ALBERT

Description: The ionosphere scale height is one of the most significant ionospheric parameters, which contains information about the ion and electron temperatures and dynamics in upper ionosphere. In this paper, an empirical orthogonal function (EOF) analysis method is applied to process all the ionospheric radio occultations of GPS/COSMIC (Constellation Observing System for Meteorology, Ionosphere and Climate) from the year 2007 to 2011 to reconstruct a global ionospheric scale height model. This monthly medium model has spatial resolution of 5° in geomagnetic latitude (-87.5° ~ 87.5°), and temporal resolution of 2 hours in local time. EOF analysis preserves the characteristics of scale height quite well in the geomagnetic latitudinal, anural, seasonal and diurnal variations. In comparison with COSMIC measurements of the year of 2012, the reconstructed model indicates a reasonable accuracy. In order to improve the topside model of International Reference Ionosphere (IRI), we attempted to adopt the scale height model in the Bent topside model by applying a scale factor q as an additional constraint. With the factor q functioning in the exponent profile of topside ionosphere, the IRI scale height should be forced equal to the precise COSMIC measurements. In this way, the IRI topside profile can be improved to get closer to the realistic density profiles. Internal quality check of this approach is carried out by comparing COSMIC realistic measurements and IRI with or without correction respectively. In general, the initial IRI model overestimates the topside electron density to some extent, and with the correction introduced by COSMIC scale height model, the deviation of vertical total electron content (VTEC) between them is reduced. Furthermore, independent validation with Global Ionospheric Maps (GIM) VTEC implies a reasonable improvement in the IRI VTEC with the topside model correction.

Description: Increasing total electron content (TEC) measurements from the low earth orbiting (LEO) satellites to Global Positioning System (GPS) satellites flourish the exploration of the ionosphere and plasmasphere for decades. This paper indicates a method that 3-D Var is applied to assimilate precise orbit determination (POD) antenna TEC measurements of Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) satellites into the background Global Core Plasma Model (GCPM). The slant TEC data archived in the COSMIC Data Analysis and Archive Center (CDAAC) from 500 km to 20,200 km are used to reconstruct a new electron density model. This model has temporal resolution of 2 hours and spatial resolution of 2.5° in geomagnetic latitude, 5° in longitude, 50 km in the upper ionosphere and several hundred kilometers in the plasmasphere. Preliminary results show that the data assimilation modifies the initial GCPM forecast to be better coincident with actual COSMIC measurements in internal quality check. Furthermore, independent validation with upper ionosphere retrieved electron density, and TEC of Global Ionosphere Maps (GIM) implies a reasonable improvement in the estimation of plasmaspheric electron density after the assimilation.

Description: Cracks are widely developed along the edge of loess platforms in NW China. Field surveys reveal that these cracks can be grouped into shallow and deeply penetrating ones. The former occur at a small distance from platform edge, normally penetrate into the top unsaturated loess with the penetration depth being controlled by the joints in loess. The latter penetrate deeper into the saturated loess farther away from the platform edge. These cracks control the inflow and drainage of irrigation water. The shallow penetrating crack can fail as a slide or fall with a volume of up to hundreds of cubic meters. The deeply penetrating crack can fail as a flow-like landslide with a volume of thousands of cubic meters or more. A full-scale field test simulating irrigation on the platform surface was conducted. The two types of crack can be interconnected so that the water applied in the test finally flowed into the deep crack and was discharged from the platform. Analysis of soil stress states and the results of field test show that the deeply-penetrating cracks could have both positive as well as negative effects on slope stability. On the one hand, water can flow more freely in the cracks, and the loess could be saturated and triggered landslide. On the other hand, the water can drain more easily along the crack and slope stability could be enhanced as the groundwater level is suppressed. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Cracks are widely developed along the edge of loess platforms in NW China. Field surveys reveal that these cracks can be grouped into shallow and deeply penetrating ones. The former occur at a small distance from platform edge, normally penetrate into the top unsaturated loess with the penetration depth being controlled by the joints in loess. The latter penetrate deeper into the saturated loess farther away from the platform edge. These cracks control the inflow and drainage of irrigation water. The shallow penetrating crack can fail as a slide or fall with a volume of up to hundreds of cubic meters. The deeply penetrating crack can fail as a flow-like landslide with a volume of thousands of cubic meters or more. A full-scale field test simulating irrigation on the platform surface was conducted. The two types of crack can be interconnected so that the water applied in the test finally flowed into the deep crack and was discharged from the platform. Analysis of soil stress states and the results of field test show that the deeply-penetrating cracks could have both positive as well as negative effects on slope stability. On the one hand, water can flow more freely in the cracks, and the loess could be saturated and triggered landslide. On the other hand, the water can drain more easily along the crack and slope stability could be enhanced as the groundwater level is suppressed. Copyright © 2012 John Wiley & Sons, Ltd.

Description: Biofuels from microalgae are potentially important sources of liquid renewable energy. Algae are not yet produced on a large scale, but research shows promising results. This study assesses the blue water footprint (WF) and land use of algae-based biofuels. It combines the WF concept with an energy balance approach to determine the blue WF of net energy. The study considers open ponds and closed photobioreactors (PBRs). All systems have a positive energy balance, ranging from output-input ratios between 1.13 and 1.98. This study shows that the WF of algae-based biofuels lies between 8 and 193 m 3 per GJ net energy provided. The land use of micro-algal biofuels ranges from 20 to 200 m 2 per GJ net energy. For a scenario in which algae-based biofuels provide 3.5% of the transportation fuels in the European Union in 2030, the system with the highest land productivity needs 3,300 km 2 to produce the 850 PJ per year. Producing all algae-based biofuels through the system with the highest water productivity, would lead to a blue WF of 7 Gm 3 per year, which is equivalent to 15% of the present blue WF in the EU28. However, a complete transition to algae-based transportation fuels will cause increased competition over water and land resources.

