Yousuke Sato

This study investigated the impact of several cloud microphysical schemes on the trade wind cumulus in the large eddy simulation model. To highlight the differences due to the cloud microphysical component, we developed a fully compressible large eddy simulation model, which excluded the implicit scheme and approximations as much as possible. The three microphysical schemes, the one-moment bulk, two-moment bulk, and spectral bin schemes were used for sensitivity experiments in which the other co

Aerosols affect climate by modifying cloud properties through their role as cloud condensation nuclei or ice nuclei, called aerosol-cloud interactions. In most global climate models (GCMs), the aerosol-cloud interactions are represented by empirical parameterisations, in which the mass of cloud liquid water (LWP) is assumed to increase monotonically with increasing aerosol loading. Recent satellite observations, however, have yielded contradictory results: LWP can decrease with increasing aeroso

Abstract. Aerosol–cloud interactions are one of the most uncertain processes in climate models due to their nonlinear complexity. A key complexity arises from the possibility that clouds can respond to perturbed aerosols in two opposite ways, as characterized by the traditional “cloud lifetime” hypothesis and more recent “buffered system” hypothesis. Their importance in climate simulations remains poorly understood. Here we investigate the response of the liquid water path (LWP) to aerosol pertu

Abstract A model intercomparison of the atmospheric dispersion of cesium‐137 ( 137 Cs) emitted after the Fukushima Daiichi Nuclear Power Plant accident in Japan was conducted to understand the behavior of atmospheric 137 Cs in greater detail. The same meteorological data with a fine spatiotemporal resolution and an emission inventory were applied to all models to exclude the differences among the models originating from differences in meteorological and emission data. The meteorological data wer

The third model intercomparison project (MIP) for investigating the atmospheric behavior of atmospheric caesium-137 (137Cs) emitted from Fukushima Daiichi Nuclear Power Plant (FDNPP) (3rd FDNPP-MIP), Japan, in March 2011, was conducted. A finer horizontal grid spacing (1 km) was used than in the previous FDNPP-MIP (2nd FDNPP-MIP, Sato et al., 2018; 3 km) to evaluate the models’ performance for high-concentration events measured near FDNPP. Nine of the models used in the 2nd FDNPP-MIP were also u

Abstract. The super-droplet method (SDM) is a particle-based numerical scheme that enables accurate cloud microphysics simulation with lower computational demand than multi-dimensional bin schemes. Using SDM, a detailed numerical model of mixed-phase clouds is developed in which ice morphologies are explicitly predicted without assuming ice categories or mass–dimension relationships. Ice particles are approximated using porous spheroids. The elementary cloud microphysics processes considered are

Abstract The sensitivity of simulated nonprecipitating cumulus clouds to grid length was investigated using a large‐eddy simulation model coupled to a particle‐based Lagrangian cloud microphysical model (LCM) and an Eulerian cloud microphysical model (ECM). For the sensitivity experiment, the horizontal/vertical grid length was decreased from 100/80 m to 6.25/5 m. The results of the sensitivity experiment indicated a similar dependency of cloud cover (CC) on the grid length in the LCM and ECM, w

Proton conductors capable of operating in the temperature range of 100–600 °C have received great interest for many application areas such as fuel cells, sensors, and electrolyzers; however, very few materials that can satisfy these demands have been reported to date. Here, we report a promising candidate for a solid electrolyte in intermediate-temperature electrochemical devices. First, MP2O7–MO2 composite ceramics (M = Sn, Si, Ti, and Zr) were prepared by reacting a porous MO2 substrate with a

Black carbon aerosol (BCA) in the Arctic has profound impacts on the global climate system through radiation processes. Despite its enormous impacts, current global scale models, powerful tools for estimating overall impact, tend to underestimate the levels of BCA in the Arctic over several seasons. Using a global aerosol transport simulation with a horizontal grid resolution of 3.5 km, we determined that a higher resolution significantly reduced the underestimation of BCA levels in the Arctic,

Cloud-aerosol interactions can be determined more accurately by isolating aerosol effects

Abstract. High-performance computing resources allow us to conduct numerical simulations with a horizontal grid spacing that is sufficiently high to resolve cloud systems on a global scale, and high-resolution models (HRMs) generally provide better simulation performance than low-resolution models (LRMs). In this study, we execute a next-generation model that is capable of simulating global aerosols using version 16 of the Nonhydrostatic Icosahedral Atmospheric Model (NICAM.16). The simulated ae

Abstract The impact of spatial resolution on the simulation of trade wind cumuli was investigated. The super‐droplet method, an efficient stochastic Lagrangian cloud microphysical model, was used to reduce uncertainties due to the empirical parameterisation of cloud microphysics and numerical diffusion for advection, which is inevitable in an Eulerian cloud microphysical model. We showed for the first time that cloud cover numerically converged with a grid resolution of 12.5 m. Our grid refineme

The usefulness of urinary hydrogen peroxide (H(2)O(2)) as an oxidative stress biomarker was evaluated in 766 healthy Japanese. The mean level of urinary concentrations of H(2)O(2) was 5.66 ± 8.27 μmol/g creatinine, and was significantly higher in females than in males. Significant correlations of H(2)O(2) were observed with age, aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-c), insulin, 8-hydroxy-2'-deoxyguanosi

Abstract The impacts of aerosols on the charge distribution of hydrometeors and lightning flash density in a tropical cyclone (TC) were investigated using a meteorological model coupled with an explicit lightning model. The meteorological model successfully simulated the tripole structure of charge density distribution in a TC, as reported by previous studies. The impacts of aerosols were investigated through a sensitivity experiment with changing the aerosol number concentration. The tripole st