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Field observations to investigate the correlation between New Particle Formation (NPF) and the long-range transport of air pollutants in the East Asia region were carried out on a rural Island of Japan in the East-China Sea (Fukue Island, 32.8°N, 128.7°E) over three periods (February 23 to March 7, 2013; November 7 to 20, 2013; and November 2 to 24, 2014). Frequent NPF events were identified (16 events in 50 days), typically in association with sudden increases in particle number concentrations and the successive growth of particles to mobility diameters of several tens of nanometers. The NPF events were classified into two types (A and B) according to the initially detected particle sizes (onset diameters). Type-A consisted of strong NPF events with onset diameters as small as 5 nm. Type-B consisted of NPF events whose onset (

Time-resolved data for size distribution, number concentration and chemical composition of atmospheric aerosols were taken from March 9 to 16, 2012 during Fukue Site Atmospheric Aerosol Observation Campaign (128.7°E, 32.8°N) organized by ASEPH (Impacts of Aerosols in East Asia on Plants and Human Health) project. A scanning mobility particle sizer was employed to continuously measure the particle size distribution from 14 nm to 670 nm and the total number concentration of particles (>3 nm) was measured by a condensation particle counter. Very large amount of polluted air mass transportation (PM2.5 > 65 μg m−3) was observed on March 11, associated with a sudden increase in particle number concentration having a mobility diameter from 100 to 300 nm. The transported air mass contained anthropogenic pollutants such as sulfate (>20 μg m−3), nitrate (>15 μg m−3) and black carbon (>3 μg m−3). Typical new particle formation and growth events were also observed on March 12–13. The onset of particle formation and nucleation bursts was identified at around noon and it is considered that these were nucleated species near the island area. It was found that some new particle formation events were associated with the long range transportation of polluted air mass from East Asian region.

Land surface albedo is one of the key parameters in the radiation budget, the hydrological cycle and climate modeling studies. It is now widely understood that large errors may occur in the estimation of surface albedo without taking into consideration the anisotropy reflectance effect, which is a general feature of the earth surface. Two major anisotropic correction methods exist for the retrieval of land surface albedo under clear sky conditions. One method involves linearly converting from top of the atmosphere (TOA) albedo to surface albedo, and another is based on the inversion of the Bidirectional Reflectance Distribution Function (BRDF) model of the surface. In the present study, a new approach that utilizes an empirical model for estimating surface albedo has been proposed for snow free land surfaces under clear sky conditions. We analyzed the bidirectional reflectance data set with numerous samples representing various land cover types, which derived from POLDER/ADEOS-1 multi-angle imagery data and distributed by MEDIAS-France. Through the analysis, an empirical relation between bidirectional reflectance and albedo was established and has been discussed in detail. The proposed model can be used for direct estimation of surface albedo from a single BRF observation when the sun-target-sensor geometry is known. No BRDF model inversion scheme is necessary. The present model has no or weak dependence on the existing land surface classifications, and is insensitive to wavelength. The theoretical absolute accuracy of the estimated albedo is approximately 0.010 for visible (0.4–0.7 μm), 0.023 for near infrared (0.7–3.0 μm) and 0.016 for shortwave (0.2–3.0 μm), respectively. Albedo consistency with viewing geometry has been verified, resulting in good agreement for albedo estimated from various viewing directions. Validation of the satellite estimated albedo derived by the proposed method, using field observations were also presented and results show it can give reasonably accurate estimation. The proposed method is expected to be a suitable candidate for practical applications of albedo estimation for sensors that do not perform multi-angle observations.

Longwave radiation flux, an important part of the surface heat budget, is generally represented by eσT r 4 , where e is the surface emissivity, σ is the Stefan–Boltzmann constant, and T r is the measured radiometric temperature. eσT r 4 differs from hemispheric emission because the measured radiometric temperature is anisotropic for an uneven surface. This paper analyzes the anisotropy-related error in measurements of longwave radiation flux from a building canopy. The flux difference between eσT r 4 and directly measured flux was up to 8% of the directly measured flux, which could be greater than the typical error in measurement of turbulent heat flux over a building canopy. The flux difference increased as the temperature variation within the urban street canyon increased, and also with increasing difference between the incident solar radiation of the building walls and street canyon floors (pavement, roads, ground surface). Theoretical calculations indicate that the flux difference is due to the structure of the building canopy and the temperature difference between the walls and canopy floors. A numerical model of a building canopy heat budget shows that the flux difference increases as the street canyon aspect ratio increases.

Seasonal variations of tropospheric aerosol properties in Chiba, Japan, are investigated by means of optical monitoring (1999–2005), ground sampling (1998–2004), and wind data. The observation site at Chiba University is located in the urban Chiba area, about 30 km southeast of Tokyo. The aerosol optical thickness (AOT) and Angstrom exponent are derived from the data taken with a sun photometer. The value of AOT at the wavelength of 500 nm exhibits a seasonal variation, showing small values (

This study compares the function of AERONET and SKYNET, which are well known components of the ground-based aerosol-monitoring network. AERONET uses the Cimel CE-318-1 and -2 sun/sky photometer system, and SKYNET adopts Prede POM-O1, -02, and -100P sun/sky photometers (aka skyradiometer). These are available for direct- or diffuse-solar radiation measurements in order to calculate aerosol optical thickness or other aerosol properties such as size distribution, respectively. The CE-318-2 (AERONET) and the POM-100P (SKYNET) instruments have recently been installed at Kinki University in Osaka, Japan, for the retrieval of aerosol data. These have been calibrated at NASA/GSFC and at the Mauna Loa Observatory, respectively, based on the Langley plot method. The difference in the aerosol optical thickness derived from simultaneous measurements using these two types of radiometer was less than 0.008 (

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 properties of aerosols in each area. A retrieval algorithm previously developed for MODIS was modified for the NOAA/AVHRR visible and near infrared channels based on the look-up table, which is pre-calculated with 6S code. Local biomass burning aerosol concentrations and contribution factor η of small radius particles over certain ocean areas between the two islands were derived from two channel data of NOAA/AVHRR. The results were validated with surface meteorological data, and sun photometer data.