Publications by authors named "Yasunori Tohjima"
Unlabelled: We developed a near-real-time estimation method for temporal changes in fossil fuel CO (FFCO) emissions from China for 3 months [January, February, March (JFM)] based on atmospheric CO and CH observations on Hateruma Island (HAT, 24.06° N, 123.81° E) and Yonaguni Island (YON, 24.
View Article and Find Full Text PDFThe dramatic increase of natural gas use in China, as a substitute for coal, helps to reduce CO emissions and air pollution, but the climate mitigation benefit can be offset by methane leakage into the atmosphere. We estimate methane emissions from 2010 to 2018 in four regions of China using the GOSAT satellite data and in-situ observations with a high-resolution (0.1° × 0.
View Article and Find Full Text PDFCharacteristics of atmospheric black carbon and other aerosol particles over the Arctic Ocean in early autumn 2016: Influence from biomass burning as assessed with observed microphysical properties and model simulations.
Sci Total Environ
November 2022
Article Synopsis
- Researchers measured marine aerosol particles and trace gases during a cruise on the R/V Mirai in the Arctic and Northwest Pacific regions from August to October 2016, finding average black carbon concentrations consistent with previous studies.
- The study highlighted that black carbon levels in the Arctic Ocean provide important benchmarks for testing atmospheric transport models, and these levels were lower than those observed at nearby ground-based stations like Barrow.
- Elevated black carbon and carbon monoxide levels were linked to biomass burning events, particularly from Siberian forest fires, with model simulations suggesting that fire plumes traveled significant distances, but the observed ratios indicated potential influences from wet removal and smoldering emissions.
The COVID-19 pandemic caused drastic reductions in carbon dioxide (CO) emissions, but due to its large atmospheric reservoir and long lifetime, no detectable signal has been observed in the atmospheric CO growth rate. Using the variabilities in CO (ΔCO) and methane (ΔCH) observed at Hateruma Island, Japan during 1997-2020, we show a traceable CO emission reduction in China during February-March 2020. The monitoring station at Hateruma Island observes the outflow of Chinese emissions during winter and spring.
View Article and Find Full Text PDFThe regional budget of methane (CH) emissions for East Asia, a crucial region in the global greenhouse gas budget, was quantified for 1990-2015 with a bottom-up method based on inventories and emission model simulations. Anthropogenic emissions associated with fossil fuel extraction, industrial activities, waste management, and agricultural activities were derived from the Emission Database for Global Atmospheric Research version 4.3.
View Article and Find Full Text PDFArticle Synopsis
- A field study on Rishiri Island, Japan, analyzed sources of atmospheric black carbon and related components, including eBC mass and gases like CO and CH.
- The research identified 16 significant eBC events, linked to both human activities and biomass burning from Siberia and China, particularly noting spikes in late July 2014 due to Siberian forest fires.
- Additionally, the study revealed that pollution in northern Japan can also come from crop residue burning in Northeast China, enhancing understanding of the impact of biomass burning in East Asia on atmospheric conditions.
Methane is a substantial contributor to climate change. It also contributes to maintaining the background levels of tropospheric ozone. Among a variety of CH4 sources, current estimates suggest that CH4 emissions from oil and gas processes account for approximately 20% of worldwide anthropogenic emissions.
View Article and Find Full Text PDF