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Chlorine-disinfected sewage effluents are typically dechlorinated by using NaHSO3, Na2SO3, or Na2S2O3, as chlorine residual could be harmful to aquatic organisms upon discharge of sewage effluents into receiving marine water. In this study, we systematically investigated the effects of dechlorination-related factors on the developmental toxicity of a chlorinated saline primary sewage effluent, via direct exposure of the embryos of a marine polychaete to the effluent. The results showed that dechlorination ratio (i.e., the ratio of the dosed amount to the requisite stoichiometric amount of a dechlorination agent) and mixing condition were critical factors affecting the toxicity of the effluent. The toxicity of the effluent under insufficient dechlorination conditions was mainly caused by residual chlorine, especially monochloramine. Although the three dechlorination agents generally performed similarly, dechlorination with Na2S2O3 required a more vigorous mixing condition than that with NaHSO3 or Na2SO3, as the relatively high density of Na2S2O3 might affect the mixing efficiency. Under insufficient mixing conditions, a prolonged dechlorination time was beneficial to achieving complete dechlorination and thus lowered the toxicity of the effluent. Moreover, because disinfection byproducts (DBPs) may have chronic effects on aquatic organisms, the developmental toxicity of the DBP mixtures in the chlorinated effluent in different dechlorination scenarios was also evaluated. The results indicated that increasing the dechlorination ratio reduced the developmental toxicity of the DBP mixture in the chlorinated saline sewage effluent, which might be ascribed to the decrease of the levels of overall brominated and iodinated DBPs; the dechlorination agent (NaHSO3 or Na2S2O3) might act as a nucleophile in the nucleophilic substitution and cause the substitution of bromine or iodine atoms in brominated and iodinated DBPs. The results from this study might aid in the design and operation of dechlorination facilities in sewage treatment plants.

Due to rising concerns about water pollution and affordability, there is a rapidly-growing public acceptance and global market for a variety of point-of-use (POU) devices for domestic uses. However, the efficiencies and mechanisms of POU technologies for removing regulated and emerging disinfection byproducts (DBPs) are still not systematically known. To facilitate the development of this field, we summarized performance trends of four common technologies (i.e., boiling, adsorption, membrane filtration, and advanced oxidation) on mitigating preformed DBPs and identified knowledge gaps. The following highest priority knowledge gaps include: 1) data on DBP levels at the tap or cup in domestic applications; 2) certainty regarding the controls of DBPs by heating processes as DBPs may form and transform simultaneously; 3) standards to evaluate the performance of carbon-based materials on varying types of DBPs; 4) long-term information on the membrane performance in removing DBPs; 5) knowledge of DBPs’ susceptibility toward advanced redox processes; 6) tools to monitor/predict the toxicity and diversity of DBPs formed in waters with varying precursors and when implementing different treatment technologies; and 7) social acceptance and regulatory frameworks of incorporating POU as a potential supplement to current centralized-treatment focused DBP control strategies. We conclude by identifying research needs necessary to assure POU systems protect the public against regulated and emerging DBPs.

Although700 disinfection byproducts (DBPs) have been identified,50% of the total organic halogen (TOX) in drinking water chlorination is unknown, and the DBPs responsible for the chlorination-associated health risks remain largely unclear. Recent studies have revealed numerous aromatic halo-DBPs, which generally present substantially higher developmental toxicity than aliphatic halo-DBPs. This raises a fascinating and important question: how much of the TOX and developmental toxicity of chlorinated drinking water can be attributed to aromatic halo-DBPs? In this study, an effective approach with ultraperformance liquid chromatography was developed to separate the DBP mixture (from chlorination of bromide-rich raw water) into aliphatic and aromatic fractions, which were then characterized for their TOX and developmental toxicity. For chlorine contact times of 0.25-72 h, aromatic fractions accounted for 49-67% of the TOX in the obtained aliphatic and aromatic fractions, which were equivalent to 26-36% of the TOX in the original chlorinated water samples. Aromatic halo-DBP fractions were more developmentally toxic than the corresponding aliphatic fractions, and the overall developmental toxicity of chlorinated water samples was dominated by aromatic halo-DBP fractions. This might be explained by the considerably higher potentials of aromatic halo-DBPs to bioconcentrate and then generate reactive oxygen species in the organism.

