著者

Yuka Kanamori Masaru Inatsu Ryoichi Tsurumaki Naoki Matsuoka Tsuyoshi Hoshino Tomohito J. Yamada

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.249-253, 2022 (Released:2022-11-26)

参考文献数

23

被引用文献数

1

---

A set of hydrological experiments for a flooding event on 11 September 2014 at Motsukisamu River in Sapporo were performed. Dynamical downscaling to 5-km resolution of a large-ensemble global simulation allowed us to estimate that a 99%-tile hourly precipitation in Sapporo would increase by 70% in a future climate, when the global-mean temperature increases by 4 K compared with the present climate. After developing a three-tank model of which parameters were optimized on the basis of the in-situ observation at the Motsukisamu River during the event period, the model was forced by hypothetical hyetographs of the event that would occur under the future climate. The results of this experiment suggested that the peak flow rate would increase by 75%. However, it was also revealed that an upstream aqueduct tunnel, just completed in autumn 2021, would effectively reduce the peak flow rate and mitigate the flooding risk even in extreme precipitation under the future climate.

著者

松田 佳久 高木 征弘

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.68, no.2, pp.67-83, 2021 (Released:2021-03-31)

参考文献数

66

---

金星の軌道に投入された気象衛星である「あかつき」が金星の気象について画期的な情報をもたらしつつある.また,大気大循環モデル(GCM:General Circulation Model)を用いた金星大気の数値シミュレーションも大きな成果をあげつつあり,両者により金星気象学が大きく刷新されつつある.この機会に,金星大気や気象の概要と今までの研究を紹介するとともに,今後の金星気象学を展望したい.

著者

Yuka Kanamori Masaru Inatsu Ryoichi Tsurumaki Naoki Matsuoka Tsuyoshi Hoshino Tomohito J. Yamada

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.2022-040, (Released:2022-11-11)

被引用文献数

1

---

A set of hydrological experiments for a flooding event on September 11, 2014 at Motsukisamu River in Sapporo were performed. Dynamical downscaling to 5-km resolution of a large-ensemble global simulation allowed us to estimate that a 99%-tile hourly precipitation in Sapporo would increase by 70% in a future climate, when the global-mean temperature increases by 4 K compared with the present climate. After developing a three-tank model of which parameters were optimized on the basis of the in-situ observation at the Motsukisamu River during the event period, the model was forced by hypothetical hyetographs of the event that would occur under the future climate. The results of this experiment suggested that the peak flow rate would increase by 75%. However, it was also revealed that an upstream aqueduct tunnel, just completed in autumn 2021, would effectively reduce the peak flow rate and mitigate the flooding risk even in extreme precipitation under the future climate.

著者

小林 茂

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.2, pp.113-140, 2019 (Released:2019-03-31)

参考文献数

90

---

From the beginning of the Sino-Japanese War in 1937 to the end of the WWII in 1945, Japanese military occupied wide areas in East and Southeast Asia and the Western Pacific. Along with the extension of the front, Japanese military's weather surveys replaced existed local ones and interrupted their continual observation. In addition to ground observation, it carried out upper-air observation with pilot-balloon and radiosonde to support its air forces on the basis of the extended survey network. As for the data accumulated up to the end of the WWII by Japanese military, however, it has been believed that they were lost in the disturbances of war and to restore this wartime discontinuity is almost impossible. Scrutinizing book stocks of several institutions at home and in the United States, such as the Library of Congress, the author found not a few unused materials, in which wartime weather data had been recorded. In this paper, following up the wartime vicissitudes of Japanese weather survey, he reviewed instructive cases, where such materials had been rescued successfully, in order to promote the efficient search of buried data in the near future.

著者

Yuta Tamaki Sosuke Okubo Kei Horie

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.2022-039, (Released:2022-10-14)

---

We examined forty-five typhoons associated with insurance losses in Japan to explicitly describe typhoon-related variables that explain insurance-loss variations. Multiple regression analysis revealed that the combination of maximum wind speed and translation speed explained more of the variation in insurance-loss size than what the regression model with maximum wind speed alone did. Using maximum wind speed and gale-area radius as explanatory variables also slightly improved the explained variance, but it was less stable than the multiple regression model combining maximum wind speed and translation speed. The translation speed suggested an inland expansion of the strong-wind area associated with wind-speed asymmetry, while considering the exposure led to similar conclusions. Our regression model can be applied to estimate changes in the damage and uncertainty by adjusting the typhoon characteristics under multiple climate-change scenarios.

