Kei Kawai 교수

Abstract Mineral dust affects the microphysical and radiative properties of mixed‐phase clouds and hence the radiative balance of the Earth by acting as ice nucleating particles (INPs). However, the importance of Asian dust as INPs is not well understood. In this study, we examined the contribution of Asian dust to global dust INPs and its effect on cloud radiative forcing (CRF) using a global aerosol‐climate model with an ice nucleation parameterization that links INP number concentrations to a

Abstract Recent observations show that dust emitted within the Arctic (Arctic dust) has a remarkably high ice nucleating ability, especially between −20°C and −5°C, but its impacts on the number concentrations of ice nucleating particles (INPs) and radiative balance in the Arctic are not well understood. Here we incorporate an observation‐based ice‐nucleation parameterization indicating the high ice nucleating ability of Arctic dust into a global aerosol‐climate model. A simulation using this pa

The Gobi Desert is one of the major sources of Asian dust, which influences the climate system both directly and indirectly through its long-range transport by the westerlies. In this desert, three ground-based lidars are operated in Dalanzadgad, Sainshand, and Zamyn-Uud, Mongolia. This study firstly combined these lidars into a lidar network and shows the spatial development of a dust layer over the desert and the long-range transport of the dust during 22 -23 May 2013 via the lidar network. Du

The emission of Asian dust in arid regions of East Asia is controlled by many land surface parameters such as snow cover, soil moisture, and vegetation. In climate models, these factors are represented by the threshold friction velocity u*t, but its treatment has large uncertainties. Here we show that the treatment of u*t is important for estimating the emissions, transport, and climate impacts of Asian dust. Our global aerosol model simulates dust event frequencies that better agree with observ

Asian dust is transported over a long range via the mid-latitude westerlies when dust is lifted to the free troposphere over the source regions, whereas dust remaining in the atmospheric boundary layer is not transported far. In the Gobi Desert, a major source region of Asian dust, a ceilometer (compact lidar) monitors the vertical distribution of dust at Dalanzadgad, Mongolia. On 29-30 April 2015, the ceilometer observed a developed dust storm over the ground, followed by a dust layer within a

A lidar network captured the evolution of a dust layer in the Gobi Desert on 22–23 May 2013. The lidar network consists of a ceilometer and two AD-Net lidars in Mongolia. The dust layer was generated by a strong wind due to a cold front and elevated over the surface of the cold front by an updraft of the warm air in the cold-front system. It was evolving from the atmospheric boundary layer to the free troposphere while moving 600 km through the desert with the cold front.

Aerosols serve as ice nucleating particles (INPs) and play a critical role in the formation of mixed-phase clouds. These clouds are prevalent in the lower and middle troposphere of the Arctic and exert a strong influence on both regional and global climate. However, limited understanding of INP sources and their temperature-dependent behavior has hindered accurate predictions ofaerosol-cloud interactions in the Arctic. In this study, we investigate the sources, spatial distributions, seasonal va

Abstract. A subset of aerosol species act as ice nucleating particles (INPs) in mixed-phase clouds, where they influence cloud distributions and lifetimes and thus Earth's radiative balance through aerosol-cloud interactions. However, few modeling studies have simultaneously considered multiple aerosol species as INPs, and the radiative effects associated with INPs remain poorly constrained. This study uses a global climate-aerosol model to evaluate the number concentrations, spatial distributio

This archive contains datasets used in the paper entitled "Dominant Role of Arctic Dust with High Ice Nucleating Ability in the Arctic Lower Troposphere".

This archive contains datasets used in the paper entitled "High Potential of Asian Dust to Act as Ice Nucleating Particles in Mixed-Phase Clouds Simulated With a Global Aerosol-Climate Model".

<strong class="journal-contentHeaderColor">Abstract.</strong> A subset of aerosol species act as ice nucleating particles (INPs) in mixed-phase clouds, where they influence cloud distributions and lifetimes and thus Earth's radiative balance through aerosol-cloud interactions. However, few modeling studies have simultaneously considered multiple aerosol species as INPs, and the radiative effects associated with INPs remain poorly constrained. This study uses a global climate-aerosol model to eva

<strong class="journal-contentHeaderColor">Abstract.</strong> A subset of aerosol species act as ice nucleating particles (INPs) in mixed-phase clouds, where they influence cloud distributions and lifetimes and thus Earth's radiative balance through aerosol-cloud interactions. However, few modeling studies have simultaneously considered multiple aerosol species as INPs, and the radiative effects associated with INPs remain poorly constrained. This study uses a global climate-aerosol model to eva