ALBERT

Description: The atmospheric reactions of halogenated formaldehydes with halogen atoms were investigated by high-accuracy molecular orbital calculation. Our studies showed that compared to X-addition pathway, the H-abstraction pathway was demonstrated to be more preferred to form halogenated formyl radicals and hydrogen halides (HX). In specific areas with abundant halogen atoms, such as the marine boundary layer (MBL), halogenated formyl radical was reacted easily with halogen atoms and finally transformed into HX and CO2 in the presence of water; otherwise, this radical was degraded to CO2, halogen gas, and halogenated oxide in the presence of O2 and halogen atoms. By using the canonical variational transition state theory, the kinetics calculations were performed within a wide atmospheric temperature range of 200–368 K, and theoretical values agreed well with the available experimental data. Under atmospheric conditions, rate constants decreased as altitude increased, and especially the rate constants of halogen atoms reacted with FCHO quickly reduced. The kinetic results showed that although the reactions of halogenated formaldehydes with F atoms occurred more easily than did those with Cl and Br atoms, the two latter reactions were still important atmospheric degradation process, especially in the MBL. The modified Arrhenius equations of rate constants within the atmospheric temperature range were fitted, which helped to understand the established atmospheric model and estimated the contribution of title reactions to atmospheric chemistry pollution.

Description: In order to monitor the changes of the glaciers in the Gongga Mountain region on the south-eastern margin of the Qinghai-Tibetan Plateau, 74 monsoonal temperate glaciers were investigated by comparing the Chinese Glacier Inventory (CGI), recorded in the 1960s, with Landsat MSS in 1974, Landsat TM in 1989, 1994, 2005, and ASTER data in 2009. The remote sensing data have been applied to map the glacier outline by threshold ratio images (TM4/TM5). Moreover, the glacier outlines were verified by GPS survey on four large glaciers (Hailuogou, Mozigou, Yanzigou, and Dagongba) in 2009. The results show that the area dominated by the 74 glaciers has shrunk by 11.3 % (29.2 km2) from 1966 to 2009. Glacier area on the eastern and western slope of the Gongga Mountains decreased by 14.1 km2 (5.5 % in 1966) and 15.1 km2 (5.9 % in 1966), respectively. The loss in glacier area and length is respectively 0.8 km2 and 1146.4 m (26.7 m yr−1) for the Hailuogou glacier, 2.1 km2 and 501.8 m (11.7 m yr−1) for the Mozigou Glacier, 0.8 km2 and 724.8 m (16.9 m yr−1) for the Yanzigou Glacier, and 2.4 km2 and 1002.3 m (23.3 m yr−1) for the Dagongba Glacier. Decades of climate records obtained from three meteorological stations in the Gongga Mountains were analyzed to evaluate the impact of the temperature and precipitation on glacier retreat. During 1966–2009, the mean annual temperature over the eastern and western slope of the Gongga Mountains has been increasing by 0.21 °C/10 yr and 0.13 °C/10 yr, respectively. Moreover, it was stable in the mean annual precipitation. This evidence indicates that the warming of the climate is probably responsible for the glacier retreat in the study region.

Description: In order to monitor the changes of the glaciers in the Gongga Mountain region on the south-eastern margin of the Qinghai-Tibetan Plateau, 74 monsoonal temperate glaciers were investigated by comparing the Chinese Glacier Inventory (CGI), recorded in the 1960s, with Landsat MSS in 1974, Landsat TM in 1989, 1994, 2005, and ASTER data in 2009. The remote sensing data have been applied to map the glacier outline by threshold ratio images (TM4/TM5). Moreover, the glacier outlines were verified by GPS survey on four large glaciers (Hailuogou (HLG), Mozigou (MZG), Yanzigou (YZG), and Dagongba (DGB)) in 2009. The results show that the area dominated by the 74 glaciers has shrunk by 11.3% (29.2 km2) from 1966 to 2009. Glacier area on the eastern and western slopes of the Gongga Mountains decreased by 9.8% and 14.6% since 1966, respectively. The loss in glacier area and length is, respectively, 0.8 km2 and 1146.4 m for the HLG Glacier, 2.1 km2 and 501.8 m for the MZG Glacier, 0.8 km2 and 724.8 m for the YZG Glacier, and 2.4 km2 and 1002.3 m for the DGB Glacier. Decades of climate records obtained from three meteorological stations in the Gongga Mountains were analyzed to evaluate the impact of the temperature and precipitation on glacier retreat. The mean annual temperatures over the eastern and western slopes of the Gongga Mountains have been increasing by 0.34 K decade−1 and 0.24 K decade−1 (1988–2009), respectively. Moreover, mean annual precipitation has only increased by 1% in the past 50 yr. The increasing amount of precipitation could not compensate for the glacier mass loss due to the temperature increase in the Gongga Mountains. This suggests that the warming of the climate is probably also responsible for the glacier retreat in the study region. At the region scale, glacier changes were also controlled by local topographical factors.

