onogawa, Tsukuba, 305-8506 Japan
AU: Hayashi, M
EM: mhayashi@hukuoka-u.ac.jp
AF: Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180 Japan
AU: Shiraishi, K
EM: siraisi@fukuoka-u.ac.jp
AF: Faculty of Science, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180 Japan
AU: Kanzawa, H
EM: kanzawa@ihas.nagoya-u.ac.jp
AF: Graduate School of Environmental Studies, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601 Japan
AU: Sasano, Y
EM: sasano@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 onogawa, Tsukuba, 305-8506 Japan
AB: The Improved Limb Atmospheric Spectrometer (ILAS) II, which is the successor to ILAS, was launched on board the Advanced Earth Observing Satellite (ADEOS) II on December 14 in 2002. ILAS-II observed stratospheric aerosol in visible/near-infrared/infrared spectral regions at both of the high latitudes, intermittently from January to March, and continuously from April through October 2003. This study reveals characteristics of aerosol extinction coefficients at 780 nm by estimating repeatability of measurements and making comparisons with other data. The repeatability of ILAS-II aerosol extinction data below 30 km is 5$\sim$30% in the Northern Hemisphere and 5$\sim$40% in the Southern Hemisphere. Aerosol extinction coefficients of ILAS-II agree to those measured by SAGE II within their errors, while ILAS-II shows smaller values by $\sim$20% from 20 to 26 km in the Northern Hemisphere; statistical comparisons between ILAS-II and SAGE III, and ILAS-II and POAM III support the result above, although the discrepancy is larger in these comparisons. The aerosol extinction profile derived from the size distribution obtained with an Optical Particle Counter and Laser Particle Counter (OPC/LPC) balloon sounding over Syowa Station (69 $^\circ$S, 40 $^\circ$E) was compared to ILAS-II and SAGE II extinction profiles which were obtained with 599 km and 414 km distances, respectively. A good agreement was shown among those three profiles except for small discrepancies attributable to fine structures in the OPC/LPC data, while ILAS-II aerosol extinction was smaller than the others from 17 km to 25 km. One of the possible major reason for the discrepancy between ILAS-II and other measurements was considered to be uncertainties in tangent height registration. ILAS-II observed Polar Stratospheric Clouds (PSCs) first in the Southern Hemisphere around May 20 in 2003, and then continuously obtained PSC data through early October. When ILAS-II and POAM III made measurements in close horizontal proximity to each other (within $\sim$50 km), small-scale vertically-layered structures in the PSC extinction coefficient profiles resembles to each other in some occasions, which suggests that both the instruments provide data with enough quality to estimate vertical and horizontal extent of PSC clouds.
DE: 1610 Atmosphere (0315, 0325)
DE: 1640 Remote sensing
DE: 0305 Aerosols and particles (0345, 4801)
DE: 0340 Middle atmosphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting