Akiko Higurashi

• National Institute for Environmental Studies

Algorithms were developed to produce ATLID (Atmospheric Lidar) L2 aerosol products using ATLID L1 data. The algorithms estimated the following four products: (1) Layer identifiers such as aerosols, clouds, clear-skies, or surfaces (feature masks) were estimated by the combined use of vertically variable criteria and spatial continuity methods devel...

We develop an algorithm to retrieve aerosol optical properties using data of 355-nm high spectral resolution lidar (HSRL) with depolarization measurement function “ATLID” onboard EarthCARE satellite. The ATLID has three channel data of Mie copolar, Mie crosspolar, and Rayleigh attenuated backscatter coefficients at 355 nm. Using the three channel d...

For the observation of the global three-dimensional distribution of aerosol composition and the evaluation of the shortwave direct radiative effect (SDRE) by aerosols, we developed a retrieval algorithm that uses observation data from the Cloud–Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the Cloud–Aerosol Lidar Infrared Pathfinder...

This paper is an overview of the progress in sky radiometer technology and the development of the network called SKYNET. It is found that the technology has produced useful on-site calibration methods, retrieval algorithms, and data analyses from sky radiometer observations of aerosol, cloud, water vapor, and ozone. A formula was proposed for estim...

Abstract. This paper overviews the progress in the sky radiometer technology and development of the network called SKYNET. It is found that the technology has produced useful on-site calibration methods, retrieval algorithms, and data analyses from the sky radiometer observation of aerosol, cloud, water vapor and ozone. Increasing collaborations of...

We developed an algorithm to derive extinction coefficients for four aerosol components (water-soluble, dust, sea salt, black carbon) from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) data. The algorithm was applied to the nine-year data for 2007–2015 and the results were compared to CALIOP standard product (CALIOP-ST) and MODerate res...

We develop a common retrieval algorithm of aerosol properties such as aerosol optical thickness, single-scattering albedo, and Ångström exponent for various satellite sensors over both land and ocean. The three main features of this algorithm are as follows: (1) automatic selection of the optimum channels for aerosol retrieval by introducing a weig...

We developed a scheme to improve hourly estimates of aerosol optical thickness (AOT) from the Advanced Himawari Imager (AHI) onboard Himawari-8, the Japan Meteorological Agency's latest geostationary satellite. Taking advantage of the sampling characteristics of the AHI (10-min temporal and subkilometer spatial resolution), we quantify temporal and...

For the monitoring of the global 3-D distribution of aerosol components, we developed the method to retrieve the vertical profiles of water-soluble, light absorbing carbonaceous, dust, and sea salt particles by the synergy of CALIOP and MODIS data. The aerosol product from the synergistic method is expected to be better than the individual products...

We have operated a ground-based lidar network AD-Net using dual wavelength (532, 1064nm) depolarization Mie lidar continuously and observed movement of Asian dust and air pollution aerosols in East Asia since 2001. This lidar network observation contributed to understanding of the occurrence and transport mechanisms of Asian dust, validation of che...

We have operated a ground-based lidar network AD-Net using dual wavelength (532, 1064nm) depolarization Mie lidar continuously and ob- served movement of Asian dust and air pollution aerosols in East Asia since 2001. This lidar net- work observation contributed to understanding of the occurrence and transport mechanisms of Asian dust, validation of...

[1] A satellite aerosol retrieval algorithm was developed to utilize a near-ultraviolet band of the Greenhouse gases Observing SATellite/Thermal And Near infrared Sensor for carbon Observation (GOSAT/TANSO)-Cloud and Aerosol Imager (CAI). At near-ultraviolet wavelengths, the surface reflectance over land is smaller than that at visible wavelengths....

EarthCARE (Earth Clouds, Aerosols and Radiation Explorer) is a joint Japanese (JAXA)-European (ESA) satellite observation mission for understanding the interaction between cloud, aerosol, and radiation processes in the earth climate. Four sensors of cloud profiling radar (CPR), multi-spectral imager (MSI), broadband radiometer (BBR), and high spe...

Potential improvements of aerosols algorithms for future climate-oriented satellites such as the coming Global Change Observation Mission Climate/Second generation Global Imager (GCOM-C/SGLI) are discussed based on a validation study of three years’ (2008–2010) daily aerosols properties, that is, the aerosol optical thickness (AOT) and the Ångström...

The potential performance of aerosols products of future satellites such as that of the Global Change Observation Mission-Climate/Second Generation GLobal Imager (GCOM-C/SGLI) and, the regional climate uncertainties due to the accuracy of these products are discussed, based on analyses of actually existing data from comparable (to the GCOM-C/SGLI)...

