- 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
- pp.2022-035, (Released:2022-09-06)
- 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, economic, and climatic impact on East Asia. A past replication experiment using MRI-ESM2.0 reproduced the decreasing trend of SDS in the Gobi Desert in the early 21st century. Prediction experiments by MRI_ESM2.0 in CMIP6 future scenarios indicated no significant 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 in SDS emissions of 3.0% for 2015-2100. Friction velocity was the factor most highly correlated with SDS emissions, with a correlation generally higher than 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 in the accelerated warming scenarios is likely due to the changes in friction velocity and erodibility due to the decrease in snow accumulation.
- 著者
- Masayuki Takigawa Prabir K. Patra Yutaka Matsumi Surendra K. Dhaka Tomoki Nakayama Kazuyo Yamaji Mizuo Kajino Sachiko Hayashida
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- vol.16, pp.86-91, 2020 (Released:2020-05-27)
- 参考文献数
- 39
- 被引用文献数
- 3 16
The severe air pollution events continue to occur every year during late October and early November in Delhi, forcing air/land traffic disruptions and anxiety in the daily life of the citizens. We analyze the behaviors of the air pollution events in October and November 2019 that arose from the crop-residue burning as seen using remote sensing techniques. Transport pathways and the mean transit time from the fire hotspots are evaluated using the FLEXPART (FLEXible PARTicle dispersion model). Our results suggest that the polluted regions in Delhi are partly influenced by the crop-residue burning. The uncertainty of our evaluation can be attributable to insufficient information on emission sources because the biomass burning emission based on daily-basis fire radiative power (FRP) of Moderate-Resolution Imaging Spectroradiometry (MODIS) is significantly degraded by the existence of hazy clouds. In future, it is desirable to establish a dense measurement network between Punjab and Delhi for the early detection of the source signals of aerosol emissions and their transport in this region. The FLEXPART model simulation shows the transport of emission signals from Punjab to Delhi, which further expands toward the Bengal region within a span of two days.
- 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
- Tsuyoshi Thomas SEKIYAMA Mizuo KAJINO Masaru KUNII
- 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.95, no.6, pp.447-454, 2017 (Released:2017-11-14)
- 参考文献数
- 26
- 被引用文献数
- 17
We investigated the predictability of plume advection in the lower troposphere and the impact of AMeDAS surface wind data assimilation by using radioactive cesium emitted by the Fukushima nuclear accident in March 2011 as an atmospheric tracer. We conducted two experiments of radioactive plume predictions over eastern Japan for March 15, 2011 with a 3-km horizontal resolution using the Japan Meteorological Agency non-hydrostatic weather forecast model and local ensemble transform Kalman filter (JMANHM-LETKF) data assimilation system. The assimilated meteorological data were obtained from the standard archives collected for the Japan Meteorological Agency operational numerical weather prediction and the AMeDAS surface wind observations. The standard archives do not contain land-surface wind observations. The modeled radioactive cesium concentrations were examined for plume arrival times at 40 observatories. The mean error of the plume arrival times for the standard experiment (assimilating only the standard archives) was 82.0 min with a 13-h lead-time on an average. In contrast, the mean error of the AMeDAS experiment (assimilating both the standard archives and AMeDAS surface wind observations) was 72.8 min, which was 9.2 min (11 %) better than that of the standard experiment. This result indicates that the plume prediction has a reasonable accuracy for the environmental emergency response and the prediction can be significantly improved by the surface wind data assimilation.
- 著者
- Masayuki Takigawa Prabir K. Patra Yutaka Matsumi Surendra K. Dhaka Tomoki Nakayama Kazuyo Yamaji Mizuo Kajino Sachiko Hayashida
- 出版者
- Meteorological Society of Japan
- 雑誌
- SOLA (ISSN:13496476)
- 巻号頁・発行日
- pp.2020-015, (Released:2020-04-06)
- 被引用文献数
- 16
The severe air pollution events continue to occur every year during late October and early November in Delhi, forcing air/land traffic disruptions and anxiety in the daily life of the citizens. We analyze the behaviors of the air pollution events in October and November 2019 that arose from the crop-residue burning as seen using remote sensing techniques. Transport pathways and the mean transit time from the fire hotspots are evaluated using the FLEXPART (FLEXible PARTicle dispersion model). Our results suggest that the polluted regions in Delhi are partly influenced by the crop-residue burning. The uncertainty of our evaluation can be attributable to insufficient information on emission sources because the biomass burning emission based on daily-basis fire radiative power (FRP) of Moderate-Resolution Imaging Spectroradiometry (MODIS) is significantly degraded by the existence of hazy clouds. In future, it is desirable to establish a dense measurement network between Punjab and Delhi for the early detection of the source signals of aerosol emissions and their transport in this region. The FLEXPART model simulation shows the transport of emission signals from Punjab to Delhi, which further expands toward the Bengal region within a span of two days.
