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Turbulence characteristics of an atmospheric surface layer over a coastal mountain area were investigated under different coordinate frames. Performances of three methods of coordinate rotation: double rotation (DR), triple rotation (TR), and classic planar-fit rotation (PF) were examined in terms of correction of eddy covariance flux. Using the commonly used DR and TR methods, unreasonable rotation angles are encountered at low wind speeds and cause significant run-to-run errors of some turbulence characteristics. The PF method rotates the coordinate system to an ensemble-averaged plane, and shows large tilt error due to an inaccurate fit plane over variable terrain slopes. In this paper, we propose another coordinate rotation scheme. The observational data were separated into two groups according to wind direction. The PF method was adapted to find an ensemble-averaged streamline plane for each group of hourly runs with wind speed exceeding 1.0 m s−1. Then, the coordinate systems were rotated to their respective best-fit planes for all available hourly observations. We call this the PF10 method. The implications of tilt corrections for the turbulence characteristics are discussed with a focus on integral turbulence characteristics, the spectra of wind-velocity components, and sensible heat and momentum fluxes under various atmospheric stabilities. Our results show that the adapted application of PF provides greatly improved estimates of integral turbulence characteristics in complex terrain and maintains data quality. The comparisons of the sensible heat fluxes for four coordinate rotation methods to fluxes before correction indicate that the PF10 scheme is the best to preserve consistency between fluxes.

In order to predict the distribution of chlorophyll a synoptically in Lake Taihu from 2006 to 2008, a common empirical algorithm was developed to relate time series chlorophyll a concentrations in the lake to reflectance derived as a function of band 2 MODIS data (r 2 = 0.907, n = 145) using time series from 2005. The empirical model was further validated with chlorophyll a data from a 2008 to 2009 dataset, with RMSE

and Aim. An accurate estimation of biogenic emissions of VOC (volatile organic compounds) is necessary for better understanding a series of current environmental problems such as summertime smog and global climate change. However, very limited studies have been reported on such emissions in China. The aim of this paper is to present an estimate of biogenic VOC emissions during summertime in China, and discuss its uncertainties and potential areas for further investigations.This study was mainly based on field data and related research available so far in China and abroad, including distributions of land use and vegetations, biomass densities and emission potentials. VOC were grouped into isoprene, monoterpenes and other VOC (OVOC). Emission potentials of forests were determined for 22 genera or species, and then assigned to 33 forest ecosystems. The NCEP/NCAR reanalysis database was used as standard environmental conditions. A typical summertime of July 1999 was chosen for detailed calculations.The biogenic VOC emissions in China in July were estimated to be 2.3×1012gC, with 42% as isoprene, 19% as monoterpenes and 39% as OVOC. About 77.3% of the emissions are generated from forests and woodlands. The averaged emission intensity was 4.11 mgC m-2 hr-1 for forests and 1.12 mgC m-2 hr-1 for all types of vegetations in China during the summertime. The uncertainty in the results arose from both the data and the assumptions used in the extrapolations. Generally, uncertainty in the field measurements is relatively small. A large part of the uncertainty mainly comes from the taxonomic method to assign emission potentials to unmeasured species, while the ARGR method serves to estimate leaf biomass and the emission algorithms to describe light and temperature dependence.This study describes a picture of the biogenic VOC emissions during summertime in China. Due to the uneven spatial and temporal distributions, biogenic VOC emissions may play an important role in the tropospheric chemistry during summertime.. Further investigations are needed to reduce uncertainties involved in the related factors such as emission potentials, leaf biomass, species distribution as well as the mechanisms of the emission activities. Besides ground measurements, attention should also be placed on other techniques such as remote-sensing and dynamic modeling. These new approaches, combined with ground measurements as basic database for calibration and evaluation, can hopefully provide more comprehensive information in the research of this field.