This study developed an algorithm for estimating solar radiation from space using a neural network (NN) with an improved learning algorithm to approximate radiative transfer code. The NN solver for the solar radiation budget is based on radiative transfer calculations. All data sets for testing and training the NN were generated from radiative tran...

A vector radiative transfer model has been developed for a coupled atmosphere–ocean system. The radiative transfer scheme is based on the discrete ordinate and matrix operator methods. The reflection/transmission matrices and source vectors are obtained for each atmospheric or oceanic layer through the discrete ordinate solution. The vertically inh...

We have been performing radiative budget measurements at a ground-based observatory located on Fukue Island. In this study, we analyzed the data from instruments installed in the observatory and the data observed by MODIS, the satellite-borne imager, to evaluate cirrus cloud radiative forcing (CRF). The result shows that CRF took a large positive v...

Using ADEOS-II/GLI aerosol and cloud products, downward and upward solar radiation at the surface and at the top of the atmosphere are estimated to study the Earth radiation budget. There is a good agreement in the main features of the global distribution of radiative fluxes as derived from GLI and from Terra/MODIS, yet, some differences can be not...

The GOSAT satellite has been designed for retrieving the carbon dioxide amount in the atmosphere by a Fourier transform spectro-radiometer (TANSO-FTS). It is, however, known that FTS-observed radiances in the near-infrared spectral region are heavily contaminated by a solar radiation component scattered by atmospheric aerosols, which is known as “p...

This article introduces an international regional experiment, East Asian Regional Experiment 2005 (EAREX 2005), carried out in March–April 2005 in the east Asian region, as one of the first phase regional experiments under the UNEP Atmospheric Brown Cloud (ABC) project, and discusses some outstanding features of aerosol characteristics and its dire...

The Atmospheric Brown Cloud-East Asia Regional Experiment (ABC-EAREX) was conducted under the UNEP/ABC-Asia project to intercompare the aerosol and gas measurements in springtime from various instruments from late February to April 2005 at the Gosan Supersite on Jeju Island, Korea. Satellite instruments such as the Moderate Resolution Imaging Spect...

Aerosol affects the Earth's climate by scattering and absorbing radiation and by altering the cloud microphysics. Since these effects are different from one type to the other, aerosol type detection from satellite remote sensing is important. This study shows temporal and spatial distribution of four major aerosol types (dust, carbonaceous, seasalt...

We have investigated the impact of atmospheric aerosols on retrieval of CO2 column amount using simulated data of Short Wavelength Infrared (SWIR) radiances measured by a Fourier Transform Spectrometer (FTS) to be onboard Greenhouse Gases Observing Satellite (GOSAT). Atmospheric aerosols are widespread over the earth, and a typical optical depth of...

1] We use aerosol size distributions measured in the size range from 0.01 to 10+ mm during Transport and Chemical Evolution over the Pacific (TRACE-P) and Aerosol Characterization Experiment–Asia (ACE-Asia), results of chemical analysis, measured/modeled humidity growth, and stratification by air mass types to explore correlations between aerosol o...

Global Imager (GLI) is the moderate spatial resolution imager which has 36 channels from near UV to infrared. It observed cloud and aerosol properties for global scale. One of the features of the GLI is that it has 380 nm channel in near UV region. Using this channel in RGB composite image, the aerosols spread over the land area clearly identified....

In order to estimate the errors of CO2 and CH4 column amounts retrieved from the measurement by using a SWIR (Short Wavelength InfraRed) FTS sensor aboard GOSAT (Greenhouse gases Observing Satellite), various error sources should be taken into account. Some possible error sources are aerosols, cirrus cloud, water vapor, surface pressure (altitude),...

Greenhouse gases Observing Satellite (GOSAT) of Japan is planned to be launched in 2008. GOSAT is equipped with a Fourier Transform Spectrometer (FTS) to monitor CO2 column density globally. The FTS covers a near infrared band and two short wavelength infrared (SWIR) bands, which cover 0.76 micron, 1.6 micron, and 2.0 micron spectral regions, respe...

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Greenhouse gases Observing SATellite (GOSAT) is a Japanese satellite to monitor column density of greenhouse gases such as carbon dioxide (CO2) and methane (CH4) globally from space. GOSAT will be launched in 2008. The data measured by a GOSAT sensor and ground-based monitoring station data will be used into an atmospheric transport inverse model t...

To estimate aerosol effects on climate change more reliably by modeling studies, it is essential to compare with a variety of measured aerosol and cloud parameters in detail. The global aerosol radiation-transport model, SPRINTARS, simulate three-dimensional distributions and direct/indirect effects of main tropospheric aerosols, i.e., black carbon...