- 著者
- Sebastian Oscar Danielache Chisato Yoshikawa Mizuo Kajino Satoshi Itou Wataru Kakeya Naohiro Yoshida Yasuhito Igarashi
- 出版者
- GEOCHEMICAL SOCIETY OF JAPAN
- 雑誌
- GEOCHEMICAL JOURNAL (ISSN:00167002)
- 巻号頁・発行日
- vol.53, no.2, pp.103-118, 2019 (Released:2019-04-05)
- 参考文献数
- 24
- 被引用文献数
- 1
We present a numerical study conducted using a regional Lagrangian model to account for the transport, deposition and radioactive decay of 35S in sulfur dioxide and sulfate aerosols emitted into the atmosphere during the Fukushima Dai-ichi Nuclear Power Plant incident. The model is a Eulerian-Lagrangian hybrid system that accounts for chemical conversion of SO2 into SO42− in a Eulerian manner. The simulations were compared to field measurements of atmospheric 35S in sulfate collected at Kawamata, Tsukuba, Kashiwa, Fuchu and Yokohama, Japan. The 35S emission scenario that best replicated the field measurements followed the same temporal variation pattern as the 134/137Cs emissions. These results suggest that 35S and 134/137Cs follow a similar release pattern. Among the considered emission scenarios, a maximum flux of emitted chemical compounds was assumed to be either 100% 35SO42− or 100% 35SO2, with values of 4.0 × 1019 molecules/hour and 4.0 × 1020 molecules/hour, respectively on March 14th. These emission scenarios reflect the findings reported in the literature, where traces of 35SO2 were measured along with 35SO42−, so the actual emission is expected to be a combination of both chemical forms. The Kawamata measurements (Figs. 5 and 6) presented a large concentration in the July–August period, several months after emissions decreased by more than an order of magnitude. To explain this anomaly, re-suspension ratios were calculated for the Kawamata site, which ranged between 0.1 and 1.5% and partially, but not fully, explain the large measured concentrations. Furthermore, they show large discrepancies with 134/137Cs re-suspension values for measurements at the town of Namie. This situation indicates a lack of understanding of the transformations of 35S that occurs after deposition and the mechanisms involved in the 35S re-suspension process.
- 著者
- Tsuyoshi T. SEKIYAMA Masaru KUNII Mizuo KAJINO Toshiki SHIMBORI
- 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.93, no.1, pp.49-64, 2015 (Released:2015-03-18)
- 参考文献数
- 55
- 被引用文献数
- 1 34
We investigated the horizontal resolution dependence of atmospheric radionuclide (Cs-137) simulations of the Fukushima nuclear accident on March 15, 2011. We used Eulerian and Lagrangian transport models with low- (15-km), medium- (3-km), and high- (500-m) resolutions; both models were driven by the same meteorological analysis that was prepared by our data assimilation system (NHM-LETKF) for each horizontal resolution. This preparation was necessary for the resolution-dependent investigation, excluding any interpolation or averaging of meteorological fields. In the results, the 15-km grid analysis could not reproduce Fukushima’s mountainous topography in detail, and consequently failed to depict a complex wind structure over mountains and valleys. In reality, the Cs-137 plume emitted from the Fukushima Daiichi Nuclear Power Plant (FDNPP) was mostly blocked by Mt. Azuma and other mountains along the Naka-dori valley after crossing over Abukuma Mountains on March 15, 2011. However, the 15-km grid simulations could not represent the blockage of the Cs-137 plume, which unnaturally spread through the Naka-dori valley. In contrast, the 3-km and 500-m grid simulations produced very similar Cs-137 concentrations and depositions, and successfully produced the plume blockage and deposition along the Naka-dori valley. In conclusion, low-resolution (15-km grid or greater) atmospheric models should be avoided for assessing the Fukushima nuclear accident when a regional analysis is needed. Meanwhile, it is reasonable to use 3-km grid models instead of 500-m grid models due to their similarities and the high computational burden of 500-m grid model simulations.