International audience; Many plant species have distinct optical properties between upper and lower leaf faces. These differences between faces are mainly attributed to the non-homogeneous distribution of absorbing and scattering materials within the leaf depth as well as particular surface features of both epidermises. We proposed the FASPECT model which is an evolution of the PROSPECT model to describe the differences in reflectance and transmittance between leaf faces. The upper and lower epidermis layers are characterized by distinct wavelength-independent reflectivities. Leaf mesophyll is made of a palisade and a spongy parenchyma layers using two parameters that describe the distribution of pigments and leaf structure between these two layers. As compared to the original PROSPECT model that treats the two leaf faces symmetrically, six additional parameters are required to describe the differences in leaf optical properties between the two faces. The specific absorption coefficients of chlorophyll and carotenoids have been recalibrated for the FASPECT model over a dedicated dataset. FASPECT was validated over eight datasets and compared with PROSPECT-5 and PROSPECT-D as well as with the DLM model that also accounts for the differences between the two faces. Results show that the FASPECT model simulates accurately the reflectance and transmittance of the two faces for species presenting distinct reflectance and transmittance properties between the faces. FASPECT outperforms PROSPECT-5 and PROSPECT-D, while providing generally more realistic simulations as compared to DLM. The capacity of the FASPECT model to retrieve leaf biochemical composition from reflectance and transmittance measurements was also evaluated. Marginal improvement is observed for the estimation of chlorophyll, carotenoids, and water content. Conversely, significant improvement is observed for dry matter content estimation. Conclusions are finally drawn on the interest and limits of the FASPECT model.

Chlorine dioxide (ClO2) is a prevalently used disinfectant alternative to chlorine, due to its effectiveness in pathogen inactivation and low yields of organic halogenated disinfection byproducts (DBPs). However, during ClO2 generation, chlorine is inevitably introduced into the obtained ClO2 solution as an "impurity", which could compromise the merits of ClO2 disinfection. In this study, drinking water disinfection with ClO2 containing 0‒25% chlorine impurity (i.e., at Cl2 to ClO2 mass ratios of 0‒25%) was simulated, and the effect of chlorine impurity on the DBP formation and developmental toxicity of the finished water was evaluated. With increasing the chlorine impurity in ClO2, the chlorite level kept decreasing and the chlorate level gradually increased; meanwhile, an unexpected trend from decline to rise was observed for the total organic halogenated DBPs, with the minimum level appearing at 5% chlorine impurity. To unravel the mechanisms for the variations of organic halogenated DBPs with chlorine impurity, a quantitative kinetic model was developed to simulate the formation of chlorinated, brominated, and iodinated DBPs in the ClO2-disinfected drinking water. The modeling results indicated that reactions involving iodide accounted for the decrease of organic halogenated DBPs at a relatively low chlorine impurity level. In accordance with DBP formation, ClO2 with 5% chlorine impurity generated less toxic drinking water than pure ClO2, while significantly higher developmental toxicity was induced until the chlorine impurity reached 25%. For E. coli inactivation, the presence of chlorine impurity enhanced the disinfection efficiency due to a synergistic effect of ClO2 and chlorine. Therefore, disinfection practices with ClO2 containing low chlorine impurity (e.g.

Halogenated disinfection byproducts (DBPs) are generated via reactions with natural organic matter (NOM) in chlorine disinfection of drinking water. How large NOM molecules are converted to halogenated aliphatic DBPs during chlorination remains a fascinating yet largely unresolved issue. Recently, many relatively toxic halogenated aromatic DBPs have been identified in chlorinated drinking waters, and they behave as intermediate DBPs to decompose to halogenated aliphatic DBPs. There is still one gap between NOM and halogenated aromatic DBPs. In this study, nine nonhalogenated aromatic compounds were identified as new intermediate DBPs in chlorination, including 4-hydroxybenzaldehyde, 4-hydroxybenzoic acid, 3-formyl-4-hydroxybenzoic acid, salicylic acid, 5-formyl-2-hydroxybenzoic acid, 4-hydroxyphthalic acid, 4'-hydroxyacetophenone, 4-methylbenzoic acid, and 4-hydroxy-3-methylbenzaldehyde. These nonhalogenated aromatic DBPs formed quickly and reached the maximum levels at relatively low chlorine doses within a short contact time, and their formation pathways were proposed. The formation kinetics of three nonhalogenated aromatic DBPs and their corresponding monochloro-/dichloro-substitutes during chlorination were then modeled. The nonhalogenated aromatic DBPs contributed up to 84% of the formed monochloro-substitutes and 22% of the formed dichloro-substitutes, demonstrating that they somewhat acted as intermediates between NOM and halogenated aromatic DBPs. Furthermore, the formed nonhalogenated aromatic DBPs were found to be removed by >50% by granular activated carbon adsorption.

