- 著者
- Sachie Kanada Akira Nishii
- 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.70-77, 2023 (Released:2023-04-19)
- 参考文献数
- 18
- 被引用文献数
- 2
Ground-based radar observations of the concentric eyewalls (CEs) of supertyphoon Hinnamnor (2022) showed that CEs evolved as follows: (Stage 0) development of a distinct stationary band complex (SBC) downshear in moderate south-southeastward vertical wind shear (VWS), (Stage 1) maturity of the secondary eyewall (SE), (Stage 2) contraction of the SE, and (Stage 3) decay of the CE structures. From Stage 0 to Stage 1, the SBCs transitioned into an axisymmetric SE, and moats appeared a few hours after SE formation. Outer rainbands formed successively in the down-to-left shear quadrants and developed wide stratiform regions with a vast anvil cloud extending outward as they moved upshear. When the anvil cloud covered the right-shear quadrants, the stratiform regions started contracting. Evolutions of the doppler velocity fields were detected under the anvil and stratiform regions of each rainband. An intense convection developed at the inner edge of the contracting SE as regions with relatively high doppler-velocity merged. When the core region was surrounded by multiple well-developed rainbands, the inner eyewall weakened rapidly. The radar observations revealed the importance of moderate-to-weak VWS and development of a SE as a rainband complex during evolution of CEs.
- 著者
- Sachie Kanada Hidenori Aiki Kazuhisa Tsuboki
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.17A, no.Special_Edition, pp.38-44, 2021 (Released:2021-07-27)
- 参考文献数
- 32
- 被引用文献数
- 3
Torrential rain associated with Typhoon Hagibis (2019) caused extensive destruction across Japan. To project future changes of the record-breaking rainfall, numerical experiments using a regional 1-km-mesh three-dimensional atmosphere–ocean coupled model were conducted in current (CNTL) and pseudo-global warming (PGW) climates. The water vapor mixing ratio in the lower troposphere increased by 23% in response to a 3.34 K increase in sea surface temperature (SST) in the PGW climate. The abundant moisture supply by the westward winds of the typhoon caused strong precipitation from its rainbands for a long period, resulting in 90% increase in total precipitation in eastern Japan before landfall. However, the strong PGW typhoon caused high SST-cooling. Mean precipitation in eastern Japan during the typhoon passage increased by 22% when the SST-cooling east of Kanto was strengthened from 0.11 K to 0.72 K from the CNTL to PGW simulations; the increase was above 29% when the SST-cooling was lowered. Since Typhoon Hagibis accelerated as it traveled northward, the magnitude of the SST-cooling and weakening of the typhoon were suppressed. Consequently, strong precipitation in the inner-core of the strong PGW typhoon caused 30% increase in precipitation in the areas on the Pacific side of northern Japan.
- 著者
- Sachie Kanada Hidenori Aiki Kazuhisa Tsuboki
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- pp.17A-007, (Released:2021-06-22)
- 被引用文献数
- 3
Torrential rain associated with Typhoon Hagibis (2019) caused extensive destruction across Japan. To project future changes of the record-breaking rainfall, numerical experiments using a regional 1-km-mesh three-dimensional atmosphere–ocean coupled model were conducted in current (CNTL) and pseudo-global warming (PGW) climates. The water vapor mixing ratio in the lower troposphere increased by 23% in response to a 3.34 K increase in sea surface temperature (SST) in the PGW climate. The abundant moisture supply by the westward winds of the typhoon caused strong precipitation from its rainbands for a long period, resulting in 90% increase in total precipitation in eastern Japan before landfall. However, the strong PGW typhoon caused high SST-cooling. Mean precipitation in eastern Japan during the typhoon passage increased by 22% when the SST-cooling east of Kanto was strengthened from 0.11 K to 0.72 K from the CNTL to PGW simulations; the increase was above 29% when the SST-cooling was lowered. Since Typhoon Hagibis accelerated as it traveled northward, the magnitude of the SST-cooling and weakening of the typhoon were suppressed. Consequently, strong precipitation in the inner-core of the strong PGW typhoon caused 30% increase in precipitation in the areas on the Pacific side of northern Japan.
