著者

Migyeong Kim Jeong Hoon Cho Sang-Boom Ryoo

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.26-32, 2023 (Released:2023-02-18)

参考文献数

22

---

Forecasts of discrete events, such as precipitation, dust storms, and typhoons, can be deterministic, categorical, or probabilistic. Ensemble-based probabilistic predictions generate more consistent forecasts than individual deterministic models. We introduce and evaluate the Ensemble Prediction System of Asian Dust Aerosol Model 3, which generates probability forecasts of Asian dust. Probability forecasts were produced for 300 μgm−3 PM10 mass concentrations, according to the air-quality standards of the Ministry of Environment of South Korea and Korea Meteorological Administration. Crisis-level information was produced to categorize the dust risk level for Asia, using a risk matrix. The model's performance was evaluated using a 2 × 2 contingency table, the Brier skill score, and a reliability diagram. For skill score evaluation via the contingency table, the average hit rate and threat score were 0.46 and 0.34 for the best three sites, Jurihe, Erenhot, and Wulatezhongqi. The Brier skill score was positive for approximately 60% of stations, with the highest (0.410) and lowest (−2.038) values in Erenhot and Yanan, respectively. The reliability diagram revealed overestimated Asian dust frequencies for all stations. Although the stations were located within the same regions, their skill scores differed. Regional characteristics of skill scores should be further investigated in the future.

著者

NAKANO Masuo CHEN Ying-Wen SATOH Masaki

出版者

公益社団法人 日本気象学会

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2023-013, (Released:2023-02-24)

---

Typhoon Krosa (2019) formed in the eastern part of the Philippine Sea and ∼ 1400 km east of another typhoon Lekima on 6 August and made landfall in the western part of Japan's mainland on 15 August. The operational global model forecasts, which were initialized just after Krosa's formation, showed a very large uncertainty and totally failed to predict the actual track of Krosa. In this study, we investigated the causes of this large uncertainty through 101-member ensemble forecast experiments by using a 28-km mesh global nonhydrostatic model. The experiments initialized at 1200 UTC 6 August, showed a large uncertainty. An ensemble-based lagged correlation analysis indicated that the western North Pacific Subtropical High (WNPSH) retreated further east in the members with large track forecast errors than in the members with small errors. For the members with a large track forecast error for Krosa, Krosa and Lekima approached each other by 250 km and Krosa moved northward faster than the observation in 36 hours from the initialization time. For the members with a small track forecast error for Krosa, two typhoons approached each other by only 50 km, and the northward moving speed was comparable with that of the observation. The typhoon-center relative composite analysis exhibited that at the initialization time, the members with a large Krosa track forecast error had a larger horizontal size of Krosa and the difference in Krosa's size was kept during the forecast period. This difference in size led to a stronger interaction between the two typhoons and retreatment of the WNPSH, thus resulting in a fast northward moving speed for the members with a large Krosa track error.

著者

Ken Sawada Naoko Seino Takuya Kawabata Hiromu Seko

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.19B-001, (Released:2023-02-13)

---

Considering urbanization effects on atmospheric states and subsequent precipitation is crucial to improve the accuracy of forecasting localized heavy rainfall around urban areas and to mitigate related disasters. For that purpose, it is effective to use a time development model that can accurately represent city-specific effects, such as urban heat island effect, in the assimilation process, and to assimilate high-frequency/high-density surface observation data that have not been used thus far. Therefore, this study incorporated a forecast model with an urban canopy scheme into an ensemble-based assimilation system and assimilated dense surface data from an Atmospheric Environmental Regional Observation System. Then, we performed analysis-forecast experiments for a heavy rain event in Tokyo metropolitan area on August 30, 2017, to examine the impact of urbanization. Our results showed that the urban scheme and surface observation improved near-surface temperature and moisture fields, thereby contributing to the formation of a clearer convergence line between the easterly and southerly winds where it was observed. Consequently, these improvements resulted in an earlier onset of rainfall and better reproduction of the heavy rainfall distribution.