著者

Amane Nakamura Tsubasa Kohyama

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.2022-038, (Released:2022-10-04)

---

Analysis of the El Ninño-Southern Oscillation (ENSO) phenomena has conventionally been performed using deviations from the mean. However, the question remains as to whether the mean is appropriate as the reference state, since it is sensitive to the existence of a few extreme events. In this study, the validity of the mean and mode as a reference is compared using an idealized simulation model. We show that the mode is not affected by the asymmetry of El Ninño and La Ninña and is more stable as a reference than the mean. Then, this result is also demonstrated using observed data. Observations also show that the relationship between the ENSO amplitude and the zonal shifts of the ENSO anomalies is more emphasized if the mode is employed. For the variables in the ocean interior, differences between the mode-based and mean-based methods appear throughout all seasons.

著者

Kazuto Takemura Yoshihiro Nakae Yoshihisa Fujihara Hirotaka Sato Hitoshi Sato Atsushi Goto Hiroaki Naoe

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.18A, no.Special_Edition, pp.21-26, 2022 (Released:2022-09-21)

参考文献数

17

被引用文献数

1

---

Several regions in western Japan experienced a record-breaking early onset of the rainy season called Baiu in mid-May 2021, which is attributed to the northward movement and enhancement of the Baiu frontal zone. This study investigates large-scale atmospheric circulation that contributes to the early onset of Baiu. Diagnostic and statistical analyses based on reanalysis datasets reveal that both enhanced convection over the western Indian Ocean associated with the Madden–Julian oscillation and a blocking high near western Russia promote the excitation of Rossby waves to propagate downstream along the upper-tropospheric jet, and thus contributing to the northward movement of the Baiu frontal zone. The anomalous convection over the western Indian Ocean and the subtropical western North Pacific also may affect anticyclonic circulation anomalies to the northeast of the Philippines in the lower troposphere, which promotes moisture inflow toward western Japan and consequently intensifies the Baiu frontal zone. Numerical and quantitative analyses of the circulation anomalies near Japan based on a linear baroclinic model confirm the aforementioned results. The results indicate that the anomalous convection over the Asian monsoon region and the blocking high near western Russia are the primary factors contributing to the early onset of Baiu.

著者

Tetsuya Kawano Ryuichi Kawamura

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.205-210, 2022 (Released:2022-09-28)

参考文献数

29

被引用文献数

1

---

In this study, we investigated the remote effect of warm sea surface temperatures (SSTs) in the Kuroshio region of the East China Sea (ECS) on heavy rainfall that occurred in southern Kyushu, Japan, on 3 July 2020 using the Weather Research and Forecasting model. To examine the effect, a simulation with realistic SSTs and two simulations with reduced SSTs in the ECS Kuroshio region were performed. Backward- and forward-trajectory analyses showed that low-level parcels in the simulation with warmer SSTs in the ECS Kuroshio region possessed larger amounts of water vapor than those in the reduced-SST experiments. The difference in the water-vapor amounts of low-level parcels between the simulations with warmer and colder SSTs remained until the parcels started to ascend in the heavy rainfall area. In addition, there were many more parcels with extremely large amounts of water vapor in the simulation with warmer SSTs. Such an increase in low-level water-vapor amounts under warmer SST conditions in the ECS Kuroshio region led not only to enhancement of the precipitation source but also to atmospheric destabilization, resulting in the production of a large amount of precipitation.

著者

Chultem Batbold Keiya Yumimoto Sonomdagva Chonokhuu Batdelger Byambaa Batdavaa Avirmed Shuukhaaz Ganbat Naoki Kaneyasu Yutaka Matsumi Teppei J. Yasunari Kenji Taniguchi Noriko Hasebe Keisuke Fukushi Atsushi Matsuki

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.2022-036, (Released:2022-09-06)

被引用文献数

1

---

In Mongolia, combined with the dry and windy climate during spring and autumn, the exposed sediment of mine tailings pond becomes an additional source of anthropogenic windblown dust and poses potential threats to the surrounding environment and human health. In this study, we reported on our first attempt to derive the spatiotemporal distribution of dust originating from the tailings pond of the Erdenet mine using a combination of ground-based in-situ measurements and Himawari-8 geostationary satellite remote sensing. Temporal evolution of the dust plume visualized by the RGB imagery corresponded well with the in-situ particle concentration measured on the ground. Under relatively cloud-free conditions, the dust RGB imagery from Himawari-8 clearly showed the spatial extent of the white dust plume originating from the tailings pond, in the range of 2,040-2,748 km2. Therefore, the dust RGB imagery by Himawari-8 is demonstrated to be sensitive enough to resolve the highly localized anthropogenic dust, even from a point source as small as the tailings pond, and is effective in studying susceptible areas subject to associated heavy metal deposition and contamination.

