ALBERT

Description: Measurements of black carbon (BC) and organic carbon (OC) were conducted in Bangkok during 2007–2008. Annual trends of BC and OC show strong seasonality with lower and higher concentrations during wet and dry seasons, respectively. Flow of cleaner air, wet removal, and negligible biomass burning resulted in the lowest concentrations of aerosols in the wet season. In addition to anthropogenic sources, long-range transport and biomass burning caused higher concentrations in the dry and hot seasons, respectively. Despite extensive biomass burning in the hot season, moderate levels of aerosols were due to the mixing with air masses from the Pacific Ocean. Diurnal distributions exhibit peaks during rush hour marked by minima in the OC/BC ratio and stagnant wind flow. The lowest concentrations in the afternoon hours could be due to deeper planetary boundary layer and reduced traffic. Overall, the concentrations of both BC and OC decrease with the increase in wind speed. The weekend effects, due to reduced emission during weekends, in the concentrations of both BC and OC were significant. Therefore, stricter abatement in vehicular emissions could substantially reduce pollution. A slope of ΔBC/ΔCO of 9.8 ngm−3 ppbv−1 for the wet season represents the emission ratio from vehicular sources. The highest of ΔOC/ΔBC (3 μg μg−1) in the hot season was due to the predominant influence of biomass burning and significant formation of secondary OC. The levels of BC and OC in Bangkok fall within the ranges of their concentrations measured in the major cities of East Asia.

Description: [1]  The new particle formation (NPF)-explicit version of the WRF-chem model, which we developed recently, can calculate the growth and sink of nucleated clusters explicitly with 20 aerosol size bins from 1 nm to 10 µm. In this study, the model is used to understand spatial and temporal variations of the frequency of NPF events and the concentrations of aerosols (condensation nuclei, CN) and cloud condensation nuclei (CCN) within the boundary layer in East Asia in spring 2009. Model simulations show distinct north–south contrast in the frequency and mechanism of NPF in East Asia. NPF mostly occurred over limited periods and regions between 30° and 45°N, such as northeast China, Korea, and Japan, including regions around active volcanoes (Miyakejima and Sakurajima). At these latitudes, NPF was considerably suppressed by high concentrations of preexisting particles under stagnant air conditions associated with high-pressure systems, while nucleation occurred more extensively on most days during the simulation period. Conversely, neither nucleation nor NPF occurred frequently south of 30°N because of lower SO 2 emissions and H 2 SO 4 concentrations. The period-averaged NPF frequency was 3 times higher at latitudes of 30° – 45°N than at latitudes of 20° – 30°N. The north–south contrast of NPF frequency is validated by surface measurements in outflow regions in East Asia. The period- and domain-averaged contribution of secondary particles is estimated to be 44% for CN (〉 10 nm) and 26% for CCN at a supersaturation of 1.0% in our simulation, though the contribution is highly sensitive to the magnitudes and size distributions of primary aerosol emissions and the coefficients in the nucleation parameterizations.

Description: Author(s): Zs. Vajta, Zs. Dombrádi, Z. Elekes, T. Aiba, N. Aoi, H. Baba, D. Bemmerer, Zs. Fülöp, N. Iwasa, Á. Kiss, T. Kobayashi, Y. Kondo, T. Motobayashi, T. Nakabayashi, T. Nannichi, H. Sakurai, D. Sohler, S. Takeuchi, K. Tanaka, Y. Togano, K. Yamada, M. Yamaguchi, and K. Yoneda The one-neutron knock-out reaction H 1 ( C 20 , C 19 γ ) was studied at RIKEN using the DALI2 array. A γ -ray transition was observed at 198(10) keV. Based on the comparison between the experimental production cross section and theoretical predictions, the transition was assigned to the de-excitation of the 3 ... [Phys. Rev. C 91, 064315] Published Tue Jun 23, 2015

Description: Continuous in situ measurements of the mass concentration of black carbon (BC) aerosols and mixing ratio of carbon monoxide (CO) were made at Cape Hedo on Okinawa Island, Japan, a remote site located in the East China Sea, from March 2008 to May 2009. For the first time, we show temporal variations of BC and CO at Hedo in Asian outflows throughout the year. Annual average concentrations of BC and CO were 0.29 μg m−3 and 150 ppbv, respectively. The origins of the observed air masses were determined by using 5-day back trajectories, suggesting that about 51% of the air masses arriving at Hedo were from the Chinese region during spring and winter, while about 78% of air masses were of maritime origin during summer. Because of the more frequent transport of Chinese air to Hedo in spring and winter, the average and background concentrations of BC and CO in these seasons were higher by about a factor of 2 than those in summer and fall. Air masses from north China made the largest contributions to elevating the BC levels at Hedo because of the high BC emission rate and frequency of transport. The observed ΔBC/ΔCO ratio systematically decreased with the decrease in model-calculated transport efficiency (TEBCcal). On the basis of this result, we derive region-specific ΔBC/ΔCO ratios by selecting data with TEBCcal 〉 80%. The annually averaged ΔBC/ΔCO ratios for air originated from north and south China were 7.0 ± 3.3 and 7.5 ± 4.6 ng m−3 ppbv−1, respectively, about half the annual BC/CO emission ratio derived from the emission inventory of Zhang et al. (2009). We evaluate the CO emission inventory of Zhang et al. (2009) for China by comparing observed (ground-based and aircraft) and model-calculated CO values. The comparison indicates that the CO emissions from China were underestimated by about a factor of 2.