著者

Kai Cao Xiao Tang Lanning Wang Xueshun Chen Qizhong Wu Lei Kong Miaomiao Lu Huangjian Wu Zifa Wang

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.16-25, 2023 (Released:2023-02-07)

参考文献数

54

---

From the end of 2019 to the beginning of 2020, Australian bushfires caused by high temperatures and drought significantly impacted the local and global atmosphere. This work uses the global atmospheric chemistry transport model and observations to assess the enormous impact of bushfire emissions on PM2.5 in Australia. During December 2019, the significant increase in biomass-burning emissions led to increases in PM2.5 observations in megacities such as Canberra, Sydney, Newcastle, Brisbane and Melbourne by 845%, 322%, 171%, 141% and 58%, respectively. Numerical simulations reveal that bushfires increased PM2.5 in Australia and in the Southern Hemisphere by 49% and 13%, respectively. Although the aerosols produced by bushfires could not cross the equator at ground level and affect the air quality in the Northern Hemisphere, they were transported to South Asian countries such as Malaysia and India, as well as Papua New Guinea and New Zealand. In addition, they were also injected upward into the stratosphere (approximately 15 km height). Aerosols injected into the stratosphere could be transported to Antarctica and South America, thus completing global transport.

著者

Yang Zhao Seok-Woo Son Seung-Yoon Back

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.2023-006, (Released:2023-02-01)

被引用文献数

2

---

On 18-20 July 2021, Henan Province in China experienced a historically rare extreme precipitation event, termed as the “21.7” event. Its synoptic environment was characterized by a large amount of moisture supply by binary typhoons located over the ocean and a potential vorticity intrusion in the upper level. The present study examines the importance of the latter by conducting WRF model experiments. A qualitatively similar rainfall amount to observation is obtained when the zonal wavenumbers 7 and larger is kept above 300 hPa in the initial and lateral boundary conditions. When only the large-scale disturbances with wavenumbers 2-4 are kept, the precipitation is greatly reduced. This result indicates that the upper-level synoptic-scale disturbance, which leads to the development of potential vorticity anomaly and its downward intrusion, has likely played a critical role in the development of this event along with a large amount of moisture transport in the low level.

著者

Migyeong Kim Jeong Hoon Cho Sang-Boom Ryoo

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.2023-004, (Released:2023-01-10)

---

Forecasts of discrete events, such as precipitation, dust storms, and typhoons, can be deterministic, categorical, or probabilistic. Ensemble-based probabilistic predictions generate more consistent forecasts than individual deterministic models. We introduce and evaluate the Ensemble Prediction System of Asian Dust Aerosol Model 3, which generates probability forecasts of Asian dust. Probability forecasts were produced for 300 μ gm−3 PM10 mass concentrations, according to the air-quality standards of the Ministry of Environment of South Korea and Korea Meteorological Administration. Crisis-level information was produced to categorize the dust risk level for Asia, using a risk matrix. The model's performance was evaluated using a 2 × 2 contingency table, the Brier skill score, and a reliability diagram. For skill score evaluation via the contingency table, the average hit rate and threat score were 0.46 and 0.34 for the best three sites, Jurihe, Erenhot, and Wulatezhongqi. The Brier skill score was positive for approximately 60% of stations, with the highest (0.401) and lowest (−2.038) values in Erenhot and Yanan, respectively. The reliability diagram revealed overestimated Asian dust frequencies for all stations. Although the stations were located within the same regions, their skill scores differed. Regional characteristics of skill scores should be further investigated in the future.

著者

Masaki Satoh Keisuke Hosotani

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.19A-001, (Released:2022-12-28)

被引用文献数

1

---

A sequence of heavy rainfall events due to quasi-stationary band-shaped precipitation systems, or “senjo-kousuitai”, was observed in the Kyushu region, Japan, from 3 to 8 July 2020. In this study, we investigate two of six indices that have previously been used to determine conditions favorable for senjo-kousuitai, i.e., water vapor flux at the height of 500 m and storm-relative environmental helicity. We examine the relationship between these indices and the occurrence of senjo-kousuitai over the past 20 years using the Japan Meteorological Agency 55-year reanalysis data. We show that the anomaly in wind speeds rather than humidity contributes more to anomalous water vapor flux. The vertical shear of zonal winds and the meridional flow in the lower layer contribute more to the storm-relative environmental helicity. We conducted 20-member ensemble experiments with a 14 km mesh Nonhydrostatic Icosahedral Atmospheric Model (NICAM) for the senjo-kousuitai event. We found that the initial variabilities of the water vapor over the area stretching from the East China Sea to the South China Sea and the wind fields over the western periphery of the North Pacific High are sensitive to the water vapor flux over the senjo-kousuitai area in Kyushu.

