Article
Meteorology & Atmospheric Sciences
Sining Ling, Riyu Lu
Summary: The study revealed that tropical cyclones in the western North Pacific contribute significantly to the East Asia-Pacific teleconnection pattern during summer, enhancing various atmospheric anomalies in the region.
ADVANCES IN ATMOSPHERIC SCIENCES
(2022)
Article
Meteorology & Atmospheric Sciences
Zhenzhen Wang, Renguang Wu, Yuqi Wang
Summary: This study investigates the independent impacts of the East Asian winter monsoon (EAWM) on winter precipitation anomalies over East Asia and the western North Pacific. The results show that strong EAWM years lead to a south-north dipole pattern of precipitation anomalies in these regions. Observations and model simulations suggest that both vertical motion and horizontal moisture transport play important roles in the formation of the precipitation anomaly pattern.
Article
Meteorology & Atmospheric Sciences
Chao-An Chen, Huang-Hsiung Hsu, Hsin-Chien Liang
Summary: This study evaluates the performance of CMIP6 models in simulating the seasonal evolution and extreme precipitation indices in the WNP-EA region, finding improvements in seasonal evolution but limited improvement in extreme indices during spring and fall.
WEATHER AND CLIMATE EXTREMES
(2021)
Article
Meteorology & Atmospheric Sciences
Haili Wang, Chunzai Wang
Summary: Based on observational data, this study finds that there are large-scale anomalous cyclones and anticyclones in the western North Pacific (WNP), with similar occurrence numbers. The WNP anomalous cyclone is identified as an interannual circulatory anomaly that can persist from autumn to spring during La Niña years and from spring to summer during developing El Niño years. The central equatorial Pacific warming contributes to the WNP anomalous cyclone during developing El Niño years, while the combination of central equatorial Pacific cooling, tropical Indian Ocean cooling, and central WNP warming induces the WNP anomalous cyclone during La Niña years.
JOURNAL OF CLIMATE
(2023)
Article
Environmental Sciences
Yangyang Yong, Ju Liang, Kai Yang
Summary: This study aims to investigate the characteristics of atmospheric rivers (ARs) from the western Pacific to Southeast Asia. The results show frequent AR activities in this region during the autumn-winter season, with increasing trends and eastward shift. These dynamic changes contribute to increasing extreme precipitation amounts in the surrounding coastal areas of the South China Sea. This study emphasizes the importance of ARs in understanding the climatology, trends, and variability of regional precipitation in Southeast Asia.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Meteorology & Atmospheric Sciences
Santosh Kumar Verma, Kimitaka Kawamura, Dhananjay Kumar Deshmukh, Md. Mozammel Haque, Chandra Mouli Pavuluri
Summary: The study investigated the formation processes of biogenic secondary organic aerosols (SOAs) over the remote oceanic region in the western North Pacific by analyzing aerosol samples collected from Chichijima Island. Results showed that the SOAs are mainly formed by the photooxidation of biogenic volatile organic compounds (BVOCs), with significant seasonal variations. The biogenic secondary organic carbon concentration ranged from 0.11 to 174 ngC m(-3), accounting for 0.02%-32.0% of the measured organic carbon and influenced by BVOC emissions and biomass burning.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2021)
Article
Environmental Sciences
Min-Woo Seok, Dongseon Kim, Geun-Ha Park, Kitack Lee, Tae-Hoon Kim, Jinyoung Jung, Kitae Kim, Ki-Tae Park, Yeo-Hun Kim, Ahra Mo, Seunghee Park, Young Ho Ko, Jeongwon Kang, Haryun Kim, Tae-Wook Kim
Summary: This study evaluated the potential impacts of atmospheric deposition on marine productivity and inorganic carbon chemistry in the northwestern Pacific Ocean. Results showed a decrease in nutrient concentration in atmospheric total suspended particles with increasing distance from land, and predicted significant differences in inorganic nitrogen deposition fluxes in different regions. Atmospheric particulate deposition was found to support a portion of marine primary production, despite temporal and spatial variabilities in atmospheric nutrient concentration.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Meteorology & Atmospheric Sciences
Daniel J. Befort, Kevin Hodges, Antje Weisheimer
Summary: This study analyzed seasonal forecasting models from five European modeling centers to study tropical cyclones over the western North Pacific and North Atlantic basins. The models were able to capture the observed seasonal cycle of cyclone frequencies, but there were large differences in numbers and spatial track densities. While predictions for the western North Pacific basin were often unreliable, most models provided reliable predictions for the North Atlantic basin and were skillful in predicting interannual cyclone variability in a region covering the Caribbean and North American coastline.