Description: A detailed paleomagnetic study conducted in the Sangiran area, Java, has provided a reliable age constraint on hominid fossil-bearing formations. A reverse-to-normal polarity transition marks a 7-m thick section across the Upper Tuff in the Bapang Formation. The transition has three short reversal episodes and is overlain by a thick normal polarity magnetozone that was fission-track dated to the Brunhes chron. This pattern closely resembles another high-resolution Matuyama–Brunhes (MB) transition record in an Osaka Bay marine core. In the Sangiran sediments, four successive transitional polarity fields lie just below the presumed main MB boundary. Their virtual geomagnetic poles cluster in the western South Pacific, partly overlapping the transitional virtual geomagnetic poles from Hawaiian and Canary Islands’ lavas, which have a mean 40Ar/39Ar age of 776 ± 2 ka. Thus, the polarity transition is unambiguously the MB boundary. A revised correlation of tuff layers in the Bapang Formation reveals that the hominid last occurrence and the tektite level in the Sangiran area are nearly coincident, just below the Upper Middle Tuff, which underlies the MB transition. The stratigraphic relationship of the tektite level to the MB transition in the Sangiran area is consistent with deep-sea core data that show that the meteorite impact preceded the MB reversal by about 12 ka. The MB boundary currently defines the uppermost horizon yielding Homo erectus fossils in the Sangiran area.

Description: [1]  Black carbon aerosol plays a unique and important role in Earth's climate system. Black carbon is a type of carbonaceous material with a unique combination of physical properties. This assessment provides an evaluation of black-carbon climate forcing that is comprehensive in its inclusion of all known and relevant processes and that is quantitative in providing best estimates and uncertainties of the main forcing terms: direct solar absorption, influence on liquid, mixed-phase, and ice clouds, and deposition on snow and ice. These effects are calculated with climate models, but when possible, they are evaluated with both microphysical measurements and field observations. Predominant sources are combustion related; namely, fossil fuels for transportation, solid fuels for industrial and residential uses, and open burning of biomass. Total global emissions of black carbon using bottom-up inventory methods are 7500 Gg yr -1 in the year 2000 with an uncertainty range of 2000 to 29000. However, global atmospheric absorption attributable to black carbon is too low in many models, and should be increased by a factor of almost three. After this scaling, the best estimate for the industrial-era (1750 to 2005) direct radiative forcing of atmospheric black carbon is +0.71 W m -2 with 90% uncertainty bounds of (+0.08, +1.27) W m -2 . Total direct forcing by all black carbon sources, without subtracting the pre-industrial background, is estimated as +0.88 (+0.17, +1.48) W m -2 . Direct radiative forcing alone does not capture important rapid adjustment mechanisms. A framework is described and used for quantifying climate forcings, including rapid adjustments. The best estimate of industrial-era climate forcing of black carbon through all forcing mechanisms, including clouds and cryosphere forcing, is +1.1 W m -2 with 90% uncertainty bounds of +0.17 to +2.1 W m -2 . Thus, there is a very high probability that black carbon emissions, independent of co-emitted species, have a positive forcing and warm the climate. We estimate that black carbon, with a total climate forcing of +1.1 W m -2 , is the second most important human emission in terms of its climate-forcing in the present-day atmosphere; only carbon dioxide is estimated to have a greater forcing. Sources that emit black carbon also emit other short-lived species that may either cool or warm climate. Climate forcings from co-emitted species are estimated and used in the framework described herein. When the principal effects of co-emissions, including cooling agents such as sulfur dioxide, are included in net forcing, energy-related sources (fossil-fuel and biofuel) have an industrial-era climate forcing of +0.22 (-0.50 to +1.08) W m -2 during the first year after emission. For a few of these sources, such as diesel engines and possibly residential biofuels, warming is strong enough that eliminating all emissions from these sources would reduce net climate forcing ( i . e ., produce cooling). When open burning emissions, which emit high levels of organic matter, are included in the total, the best estimate of net industrial-era climate forcing by all black-carbon-rich sources becomes slightly negative (-0.06 W m -2 with 90% uncertainty bounds of -1.45 to +1.29 W m -2 ). The uncertainties in net climate forcing from black-carbon-rich sources are substantial, largely due to lack of knowledge about cloud interactions with both black carbon and co-emitted organic carbon. In prioritizing potential black-carbon mitigation actions, non-science factors, such as technical feasibility, costs, policy design, and implementation feasibility play important roles. The major sources of black carbon are presently in different stages with regard to the feasibility for near-term mitigation. This assessment, by evaluating the large number and complexity of the associated physical and radiative processes in black-carbon climate forcing, sets a baseline from which to improve future climate forcing estimates.