Description: A coupler is a fundamental software tool for Earth system modeling. Targeting the requirements of 3-D coupling, high-level sharing, common model software platform and better parallel performance, we started to design and develop a community coupler (C-Coupler) from 2010 in China, and finished the first version (C-Coupler1) recently. C-Coupler1 is a parallel 3-D coupler that achieves the same (bitwise-identical) results with any number of processes. Guided by the general design of C-Coupler, C-Coupler1 enables various component models and various coupled models to be integrated on the same common model software platform to achieve a higher-level sharing, where the component models and the coupler can keep the same code version in various model configurations for simulation. Moreover, it provides the C-Coupler platform, a uniform runtime environment for operating various kinds of model simulations in the same manner. C-Coupler1 is ready for Earth system modeling, and it is publicly available. In China, there are more and more modeling groups using C-Coupler1 for the development and application of models.

Description: Straw incorporation generally increases CH4 emission from rice fields, but its effects on the mechanism of CH4 emission, especially on the pathway of CH4 production and the fraction of CH4 oxidized are not well known. To investigate the methanogenic pathway, the fraction of CH4 oxidized as well as the stable carbon isotope fractionation during the oxidation and transport of CH4 as affected by straw incorporation, production and oxidation of CH4 in paddy soil and rice roots and δ13C-values of produced CH4 and CO2, and emitted CH4 were observed in incubation and field experiments. Straw incorporation significantly enhanced CH4 production potentials of the paddy soil and rice roots. However, it increased the relative contribution of acetate to total CH4 production (Fac) in the paddy soil by ~ 10–30%, but decreased Fac-value of the rice roots by ~ 5–20%. Compared with rice roots, paddy soil was more important in acetoclastic methanogenesis, with Fac-value being 6–30% higher. Straw incorporation highly decreased the fraction of CH4 oxidized (Fox) by 41–71%, probably attributed to the fact that it increased CH4 oxidation potential whereas CH4 production potential was increased to a larger extent. There was little CH4 formed during aerobic incubation, and the produced CH4 was more 13C-enriched relative to that of anaerobic incubation. Assuming δ13C-values of CH4 aerobically produced in paddy soil to be the δ13C-values of residual CH4 after being oxidized, Fox-value still appeared to be 45–68% lower when straw was incorporated. Oxidation fractionation factor (αox) was higher with straw incorporation (1.033) than without straw incorporation (1.025). The δ13C-values of CH4 emitted after cutting of the plants (−50–−43‰) were more positive than those of before (−58–−55‰), suggesting a transport fractionation factor (ϵtransport) was −8.0‰ with straw incorporation and −12.0‰ without straw incorporation. Reasons for this difference may be related to the decrease in growth of the rice crop as a result of straw incorporation. The experiment shows that straw incorporation increases the contribution of acetate to total methanogenesis in paddy soil but decreases it on rice roots, and it significantly decreases the fraction of CH4 oxidized in the field, and expands oxidation fractionation while reducing transport fractionation.

Description: The atmospheric reactions of halogenated formaldehydes with halogen atoms were investigated by high-accuracy molecular orbital calculation. Studies showed that halogen atoms could easily abstract hydrogen atom from halogenated formaldehydes to form halogenated formyl radical and hydrogen halide (HX). In specific areas with high concentration of halogen atoms, such as the marine boundary layer (MBL), halogenated formyl radical was easily to react with halogen atoms and finally transformed into HX and CO2 in the presence of water; otherwise, this radical was degraded to CO2, halogen gas, and halogenated oxide. By using the canonical variational transition state theory, the kinetics calculations were performed within a wide atmospheric temperature range of 200–368 K, and theoretical values agreed well with the available experimental data. Under atmospheric conditions, the rate constants decreased as altitude increased, and especially the rate constants of halogen atoms reaction with FCHO quickly reduced. Although the reactions of halogenated formaldehydes with F atoms were more easily occurred than did those with Cl and Br atoms, the two latter reactions were still important atmospheric degradation process, especially in the MBL. The modified Arrhenius formulas of rate constants within the atmospheric temperature range were fitted, which helped to understand the established atmospheric model and estimate the contribution of title reactions to atmospheric chemistry pollution.