JOURNAL OF CLIMATE
(2022)
Article
Environmental Sciences
Kelvin T. F. Chan, Zhenyuan Dong, Minglin Zheng
Summary: A statistical seasonal forecasting model, the SYSU Model, is proposed to predict the number of tropical cyclones over the western North Pacific based on environmental factors in the preseason, achieving a 95% hit rate in forecasting accuracy over a 41-year period.
ENVIRONMENTAL RESEARCH LETTERS
(2021)
Article
Engineering, Civil
Yu Chen, Zhongdong Duan, Jian Yang, Yi Deng, Tiantian Wu, Jinping Ou
Summary: The study shows that future climate change will lead to changes in typhoon activities, including shifts in typhoon tracks and an increase in the proportion of super typhoons, which will increase typhoon risks in East Asia.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2021)
Article
Meteorology & Atmospheric Sciences
Jiangbo Jin, Xiao Dong, Juanxiong He, Xin Gao, Banglin Zhang, Qingcun Zeng
Summary: In this study, a regional coupled model for the western North Pacific (WNP) and East Asian region was developed and evaluated for its ability to simulate the summer monsoon climate. The results showed that the coupled model performed well in modeling the climate features in the study region, including precipitation, circulation, and the seasonal cycle.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Meteorology & Atmospheric Sciences
Ke Xu, Riyu Lu
Summary: The study identifies the characteristics of all break events of the western North Pacific summer monsoon, indicating that suppressed convection, anticyclonic anomalies, and cyclonic convergence play important roles in the occurrence of breaks.
JOURNAL OF CLIMATE
(2022)
Article
Geosciences, Multidisciplinary
Xin Lin, Lan Wang, Jianyun Gao, Xiaoxiao Chen, Wei Zhang
Summary: The study found that the seasonal variability (ISV) of the East Asia-Pacific (EAP) teleconnection index has a significant impact on the genesis of tropical cyclones, with different ISV characteristics during different ENOS years affecting the frequency and location of MTCs. Low-level absolute vorticity and mid-level relative humidity are important factors modulating MTC genesis.
FRONTIERS IN EARTH SCIENCE
(2021)
Article
Meteorology & Atmospheric Sciences
Xiaofang Feng, Liguan Wu, Chao Wang
Summary: The impact of climate change on tropical cyclone activity is assessed using various approaches, models, and downscaling techniques. The simulation and projection of large-scale circulation patterns are crucial for predicting tropical cyclone activity in a warming climate. This study examines the biases in simulating the western North Pacific monsoon trough (MT), a major circulation system for tropical cyclone formation, based on the output from CMIP6 models. The analysis reveals biases in the exact location and historical changes of the MT, with the simulation of sea surface temperature anomalies in the tropical Pacific being a contributing factor.
JOURNAL OF CLIMATE
(2023)
Article
Meteorology & Atmospheric Sciences
Simchan Yook, David W. J. Thompson, Lantao Sun, Casey Patrizio
Summary: Observations reveal two distinct patterns of atmospheric variability associated with wintertime variations in midlatitude sea surface temperatures (SSTs) in the North Pacific sector. One pattern is characterized by peak atmospheric circulation anomalies 2-3 weeks prior to large SST anomalies in the western North Pacific, consistent with atmospheric forcing of the SST field. The other pattern shows atmospheric circulation anomalies lagging behind SST anomalies in the western North Pacific by several weeks, consistent with the atmospheric response to the SST field. Numerical simulations support the interpretation of these lead-lag relationships, providing evidence for the influence of SST variability on the large-scale atmospheric circulation.
JOURNAL OF CLIMATE
(2022)
Article
Multidisciplinary Sciences
Prakhar Misra, Masayuki Takigawa, Pradeep Khatri, Surendra K. Dhaka, A. P. Dimri, Kazuyo Yamaji, Mizuo Kajino, Wataru Takeuchi, Ryoichi Imasu, Kaho Nitta, Prabir K. Patra, Sachiko Hayashida
Summary: This study analyzed the impact of COVID-19 related restrictions on air pollution in Delhi, India. The research found a significant decrease in NO2 concentrations in urban areas during the lockdown, while rural areas showed no substantial change. Furthermore, NOx emissions from urban areas and power plants exhibited a significant decline during the lockdown period.