Description: Author(s): S. Sakaguchi, T. Uesaka, N. Aoi, Y. Ichikawa, K. Itoh, M. Itoh, T. Kawabata, T. Kawahara, Y. Kondo, H. Kuboki, T. Nakamura, T. Nakao, Y. Nakayama, H. Sakai, Y. Sasamoto, K. Sekiguchi, T. Shimamura, Y. Shimizu, and T. Wakui Vector analyzing powers for proton elastic scattering from 8 He at 71 MeV/nucleon have been measured using a solid polarized proton target operated in a low magnetic field of 0.1 T. The spin-orbit potential obtained from a phenomenological optical model analysis is found to be significantly shallower... [Phys. Rev. C 87, 021601] Published Wed Feb 20, 2013

Description: Author(s): Y. Kondo, S. Amaha, K. Ono, K. Kono, and S. Tarucha Nuclear spins in a spin-blocked quantum dot can be pumped and eventually polarized in either of two opposite directions that are selected by applying two different source-drain voltages. Applying a square pulse train as the source-drain voltage can continuously switch the pumping direction alternate… [Phys. Rev. Lett. 115, 186803] Published Tue Oct 27, 2015

Description: Cloud microphysical properties and aerosol concentrations were measured aboard an aircraft over the East China Sea and Yellow Sea in April 2009 during the Aerosol Radiative Forcing in East Asia (A-FORCE) experiment. We sampled stratocumulus and shallow cumulus clouds over the ocean in 9 cases during 7 flights 500–900 km off the east coast of Mainland China. In this study we report aerosol impacts on cloud microphysical properties by focusing on regional characteristics of two key parameters, namely updraft velocity and aerosol size distribution. First, we show that the cloud droplet number concentration (highest 5%, Nc_max) correlates well with the accumulation-mode aerosol number concentration (Na) below the clouds. We then show that Nc_max correlates partly with near-surface stratification evaluated as the difference between the sea surface temperature (SST) and 950-hPa temperature (SST − T950). Cold air advection from China to the East China Sea was found to bring not only a large number of aerosols but also a dry and cold air mass that destabilized the atmospheric boundary layer, especially over the warm Kuroshio ocean current. Over this high-SST region, greater updraft velocities and hence greater Nc_max likely resulted. We hypothesize that the low-level static stability determined by SST and regional-scale airflow modulates both the cloud microphysics (aerosol impact on clouds) and macro-structure of clouds (cloud base and top altitudes, hence cloud liquid water path). Second, we show that not only higher aerosol loading in terms of total aerosol number concentration (NCN, D 〉 10 nm) but also larger aerosol mode diameters likely contributed to high Nc during A-FORCE. The mean Nc of 650 ± 240 cm−3 was more than a factor of 2 larger than the global average for clouds influenced by continental sources. A crude estimate of the aerosol-induced cloud albedo radiative forcing is also given.

Description: The impact of aerosols on regional air quality and climate necessitates improved understanding of their emission and microphysical properties. The size distributions of black carbon (BC) and light scattering particles (LSP) were measured with a single particle soot photometer on board the NASA DC-8 aircraft during the ARCTAS mission 2008. Air sampling was made in the air plumes of both urban and forest fire emissions over California during the CARB (California Air Resources Board) phase of the mission. A total of eleven plumes were identified using SO2 and CH3CN tracers for fossil fuel (FF) combustion and biomass burning (BB), respectively. The enhancements of BC and LSP in BB plumes were significantly higher compared to those in FF plumes. The average mass concentration of BC in BB plumes was more than twice that in FF plumes. Except for the BC/CO ratio, distinct emission ratios of BC/CO2, BC/CH3CN, CH3CN/CO, and CO/CO2 were observed in the plumes from the two sources. Similarly, the microphysical properties of BC and LSP also showed distinct behaviors. The BC count median diameter (CMD) of 115 ± 5 nm in FF plumes was smaller compared to 141 ± 9 nm in the BB plumes. BC aerosols were thickly coated in BB plumes, the average shell/core ratios were 1.47 and 1.24 in BB and FF plumes, respectively. In the total mass of submicron aerosols, organic aerosols constituted about 67% in the FF plumes and 84% in BB plumes. The contribution of sulfate was also significant in the FF plumes.