著者

Kazuaki Nishii Bunmei Taguchi Masato Mori Yu Kosaka Hisashi Nakamura

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.199-204, 2022 (Released:2022-09-12)

参考文献数

23

---

Anomalous coldness was observed over midlatitude Eurasia in December 2020 and over subpolar Eurasia in January 2021. The former was accompanied by the Warm Arctic and Cold Eurasia (WACE) pattern, while the latter by the negative phase of the Arctic Oscillation (AO). A set of large ensemble experiments with an atmospheric general circulation model suggests a contribution of reduced Arctic Sea ice to the midlatitude cooling and WACE pattern in December 2020. The tropical and extratropical sea surface temperature (SST) anomalies, however, contribute to warming over midlatitude Eurasia. In January 2021, neither the sea ice nor SST anomalies can explain the subpolar Eurasian cooling and the negative AO in our experiments.

著者

Zuowei Xie Zelun Cheng Cholaw Bueh Mei Yong Chenglai Wu Purevjav Gomboluudev

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.159-166, 2022 (Released:2022-07-25)

参考文献数

23

被引用文献数

1

---

This study examines the pattern transition of dust events identified based on dust RGB images from the Himawari-8 satellite, along with associated key circulations and dynamic features, during spring 2016-2020. The dust RGB images are ordered onto a 4 × 3 topological map according to the spatial similarity of the dust distribution using self-organizing maps. In this topological map, the dust distribution exhibits mainly an eastward displacement or amplification from the Taklimakan Desert to the Gobi Desert. The key circulation triggering the transition of dust pattern is the large-scale tilted ridge from Xinjiang to Siberia. Such a northeast–southwest-oriented ridge conveys cold air into Tibet and causes the near-surface Siberian high extending southward from the Sayan mountains to central China. Consequently, dust intrudes from the Gobi Desert into northern China. In contrast, a zonal “+ − +” wave train in the upper troposphere confines the near-surface high over western Siberia and induces the near-surface cyclogenesis over Mongolia and northern China. As a result, the dust is mainly concentrated over the Taklimakan Desert, with weak influence over Mongolia and northern China.

著者

Saat Mubarrok Chan Joo Jang

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.2022-030, (Released:2022-08-03)

被引用文献数

2

---

Extreme rainfall (ER) in Indonesia frequently leads to floods and landslides, disrupting economic activity and impacting human lives. Here, we investigate ER variability in association with climate teleconnection patterns (CTP) including the El Niño Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), and Madden-Julian Oscillation (MJO), using extreme value analysis based on daily rainfall data from 32 stations for 30 years (1985-2014). By fitting a generalized extreme value distribution, a significant association between the annual maximum rainfall (AMR) and CTP was found in 12 of 32 stations. The sensitivity test of location parameter showed that the AMR-CTP interconnection was spatially inhomogeneous. The positive (negative) significant association of ENSO and IOD to AMR was noticeable in south-western (eastern) Indonesia. Additionally, MJO positive (negative) association was detected at 4 (3) stations mostly located in Sumatra (Java) Island. Furthermore, the return level analysis shows that the 20-year ER intensity waiting time will be shorter and longer when CTP indexes strengthen and weaken, suggesting a potential increase and decrease in the likelihood of future ER occurrences, respectively. These results are relevant for understanding the relationship between ER and CTP that should be considered in the adaptation and mitigation plans to minimize the ER impacts.

著者

Tetsuya Kawano Ryuichi Kawamura

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.2022-033, (Released:2022-08-05)

被引用文献数

1

---

In this study, we investigated the remote effect of warm sea surface temperatures (SSTs) in the Kuroshio region of the East China Sea (ECS) on heavy rainfall that occurred in southern Kyushu, Japan on 3 July 2020 using the Weather Research and Forecasting model. To examine the effect, a simulation with realistic SSTs and two simulations with reduced SSTs in the ECS Kuroshio region were performed. Backward- and forward-trajectory analyses showed that low-level parcels in the simulation with warmer SSTs in the ECS Kuroshio region possessed larger amounts of water vapor than those in the reduced-SST experiments. The difference in the water-vapor amounts of low-level parcels between the simulations with warmer and colder SSTs remained until the parcels started to ascend in the heavy rainfall area. In addition, there were many more parcels with extremely large amounts of water vapor in the simulation with warmer SSTs. Such an increase in low-level water-vapor amounts under warmer SST conditions in the ECS Kuroshio region led not only to enhancement of the precipitation source but also to atmospheric destabilization, resulting in the production of a large amount of precipitation.