Description: Brown carbon aerosol consists of light-absorbing organic particulate matter with wavelength-dependent absorption. Aerosol optical extinction, absorption, size distributions, and chemical composition were measured in rural Alabama during summer 2013. The field site was well-located to examine sources of brown carbon aerosol, with influence by high biogenic organic aerosol concentrations, pollution from two nearby cities, and biomass burning aerosol. We report the optical closure between measured dry aerosol extinction at 365 nm and calculated extinction from composition and size distribution, showing agreement within experiment uncertainties. We find that aerosol optical extinction is dominated by scattering, with single scattering albedo values of 0.94 ± 0.02. Black carbon aerosol accounts for 91 ± 9% of the total carbonaceous aerosol absorption at 365 nm, while organic aerosol accounts for 9 ± 9%. The majority of brown carbon aerosol mass is associated with biomass burning, with smaller contributions from biogenically derived secondary organic aerosol.

Description: Based on the experiments of pulverized coal pneumatic conveying using nitrogen as carrier, the influences of riser inlet height above the gas distribution plate, riser diameter, pulverized coal external moisture content, and supplemental gas flow rate on the conveying characteristics such as pulverized coal mass flow rate and solid-gas ratio were investigated in a laboratory-scale experimental setup of a top-discharge blow tank under atmospheric pressure. There exists an optimal riser inlet height for a given top-discharge blow tank. The supplemental gas is one of the critical factors affecting the conveying stability and continuity. A model for material mass flow rate prediction with errors ranging from –25 % to +15 % is presented. Dense-phase pneumatic conveying of pulverized coal has been widely employed to feed the coal to the gasifier. The blow tank is one of the most important instruments in the dense-phase conveying system. The influences of riser inlet height, riser diameter, pulverized coal external moisture content, and supplemental gas flow rate on the conveying characteristics are investigated.

Description: Internally heat-integrated distillation columns (HIDiCs) need heat transfer between the two column sections. Intermediate condensing and reboiling of the rectifying and stripping sections favor the reversibility of the separation process and lead to the increase of heat loads for the two sections but the heat transfer to cover the heat load is costly and generates major difficulties in design. A higher number of stages can reduce the heat load but will also raise the investment cost. The influence of increasing stage numbers on operating cost and capital investment of the HIDiC was evaluated by two HIDiC design cases, and the stage numbers or equivalently the heat loads were optimized to achieve the balance between the two kinds of cost. The internally heat-integrated distillation column (HIDiC) is considered as a promising option to improve significantly the energy efficiency of distillation columns. The effect of a higher stage number on operating cost and capital investment for an HIDiC was analyzed by two HIDiC design cases. Cost estimation parameters were defined by numerical simulation.

Description: Accurate estimation of soil organic carbon (SOC) storage is important for evaluating carbon sequestration of terrestrial ecosystems at regional scale. How the selected pedotransfer functions (PTFs) of bulk density (BD) influence the estimates of SOC storage is still unclear at large scales, although BD is an important parameter in all equations. Here, we used data from the second national soil survey in China (8210 soil profiles) to evaluate the influence of eight selected PTFs on the estimation of SOC storage. The results showed that different PTFs may result in a higher uncertainty of SOC storage estimation, and the coefficient of variation (CV, %) for the eight PTFs varied from 10.61% to 70.46% (mean = 12.75%). The observed CV values were higher in the 0–20 cm layer (12.48%) than in the 20–100 cm layer (10.05%). CV values were relatively stable (10–15%) when SOC content ranged from 0.13% to 3.45%. The findings indicate that PTFs may be used cautiously in soils with higher or lower SOC content. Estimates of SOC storage in the 0–100 cm soil layer varied from 67.19 to 95.97 Pg C in the eight PTFs in China, with an average of 87.36 ± 8.93 Pg C (CV = 10.23%). Our findings provide the insight that differences in PTFs are important sources of uncertainty in SOC estimates. The development of better PFTs, or the integration of various PFTs, is essential to accurately estimate SOC storage at regional scales.

Description: We report four profiles of the radiocarbon content of dissolved organic carbon (DOC) spanning the South Indian Ocean (SIO), ranging from the Polar Front (56 o S) to the subtropics (29 o S). Surface waters held mean DOC Δ 14 C values of -426±6‰ (~4400 14 C years) at the Polar Front and DOC Δ 14 C values of -252±22‰ (~2000 14 C years) in the subtropics. At depth, Circumpolar Deep Waters held DOC Δ 14 C values of -491±13‰ (~5400 years), while values in Indian Deep Water were more depleted, holding DOC Δ 14 C values of -503±8‰ (~5600 14 C years). High-salinity North Atlantic Deep Water intruding into the deep SIO had a distinctly less depleted DOC Δ 14 C value of -481±8‰ (~5100 14 C years). We use multiple linear regression to assess the dynamics of DOC Δ 14 C values in the deep Indian Ocean, finding that their distribution is characteristic of water masses in that region.