We are using aerosol size distributions measured in the size range from 0.01 to 10+ um during TRACE-P and ACE-Asia, results of chemical analysis, measured/modeled humidity growth and stratification by air mass types to explore correlation between aerosol optical parameters and aerosol number concentration. Size distributions allow us to integrate a...

Widespread boreal forest fires persisted in Eastern Asia for several months from the beginning of April until September 2003. This resulted in enhanced concentrations of smoke aerosol in a very large region, ranging from the source area of the fires in eastern Siberia to northern and eastern China, Korea, and Japan. The smoke was also detected over...

1] As part of the Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia), the upward and downward spectral solar radiant fluxes were measured with the Spectral Solar Flux Radiometer (SSFR), and the aerosol optical depth was measured with the Ames Airborne Tracking Sunphotometer (AATS-14) aboard the Center for Interdisciplinary Remote...

For an 8-month period aerosol optical depth (AOD) is compared, derived over global oceans with five different retrieval algorithms applied to four satellite instruments flown on board three satellite platforms. The Advanced Very High Resolution Radiometer (AVHRR) was flown on board NOAA-14, the Ocean Color and Temperature Scanner (OCTS) and the Pol...

The indirect effect of aerosols was simulated by a GCM for nonconvective water clouds and was compared with remote sensing results from the Advanced Very High Resolution Radiometer (AVHRR) satellite-borne sensor for January, April, July, and October of 1990.The simulated global distribution of cloud droplet radius showed a land sea contrast and a c...

The Global Imager (GLI) onboard ADEOS-2 is the first medium-resolution Earth observation satellite sensor that is able to combine measurements from the near-UV to the IR wavelength region. This work investigates a newly available channel in the near-UV to retrieve the optical thickness and single-scattering albedo of aerosols. Due to the low reflec...

A three-dimensional aerosol transport-radiation model coupled with a general circulation model, Spectral Radiation-Transport Model for Aerosol Species (SPRINTARS), simulates atmospheric aerosol distributions and optical properties. The simulated results are compared with aerosol sampling and optical observations from ground, aircraft, and satellite...

Radiative forcings of aerosols and clouds in the East China Sea region are studied using data from surface radiation measurements, satellite remote sensing, and model simulation conducted in April 2001 as a study of Asian Atmospheric Particle Environmental Change Studies (APEX) cooperating with International Global Atmospheric Chemistry (IGAC)/ACE-...

The present study investigated the correlations between aerosol and cloud parameters derived from satellite remote sensing for evaluating the radiative forcing of the aerosol indirect effect. The global statistics showed that the effective particle radius and the optical thickness of low clouds correlate well with the column number concentration of...

A three-dimensional aerosol transport-radiation model, SPRINTARS, successfully simulates the long-range transport of the large-scale Asian dust storms from East Asia to North America which crossed the North Pacific Ocean during the springtime of 2001 and 2002. It is found from the calculated dust optical thickness that 10 to 20% of the Asian dust a...

Aerosol-type detection from satellite remote sensing is difficult but an important challenge for improving the estimation of aerosol radiative forcing. In this paper, we have classified aerosols into four major aerosol types, that is, soil dust, carbonaceous, sulfate and sea salt aerosols using SeaWiFS four-channel data. The retrieved results show...

The Georgia Institute of Technology–Goddard Global Ozone Chemistry Aerosol Radiation and Transport (GOCART) model is used to simulate the aerosol optical thickness � for major types of tropospheric aerosols including sulfate, dust, organic carbon (OC), black carbon (BC), and sea salt. The GOCART model uses a dust emission algorithm that quantifies...

The determination of an accurate quantitative understanding of the role of tropospheric aerosols in the earth's radiation budget is extremely important because forcing by anthropogenic aerosols presently represents one of the most uncertain aspects of climate models. Here the authors present a systematic comparison of three different analyses of sa...

This paper overviews the activities of the ADEOS-II/GLI Sensor Team for developing algorithms and validation system for remote sensing of aerosol and cloud microphysical parameters from ADEOS-II/GLI satellite-borne imager with 36 visible and infrared channels. Standard algorithms have been implemented to the NASDA EOC data processing system. Severa...

The column aerosol particle number and low cloud microphysical parameters derived from AVHRR remote sensing are compared over ocean for four months in 1990. There is a positive correlation between cloud optical thickness and aerosol number concentration, whereas the effective particle radius has a negative correlation with aerosol number. The cloud...

A global three-dimensional transport model that can simultaneously treat main tropospheric aerosols, i.e., carbonaceous (organic and black carbons), sulfate, soil dust, and sea salt, is developed. It is coupled with a Center for Climate System Research (CCSR)/National Institute for Enviormental Studies (NIES) atmospheric general circulation model (...

