著者

Takashi Maki Taichu Y. Tanaka Tsuyoshi Koshiro Atsushi Shimizu Tsuyoshi T. Sekiyama Mizuo Kajino Yasunori Kurosaki Toshiya Okuro Naga Oshima

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.218-224, 2022 (Released:2022-10-27)

参考文献数

29

被引用文献数

1

---

Ensemble future climate projections were performed using the Meteorological Research Institute Earth System Model version 2.0 (MRI-ESM2.0) for sand and dust storms (SDS), which have a significant social and climatic impact on East Asia. A replication experiment using MRI-ESM2.0 reproduced the decreasing trend of SDS emissions in the Gobi Desert in the early 21st century. Prediction experiments using MRI-ESM2.0 in Coupled Model Intercomparison Project phase 6 future scenarios indicated no considerable differences in the total amount of SDS emissions in the Gobi Desert for 2015-2100; however, SDS emissions increased with warmer scenarios in spring and autumn. In particular, March in the highest warming scenario (SSP5-8.5) exhibited an annual increase rate of 3.0% in SDS emissions for the years 2015-2100. Friction velocity was highly correlated with SDS emissions, with a correlation of ∼0.6 for all climate scenarios throughout the year. In spring and autumn, snow cover exhibited a low negative correlation with SDS emissions, while ground temperature exhibited a positive correlation. The increase in SDS emissions and subsequent dust transport by midlatitude westerlies in spring and autumn during accelerated warming scenarios could be attributed to the changes in friction velocity and erodibility due to the decrease in snow accumulation.

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

vol.18, pp.225-230, 2022 (Released:2022-10-28)

参考文献数

31

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

Takehiko Kobori Masayuki Maki Yasushi Fujiyoshi Masato Iguchi Seiji Fukushima

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.231-235, 2022 (Released:2022-10-28)

参考文献数

13

被引用文献数

1

---

We developed a method for estimating the height and growth rate of volcanic eruption columns, at high-temporal resolution, by processing vertical cross-sectional images of areas around the crater obtained with a marine radar tilted on its side. We applied our method to 127 eruptions occurring at Sakurajima (Kagoshima, Japan) from June to December 2019 and successfully estimated the time-series height of the eruption column and its growth rate every 2.5 seconds. In 48 cases, we obtained the maximum height of the eruption column and confirmed that these results were consistent with those estimated using meteorological radar. Although the maximum height estimated with our method tended to be lower than that observed by monitoring cameras, results could be obtained even when observations were difficult due to cloud effects, etc.

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

vol.18, pp.187-192, 2022 (Released:2022-09-06)

参考文献数

42

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

Anu Gupta Jun Matsumoto

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.2022-034, (Released:2022-08-26)

---

This study investigated the spatial and temporal modulation of aerosol species by monsoon intraseasonal oscillation (MISO) using the Copernicus Atmosphere Monitoring Service (CAMS) reanalysis and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite observations from 2003 to 2019. The climatological spatial distribution of aerosol species showed long-range transport of sea-salt and dust to Indian landmass from the Arabian Sea and desert regions of the Arabian Peninsula, respectively. While organic matter, black carbon, and sulfate originated mainly in India. In the eight MISO phases, southwesterly/westerly strengthening/weakening was responsible for aerosol species transport and spatial distribution. During MISO break to active transition phases 2-5, strong southwest monsoon winds transported sea-salt aerosols from the Arabian Sea to the Indian region. In the active-to-break transition phases 5-7, dust transport strengthened from the Arabian Peninsula. The dust aerosols over the Indian subcontinent peaked in phases 6 and 7. In phases 2-5 (6-8, 1), direction of strong winds along the Indo-Gangetic Plain influenced increased levels of organic matter, sulfate, and black carbon aerosols in the western/northwestern (eastern/northeastern) regions of India. These dynamic spatial changes in aerosols caused by MISO over the Indian region influence the shortwave and longwave radiation balances that can influence monsoon circulation.