著者

Kazuto Takemura Yoshihiro Nakae Yoshihisa Fujihara Hirotaka Sato Hitoshi Sato Atsushi Goto Hiroaki Naoe

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.18A-004, (Released:2022-08-18)

被引用文献数

1

---

Several regions in western Japan experienced a record-breaking early onset of the rainy season called Baiu in mid-May 2021, which is attributed to the northward movement and enhancement of the Baiu frontal zone. This study investigates large-scale atmospheric circulation that contributes to the early onset of Baiu. Diagnostic and statistical analyses based on reanalysis datasets reveal that both enhanced convection over the western Indian Ocean associated with the Madden–Julian oscillation and a blocking high near western Russia promotes the excitation of Rossby waves to propagate downstream along the upper-tropospheric jet, and thus contributing to the northward movement of the Baiu frontal zone. The anomalous convection over the western Indian Ocean and the subtropical western North Pacific also may affect anticyclonic circulation anomalies to the northeast of the Philippines in the lower troposphere, which promotes moisture inflow toward western Japan and consequently intensifies the Baiu frontal zone. Numerical and quantitative analyses of the circulation anomalies near Japan based on a linear baroclinic model confirms the aforementioned results. The results indicate that the anomalous convection over the Asian monsoon region and the blocking high near western Russia are the primary factors contributing to the early onset of Baiu.

著者

Jae-yong Lee Seung-Min Lee Seung-Jae Lee

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.173-180, 2022 (Released:2022-08-31)

参考文献数

33

被引用文献数

1

---

This study performed 4-day numerical integration in 1-hour intervals using the Weather Research and Forecasting (WRF) model for four major cases of heavy snowfall that occurred from 2020 to 2021. The model-predicted snow depth data were compared with the ground-observed snow depth and the satellite-observed snow cover data and then were statistically verified. The scalar verification results for ground data from the four cases showed a root–mean–square error of 2.55-16.67 cm and a correlation coefficient of 0.48-0.80, whereas the verification results with satellite data showed the correlation coefficients of 0.38-0.60. For categorical verification, using a threshold value of a snow depth exceeding 5 cm, the proportion correct was 90% or higher for ground observations of each case. In addition, in the satellite categorical verification, when the threshold value of the Snow Cover Fraction (SCF) exceeds 0.5, the proportion correct was 50% or more. These results are meaningful because the model snow depth verification methods were devised strategically for the first time using both the snow depth data of the mesoscale ground observation networks and ultra-high-resolution Sentinel-2 satellite data currently available in Korea. The findings of this study will contribute to the development of a high-resolution numerical prediction model and its verification methodology for snowfalls in the Korean Peninsula, eventually leading to increased prediction accuracy and reduced snow damage.

著者

Inovasita Alifdini Teruhisa Shimada

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.154-158, 2022 (Released:2022-07-17)

参考文献数

23

被引用文献数

2

---

This study investigates the diurnal variation of surface wind divergence in the seas of the Maritime Continent by using satellite scatterometer observations and atmospheric reanalysis data. This is the first study to demonstrate the distribution and seasonal variation of the diurnally varying surface winds in the Maritime Continent in terms of wind divergence. Wind divergence develops from the coasts of the islands toward the center of the seas and dominates during the afternoon and evening hours. Wind convergence dominates over the seas during the nighttime and morning hours. The offshore extensions of the wind divergence and convergence from the coast differ regionally and thus show the asymmetric patterns with respect to the center of the seas. In particular, strong wind divergence develops from the southern coasts of the Java Sea and the Arafura Sea to extend northward beyond the center of the seas. The diurnal amplitudes of wind divergence vary seasonally and reach a peak in September in most of the seas. The switching times between wind divergence and convergence are almost fixed throughout the year regardless of the monsoon reversal.

著者

Sho Kawazoe 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.18, pp.147-153, 2022 (Released:2022-07-17)

参考文献数

23

被引用文献数

2

---

We investigated the sub-seasonal predictability of heavy snowfall events in Iwamizawa, Hokkaido, using the Japan Meteorological Agency's 1-month ensemble predictions. First, the self-organizing map (SOM) technique was applied to the Japanese 55-year Reanalysis sea-level pressure anomalies to identify weather patterns resulting in heavy snowfall. It revealed that heavy snowfall developed in SOM nodes (weather patterns) with low-pressure centers to the east/northeast of Hokkaido and Siberian high to the west, resulting in westerly to northwesterly monsoon winds traversing the Sea of Japan towards western Hokkaido. Next, ensemble forecasts were projected onto the SOM map to determine the predictability of weather patterns up to a month in advance. For winter 2019, there was relatively low probability of projecting a high number of ensembles in SOM nodes to those observed in the reanalysis. In contrast, much higher probability was seen in 2020 to ∼10 forecast days. When considering multiple SOM nodes that contribute to heavy snowfall in the forecast, both winters saw more ensemble members predicting heavy snowfall to ∼10 forecast days. We also saw a higher probability of heavy snowfall beyond 10-days in 2020. These results highlight the potential benefit of incorporating multiple weather patterns to forecast heavy snowfall.