著者

Kai Cao Xiao Tang Lanning Wang Xueshun Chen Qizhong Wu Lei Kong Miaomiao Lu Huangjian Wu Zifa Wang

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.2023-003, (Released:2022-12-28)

---

From the end of 2019 to the beginning of 2020, Australian bushfires caused by high temperatures and drought significantly impacted the local and global atmosphere. This work uses the global atmospheric chemistry transport model and observations to assess the enormous impact of bushfire emissions on PM2.5 in Australia. During December 2019, the significant increase in biomass-burning emissions led to increases in PM2.5 observations in megacities such as Canberra, Sydney, Newcastle, Brisbane and Melbourne by 845%, 322%, 171%, 141% and 58%, respectively. Numerical simulations reveal that bushfires increased PM2.5 in Australia and in the Southern Hemisphere by 49% and 13%, respectively. Although the aerosols produced by bushfires could not cross the equator at ground level and affect the air quality in the Northern Hemisphere, they were transported to South Asian countries such as Malaysia and India, as well as Papua New Guinea and New Zealand. In addition, they were also injected upward into the stratosphere (approximately 15 km height). Aerosols injected into the stratosphere could be transported to Antarctica and South America, thus completing global transport.

著者

Kazuto Takemura Hitoshi Mukougawa

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.1-8, 2023 (Released:2023-01-01)

参考文献数

23

---

This study shows a possible mechanism of abnormal extension of North Pacific subtropical high (NPSH) toward western and eastern Japan observed in late June 2022, when Japan experienced an unprecedented heat wave lasting more than a week. During the period, an upper-tropospheric anticyclonic circulation anomaly amplifies to the east of northern Japan associated with the Silk-Road pattern.  A diagnosis using quasi-geostrophic potential vorticity (QGPV) inversion shows that the lower-level anticyclonic circulation anomalies induced by the upper-level anticyclone are the primary factor in the generation of lower-level negative QGPV anomalies from mainland Japan to its south associated with the anomalous extension of the NPSH. The induced circulation causes the lower-level negative QGPV anomalies by upgradient horizontal advection of the climatological QGPV, which has a strong gradient from mainland Japan to its south associated with the Baiu frontal zone. The proposed mechanism well explains a peculiar vertical structure of the observed anticyclone near Japan.  A sensitivity diagnosis considering the sub-seasonal variation of the climatological lower-tropospheric QGPV distribution during summer indicates that the proposed NPSH extension mechanism toward Japan becomes most efficient from late June to early July, when the Baiu frontal zone is most enhanced near Japan.

著者

Shengning Zhang Yaokun Li

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.18, pp.254-258, 2022 (Released:2022-12-09)

参考文献数

22

---

The ENSO phenomenon is investigated by building a fractional derivative recharge-discharge model in which the integer derivative is replaced with the left-sided Caputo type fractional derivative. The results suggest that when the highest order fractional derivative is larger than 1 but smaller than or equal to 2, the model exhibits a variation between exponential decay and pure harmonic oscillation. The system will strengthen to an El Niño/La Niña event and then weaken to the neutral state which does not require a zero value. Therefore, there is only a life cycle of an El Niño/La Niña event, rather than the life cycle of a complete ENSO event in the pure harmonic oscillation. When the highest order fractional derivative is larger than 2, the model exhibits an exponential-like amplified oscillation. The system benefits to exhibit the life cycle of strong ENSO events. The fractional derivative recharge-discharge model, in general, extends the integer model and can be applied in studying the complexity in ENSO phenomenon.