SCIENTIFIC REPORTS
(2021)
Article
Multidisciplinary Sciences
Kazuyuki Miyazaki, Kevin Bowman, Takashi Sekiya, Masayuki Takigawa, Jessica L. Neu, Kengo Sudo, Greg Osterman, Henk Eskes
Summary: Efforts to control COVID-19 led to significant reductions in global NOx emissions, resulting in a decrease in tropospheric ozone, which in turn impacted atmospheric oxidative capacity and climate radiative forcing.
Article
Environmental Sciences
Satoru Chatani, Syuichi Itahashi, Kazuyo Yamaji
Summary: Continuous monitoring of hourly PM2.5 component concentrations in Japan showed advantages for regional air quality simulations, with improvements when including transboundary transport, volcanic and dust emissions. However, challenges remain in accurately estimating certain pollutants and addressing speciation profiles. Comparing observed and simulated hourly concentrations can help identify key processes impacting air quality, such as evening peaks in black carbon and morning peaks in NO3- concentrations.
ASIAN JOURNAL OF ATMOSPHERIC ENVIRONMENT
(2021)
Article
Multidisciplinary Sciences
Yugo Kanaya, Kazuyo Yamaji, Takuma Miyakawa, Fumikazu Taketani, Chunmao Zhu, Yongjoo Choi, Kohei Ikeda, Hiroshi Tanimoto, Daichi Yamada, Daiju Narita, Yutaka Kondo, Zbigniew Klimont
Summary: Emissions of black carbon (BC) particles from anthropogenic and natural sources are crucial for climate change and human health. Recent studies in China suggest that the residential sector contributed 64% of BC emissions in 2019, while carbon monoxide (CO) emissions were mainly dominated by non-residential sectors like transport and industry. The findings will help to improve emission inventories and support policies targeting reduction in residential BC emissions.
SCIENTIFIC REPORTS
(2021)
Article
Transportation
Moe Tauchi, Kazuyo Yamaji, Ryohei Nakatsubo, Yoshie Oshita, Katsuhiro Kawamoto, Yasuyuki Itano, Mitsuru Hayashi, Takatoshi Hiraki, Yutaka Takaishi, Ayami Futamura
Summary: This study conducted measurements on ship emissions in the congested Seto Inland Sea in Japan and found that the implementation of the Global Sulfur Cap 2020 regulation led to a rapid decrease in ship emission indices. Onboard observations showed a significant decrease in maritime gaseous SO2 after the regulation came into effect, and similar changes were observed in coastal areas. These findings are important for policymakers in addressing atmospheric pollution issues in congested sea areas.
CASE STUDIES ON TRANSPORT POLICY
(2022)
Article
Environmental Sciences
Hiroshi Hayami, Yuta Iga, Syuichi Itahashi, Kazuhiko Miura, Tatsuhiro Mori, Tatsuya Sakurai
Summary: This study compared data before and after the introduction of the new global limit on sulfur content in ship fuel and found a significant reduction in ship emissions of SO2. The results of the study indicate that the 2020 global limit led to much greater reductions in SO2 emissions from ships than expected.
ASIAN JOURNAL OF ATMOSPHERIC ENVIRONMENT
(2022)
Article
Geochemistry & Geophysics
Hiroki Karyu, Takeshi Kuroda, Kazunari Itoh, Akira Nitta, Kohei Ikeda, Masaru Yamamoto, Norihiko Sugimoto, Naoki Terada, Yasumasa Kasaba, Masaaki Takahashi, Paul Hartogh
Summary: By developing a Venus General Circulation Model (GCM) that incorporates cloud physics and atmospheric chemistry, we are able to simulate and understand the structure and variation of Venusian clouds. The simulated results are consistent with past observations and reveal rapid small-scale variations induced by gravity waves and quasi-periodic zonal-wavenumber-1 variations coupled with equatorial Kelvin waves, which are similar to observed cloud features.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Article
Astronomy & Astrophysics
Masaru Yamamoto, Takumi Hirose, Kohei Ikeda, Masaaki Takahashi, Masaki Satoh
Summary: By investigating the three-dimensional wave structure in an AORI Venus general circulation model, we have revealed the generation and coupling mechanism of short-period waves in the Venus atmosphere. The most predominant waves are 7.5-day waves with zonal wavenumber 1 and slower than observed planetary-scale 5.5-day waves. The 7.5-day waves comprise three types: Type I, a Rossby wave in the upper cloud layer; Type II, a Rossby wave around the polar tropopause; and Type III, an equatorial Kelvin-like wave around and below the cloud bottom. These waves are connected and separated at different altitudes and latitudes, playing important roles in momentum transport and energy conversion.