Numerical experiment was performed using a general circulation model (GCM) including aerosol indirect effect into water cloud and the simulated global distribution of cloud droplet radii was compared with the global distribution of cloud effective radii retrieved from Advanced Very High Resolution Radiometer (AVHRR). Comparisons of GCM calculation...

Indonesian forest fire took place in wide area of Kalimantan and Sumatera Islands in 1997 and continuously influenced the atmospheric environment and meteorological conditions of South-East Asia nearly throughout the last half of the year. The fire produced various materials including chemical gas and particles, which acted on the optical propertie...

A global three-dimensional model that can treat transportation of various species of aerosols in the atmosphere is developed using a framework of an atmospheric general circulation model (AGCM). Main aerosols in the troposphere, i.e., soil dust, carbonaceous (organic and black carbon), sulfate, and sea-salt aerosols, are introduced into this model....

Global distributions of the aerosol optical thickness and Ångström exponent are estimated from National Oceanic and Atmospheric Administration Advanced Very High Resolution Radiometer channel-1 and -2 radiances for four months in 1990. Global distributions of those Ångström parameters are consistent with present knowledge on the distributions of de...

Optical properties of biomass burning aerosols in the event of Indonesian forest fires in 1997 were studied by groundbased sky radiometry and satellite remote sensing with AVHRR and TOMS radiometers. The AVHRR‐derived optical thickness distribution agreed with the distribution of TOMS‐derived UV‐absorbing aerosol index and with the optical thicknes...

An analysis of ocean color temperature scanner [(OCTS) on board the advanced earth observation satellite (ADEOS)] spectral radiance data was performed for retrieving global distributions of Angstrom factor and exponent, which represent the aerosol optical thickness at a reference wavelength (500 nm in the authors' study) and a spectral dependence o...

This study proposes a two-channel satellite remote sensing algorithm for retrieving the aerosol optical thickness and the Ångström exponent, which is an index for the aerosol size distribution. An efficient lookup table method is adopted in this algorithm to generate spectral radiances in channels 1 and 2 of National Oceanic and Atmospheric Adminis...

We report new satellite retrievals of an aerosol particle size index, Ångström exponent, along with aerosol optical thickness, obtained from a two channel algorithm for NOAA/AVHRR and ADEOS/OCTS satellite‐borne radiometers. The results show characteristic features of the global aerosol size index on global scale. Small aerosol particles were detect...

This paper first describes the atmospheric correction algorithm for OCTS visible band data used at NASDA/EOC. Sharing a basic structure with Gordon and Wang’s Sea WiFS algorithm, it uses 10 candidate aerosol models including the “Asian dust model” introduced in consideration of the unique feature of aerosols over the east Asian waters. Based on the...

Satellite remote sensing is studied in this paper for retrieving aerosol parameters, i.e., aerosol optical thickness at 0.5 μm τ0.5, size exponent p, and absorption index κ, from channel 1 and 2 radiances of the NOAA 11 advanced very high resolution radiometer (AVHRR) in the Persian Gulf region in the summer of 1991. Results of the remote sensing a...

Solar radiation measurements were made using sun photometers and pyranometers during 31 May-7 June 1991 at several places in Iran and during 12 June-17 September 1991 at a fixed place, Bushehr, Iran. In the first period the aerosol optical thickness had values about 0.4 at the wavelength of 0.5 m in the coastal area and about 0.2 in the plateau are...

Optical properties of Persian Gulf oil fire aerosols were investigated by simultaneous analyses of ground based solar radiation measurements and satellite remote sensing technique for a period of June 12-September 17, 1991 at Bushehr, Iran. The atmospheric turbidity at Bushehr increased nearly regularly with a period of one week. This phenomenon wa...

Global distributions of the aerosol optical thickness and A ˚ ngström exponent are estimated from National Oceanic and Atmospheric Administration Advanced Very High Resolution Radiometer channel-1 and-2 radiances for four months in 1990. Global distributions of those A ˚ ngström parameters are consistent with present knowledge on the distributions...

Radiative fluxes drive the surface hydrologic and energy budgets on time scales from diurnal to interannual, they are needed for the evaluation of land surface parameterizations, and for estimation of net primary productivity. Most efforts that attempt to derive such fluxes from satellite observations have been designed with a particular satellite...

1990?s was the big ban era of the second generation aerosol remote sensing technology. AVHRR remote sensing with one and two channel algorithms has depicted characteristic outflow of anthropogenic and mineral dust aerosols from continents to the ocean environment. Second generation ocean color sensors, such as OCTS and SeaWiFS, and new general purp...

A vicarious calibration methodology for geostationary satellites visible channel has been developed. The approach is based on comparison between satellite visible observations and radiative transfer calculations. It is important for reliable calibration to perform the comparison for proper observation condition. This study employs three types of re...