A semi-Lagrangian advection scheme for radioactive tracers in the NCEP Regional Spectral Model (RSM)

Chang, Eun‐Chul; Yoshimura, Kei

doi:10.5194/gmd-8-3247-2015

Cited by 10 publications

(5 citation statements)

References 25 publications

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“…We conduct hindcast (HC) simulations from 11 to 31 March 2011 using the Isotopic Regional Spectral Model (IsoRSM) 25 , 26 . The height of the emission source is set to the surface because the emission height is estimated to range from 20 to 120 m (fairly close to the surface) in the reverse-estimation method 27 – 29 .…”

Section: Methodsmentioning

confidence: 99%

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Dispersion characteristics of radioactive materials estimated by wind patterns

Yoshikane

Yoshimura

2018

Sci Rep

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The radioactive materials are generally concentrated downwind of their origins when the prevailing winds blow continuously in one direction. If this principle determined the pattern of dispersion in all cases, dispersion directions could be estimated by wind patterns. However, this hypothesis has not been sufficiently verified because of the complexity of dispersion processes and weather systems. Here, we show that dispersion directions, which are divided into four ranges, can be estimated by wind patterns using a machine learning approach. The five-year average hit rates of the directions of dispersion estimated using near-surface winds exceed 0.85 in all months. The dispersion directions can be estimated up to 33 hours in advance using forecast winds. In particular, high hit rates exceeding 0.95 are achieved in January and March, when large-scale weather systems dominate. These results indicate that the dispersion directions are determined by the wind patterns that correspond to large-scale weather systems and diurnal circulation patterns in most cases. Our findings also provide more reliable information on dispersion patterns with reduced uncertainties, given that reasonable skill is achieved at a sufficient lead time for evacuation.

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Section: Methodsmentioning

confidence: 99%

“…The horizontal and meridional ranges of the domain are 800 km and 950 km, respectively. A semi-Lagrangian model is used to calculate the transport of radioactive materials 26 .…”

Section: Methodsmentioning

confidence: 99%

Dispersion characteristics of radioactive materials estimated by wind patterns

Yoshikane

Yoshimura

2018

Sci Rep

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“…The grid spacing was 5 km in this domain. A semi-Lagrangian model was used to calculate the transport of radioactive materials32. The deposition distributions of 137 Cs are reasonably simulated around the Fukushima-Daiichi nuclear power plant and around the Tokyo metropolitan area.…”

Section: Methodsmentioning

confidence: 99%

Long-distance transport of radioactive plume by nocturnal local winds

Yoshikane

Yoshimura

Chang

et al. 2016

Sci Rep

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Radioactive plumes can spread far and wide depending on wind conditions. The plumes often frequently reached the Tokyo metropolitan area, which is approximately 200 km away from the Fukushima Daiichi nuclear power plant, under spatially heterogeneous wind fields in March 2011. To reduce exposure to radioactive plumes, the behaviour of the plumes must be known. However, the transport mechanism of radioactive plumes is not fully understood. Using a regional climate model, we show that multiple diurnal cycle processes play a key role in the frequent transport of radioactive plumes to the Tokyo metropolitan area. The observed data and hindcast results indicate that the radioactive plume moves along the local winds, which comprise the northeasterly local wind (NELW) associated with the meso-scale low-pressure system (meso-low) and the northerly sea wind (NSW) during the night. The long-term analysis and sensitivity simulations also show the nocturnal processes that the NELW caused by the meso-low and the NSW are formed east of the Tokyo metropolitan area and from Fukushima offshore east of the Tokyo metropolitan area, respectively, when neither winter monsoons nor extra-tropical cyclones are predominant. These findings indicate that the radioactive plumes could reach faraway places frequently via nocturnal local processes.

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“…By employing the NDSL scheme, negative specific humidity values produced during spectral calculations can be eliminated without sacrificing the detailed features and accuracy of the model. This helps to alleviate the Gibbs phenomenon and ensures more reliable simulations using the IsoRSM (Chang & Yoshimura, 2015).…”

Section: Methodsmentioning

confidence: 99%

Simulation of water isotopes in combustion-derived vapor emissions in winter

Yang,

Yoshimura

2024

Preprint

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With urbanization, anthropogenic water vapor emissions have become a significant component of the urban atmosphere. Fossil fuel combustion-derived vapor (CDV) is a primary source of these emissions. Owing to the notably low CDV d-excess, stable hydrogen and oxygen isotopes are promising for distinguishing CDV from natural sources. Considering the limitations of in situ observations, this study aims to explore the feasibility of using IsoRSM, an isotopically enabled regional atmospheric model, to simulate CDV emissions in urban areas in winter. Two experiments were conducted: one in Salt Lake City in January 2017 and another in Beijing in January 2007. The simulation results showed that the CDV addition significantly reduced the water vapor d-excess, particularly when the boundary layer was stable. The simulation with CDV emissions aligned better with the time series of in situ observations in Salt Lake City. The modification led to a more pronounced positive correlation between vapor d-excess and specific humidity, which was similar to the observation of Salt Lake City. The CDV inclusion significantly increased the vapor d-excess variability with varying wind directions in both sites. However, in Beijing, the underestimation of d-excess variation from natural sources caused a bigger discrepancy between the observed and simulated d-excess and CDV fraction. Thus, though there were still biases, the inclusion of CDV could improve the accuracy of isotopic simulation in the urban regions where CDV was one of the controlling factors of vapor d-excess.

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A semi-Lagrangian advection scheme for radioactive tracers in the NCEP Regional Spectral Model (RSM)

Cited by 10 publications

References 25 publications

Dispersion characteristics of radioactive materials estimated by wind patterns

Dispersion characteristics of radioactive materials estimated by wind patterns

Long-distance transport of radioactive plume by nocturnal local winds

Simulation of water isotopes in combustion-derived vapor emissions in winter

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