著者

平田 徳太郎

出版者

公益社団法人 日本気象学会

雑誌

氣象集誌. 第1輯 (ISSN:00261165)

巻号頁・発行日

vol.41, no.11, pp.585-592, 1922-11-10 (Released:2009-02-05)

著者

Ken Usui Toshiki Iwasaki Takeshi Yamazaki Junshi Ito

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.140-146, 2022 (Released:2022-07-06)

参考文献数

15

---

We conducted numerical simulations on a case of local “Karakkaze” wind on 23 March 2009. On this day, an aircraft crashed on landing at Narita Airport in the eastern Kanto Plain in Japan in the early morning when surface winds were significantly strengthened. Numerical simulations were used to elucidate the characteristics and mechanism of the strong wind over the Kanto Plain. This strong wind was identified as the Karakkaze wind, which occurs in the lee of the convex mountain range northwest of the Kanto Plain. The vertical shear associated with the Karakkaze wind could cause strong turbulence near the surface. The results of a sensitivity experiment suggest that the presence of the mountain convexity is essential for the development of the Karakkaze wind. Backward trajectory analyses reveal the area where the Karakkaze wind originated upstream of the mountain range. The horizontal wind speed in this area is even weaker than in the northern area. However, unlike in the northern area, the air with large momentum descends from altitudes much higher than the height of the dividing streamline owing to the mountain convexity, thereby driving strong surface winds in the leeward area.

著者

Ken Usui Toshiki Iwasaki Takeshi Yamazaki Junshi Ito

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.2022-023, (Released:2022-06-02)

---

We conducted numerical simulations on a case of local “Karakkaze” wind on 23 March 2009. On this day, an aircraft crashed on landing at Narita Airport in the eastern Kanto Plain in Japan in the early morning when surface winds were significantly strengthened. Numerical simulations were used to elucidate the characteristics and mechanism of the strong wind over the Kanto Plain. This strong wind was identified as the Karakkaze wind, which occurs in the lee of the convex mountain range northwest of the Kanto Plain. The vertical shear associated with the Karakkaze wind could cause strong turbulence near the surface. The results of a sensitivity experiment suggest that the presence of the mountain convexity is essential for the development of the Karakkaze wind. Backward trajectory analyses reveal the area where the Karakkaze wind originated upstream of the mountain range. The horizontal wind speed in this area is even weaker than in the northern area. However, unlike in the northern area, the air with large momentum descends from altitudes much higher than the height of the dividing streamline owing to the mountain convexity, thereby driving strong surface winds in the leeward area.

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

pp.2022-022, (Released:2022-05-31)

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 μg/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 μg/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

Takumi Matsunobu Julian F. Quinting Christian M. Grams Mio Matsueda

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.253-260, 2023 (Released:2023-10-31)

参考文献数

35

---

The statistical and dynamical relationships between regional extreme precipitation events (EPEs) during wintertime in five Japanese regions and East-Asian synoptic weather patterns are addressed. Two of the five weather patterns, the southerly flow (SF) and low pressure (LP), are associated with about 50% of EPEs in all the regions. A regional dependency is found, with SF being more likely to cause extreme precipitation in two regions in the south of Japan and LP in the other regions, respectively. The large-scale dynamics leading to EPEs in each region are assessed by a combined Lagrangian and Eulerian analysis. In the two southern regions, EPEs are predominantly associated with direct moisture supply from the subtropical oceans. This is modulated by the large-scale flow pattern of SF. In contrast, EPEs in the northern coastal areas of the Sea of Japan and the Pacific Ocean are influenced by anomalous moisture supply from the cyclone-induced moisture convergence modulated by LP. The eastern coastal region of the Sea of Japan shows a mixture of both these moisture supply mechanisms. The strong link between EPEs and synoptic patterns might help to improve predictions of extreme events, even on the sub-seasonal forecast skill horizon.

著者

Takumi Matsunobu Julian F. Quinting Christian M. Grams Mio Matsueda

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.2023-033, (Released:2023-09-16)

---

The statistical and dynamical relationships between regional extreme precipitation events (EPEs) during wintertime in five Japanese regions and East-Asian synoptic weather patterns are addressed. 4 Two of the five weather patterns, the southerly flow (SF) and low pressure (LP), are associated with about 50% of EPEs in all the regions. A regional dependency is found, with SF being more likely to cause extreme precipitation in two regions in the south of Japan and LP in the other regions, respectively. The large-scale dynamics leading to EPEs in each region are assessed by a combined Lagrangian and Eulerian analysis. In the two southern regions, EPEs are predominantly associated with direct moisture supply from the subtropical oceans. This is modulated by the large-scale flow pattern of SF. In contrast, EPEs in the northern coastal areas of the Sea of Japan and the Pacific Ocean are influenced by anomalous moisture supply from the cyclone-induced moisture convergence modulated by LP. The eastern coastal region of the Sea of Japan shows a mixture of both these moisture supply mechanisms. The strong link between EPEs and synoptic patterns might help to improve predictions of extreme events, even on the sub-seasonal forecast horizon.

