- 著者
- Hossain Mohammed Syedul Hoque Hitoshi Irie Alessandro Damiani Prajjwal Rawat Manish Naja
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.14, pp.159-164, 2018 (Released:2018-11-09)
- 参考文献数
- 56
- 被引用文献数
- 9
Since January 2017 continuous multi-axis differential optical absorption spectroscopy (MAX-DOAS) observations have been performed for the first time at Pantnagar (29.03°N, 79.47°E), a semi-urban site located in the Indo-Gangetic Plain region in India. Here we report the formaldehyde (HCHO), glyoxal (CHOCHO), and nitrogen dioxide (NO2) concentrations for the lowest layer (0-1 km) of the retrieved vertical profiles. The ratio of CHOCHO to HCHO concentrations (RGF), an important tracer indicative of changes in volatile organic compound emissions was estimated. During spring and autumn enhanced concentrations of HCHO and CHOCHO were observed under the influence of biomass burning. The mean RGF for the whole observation period (January–November) in Pantnagar was estimated to be 0.029 ± 0.006. Comparing with similar MAX-DOAS observations in central Thailand and reported literature values, we found that the RGF tends to be < ∼0.04 under the influence of biomass burning and/or anthropogenic emissions.
- 著者
- Alessandro Damiani Hitoshi Irie Tamio Takamura Rei Kudo Pradeep Khatri Hironobu Iwabuchi Ryosuke Masuda Takashi Nagao
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.15, pp.198-204, 2019 (Released:2019-09-27)
- 参考文献数
- 39
- 被引用文献数
- 4
We used observations recorded at Chiba University in November 2018 to examine the variability in cloud optical depth (COD) under overcast conditions. First, we conducted a careful evaluation of four COD datasets retrieved from three types of surface observations: i) zenith radiance recorded by two sky radiometers; ii) solar radiation data collected by a pyranometer; and iii) spatial distribution of radiance recorded using a sky camera system. Although the COD retrieved from the pyranometer (camera) slightly (moderately) overestimated the COD from zenith radiance, we found a satisfactory correlation among all surface estimates. This result suggests the efficacy of both pyranometer- and camera-based approaches and supports their broader use when dedicated cloud observations are not available. We then assessed satellite-based COD estimates retrieved from the recently launched Advanced Himawari Imager (AHI) aboard Himawari-8 (H-8) and Second-generation Global Imager (SGLI) on the Global Change Observation Mission for Climate (GCOM-C). Overall, we found good agreement between ground and satellite estimates; their correlation and root mean square error were virtually equivalent to values reported for co-located surface-based instruments. Nevertheless, the AHI-based COD was found to be slightly positively biased with respect to surface datasets.