- 著者
- Sachie Kanada Hidenori Aiki Kazuhisa Tsuboki Izuru Takayabu
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- pp.17A-003, (Released:2020-12-16)
- 被引用文献数
- 8
Numerical experiments on Typhoon Trami (2018) using a regional 1-km-mesh three-dimensional atmosphere–ocean coupled model in current and pseudo-global warming (PGW) climates were conducted to investigate future changes of a slow-moving intense typhoon under the warming climate. Over the warmer sea in the PGW climate, the maximum near-surface wind speed rapidly increased around the large eye of the simulated Trami. The stronger winds in the PGW simulation versus the current simulation caused a 1.5-fold larger decrease of sea surface temperature (SST) in the storm core-region. In the PGW climate, near-surface air temperature increased by 3.1°C. A large SST decrease due to ocean upwelling caused downward heat fluxes from the atmosphere to the ocean. The magnitude of the SST decrease depended strongly on initial ocean conditions. Consideration of the SST decrease induced by an intense typhoon, and a slow-moving storm in particular, indicated that such a typhoon would not always become more intense under the warmer climate conditions. An atmosphere–ocean coupled model should facilitate making more reliable projections of typhoon intensities in a warming climate.
- 著者
- Sachie Kanada Kazuhisa Tsuboki Izuru Takayabu
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.16, pp.57-63, 2020 (Released:2020-04-09)
- 参考文献数
- 31
- 被引用文献数
- 9
To understand the impacts of global warming on tropical cyclones (TCs) in midlatitude regions, dynamical downscaling experiments were performed using a 4-km-mesh regional model with a one-dimensional slab ocean model. Around 100 downscaling experiments for midlatitude TCs that traveled over the sea east of Japan were forced by large-ensemble climate change simulations of both current and warming climates. Mean central pressure and radius of maximum wind speed of simulated current-climate TCs increased as the TCs moved northward into a baroclinic environment with decreasing sea surface temperature (SST). In the warming-climate simulations, the mean central pressure of TCs in the analysis regions decreased from 958 hPa to 948 hPa: 12% of the warming-climate TCs were of an unusual central pressure lower than 925 hPa. In the warming climate, atmospheric conditions were strongly stabilized, however, the warming-climate TCs could develope, because the storms developed taller and stronger eyewall updrafts owing to higher SSTs and larger amounts of near-surface water vapor. When mean SST and near-surface water vapor were significantly higher and baroclinicity was significantly smaller, unusual intense TCs with extreme wind speeds and large amounts of precipitation around a small eye, could develop in midlatitude regions, retaining the axisymetric TC structures.
- 著者
- Sachie Kanada Kazuhisa Tsuboki Izuru Takayabu
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- pp.2020-010, (Released:2020-03-03)
- 被引用文献数
- 9
To understand the impacts of global warming on tropical cyclones (TCs) in midlatitude regions, dynamical downscaling experiments were performed using a 4-km-mesh regional model with a one-dimensional slab ocean model. Around 100 downscaling experiments for midlatitude TCs that traveled over the sea east of Japan were forced by large-ensemble climate change simulations of both current and warming climates. Mean central pressure and radius of maximum wind speed of simulated current-climate TCs increased as the TCs moved northward into a baroclinic environment with decreasing sea surface temperature (SST). In the warming-climate simulations, the mean central pressure of TCs in the analysis regions decreased from 958 hPa to 948 hPa: 12% of the warming-climate TCs were of an unusual central pressure lower than 925 hPa. In the warming climate, atmospheric conditions were strongly stabilized, however, the warming-climate TCs could develope, because the storms developed taller and stronger eyewall updrafts owing to higher SSTs and larger amounts of near-surface water vapor. When mean SST and near-surface water vapor were significantly higher and baroclinicity was significantly smaller, unusual intense TCs with extreme wind speeds and large amounts of precipitation around a small eye, could develop in midlatitude regions, retaining the axisymetric TC structures.
- 著者
- Sachie Kanada Hidenori Aiki Kazuhisa Tsuboki Izuru Takayabu
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.15, pp.244-249, 2019 (Released:2019-12-05)
- 参考文献数
- 36
- 被引用文献数
- 8
From 16 to 23 August 2016, typhoons T1607, T1609, and T1611 hit eastern Hokkaido in northern Japan and caused heavy rainfall that resulted in severe disasters. To understand future changes in typhoon-related precipitation (TRP) in midlatitude regions, climate change experiments on these three typhoons were conducted using a high-resolution three-dimensional atmosphere–ocean coupled regional model in current and pseudo-global warming (PGW) climates. All PGW simulations projected decreases in precipitation frequency with an increased frequency of strong TRP and decreased frequency of weak TRP in eastern Hokkaido. In the current climate, snow-dominant precipitation systems start to cause precipitation in eastern Hokkaido about 24 hours before landfall. In the PGW climate, increases in convective available potential energy (CAPE) developed tall and intense updrafts and the snow-dominant precipitation systems turned to have more convective property with less snow mixing ratio (QS). Decreased QS reduced precipitation area, although strong precipitation increased or remained almost the same. Only TRP of T1607 increased the amounts before landfall. In contrast, all typhoons projected to increase TRP amount associated with landfall, because in addition to increased CAPE, the PGW typhoon and thereby its circulations intensified, and a large amount of rain was produced in the core region.