著者

Mikio Nakanishi

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.2023-018, (Released:2023-05-30)

被引用文献数

1

---

The Noah multi-parameterization (Noah-MP) scheme is one of several land surface schemes implemented in the Weather Research and Forecasting (WRF) model. Our simulations by the WRF model with the Noah-MP scheme show that surface air temperatures in the morning and evening tend to be higher and lower, respectively, than observed, and that the temperatures at an urban station with snow cover increase little from 0 ℃ even in the daytime. The former depends on surface energy balance in the skin layer and the latter results from snow cover assumed to be uniform over a grid cell. These weaknesses are improved by considering the partial transmission of the solar radiation through the skin layer to the soil layer, the heat capacity of the vegetation canopy, and a mixture of soil layers with and without snow cover. The present scheme will contribute to an improvement of the Noah-MP scheme.

著者

Biao Geng

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.2023-017, (Released:2023-05-24)

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This study investigated the internal precipitation and kinematic structure of the South Pacific convergence zone (SPCZ) observed by the Doppler radar aboard the research vessel Mirai, which passed through the western tropical portion of the SPCZ on December 17-21, 2016. Convective precipitation developed in association with the low-level convergence induced by the monsoon and the upper-level divergence associated with extratropical Rossby wave breaking. Mesoscale convective systems (MCSs) developed from either intersecting (northeast–southwest/northwest–southeast) or zonally oriented convective bands. For the MCS developing from the former mode, the zonal and meridional divergence fields made comparable contributions to convective development. For the MCS developing from the latter mode, the divergence field induced by the meridional wind had the largest contribution to producing convection. The MCS with stronger convective updrafts and higher echo tops and coverage occurred in the region where more intense convergence was observed near the surface. The results of this study highlight the dependence of organizational modes of SPCZ convection on the coupling of the tropical low-level and extratropical upper-level forcings, as well as on the zonal and meridional forcing structures.

著者

Soichiro Hirano Kosuke Ito Hiroyuki 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.2023-015, (Released:2023-05-16)

---

In the western North Pacific, as a tropical cyclone (TC) translates northward and approaches the midlatitude jet region, a front is often observed to the northeast of the TC, especially in fall. Theoretically, a front accompanies positive vorticity in the lower troposphere because convergence of cross-frontal circulation generates positive vorticity. Horizontal winds accompanied by positive vorticity along a front can impact the TC track. This study estimates the influence of frontal positive potential vorticity (PV) on the TC track using reanalysis data for a case of TC Chan-hom (2020). Horizontal winds due to frontal PV (FPV) are calculated using PV inversion. The FPV produces west-southwesterlies around the TC center just after the FPV formation. Thereafter, it mainly produces northwesterlies. Steering flow due to the FPV displaces Chan-hom 50 km east-southeastward for 72 h.

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)

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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

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

vol.19, pp.42-49, 2023 (Released:2023-03-04)

参考文献数

25

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 wavenumber 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

川端 康弘 梶野 瑞王 財前 祐二 足立 光司 田中 泰宙 清野 直子

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.1, pp.5-12, 2021 (Released:2021-02-28)

参考文献数

53

---

Visibility is important information not only for meteorological analysis but also for operations of transport and monitoring air pollution. In this study, climatological features of visibility in the Tokyo urban area are investigated. The number of days with low visibility decreases year by year. The factors can be drying in urban areas and the improvement of air quality, and the reduction of suspended particle matters contributes more to improve the visibility than the relative humidity. The visibility shows seasonal changes; during summer, visibility decreases when photochemical smog is likely to occur, whereas the visibility increases in winter. Visibility in Tokyo can be largely affected by anthropogenic hygroscopic aerosols, which decrease visibility when relative humidity is high.

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

Hidetaka Sasaki Noriko N. Ishizaki Akihiko Murata Hiroaki Kawase Masaya Nosaka

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.9-15, 2023 (Released:2023-01-12)

参考文献数

16

被引用文献数

1

---

The surface temperature was projected to increase from 4 to 5°C in most regions around Japan in winter at the end of the 21st century, according to the Non-Hydrostatic Regional Climate Model (NHRCM) under the Representative Concentration Pathway 8.5 scenario. The melting of sea ice in the Sea of Okhotsk significantly affected the temperature around Hokkaido Prefecture, raising it by more than 8°C in some places. The temperature also rose by more than 8°C in some areas in Honshu where the atmosphere was not susceptible to sea ice. The reduction in snow-covered areas due to global warming raised the temperature further and induced changes in local wind, such as airflows over mountains and wind blowing from the sea. These changes raised the seasonal average temperature and caused the temperature to rise by over 8°C. The dynamical downscaling method played a significant role in projecting such small-scale features in the future climate.