Granular activated carbon (GAC) adsorption has been traditionally used to remove natural organic matter (NOM), the major precursor of halogenated disinfection byproducts (DBPs), in drinking water treatment plants. Recently, a new approach has been developed to effectively control the formation of trihalomethanes, haloacetic acids, and total organic halogen (TOX) in chlorinated drinking water by targeting intermediate aromatic halogenated DBPs instead of NOM using GAC adsorption. However, the applicability of this new approach to different source water matrices and disinfection conditions remained unclear. In this study, the effects of bromide and contact time on the performance of the new approach for DBP control were investigated. Same source waters were also treated with the traditional approach (i.e., using GAC to remove NOM prior to chlorination) and with chlorination only for comparison. With increasing the initial bromide level from 0 to 2 mg/L, the TOX removal with the new approach increased from 52% to 74%, while the removal with the traditional approach increased from 18% to 37%. Besides, as the chlorine contact time increased from 0.5 to 3.0 h, the TOX removal with the new approach increased from 61% to 75%, while the removal with the traditional approach increased from 21% to 36%. Increasing the bromide level and chlorine contact time enhanced the halogenated DBP removal with both new and traditional approaches, but the removal with the new approach was always two times higher or more than that with the traditional approach, which justified the superiority of the new approach. Moreover, various intermediate aromatic halogenated DBPs were detected in the chlorinated water samples and their levels were significantly decreased after the GAC adsorption, which further corroborated the effectiveness of the new approach for DBP control.

International audience; Several crops bear reproductive organs (RO) at the top of the canopy after the flowering stage, such as ears for wheat, tassels for maize, and heads for sunflowers. RO present specific architecture and optical properties as compared to leaves and stems, which may impact canopy reflectance. This study aims to understand and quantify the influence of RO on the bi-directional variation of canopy reflectance and NDVI.Multispectral camera observations from a UAV were completed over wheat, maize, and sunflower just after flowering when the RO are fully developed and the leaf layer with only marginal senescence. The flights were designed to sample the BRDF with view zenith angles spanning from nadir to 60°and many compass directions. Three flights corresponding to three sun positions were completed under clear sly conditions. The camera was always pointing to two adjacent plots of few tenths of square meters: the RO were manually removed on one plot, while the other plot was kept undisturbed.Results showed that the three visible bands (450 nm, 570 nm, 675 nm), and in a lesser way the red edge band (730 nm) were strongly correlated. We, therefore, focused on the 675 nm and 850 nm bands. The Bi-Directional Reflectance (BRF) of the canopy without RO shows that the BRF values were almost symmetrical across the principal plane, even for maize and sunflower canopies with a strong row structure. Examination of the BRF difference between the canopy with and without RO indicate that the RO impact canopy BRDF for the three crops. The magnitude of the impacts depends on crop, wavelength and observational geometry. These observations are generally consistent with realistic 3D reflectance simulations. However, some discrepancies were noticed, mainly explained by the small magnitude of the RO effect on canopy BRF, and the approximations made when simulating the RO layer and its coupling with the bottom canopy layer. We finally demonstrated that the RO layer impact the estimates of canopy traits such as GAI as derived from the multispectral observations.

grant entitled "Study on Agricultural Drought Risk Formation Mechanism of the Rain-fed Agricultural Typical Area in China" from the National Science and Technology Foundation 41001059; Climate change is affecting every aspect of human activities, especially the agriculture. In China, extreme drought events caused by climate change have posed a great threat to food safety. In this work we aimed to study the drought risk of maize in the farming-pastoral ecotone in Northern China based on physical vulnerability assessment. The physical vulnerability curve was constructed from the relationship between drought hazard intensity index and yield loss rate. The risk assessment of agricultural drought was conducted from the drought hazard intensity index and physical vulnerability curve. The probability distribution of drought hazard intensity index decreased from south-west to north-east and increased from south-east to north-west along the rainfall isoline. The physical vulnerability curve had a reduction effect in three parts of the farming-pastoral ecotone in Northern China, which helped to reduce drought hazard vulnerability on spring maize. The risk of yield loss ratio calculated based on physical vulnerability curve was lower compared with the drought hazard intensity index, which suggested that the capacity of spring maize to resist and adapt to drought is increasing. In conclusion, the farming-pastoral ecotone in Northern China is greatly sensitive to climate change and has a high probability of severe drought hazard. Risk assessment of physical vulnerability can help better understand the physical vulnerability to agricultural drought and can also promote measurements to adapt to climate change.