著者

Jae-yong Lee Seung-Min Lee Seung-Jae Lee

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.2022-028, (Released:2022-07-19)

被引用文献数

1

---

This study performed 4-day numerical integration in 1-hour intervals using the Weather Research and Forecasting (WRF) model for four major cases of heavy snowfall that occurred from 2020 to 2021. The model-predicted snow depth data were compared with the ground-observed snow depth and the satellite-observed snow cover data and then were statistically verified. The scalar verification results for ground data from the four cases showed a root–mean–square error of 2.55-16.67 cm and a correlation coefficient of 0.48-0.80, whereas the verification results with satellite data showed the correlation coefficients of 0.38-0.60. For categorical verification, using a threshold value of a snow depth exceeding 5 cm, the proportion correct was 90% or higher for ground observations of each case. In addition, in the satellite categorical verification, when the threshold value of the Snow Cover Fraction (SCF) exceeds 0.5, the proportion correct was 50% or more. These results are meaningful because the model snow depth verification methods were devised strategically for the first time using both the snow depth data of the mesoscale ground observation networks and ultra-high-resolution Sentinel-2 satellite data currently available in Korea. The findings of this study will contribute to the development of a high-resolution numerical prediction model and its verification methodology for snowfalls in the Korean Peninsula, eventually leading to increased prediction accuracy and reduced snow damage.

著者

Yiming Sun Qizhong Wu Lanning Wang Baogang Zhang Pingzhong Yan Lingling Wang Huaqiong Cheng Mengfei Lv Nan Wang Shuangliang Ma

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.135-139, 2022 (Released:2022-07-06)

参考文献数

17

被引用文献数

1

---

The numbers of heavy air pollution events per year in Beijing have decreased significantly since 2017. To find out the reasons and how meteorology and emissions control have played a role in this change, we used the WRF-SMOKE-CMAQ modeling system to reconstruct the characteristics of the fine particulate matter (PM2.5) concentrations from 2013 to 2019. The model system performed well, and the correlation coefficients (R) between the simulated and observed daily PM2.5 concentrations were all above 0.64. The model results also show that the meteorology contributed approximately ±5 g/m3 to the annual average PM2.5 concentrations. More interestingly, the coincidence degrees of the simulated PM2.5 concentrations to the heavy pollution (daily PM2.5 concentration > 150 g/m3) dates decreased significantly after 2016. Meteorology plays an important role in reducing the number of heavy pollution days. According to the model results under the same emission scenarios, the average numbers of heavy pollution days from 2017 to 2019 decreased by 33% compared to the period from 2013 to 2016, while the numbers of good days changed by less than 1%. These results also indicate that meteorology made a significant contribution to decreasing the number of heavily polluted days after 2016.

著者

Zuowei Xie Zelun Cheng Cholaw Bueh Mei Yong Chenglai Wu Purevjav Gomboluudev

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.2022-026, (Released:2022-07-01)

被引用文献数

1

---

This study examines the pattern transition of dust events identified based on dust RGB images from the Himawari-8 satellite, along with associated key circulations and dynamic features, during spring 2016-2020. The dust RGB images are ordered onto a 4 × 3 topological map according to the spatial similarity of the dust distribution using self-organizing maps. In this topological map, the dust distribution exhibits mainly an eastward displacement or amplification from the Taklimakan Desert to the Gobi Desert. The key circulation triggering the transition of dust pattern is the large-scale tilted ridge from Xinjiang to Siberia. Such a northeast–southwest-oriented ridge conveys cold air into Tibet and causes the near-surface Siberian high extending southward from the Sayan mountains to central China. Consequently, dust intrudes from the Gobi Desert into northern China. In contrast, a zonal “+ – +” wave train in the upper troposphere confines the near-surface high over western Siberia and induces the near-surface cyclogenesis over Mongolia and northern China. As a result, the dust is mainly concentrated over the Taklimakan Desert, with weak influence over Mongolia and northern China.