[1] A comprehensive aerosol model was developed and incorporated into a regional air quality model system (RAQMS). It was used to study the behavior and the regional characteristics of carbonaceous aerosols over China in summertime with focus on organic carbon aerosols (OC), especially the secondary organic carbon aerosol (SOC). The whole month of July and August 2003 were selected as simulation period when biogenic volatile organic compounds (VOCs) emitted from vegetation reach the annual maximum. A number of measurements for organic and elemental carbon (EC) aerosols were conducted simultaneously over China during this period, which allow for a rigorous evaluation of model performance and an in-depth investigation of organic aerosols. The comparison of model results with observations indicates that the developed model system is able to represent the atmospheric oxidative capacity and the major evolutionary features of OC and EC reasonably well, but a tendency was found toward underprediction of both OC and EC aerosols. Sensitivity simulations regarding absorbing matter for condensation (AMC) and enthalpy of vaporization (EOV) were conducted to understand the effects of key factors on secondary organic aerosol (SOA) formation and to provide possible ranges of SOA yields in the troposphere of East Asia. It is found that the overall SOA formation tends to increase with increasing EOV and AMC, but the sensitivity of SOA formation to EOV depends on ambient temperature as well. High OC concentrations mainly occurred in the areas along the Yangtze River, in central China and most parts of north China including Beijing and Tianjin districts, with the maximum monthly mean as high as 15 μg m−3. SOC concentration was high in the forest areas of southeastern, southwestern and northeastern China, with maximum concentration exceeding 5.0 μg m−3 to the south of the Yangtze Delta. The contribution of SOC to OC is around 50% in these areas, whereas in the broad areas north of the Yangtze River, primary organic carbon aerosol (POC) accounts for a high fraction of the total OC (>60%). The estimated regional burdens of EC, OC, POC, and SOC for base case are 28.13, 61.16, 46.05, and 15.11 Gg, respectively. Of the SOC burden, contributions from oxidation of anthropogenic aromatics, monoterpene and isoprene are 17% (2.58 Gg), 48% (7.32 Gg) and 35% (5.21 Gg), respectively. The regional SOC burden varies from 15.1 to 40.3 Gg in different scenarios. For the base case, the total burdens of EC, OC, POC and SOC are estimated to be 13.8, 37.3, 25.6, and 11.8 Gg, respectively, while using emissions solely from China (20°N∼50°N and west of 100°E) in model simulation.

This study is intended to understand and quantify the impacts of biogenic emissions of volatile organic compounds (VOC) and nitrogen oxides (NO(x)) on the formation of tropospheric ozone during summertime in eastern China. The model system consists of the non-hydrostatic mesoscale meteorological model (MM5) and a tropospheric chemical and transport model (TCTM) with the updated carbon-bond chemical reaction mechanism (CBM-IV). The spatial resolution of the system domain is 30 km x 30 km. The impacts of biogenic emissions are investigated by performing simulations (36 h) with and without biogenic emissions, while anthropogenic emissions are constant. The results indicate that biogenic emissions have remarkable impacts on surface ozone in eastern China. In big cities and their surrounding areas, surface ozone formation tends to be VOC-limited. The increase in ozone concentration by biogenic VOC is generally 5 ppbv or less, but could be more than 10 ppbv or even 30 ppbv in some local places. The impacts of biogenic NO(x) are different or even contrary in different regions, depending on the relative availability of NO(x) and VOC. The surface ozone concentrations reduced or increased by the biogenic NO(x) could be as much as 10 ppbv or 20 ppbv, respectively. The impacts of biogenic emissions on ozone aloft are generally restricted to the boundary layer and generally more obvious during the daytime than during the nighttime. This study is useful for understanding the role of biogenic emissions and for planning strategies for surface ozone abatement in eastern China. Due to limitations of the emission inventories used and the highly non-linear nature of zone formation, however, some uncertainties remain in the results.

Lake Taihu is the third largest freshwater lake in China. It serves many social, economic, and ecological purposes in the drainage basin. Unfortunately, the water has been heavily polluted due to rapid industrialization and urbanization during the last two decades. Notwithstanding great efforts made so far to improve the water quality, the environmental situation is still far from being optimistic. The basin and the lake are facing a range of severe environmental challenges: rapid socio-economic development continues to place great pressures on the environment, current pollution control projects have many problems from the viewpoint of effectiveness and efficiency of their implementations, and the non-point sources of pollution such as agricultural fields, for which control is more difficult than for industrial point sources, have become the main contributors to serious eutrophication of the lake. Considering the characteristics of the environmental challenges and problems confronting the basin and the lake, we focus on integrated environmental management (IEM) as a promising and effective approach to overcome these predicaments. Current practices and problems of environmental management in the basin are examined, and potential future developments are discussed. Three aspects of the IEM are emphasized: institutional cooperation, public participation, and internalization of environmental externalities. We think these are the most critical for not only the basin but also for the whole of China to achieve a sustainable society.