Chlorine disinfection is a vital treatment process to inactivate pathogens, but it also generates numerous halogenated disinfection byproducts (DBPs) via reactions with halides and natural organic matter (NOM). Epidemiological studies have shown that consumption of chlorinated drinking water with halogenated DBPs is related to increased spontaneous abortions, stillbirth, birth defects, and bladder and colorectal cancers. To control DBPs, efforts have been devoted to minimizing the formation of DBPs by removing the major DBP precursor, NOM, or by adopting alternative disinfectants. Notably, the precursor removal may not be very effective and the application of alternative disinfectants may generate their own sets of DBPs. It has remained a grand challenge to develop a new DBP control strategy which can effectively decrease the DBP formation and reduce the health risks of chlorinated drinking water. To solve this problem, Zhang’s group reported a new approach to effectively control halogenated DBPs by removing intermediate aromatic halogenated DBPs, which were formed from chlorine disinfection, via granular activated carbon (GAC) adsorption.

International audience; Green Area Index (GAI) and Leaf Chlorophyll Content (LCC) are key variables that reflect the potential growth of the canopy. In the past decades, the retrieval of these variables from remote sensing data to generate operational products at high spatial resolution (lower than decametric) was mainly based on 1D radiative transfer model inversion. However, due to the recent advances in computational facility, it is now possible to invert 3D radiative transfer models to improve the operational product accuracy. The use of 3D models allows taking into account more realistic canopy architectures than when using the turbid medium assumption from the 1D radiative transfer models. In this study, we demonstrate the gain in accuracy when inverting crop specific using 3D radiative transfer models as compared to a generic algorithm based on 1D model. We investigate two crops characterized by contrasted architectures along the vegetation cycle, e.g. wheat and maize.

International audience; Local topography significantly affects remotely sensed reflectance data and subsequently impacts leaf area index (LAI) retrieval over mountainous areas. Therefore, mountain vegetation LAI mapping from satellite observations at multiple scale levels is often obstructed by topographic distortion. To analyze the effects of topography on multiresolution LAI retrievals, consistent LAI estimations were first generated across six spatial scales (i.e., 960 m, 480 m, 240 m, 120 m, 60 m and 30 m) from MODIS and Landsat OLI reflectance data using the ensemble multiscale filter (EnMsF) approach over rugged surfaces. Subsequently, the topographic influence on LAI was evaluated based on spatial patterns and retrieval accuracies at multiple scale levels by comparing the EnMsF-based multiscale LAI results obtained before and after terrain correction of a Landsat image. The results demonstrated that the multiresolution LAI values retrieved from topographically corrected surface reflectance data outperformed those without topographic correction, regardless of various slopes or aspects at the 30 m scale or the differences in spatial resolutions. The accuracies were determined for the retrieved LAI values before (coefficient of determination (R2) = 0.32 and root mean square error (RMSE) = 1.03) and after (R2 = 0.60 and RMSE = 0.82) topographic correction when compared to the field measurements over slopes facing toward the sun at the 30 m resolution. The R2 and RMSE values were 0.57 and 0.54, respectively, for the LAI estimations with terrain corrections in the shady aspects. Moreover, the topographic effect on the LAI estimations depended on our spatial scales. The finer the spatial resolution is, the more significant the topographic effects on the multiscale LAI retrieval are, and vice versa. Thus, the results of this study open an encouraging path to deepen the understanding of terrain effects on multiscale LAI estimations, and further improve the LAI retrieval algorithm across different spatial scales over mountainous areas.

