- 著者
- Hironobu IWABUCHI Nurfiena Sagita PUTRI Masanori SAITO Yuka TOKORO Miho SEKIGUCHI Ping YANG Bryan A. BAUM
- 出版者
- Meteorological Society of Japan
- 雑誌
- 気象集誌. 第2輯 (ISSN:00261165)
- 巻号頁・発行日
- vol.96B, pp.27-42, 2018 (Released:2018-03-16)
- 参考文献数
- 35
- 被引用文献数
- 44
An algorithm for retrieving the macroscopic, physical, and optical properties of clouds from thermal infrared measurements is applied to the Himawari-8 multiband observations. A sensitivity study demonstrates that the addition of the single CO2 band of Himawari-8 is effective for the estimation of cloud top height. For validation, retrieved cloud properties are compared systematically with collocated active remote sensing counterparts with small time lags. While retrievals agree reasonably for single-layer clouds, multilayer cloud systems with optically thin upper clouds overlying lower clouds are the major source of error in the present algorithm. Validation of cloud products is critical for identifying the characteristics, advantages, and limitation of each product and should be continued in the future. As an application example, data are analyzed for eight days in the vicinity of the New Guinea to study the diurnal cycle of the cloud system. The present cloud property analysis investigates cloud evolution through separation of different cloud types and reveals typical features of diurnal cycles related to the topography. Over land, middle clouds increase from 0900 to 1200 local solar time (LST), deep convective clouds develop rapidly during 1200-1700 LST with a subsequent increase in cirrus and cirrostratus cloud amounts. Over the ocean near coastlines, a broad peak of convective cloud fraction is seen in the early morning. The present study demonstrates the utility of frequent observations by Himawari-8 for life cycle study of cloud systems, owing to the ability to capture their continuous temporal variations.
- 著者
- Ken Hirata Miho Sekiguchi Yousuke Sato Masaru Inatsu
- 出版者
- 公益社団法人 日本気象学会
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.19, pp.50-56, 2023 (Released:2023-03-23)
- 参考文献数
- 22
This study investigated biases of diffuse radiation in a look-up table approach, which pre-computed the sequential ray tracing to avoid heavy computation in full three-dimensional radiative transfer calculation. We introduced corrections that enhanced directionality of radiative propagation in the solar angle and horizontal direction. By comparing irradiance calculations with and without the corrections for cloudy field in an idealized atmospheric simulation, it was found that the corrections helped mitigate vertically localized false signals by diffuse irradiance. The results suggested that the two types of directionalities are important to accurately represent the three-dimensional transfer of diffuse radiation in an inhomogeneous atmosphere.
- 著者
- Ken Hirata Miho Sekiguchi Yousuke Sato Masaru Inatsu
- 出版者
- 公益社団法人 日本気象学会
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- pp.2023-007, (Released:2023-01-30)
This study investigated biases of diffuse radiation in a look-up table approach, which pre-computed the sequential ray tracing to avoid heavy computation in full three-dimensional radiative transfer calculation. We introduced corrections that enhanced directionality of radiative propagation in the solar angle and horizontal direction. By comparing irradiance calculations with and without the corrections for cloudy field in an idealized atmospheric simulation, it was found that the corrections helped mitigate vertically localized false signals by diffuse irradiance. The results suggested that the two types of directionalities are important to accurately represent the three-dimensional transfer of diffuse radiation in an inhomogeneous atmosphere.
- 著者
- Yoshifumi Ota Miho Sekiguchi Yousuke Sato
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.17, pp.228-233, 2021 (Released:2021-12-16)
- 参考文献数
- 19
A three-dimensional (3D) atmospheric radiative transfer (RT) model based on the Monte Carlo method was developed to evaluate the cloud-resolving radiation budget. The simulation data of stratocumulus (open and closed cell types) stimulated by a large eddy simulation model were used to obtain a detailed cloud field dataset at different spatial resolutions between 100 m and 1 km orders. By applying the 3D RT model offline to a multiscale cloud field dataset, the 3D distribution and magnitude of the solar radiative heating rate were estimated for each spatial resolution. The results showed that the magnitude of the local solar radiative heating effect significantly changes in the range of spatial resolution between 100 m and 1 km. The solar radiative heating rate can reach 6 K/hr locally in the case of the spatial resolution at 100-m order, whereas it is approximately 1 K/hr at most in the case of the spatial resolution at 1-km order. However, the domain-averaged values of the solar radiative heating rates were almost invariant at different spatial resolutions. The results indicate that a radiation scheme for the cloud-resolving model needs to be constructed while considering spatial resolutions, along with cloud parameterization.
- 著者
- Yoshifumi Ota Miho Sekiguchi Yousuke Sato
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- pp.2021-040, (Released:2021-10-26)
A three-dimensional (3D) atmospheric radiative transfer (RT) model based on the Monte Carlo method was developed to evaluate the cloud-resolving radiation budget. The simulation data of stratocumulus (open and closed cell types) stimulated by a large eddy simulation model were used to obtain a detailed cloud field dataset at different spatial resolutions between 100 m and 1 km orders. By applying the 3D RT model offline to a multiscale cloud field dataset, the 3D distribution and magnitude of the solar radiative heating rate were estimated for each spatial resolution. The results showed that the magnitude of the local solar radiative heating effect significantly changes in the range of spatial resolution between 100 m and 1 km. The solar radiative heating rate can reach 6 K/hr locally in the case of the spatial resolution at 100-m order, whereas it is approximately 1 K/hr at most in the case of the spatial resolution at 1-km order. However, the domain-averaged values of the solar radiative heating rates were almost invariant at different spatial resolutions. The results indicate that a radiation scheme for the cloud-resolving model needs to be constructed while considering spatial resolutions, along with cloud parameterization.
- 著者
- Miho SEKIGUCHI Hironobu IWABUCHI Takashi M. NAGAO Teruyuki NAKAJIMA
- 出版者
- Meteorological Society of Japan
- 雑誌
- Journal of the Meteorological Society of Japan. Ser. II (ISSN:00261165)
- 巻号頁・発行日
- pp.2018-007, (Released:2017-12-08)
- 被引用文献数
- 2
We developed an atmospheric gas absorption table for the Advanced Himawari Imager (AHI) based on the correlated k-distribution (CKD) method with the optimization method, which was used to determine quadrature weights and abscissas. We incorporated the table and band information of the AHI into a multi-purpose atmospheric radiative transfer package, Rstar. We updated the package so that users could easily specify the satellite and band number. Use of this update made it possible for the optimized CKD method to carry out calculations rapidly and accurately. Rstar is easy for beginners to use and facilitates comparison of results. Cloud retrieval tests using different numbers of quadrature points showed that cloud retrievals could be significantly affected by the accuracy of the CKD model.