U atmospheric pollution is one of the most serious global environmental issues of the past decade. Atmospheric particulate matter (PM) is of great concern to the public and to government agencies because of the health effects and haze episodes associated with it. PM has the strong potential for adsorbing toxic metals, which may then enter the human body through inhalation and have adverse physiological effects. Exposure to PM has been linked to a wide range of diseases, including cardiovascular and respiratory diseases and lung cancer. There is growing evidence that heavy metals adsorbed to PM are crucial to the toxicity and adverse health effects of PM. Metal elements adsorbed to atmospheric PM can also be deposited to soils, water bodies, and plant leaves via wet and dry deposition. They may then accumulate in plants or animals through biochemical processes; and humans may then be exposed by consumption of contaminated plants or animals. In order to control the atmospheric heavy metal pollution, it is essential to conduct effective environmental risk management. Rapid evaluation models on spatiotemporal distributions of heavy metals and practical early warning programs could be developed by combining the monitoring data with interdisciplinary research, such as atmospheric pollutant diffusion models, epidemiological investigations, toxicological experiments, and geographical information systems. Recent scientific research on heavy metals in PM has been focused on the pollution levels, source analysis, temporal variations, spatial distributions, and health effects of heavy metals adsorbed to PM. However, heavy metals are important components of PM in the atmospheric environment and they have complex pollution feature. There are still several potentially important problems that require special attention and further study before we will have a comprehensive understanding of the occurrence and behavior of heavy metals in PM. First, when compared with coarse PM, fine particulate matter (PM2.5, particles with aerodynamic diameters ≤2.5 μm) has a greater surface area per unit mass, allowing PM2.5 to accumulate heavy metals more effectively; PM2.5 is also more hazardous than coarser PM because of its longer residence time in the atmosphere and deeper penetration into the lungs. The standards or reference values for atmospheric Pb, Cd, As, Ni, and Cr (VI) concentrations proposed by the European Union and the World Health Organization, as well as the newest Chinese “Ambient Air Quality Standards” (GB3095−2012) which were issued in 2012, are currently based on heavy metal concentrations in coarse PM. Atmospheric Hg concentrations are determined as elemental mercury vapor (Hg 0). Although monitoring data may be appropriate to meet safety standard requirements, ambient heavy metal concentrations and the extent of adverse effects caused by heavy metals in PM2.5 remain uncertain. It is necessary to conduct more surveys and analyses on heavy metals in fine PM or even ultrafine PM (PM0.1, particles with aerodynamic diameters ≤0.1 μm) to improve the usefulness of monitoring atmospheric heavy metals. Second, the total amount of heavy metals in the environment is usually used as the main or only evaluation criteria in assessing the pollution conditions. However, it is generally recognized that the chemical speciation of a heavy metal probably determines its bioavailability and the potential risks it poses to the environment and to human health. The heavy metal chemical speciation in a solid environmental sample can generally be determined by sequentially extracting the different species as the adsorbed−exchangeable carbonate phase, the reducible phase, the oxidizable phase, and the residual fraction. The first three of those species types, especially the adsorbed− exchangeable carbonate phase, are considered to be more mobile in the environment and more hazardous to organisms than is the resistant fraction. Attention should therefore be paid to the chemical speciation of heavy metals in PM. Third, PM can either be directly emitted into the air (primary PM), or it can be formed secondarily in the

The emission of NO was parameterized using empirical relationships with landuse type, fertilization rate and soil temperature. Eight landuse types (including four arable lands) were considered. Fertilization rates were distinguished for different regions and crops. A typical summer period of July in 1999 was chosen for detailed calculations. The total NO emission in the July is 141.1 Gg N, with 73.7% from arable lands and 22.0% from grasslands. The highest emission intensity can be more than 40 ng N m −2 s −1 in the heavily fertilized North China Plain, and the average of the whole lands is 6.5 ng N m −2 s −1 . The annual emission was roughly estimated to be 657 Gg N, about 11.7% of the global total (5600 Gg N, reported by IPCC in 2000), and about 12.5% of the anthropogenic origin in China. Our results were compared with some earlier findings, and uncertainties were discussed.

In addition to several widespread plant constituents and two closely related germacranolides, chromatographic fractionation of the extract of the aerial parts of Ajania fruticulosa afforded a minor new sesquiterpene lactone whose structure was established as lα,4a,10α-trihydroxy-9α-angeloyloxy-guai-2,11(13)-dien-12,6α-olide. Furthermore, detailed NMR data of ketopelenolide b were added.