Haloacetic acids (HAAs) are the major disinfection byproducts (DBPs) that are formed during chlorination of drinking water. In this paper, the conversion of HAAs to amino acids (e.g., glycine) via ammonolysis was studied. First, a new and sensitive method for detecting glycine was developed by setting selected ion recording m/z 76 in positive electrospray ionization mass spectrometry coupled with ultra performance liquid chromatography. Second, among the mono-HAAs under the same test conditions, iodoacetic acid (49.3%) showed a considerably higher conversion to glycine during ammonolysis than chloroacetic acid (4.2%) and bromoacetic acid (27.7%). The conversion of iodoacetic acid to glycine increased with increasing temperature, increasing reaction time, or decreasing the ratio of (NH4)2CO3 to NH3·H2O in the aminating agent. Hydrolysis of iodoacetic acid to glycolic acid was also observed during ammonolysis, and it accounted for at most 50% of the iodoacetic acid conversion. The conversion to amino acids and the hydrolysis were the two major pathways during ammonolysis of HAAs. Third, compared with the iodoacetic acid sample and the simulated tap water sample without ammonolysis, the developmental toxicity of the corresponding samples with ammonolysis decreased by up to 10.4% and 32.1%, respectively. The ammonolysis was thus demonstrated to be a detoxification process for both individual HAAs and DBP mixture in chlorinated tap water. In practice, the ammonolysis of haloacid DBPs in tap water may be realized by simply adding an appropriate amount of an aminating agent during cooking.

The nationwide lockdown due to the COVID-19 pandemic in 2020 reduced industrial and human activities in China. In this study, we investigate atmospheric carbon monoxide (CO) concentration changes during the lockdown from observations at the surface and from two satellites (TROPOspheric Monitoring Instrument (TROPOMI) and Infrared Atmospheric Sounding Interferometer (IASI)). It is found that the average CO surface concentration in 2020 was close to that in 2019 before the lockdown, and became 18.7% lower as compared to 2019 during the lockdown. The spatial variation of the change in the CO surface concentration is high, with an 8–27% reduction observed for Beijing, Shanghai, Chengdu, Zhengzhou, and Guangzhou, and almost no change in Wuhan. The TROPOMI and IASI satellite observations show that the CO columns decreased by 2–13% during the lockdown in most regions in China. However in South China, there was an 8.8% increase in the CO columns observed by TROPOMI and a 36.7% increase observed by IASI, which is contrary to the 23% decrease in the surface CO concentration. The enhancement of the CO column in South China is strongly affected by the fire emissions transported from Southeast Asia. This study provides an insight into the impact of COVID-19 on CO concentrations both at the surface and in the columns in China, and it can be extended to evaluate other areas using the same approach.

Chlorine disinfection inactivates pathogens in drinking water, but meanwhile it causes the formation of halogenated disinfection byproducts (DBPs), which may induce adverse health effects. Humans are unavoidably exposed to halogenated DBPs via tap water ingestion. Boiling of tap water has been found to significantly reduce the concentrations of halogenated DBPs. In this study, we found that compared with boiling only, adding ascorbate (vitamin C) or carbonate (baking soda) to tap water and then boiling the water further reduced the level of total organic halogen (a collective parameter for all halogenated DBPs) by up to 36% or 28%, respectively. Adding ascorbate removed the chlorine residual in tap water and thus prevented the formation of more halogenated DBPs in the boiling process. Adding carbonate elevated pH of tap water and consequently enhanced the hydrolysis (dehalogenation) of halogenated DBPs or led to the formation of more trihalomethanes that might volatilize to air during the boiling process. The comparative developmental toxicity of the DBP mixtures in the water samples was also evaluated. The results showed that adding a tiny amount of sodium ascorbate or carbonate (2.5–5.0 mg/L) to tap water followed by boiling for 5 min reduced the developmental toxicity of tap water to a substantially lower level than boiling only. The addition of sodium ascorbate or carbonate to tap water in household could be realized by preparing them in tiny pills. This study suggests simple and effective methods to reduce the adverse effects of halogenated DBPs on humans through tap water ingestion.