著者

Kazuto Takemura Hitoshi Mukougawa

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.2023-001, (Released:2022-11-29)

---

This study shows a possible mechanism of abnormal extension of North Pacific subtropical high (NPSH) toward western and eastern Japan observed in late June 2022, when Japan experienced an unprecedented heat wave lasting more than a week. During the period, an upper-tropospheric anticyclonic circulation anomaly amplifies to the east of northern Japan associated with the Silk-Road pattern.  A diagnosis using quasi-geostrophic potential vorticity (QGPV) inversion shows that the lower-level anticyclonic circulation anomalies induced by the upper-level anticyclone are the primary factor in the generation of lower-level negative QGPV anomalies from mainland Japan to its south associated with the anomalous extension of the NPSH. The induced circulation causes the lower-level negative QGPV anomalies by upgradient horizontal advection of the climatological QGPV, which has a strong gradient from mainland Japan to its south associated with the Baiu frontal zone. The proposed mechanism well explains a peculiar vertical structure of the observed anticyclone near Japan.  A sensitivity diagnosis considering the sub-seasonal variation of the climatological lower-tropospheric QGPV distribution during summer indicates that the proposed NPSH extension mechanism toward Japan becomes most efficient from late June to early July, when the Baiu frontal zone is most enhanced near Japan.

著者

Shengning Zhang Yaokun Li

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.2022-041, (Released:2022-11-11)

---

The ENSO phenomenon is investigated by building a fractional derivative recharge-discharge model in which the integer derivative is replaced with the left-sided Caputo type fractional derivative. The results suggest that when the highest order fractional derivative is larger than 1 but smaller than or equal to 2, the model exhibits a variation between exponential decay and pure harmonic oscillation. The system will strengthen to an El Niño/La Niña event and then weaken to the neutral state which does not require a zero value. Therefore, there is only a life cycle of an El Niño/La Niña event, rather than the life cycle of a complete ENSO event in the pure harmonic oscillation. When the highest order fractional derivative is larger than 2, the model exhibits an exponential-like amplified oscillation. The system benefits to exhibit the life cycle of strong ENSO events. The fractional derivative recharge-discharge model, in general, extends the integer model and can be applied in studying the complexity in ENSO phenomenon.

著者

LI Linhui LI Shuanglin

出版者

公益社団法人 日本気象学会

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2022-042, (Released:2022-07-07)

---

Twentieth-century atmospheric reanalysis datasets are substantially important for understanding climate in the early era of the century. This paper first compares two sets of the twentieth-century atmospheric reanalyses, the NOAA-CIRES-DOE 20th Century Reanalysis Version 3 (20CRv3) and the ECMWF 20th century reanalysis (ERA20C), as far as the summer low-level cross-equatorial flows (CEFs) over the Asian-Australian monsoon region are concerned. The results show evident regional differences in intensity of individual branches of CEFs between the two reanalyses, in spite of an overall agreement in climatological seasonal mean and variability. At interannual timescale, significant differences are seen prior to 1925 and in the 1940s. During the two periods there are often opposite variations in Somali CEF in the two datasets, along with obvious different amplitudes (variances) in the Bay of Bengal (BOB) and Australian CEFs. At interdecadal timescale, the two datasets have different periodicities in Somali CEF, and have a greater fluctuation of BOB CEF after 1925 in ERA20C than 20CRv3, as well as an opposite decadal variation in the Australian CEF prior to 1940 and in the 1960s. As for the long-term trend, both the Somali and BOB CEFs exhibit intensification in both the datasets, but the intensification amplitude is bigger in 20CRv3 than ERA20C for Somali CEF; the Australian CEF exhibits a weakening trend in both the datasets, but is less evident in 20CRv3. To figure out which of the two datasets is relatively more reliable, the observed cross-equatorial meridional gradient of sea-level pressure index and the Indian summer monsoon rainfall index, which both have longer instrumental records, are used as benchmarks to validate the CEFs in view of their close connections. The results suggest that ERA20C is more reliable, and thus more suitable for investigating decadal climate variability of the 20th century across the hemispheres.

