- 著者
- Makoto Kondo Yousuke Sato Masaru Inatsu Yuta Katsuyama
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- pp.2021-012, (Released:2021-03-12)
- 被引用文献数
- 4
The performances of bulk microphysical schemes were evaluated through comparisons with observations, including a new volume scanning video disdrometer targeting one of a typical snowfall event in Hokkaido, Japan. For the evaluation, downscaling experiments using three bulk microphysical schemes were conducted: a two-moment bulk scheme, a one-moment bulk scheme, and an improved version of the one-moment bulk scheme coupled with an identical dynamical core. The two-moment scheme successfully simulated the measured relationship between particle size and terminal velocity distribution (PSVD). On the other hand, the one-moment scheme overestimated the graupel frequency, its terminal velocity, and underestimated the particle diameter. The improved version of the one-moment bulk scheme reduced the overestimation of the terminal velocity of hydrometeors, but still overestimated the graupel frequency. We improved the overestimation of terminal velocity and the frequency of graupel in the one-moment scheme by modifying the assumption of the velocity–diameter relationship and the intercept parameter of the size distribution of graupel based on the results of the new disdrometeor. The observation of the new disdrometer would give us hints to improve the microphysics schemes in snowfall cases.
- 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
- Yu Matsumoto Minrui Wang Yousuke Sato Takashi Y. Nakajima
- 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.2023-009, (Released:2023-03-14)
This paper shows the CFODD of the regional dependence of cloud growth processes in low-level clouds obtained by the combined use of the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite and the Cloud Profiling Radar (CPR) on the CloudSat satellite. This enabled the evaluation of the cloud growth process based on the cloud optical thickness (τ) and the effective radius of cloud particle (Re), similar to previous studies that performed statical analysis on low-level clouds over the globe. Our targets were regions in East Asian, Californian, and Peruvian. In all analysis areas, our results showed that the internal structure of clouds changed as Re increased, indicating cloud growth. In the East Asian region, the maximum τ remained relatively constant even when cloud droplet size grew. In contrast, in the regions of Californian and Peruvian, the maximum τ increased with Re during the condensation growth process and then decreased as drizzle particles transformed into rain. It was also found that Re was smaller in the East Asian region unlike in Californian and Peruvian. This indicates that there are more aerosols in the East Asian region, which is consistent with its geographical characteristics.
- 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
- Makoto Kondo Yousuke Sato Masaru Inatsu Yuta Katsuyama
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.17, pp.74-80, 2021 (Released:2021-04-24)
- 参考文献数
- 51
- 被引用文献数
- 4
The performances of bulk microphysical schemes were evaluated through comparisons with observations, including a new volume scanning video disdrometer targeting one of a typical snowfall event in Hokkaido, Japan. For the evaluation, downscaling experiments using three bulk microphysical schemes were conducted: a two-moment bulk scheme, a one-moment bulk scheme, and an improved version of the one-moment bulk scheme coupled with an identical dynamical core. The two-moment scheme successfully simulated the measured relationship between particle size and terminal velocity distribution (PSVD). On the other hand, the one-moment scheme overestimated the graupel frequency, its terminal velocity, and underestimated the particle diameter. The improved version of the one-moment bulk scheme reduced the overestimation of the terminal velocity of hydrometeors, but still overestimated the graupel frequency. We improved the overestimation of terminal velocity and the frequency of graupel in the one-moment scheme by modifying the assumption of the velocity–diameter relationship and the intercept parameter of the size distribution of graupel based on the results of the new disdrometeor. The observation of the new disdrometer would give us hints to improve the microphysics schemes in snowfall cases.
- 著者
- Yu Matsumoto Minrui Wang Yousuke Sato Takashi Y. Nakajima
- 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.63-69, 2023 (Released:2023-04-15)
- 参考文献数
- 38
This paper shows the CFODD of the regional dependence of cloud growth processes in low-level clouds obtained by the combined use of the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard the Aqua satellite and the Cloud Profiling Radar (CPR) on the CloudSat satellite. This enabled the evaluation of the cloud growth process based on the cloud optical thickness (τ) and the effective radius of cloud particle (Re), similar to previous studies that performed statical analysis on low-level clouds over the globe. Our targets were regions in East Asian, Californian, and Peruvian. In all analysis areas, our results showed that the internal structure of clouds changed as Re increased, indicating cloud growth. In the East Asian region, the maximum τ remained relatively constant even when cloud droplet size grew. In contrast, in the regions of Californian and Peruvian, the maximum τ increased with Re during the condensation growth process and then decreased as drizzle particles transformed into rain. It was also found that Re was smaller in the East Asian region unlike in Californian and Peruvian. This indicates that there are more aerosols in the East Asian region, which is consistent with its geographical characteristics.