Rei Kudo
Japan Meteorological Agency
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Featured researches published by Rei Kudo.
Remote Sensing | 2018
Yukari Hara; Tomoaki Nishizawa; Nobuo Sugimoto; Kazuo Osada; Keiya Yumimoto; Itsushi Uno; Rei Kudo; Hiroshi Ishimoto
We verified an algorithm using multi-wavelength Mie-Raman lidar (MMRL) observations to retrieve four aerosol components (black carbon (BC), sea salt (SS), air pollution (AP), and mineral dust (DS)) with in-situ aerosol measurements, and determined the seasonal variation of aerosol components in Fukuoka, in the western region of Japan. PM2.5, PM10, and mass concentrations of BC and SS components are derived from in-situ measurements. MMRL provides the aerosol extinction coefficient (α), particle linear depolarization ratio (δ), backscatter coefficient (β), and lidar ratio (S) at 355 and 532 nm, and the attenuated backscatter coefficient (βatt) at 1064 nm. We retrieved vertical distributions of extinction coefficients at 532 nm for four aerosol components (BC, SS, AP, and DS) using 1α532 + 1β532 + 1βatt,1064 + 1δ532 data of MMRL. The retrieved extinction coefficients of the four aerosol components at 532 nm were converted to mass concentrations using the theoretical computed conversion factor assuming the prescribed size distribution, particle shape, and refractive index for each aerosol component. MMRL and in-situ measurements confirmed that seasonal variation of aerosol optical properties was affected by internal/external mixing of various aerosol components, in addition to hygroscopic growth of water-soluble aerosols. MMRL overestimates BC mass concentration compared to in-situ observation using the pure BC model. This overestimation was reduced drastically by introducing the internal mixture model of BC and water-soluble substances (Core-Gray Shell (CGS) model). This result suggests that considering the internal mixture of BC and water-soluble substances is essential for evaluating BC mass concentration in this area. Systematic overestimation of BC mass concentration was found during summer, even when we applied the CGS model. The observational facts based on in-situ and MMRL measurements suggested that misclassification of AP as CGS particles was due to underestimation of relative humidity (RH) by the numerical model in lidar analysis, as well as mismatching of the optical models of AP and CGS assumed in the retrieval with aerosol properties in the actual atmosphere. The time variation of lidar-derived SS was generally consistent with in-situ measurement; however, we found some overestimation of SS during dust events. The cause of this SS overestimation is mainly due to misclassifying internally mixing DS as SS, implying that to consider internal mixing between DS and water-soluble substances leads to better estimation. The time-variations of PM2.5 and PM10 generally showed good agreement with in-situ measurement although lidar-derived PM2.5 and PM10 overestimated in dust events.
RADIATION PROCESSES IN THE ATMOSPHERE AND OCEAN (IRS2016): Proceedings of the International Radiation Symposium (IRC/IAMAS) | 2017
Rei Kudo; Tomoaki Nishizawa; Toshinori Aoyagi; Yasushi Fujiyoshi; Yuji Higuchi; Masahiko Hayashi; Atsushi Shimizu; Kazuma Aoki
The SKYLIDAR algorithm was developed to estimate the vertical profiles of aerosol optical properties from combining the measurements of the sky radiometer in SKYNET and the lidar in AD-Net. The derived parameters are the vertical profiles of extinction coefficient, single-scattering albedo, asymmetry factor, real and imaginary parts of the refractive index, and size distribution. The solar heating rate was estimated from these parameters. The algorithm was applied to the transported dust case, and the detailed vertical structures of the optical properties and the solar heating rate and their relationship were shown. For the validation of the SKYLIDAR algorithm, the vertical profile of the aerosol size distribution from the surface to the altitude of about 3 km was directly observed by the optical particle counter on board the glider. The comparison of the SKYLIDAR derived extinction coefficient with that estimated from OPC measurements showed that the SKYLIDAR result had a bias error due to the optimizati...
Atmospheric Environment | 2010
Tomoki Nakayama; Rie Hagino; Yutaka Matsumi; Yosuke Sakamoto; Masahiro Kawasaki; Akihiro Yamazaki; Akihiro Uchiyama; Rei Kudo; N. Moteki; Yutaka Kondo; Kenichi Tonokura
Journal of The Meteorological Society of Japan | 2010
Eriko Kobayashi; Akihiro Uchiyama; Akihiro Yamazaki; Rei Kudo
Journal of Geophysical Research | 2012
Rei Kudo; Akihiro Uchiyama; Osamu Ijima; Nozomu Ohkawara; Sachio Ohta
Journal of Geophysical Research | 2011
Rei Kudo; Akihiro Uchiyama; Akihiro Yamazaki; Tomonori Sakami; Osamu Ijima
Journal of Geophysical Research | 2010
Rei Kudo; Akihiro Uchiyama; Akihiro Yamazaki; Eriko Kobayashi
Journal of Quantitative Spectroscopy & Radiative Transfer | 2017
Tomoaki Nishizawa; Nobuo Sugimoto; Ichiro Matsui; Atsushi Shimizu; Yukari Hara; Uno Itsushi; Kazuaki Yasunaga; Rei Kudo; Sang-Woo Kim
Geophysical Research Letters | 2010
Rei Kudo; Akihiro Uchiyama; Akihiro Yamazaki; Tomonori Sakami; Eriko Kobayashi
Journal of Geophysical Research | 2008
Rei Kudo; Akihiro Uchiyama; Akihiro Yamazaki; Eriko Kobayashi; Tomoaki Nishizawa