著者

WU Jing KUROSAKI Yasunori SEKIYAMA Tsuyoshi Thomas MAKI Takashi

出版者

公益社団法人 日本気象学会

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2023-004, (Released:2022-10-27)

---

In drylands, the dry vegetation coverage affects dust occurrence by modulating threshold friction velocity (or wind speed) for dust emission. However, there has been little research into quantifying the effect of dry vegetation coverage on dust occurrence. This study investigated spatial and temporal variations of dust occurrence and three definitions of strong wind frequency over the Gobi Desert and surrounding regions in March and April, months when dust occurrence is frequent, during 2001-2021. We evaluated the effects of variations in dry vegetation on dust occurrence by using the threat scores of forecasted dust occurrences for each strong wind definition. Our results indicate that dry vegetation, which was derived from the MODIS Soil Tillage Index, affects dust occurrence more remarkably in April than in March. In March, land surface parameters such as soil freeze-thaw and snow cover, in addition to dry vegetation coverage, should be considered to explain dust variations in that month. However, use of the threshold wind speed estimated from dry vegetation coverage improved the prediction accuracy of dust occurrence in April. Therefore, we propose that the dry vegetation coverage is a key factor controlling dust occurrence variations in April. The findings imply that estimation of dry vegetation coverage should be applied to dust models.

著者

石原 正仁

出版者

公益社団法人 日本気象学会

雑誌

天気 (ISSN:05460921)

巻号頁・発行日

vol.66, no.4, pp.277-297, 2019 (Released:2019-05-31)

参考文献数

86

著者

藤部 文昭 松本 淳

出版者

公益社団法人 日本気象学会

雑誌

天気 (ISSN:05460921)

巻号頁・発行日

vol.69, no.6, pp.319-325, 2022 (Released:2022-07-31)

参考文献数

9

---

新聞4紙の記事検索サイトを使い,気象や気象災害に関連する45語について,1990~2020年の記事数の長期変化を調べた.その結果,近年は極端気象や災害に関わる用語の記事が増える傾向にあることが見出された.しかし,変化傾向は用語によって違い,“豪雨” の記事数は大幅に増えたのに対して “集中豪雨” の記事数は減っている.また,災害に直結しない一般的・日常的な気象用語の記事数は,横ばいあるいは減る傾向にある.

著者

SATO Kazutoshi KAMEDA Takao SHIRAKAWA Tatsuo

出版者

公益社団法人 日本気象学会

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2022-045, (Released:2022-07-22)

---

Iwamizawa on the Sea of Japan side of Hokkaido is one of the cities in Japan that experience frequent heavy snowfall events. Warm surface-layer ocean anomalies over the Sea of Japan can induce heavy snowfall over the Sea of Japan side of Japan; however, the relationship between ocean temperature over the northern Sea of Japan and snowfall events at Iwamizawa remains uncertain. This study used reanalysis data to investigate atmospheric and oceanic circulation anomalies associated with each anomalous heavy snowfall winter month at Iwamizawa. During all anomalous snowfall winter months at Iwamizawa, a cold air anomaly with northwesterly winds existed over the Far East that was associated with a dipole pattern with anticyclone anomalies over the north coast of the Eurasian Continent and cyclonic anomalies extending zonally over the Far East and northern Pacific Ocean. The surface cold air temperature and strong wind speed anomalies are major factor for anomalous upward turbulent heat flux over the northern Sea of Japan during all anomalous snowfall winter months at Iwamizawa. Additionally, during anomalous snowfall January, warm surface-layer ocean anomaly over the northern Sea of Japan, which preceded the heavy snowfall events at Iwamizawa by two months, has an important role in upward turbulent heat flux anomaly. This preceding warm ocean temperature anomaly was associated with a strong Tsushima Warm Current anomaly. Results showed that warm surface-layer ocean anomaly over the northern Sea of Japan that precedes anomalous cold advection from the Eurasian Continent has also large impact on producing heavy snowfall events over western Hokkaido coastal regions near Iwamizawa in January.

