Takuma Yokomae

Characterization of aerosols based on the simultaneous measurements

The aerosol distribution in Asia is complicated due to the increasing emissions of sulfuric, nitric, carbonaceous and other aerosols in association with economic growth. Anthropogenic small aerosols dominate the air over urban areas because of local emissions by diesel vehicles and industries, and in addition, behavior of natural dusts significantly varies with the seasons. Thus, studying various properties of aerosols in Asian urban areas is an important subject. In this work, we classify aerosol properties with a clustering method, by utilizing the ground observations provided by multi-spectral photometers which are installed in Kinki University Campus, Higashi-Osaka, Japan. Cluster information can be used to improve estimation of relations between spectral and particle observations.

Multiple light scattering calculations for aerosol retrieval

In this work we focus on aerosol retrieval in the heavy events such as dust storm and biomass burning plume. It is natural to consider that incident solar light multiply interacts with the atmospheric aerosols due to dense radiation field in the aerosol event, that is to say the optical thickness of Earth atmosphere increases too much to do sun/sky photometry from surface-level. However the space-based observations are available for monitoring the atmospheric aerosols even in the heavy aerosol events. Here retrieval algorithms from space for such aerosol events are proposed. In practice, appropriate index for detection of dust storm or biomass burning plume, diagnostic method of core part of the aerosol event, and simulation code of radiative transfer for semi-infinite atmosphere model are newly developed. In this work, the space- or surface-based measurements, multiple scattering calculations and model simulations are synthesized together for aerosol retrieval.

Interpretation of aerosol events in terms of radiation simulations and satellite data

The aerosol properties are estimated by comparing satellite measurements with the numerical values of radiation simulations in the Earth-atmosphere-surface model. This work is aimed at developing the practical and efficient algorithms for retrieving aerosol characteristics. The standard radiative transfer problem in a case of finite optical thickness is treated first, and then the problem in aerosol events such as dust storms or biomass burning plumes that are associated with excessive loading of aerosols in the atmosphere is considered. Finally our algorithms are practically applied for space-based measurements by MODIS.

The successive scattering in radiative transfer theory and its application for aerosol retrieval

Retrieval of atmospheric aerosol characteristics from satellite data, i.e. aerosol remote sensing, is based on the light scattering theory. The aerosol properties are estimated by comparing satellite measurements with the numerical values of radiation simulations in the Earth atmosphere model. This study was designed to develop an efficient algorithm to retrieve aerosol characteristics in aerosol events, which are associated with extreme concentrations of aerosols in the atmosphere such as a yellow-sand storm. It is known that the large increase in the optical thickness of the atmosphere during aerosol events prevents the use of sun/sky photometry from the surface level. However, space-based observations are possible for monitoring the atmospheric aerosols during such events. This study focuses on new algorithms being used to detect the event core with a high optical thickness and a simulation scheme for radiative transfer in the dense radiation field being employed. Finally, the practical application of our algorithms was tested using Aqua/MODIS data for a yellow-sand storm.

Environmental Information Viewing System (EIVS) Using Squeak on OLPC-XO

Our software (the EIVS) is designed for supporting environmental education by providing tools for 1) automatic data collection through networks, 2) data analysis, and 3) graph drawing of the environmental data measured by sensor-robots located at remote areas. Our software using Squeak (the Smalltalk environment) works on the hardware OLPC-XO with Squeak Virtual Machine. Our software on the OLPC-XO will allow a larger number of children using the OLPC-XO to recognize situations and problems of our environment for the discussions and the considerations of their better solutions.

Synthetic monitoring of Asian dust from space, ground and/or simulations

It is well known that the heavy soil dust has been transported from the China continent to Japan on westerly winds, especially in spring. It is also known that the increasing emissions of anthropogenic aerosols associated with continuing economic growth in Asia has caused serious air pollution over the wide range of East Asia. Accordingly the dust particles involve anthropogenic aerosols as well as soil dust. Thus aerosols in Asia are very complex due to mixing of small anthropogenic particles and large dust particles, which are called Asian dust. The satellite observation is an effective tool for global monitoring of the Asian dust. A new algorithm for detection of Asian dust from space is proposed based on the multispectral satellite (Terra/Aqua/MODIS) data. The derived space-based results are validated with the ground-based measurements and/or model simulations. The sun/sky photometry has been undertaken at NASA/AERONET stations at Higashi-Osaka in Japan, where the suspended particulate matter (SPM) sampling and NIES/LIDAR network equipment have been simultaneously working. In order to validate the satellite results with these surface-level data, an aerosol transportation model is available. In other word, the space-based and/or surface-based measurements are examined with the model simulations, and vice-versa.