Description: To understand the impact of fireworks burning (FW) particles on air quality and human health during winter haze period, thirty-nine elements, ten water-soluble ions and eight fractions of carbonaceous species in atmospheric PM2.5 at Nanjing were investigated during 2014 Chinese Spring Festival (SF). Serious regional haze pollution persisted throughout the entire sampling period, PM2.5 averaging at 113 ± 69 μg m−3 and visibility at 4.8 ± 3.2 km. The holiday effect led to almost all the chemical species decreasing during the SF, except for Al, K, Ba and Sr which were related to FW. The source contributions of coal combustion, vehicle emission and road dust descreased dramatically, whereas FW contributed to about half of the PM2.5 during SF period. The intensive emission of FW particles at New Year's Eve accounted for 60.1% of the PM2.5. They also significnatly modified the chemical compositions of PM2.5, with 39.3% contributed by increased organic matter, followed by steadly increased loadings of secondary inorganic ions. The aging processes of the FW particles lasted for at least six days reflected by the variation of SO42−, characterized by heterogeneous reactions of SO2 and NOx on crustal materials directly from FW, the replacement of Cl− by NO3− and SO42− coating of NO3− and SO42− on soot, formation of secondary organic aerosols and metal-catalyzed formation of NO3− and SO42− at higher relative humidity. During aging, the main contributors to the extinction coefficient shifted from elemental carbon and organic matter to sulfate ammonium. The particles raised higher cancer risks by heavy metals (especially for Cd and As) as 1.62 ×10−6. This study provided detailed composition data and first comprehensive analysis of the aging processes of FW particles at serious haze pollution period and their potential impact on human health.

Description: Generoso et al. (2003) suggest a method for improving current inventories of aerosol emission from biomass burning based on the Along Track Scanning Radiometer (ATSR) nighttime hot spot product. In order to show the validity and representative of the nighttime burning product for such applications, Genoroso et al. (2003) compared the ATSR nighttime products to the daily fire products from TRMM, AVHRR etc. in nine selected regions. Their analyses demonstrate that in most cases, the nighttime products show a seasonal cycle that is consistent with the daily observations. However, they noticed significant discrepancies in biomass seasonality between ATSR nighttime product and TRMM daily product in Sahel region. In a commentary paper, Giglio and Kendall (2003) clarify that the origin of TRMM fire data used in Generoso et al. (2003) is from TRMM Science Data and Information System (Ji and Stocker, 2002). We thank Giglio and Kendall for such clarifications that provide an opportunity for us to clarify several issues on the applications of TSDIS fire data.

Description: Straw incorporation generally increases CH4 emission from rice fields, but its effects on the mechanism of CH4 emission, especially on the pathway of CH4 production and the fraction of CH4 oxidized, are not well known. To investigate the methanogenic pathway, the fraction of CH4 oxidized as well as the stable carbon isotope fractionation during the oxidation and transport of CH4 as affected by straw incorporation, observations were conducted of production and oxidation of CH4 in paddy soil and rice roots and δ13C-values of produced CH4 and CO2, and emitted CH4 in incubation and field experiments. Straw incorporation significantly enhanced CH4 production potentials of the paddy soil and rice roots. However, it increased the relative contribution of acetate to total CH4 production (Fac) in the paddy soil by ∼10–30%, but decreased Fac-value of the rice roots by ∼5–20%. Compared with rice roots, paddy soil was more important in acetoclastic methanogenesis, with Fac-value being 6–30% higher. Straw incorporation highly decreased the fraction of CH4 oxidized (Fox) by 41–71%, probably attributed to the fact that it increased CH4 oxidation potential whereas CH4 production potential was increased to a larger extent. There was little CH4 formed during aerobic incubation, and the produced CH4 was more 13C-enriched relative to that of anaerobic incubation. Assuming δ13C-values of CH4 aerobically produced in paddy soil to be the δ13C-values of residual CH4 after being oxidized, (Fox-value still appeared to be 45–68% lower when straw was incorporated. Oxidation fractionation factor (αox) was higher with straw incorporation (1.033) than without straw incorporation (1.025). The δ13C-values of CH4 emitted after cutting of the plants (−50 to −43‰) were more positive than those of before (−58 to −55‰), suggesting a transport fractionation factor (ϵtransport) was −8.0‰ with straw incorporation and −12.0‰ without straw incorporation. Causes of this difference may be related to the diffusion process in transport as affected by growth of rice plants and pressure in the rhizosphere. The experiment shows that straw incorporation increases the contribution of acetate to total methanogenesis in paddy soil but decreases it on rice roots, and it significantly decreases the fraction of CH4 oxidized in the field and expands oxidation fractionation while reducing transport fractionation.

Description: Coupler is a fundamental software tool for Earth System Modelling. Targeting the requirements of 3-D coupling, high-level sharing, common model software platform and better parallel performance, we started to design and develop a community coupler (C-Coupler) from 2010 in China, and finished the first version (C-Coupler1) recently. The C-Coupler1 is a parallel 3-D coupler that achieves the same (bit-identical) result with any number of processes. Guided by the general design of the C-Coupler, the C-Coupler1 enables various component models and various coupled model versions to be integrated on the same common model software platform to achieve a~higher-level sharing, where the component models and the coupler can keep the same code version in various model versions for simulation. Moreover, it provides the C-Coupler platform, a uniform runtime environment for operating various kinds of model simulations in the same manner. Now the C-Coupler1 is ready for Earth System Modelling, and it is publicly available. In China, there are more and more model groups using the C-Coupler1 for the development and application of models.