著者

YAMADA Shunsuke KUSAKA Hiroyuki

出版者

公益社団法人 日本気象学会

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2022-039, (Released:2022-06-21)

被引用文献数

1

---

We examined the essential features and formation mechanism of the strong local “Suzuka-oroshi” winds, which are located leeward of the Suzuka Mountains in Japan. This area features a favorable topography for downslope windstorms. Climatological analysis revealed that Suzuka-oroshi mainly occurred after an extratropical cyclone with a cold front and passed the Sea of Japan (55 % of all occurrences). Additionally, inversion layers (1-5 km level) were observed in 74 % of cases. Climatological analysis using spatially dense observational data showed that the strongest winds tended to blow in the northern part of the plain on the leeward side. Numerical simulations for one case by the Weather Research and Forecasting (WRF) model with 1 km grid increment supported this finding. Simulation results with and without the Suzuka Mountains demonstrated that the strong Suzuka-oroshi in the northern part of the plain comprised downslope windstorms with transition of flow regime (internal Froude number was less than 1.0 at the windward of mountains and larger than 1.0 above the leeward slope). Additionally, differences in height of the mountains between the north and south parts results in the greater wind speed in the northern parts compared to the southern parts.

著者

YANASE Wataru ARAKI Kentaro WADA Akiyoshi SHIMADA Udai HAYASHI Masahiro HORINOUCHI Takeshi

出版者

公益社団法人 日本気象学会

雑誌

気象集誌. 第2輯 (ISSN:00261165)

巻号頁・発行日

pp.2022-041, (Released:2022-06-30)

被引用文献数

6

---

Torrential rain in Typhoon Hagibis caused a devastating disaster in Japan in October 2019. The precipitation was concentrated in the northern half of Hagibis during extratropical transition (ET). To elucidate the mechanisms of this asymmetric precipitation, synoptic- and meso-scale processes were analyzed mainly using the Japan Meteorological Agency Non-Hydrostatic Model. The present study demonstrates that the asymmetric processes were different depending on the ET stages. When Hagibis was close to the baroclinic zone at middle latitudes around 12 October (the frontal stage), heavy precipitation in the northeastern part of Hagibis was attributed to warm frontogenesis and a quasi-geostrophic ascent, as reported in many previous studies. In contrast, when Hagibis was moderately distant from the baroclinic zone around 11 October (the prefrontal stage), heavy precipitation in the northern part occurred in slantwise northward ascending motion in the outer region. This slantwise motion developed in a region with strong westerly vertical shear, which was enhanced between Hagibis and a westerly jet stream. Based on the analyses of potential vorticity and absolute angular momentum, this region was characterized by reduced moist symmetric stability in the lower and middle troposphere accompanied by inertial instability in the upper troposphere and conditional instability in the lower troposphere. These results provide additional insights into the time evolution of asymmetric processes during ET in the absence of a distinct upper-tropospheric trough, particularly the slantwise motion in the prefrontal stage.

著者

Yoshio Kawatani Takeshi Horinouchi Naoki Sato

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.18, pp.122-128, 2022 (Released:2022-06-16)

参考文献数

11

被引用文献数

1

---

Climate changes around Japan associated with upper troposphere and stratosphere responses of global warming during December-January-February were investigated using the storyline approach and the Coupled Model Intercomparison Project 5 dataset. Climate change was calculated by subtracting the 1959-1990 mean in historical simulations from the 2068-2099 mean in the Representative Concentration Pathways 8.5. Four storylines in plausible future climates were discussed by considering two remote indices representing tropical amplification (tropical upper tropospheric temperature changes) and stratospheric vortex strength. Stratosphere-troposphere connections in terms of zonal wind responses are most pronounced in the storyline of high tropical amplification with strong stratospheric vortex in which the subtropical jet shifts substantially northward. The multimodel mean displays more (less) precipitation in the northern (southern) parts of Japan, while the storyline of high (low) tropical amplification with strong (weak) stratospheric vortex shows increasing (decreasing) precipitation in most parts of Japan. Projected precipitation changes around Japan depend heavily on the storyline adopted and the degree of global warming in these two storylines. Alternatively, precipitation changes depend mostly on the overall strength of global warming with minor influences from storylines in the case of low (high) tropical amplification with strong (weak) stratospheric vortex.