Article
Multidisciplinary Sciences
Takashi Sekiya, Kazuyuki Miyazaki, Henk Eskes, Kevin Bowman, Kengo Sudo, Yugo Kanaya, Masayuki Takigawa
Summary: Global lockdown measures due to COVID-19 led to significant reductions in air pollutant emissions, including NOx and SO2. This study quantifies the impacts of the lockdown on these emissions and secondary aerosol formation, finding that anthropogenic emissions were reduced by 19 to 25% for NOx and 14 to 20% for SO2 in April 2020. These reductions led to decreases in sulfate and nitrate aerosols over polluted areas, accounting for a substantial portion of observed aerosol optical depth declines and global aerosol radiative forcing. The findings highlight the critical role of secondary aerosol pollutants in understanding the climate impacts of future mitigation measures.
Article
Geosciences, Multidisciplinary
Jagat S. H. Bisht, Prabir K. Patra, Masayuki Takigawa, Takashi Sekiya, Yugo Kanaya, Naoko Saitoh, Kazuyuki Miyazaki
Summary: Methane (CH4) is the second major greenhouse gas and its increase in the atmosphere raises concerns about sustainability and climate change. A data assimilation system using a local ensemble transform Kalman filter (LETKF) is developed to estimate surface emissions of CH4. The performance of the system is tested and optimized using simulated observations and three covariance inflation methods. The results show that the RTPS covariance inflation method performs better and produces estimates that are consistent with the true values.
GEOSCIENTIFIC MODEL DEVELOPMENT
(2023)
Article
Meteorology & Atmospheric Sciences
Kohei Ikeda, Hiroshi Tanimoto, Yugo Kanaya, Fumikazu Taketani, Atsushi Matsuki
Summary: This study evaluated the mass concentration levels and long-term trends of black carbon (BC) in East Asia using CMIP6 climate models. The results revealed that the models overestimated BC concentrations and did not replicate the observed decreasing trend. Sensitivity simulations using different emission inventories showed that the overestimation of Chinese BC emissions was responsible for these discrepancies.
Article
Environmental Sciences
Kohei Ikeda, Hiroshi Tanimoto, Yugo Kanaya, Fumikazu Taketani
Summary: This study assessed anthropogenic black carbon (BC) emissions in East Asia using a chemical transport model and observations, and compared six global inventories. The results showed significant uncertainty in BC emissions from China, with some inventories overestimating the emissions, mostly due to overestimation in the domestic sector during winter.
ENVIRONMENTAL SCIENCE-ATMOSPHERES
(2022)
Article
Meteorology & Atmospheric Sciences
Takashi Sekiya, Kazuyuki Miyazaki, Henk Eskes, Kengo Sudo, Masayuki Takigawa, Yugo Kanaya
Summary: This study provides a comprehensive comparison of the TROPOMI and OMI instruments in assessing tropospheric NO2 column through global chemical data assimilation. The results demonstrate that TROPOMI outperforms OMI in terms of smaller observation errors and improved global analyses of NO2 and ozone. TROPOMI also provides city-scale emission estimates and contributes to the evaluation of detailed spatial and temporal variations in ozone and nitrate aerosols.
ATMOSPHERIC MEASUREMENT TECHNIQUES
(2022)
Article
Environmental Sciences
Zhe Jiang, Hongrong Shi, Bin Zhao, Yu Gu, Yifang Zhu, Kazuyuki Miyazaki, Xin Lu, Yuqiang Zhang, Kevin W. Bowman, Takashi Sekiya, Kuo-Nan Liou
Summary: The COVID-19 lockdown measures in southern California led to a significant improvement in air quality, with a 15% decrease in PM2.5 concentrations primarily due to emission reductions. Emission reductions contributed 68% to the decrease in PM2.5 concentrations, while meteorology variations contributed 32%. Additionally, emission reductions also caused changes in O-3 concentrations.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2021)
Article
Environmental Sciences
Syuichi Itahashi, Baozhu Ge, Keiichi Sato, Zhe Wang, Junichi Kurokawa, Jiani Tan, Kan Huang, Joshua S. Fu, Xuemei Wang, Kazuyo Yamaji, Tatsuya Nagashima, Jie Li, Mizuo Kajino, Gregory R. Carmichael, Zifa Wang
Summary: The study analyzed wet deposition in Southeast Asian countries to understand seasonal variations, finding that while models generally captured wet deposition, there were difficulties in some cases. Adjusting precipitation improved model performance, and utilizing satellite measurements for precipitation adjustment led to more accurate estimates of wet deposition.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2021)