- 著者
- Sachie Kanada Hidenori Aiki Kazuhisa Tsuboki Izuru Takayabu
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.17A, no.Special_Edition, pp.14-20, 2021 (Released:2021-01-28)
- 参考文献数
- 37
- 被引用文献数
- 8
Numerical experiments on Typhoon Trami (2018) using a regional 1-km-mesh three-dimensional atmosphere–ocean coupled model in current and pseudo-global warming (PGW) climates were conducted to investigate future changes of a slow-moving intense typhoon under the warming climate. Over the warmer sea in the PGW climate, the maximum near-surface wind speed rapidly increased around the large eye of the simulated Trami. The stronger winds in the PGW simulation versus the current simulation caused a 1.5-fold larger decrease of sea surface temperature (SST) in the storm core-region. In the PGW climate, near-surface air temperature increased by 3.1°C. A large SST decrease due to ocean upwelling caused downward heat fluxes from the atmosphere to the ocean. The magnitude of the SST decrease depended strongly on initial ocean conditions. Consideration of the SST decrease induced by an intense typhoon, and a slow-moving storm in particular, indicated that such a typhoon would not always become more intense under the warmer climate conditions. An atmosphere–ocean coupled model should facilitate making more reliable projections of typhoon intensities in a warming climate.
- 著者
- Masuo NAKANO Teruyuki KATO Syugo HAYASHI Sachie KANADA Yoshinori YAMADA Kazuo KURIHARA
- 出版者
- (公社)日本気象学会
- 雑誌
- 気象集誌. 第2輯 (ISSN:00261165)
- 巻号頁・発行日
- vol.90A, pp.339-350, 2012 (Released:2012-06-07)
- 参考文献数
- 32
- 被引用文献数
- 14 34
A 5-km-mesh nonhydrostatic cloud-system-resolving regional climate model (NHM-5km) has been developed at the Meteorological Research Institute (MRI) of the Japan Meteorological Agency (JMA) by improving upon the JMA operational mesoscale model (MSM). Three major changes have been made to MSM: the Kain-Frisch convective parameterization scheme has been improved to reduce the incidence of false predictions of rainfall areas along coastlines during the warm season, a spectral nudging method has been introduced to avoid phase-gap between the inner model (NHM-5km) and the outer model, and a Simple Biosphere model has been applied for sophisticated representation of land surface processes. This article presents details of the first two of these modifications.A present-day climate simulation is performed using NHM-5km by nesting within the results of a 20-kmmesh atmospheric global climate model (MRI-AGCM3.2S). Taylor’s skill score is used to compare the performances of NHM-5km and MRI-AGCM3.2S in terms of reproducing the spatial pattern of precipitation-based extreme indices over the Japanese Islands. The comparison shows that NHM-5km yields a significant improvement in reproducing the present-day climatology (e.g., the maximum number of consecutive dry days and the simple daily precipitation intensity index), suggesting that NHM-5km is a reliable tool for accurately predicting future changes in extreme weather at a fine spatial resolution.
- 著者
- Sachie Kanada Hidenori Aiki Kazuhisa Tsuboki Izuru Takayabu
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- pp.2019-044, (Released:2019-11-07)
- 被引用文献数
- 8
From 16 to 23 August 2016, typhoons T1607, T1609, and T1611 hit eastern Hokkaido in northern Japan and caused heavy rainfall that resulted in severe disasters. To understand future changes in typhoon-related precipitation (TRP) in midlatitude regions, climate change experiments on these three typhoons were conducted using a high-resolution three-dimensional atmosphere–ocean coupled regional model in current and pseudo-global warming (PGW) climates. All PGW simulations projected decreases in precipitation frequency with an increased frequency of strong TRP and decreased frequency of weak TRP in eastern Hokkaido. In the current climate, snow-dominant precipitation systems start to cause precipitation in eastern Hokkaido about 24 hours before landfall. In the PGW climate, increases in convective available potential energy (CAPE) developed tall and intense updrafts and the snow-dominant precipitation systems turned to have more convective property with less snow mixing ratio (QS). Decreased QS reduced precipitation area, although strong precipitation increased or remained almost the same. Only TRP of T1607 increased the amounts before landfall. In contrast, all typhoons projected to increase TRP amount associated with landfall, because in addition to increased CAPE, the PGW typhoon and thereby its circulations intensified, and a large amount of rain was produced in the core region.