Halogenated disinfection byproducts (DBPs) are formed during chlorine disinfection of drinking water. The complicated natural organic matter in source water causes the formation of an even more complicated mixture of DBPs. To evaluate the toxicity of a DBP mixture in a disinfected water sample, the sample needs to be pretreated in order to attain an observable acute adverse effect in the toxicity test. During sample pretreatment, volatile DBPs including trihalomethanes, haloacetonitriles and haloketones may be lost, which could affect the toxicity evaluation of the DBP mixture. In this study, we intentionally prepared “concentrated” simulated drinking water samples, which contained sufficiently high levels of volatile and nonvolatile DBPs and thus enabled directly evaluating the toxicity of the DBP mixtures without sample pretreatment. Specifically, the natural organic matter and bromide concentrations and the chlorine dose in the concentrated water samples were 250 times higher than those in a typical drinking water sample. Each concentrated water sample was divided into two aliquots, and one of them was nitrogen sparged to eliminate volatile DBPs; then, both aliquots were used directly in a well-established developmental toxicity test. No significant difference (p > 0.10) was found between the developmental toxicity indexes of each concentrated water sample without and with nitrogen sparging, indicating that the contribution of volatile DBPs to the developmental toxicity of the DBP mixture might be marginal. A reasonable interpretation is that nonvolatile halogenated DBPs (especially the aromatic ones) in the DBP mixture could be the major developmental toxicity contributor that warrants more attention.

As cattle represent one of the most important livestock species for meat production, control of muscle development in regards to quality is an important research focus. In this study, the phenotypic quality traits and its associations with DNA methylation levels of the longissimus muscle in two cattle breeds were studied. The pH value, water loss rate, fat and protein and fatty acid content were measured in three beef cattle breeds of longissimus mucle; The longissimus mucle was analyzed by MethylRAD-seq and RNA-seq. The differentially methylated and differentially expressed related genes were subjected to BSP. Methylation status of longissimus mucle was analyzed by MethylRAD-seq. Compared with Simmental, there were 39 differentially methylated and expressed genes in muscle of Yunling cattle, and 123 differentially methylated and expressed genes in Wenshan muscle. A combined analysis of MethylRAD-seq and RNA-seq results revealed differential methylation and expression level of 18 genes between Simmental and Wenshan cattle, and 14 genes between Simmental and Yunling cattle. In addition, 28 genes were differentially methylated between Wenshan and Yunling cattle. Results of promoter methylation analysis of ACAD11, FADS6 and FASN showed that the overall degree of DNA methylation of FADS6 and FASN was negatively correlated with their expression levels. Methylation level of FASN in Simmental was greater than Yunling and Wenshan. The degree of methylation at the FADS6 CpG4 site was significantly higher in Simmental than that in Yunling. The levels of methylation at the CpG7 locus of the Simmental and Yunling breeds were greater than Wenshan cattle. A negative correlation was detected between the methylation levels and the expression of FASN CpG1, CpG2, CpG3, CpG5, CpG7, and CpG10. The functional and molecular regulatory mechanism of the genes related to meat quality can be revealed systematically from aspects of the genetic and epigenetic regulation. These studies will help to further explore the molecular mechanisms and phenotypic differences that regulate growth and quality of different breeds of cattle.

Satellite observations are affected by clouds, aerosol and other factors, resulting in temporal discontinuities and spatial incompleteness in leaf area index (LAI) products. Furthermore, the currently available LAI products are generally retrieved from mono-temporal remote sensing data acquired by a single sensor, without comprehensive utilization of multi-source satellite observations. This paper proposes a new data assimilation method to retrieve temporally continuous LAI at different spatial scales from time-series multi-source remote sensing data with different spatial resolutions using an ensemble multiscale tree model (EnMsT). A dynamic model was constructed to describe the change rule of LAI in time series. At each time-step, the forecast of LAI from the dynamic model was used to construct an initial EnMsT. Then, satellite surface reflectance data with different spatial resolutions were used to update the LAI at each node of the EnMsT using an ensemble multiscale filter (EnMsF) technique. The final results demonstrate that this new method can estimate temporally continuous LAI at different spatial scales and the retrieved LAI values are in good agreement with the field measurements.

As global surface temperature continues to rise, increasing evidences have shown that social and natural systems are deeply influenced by climate change. The government and farmers' awareness, as well as measures to adapt to these climate-driven changes, are critical for local sustainable development. In this study, we established a conceptual model of the relationship among human adaptation, development demand and environment changes to analyze the mechanism of agricultural drought adaptation based on an empirical research at the famer and government level. These results show that under the impact of climate change, the study area of drought risk has continued to expand. With this condition, the government and farmers have constantly taken measures to control the development demand and adjust to environmental changes in order to adapt to agricultural drought. Interactions among environmental changes, development demand and adaptation measures have kept the regional nature-society-economy compound ecosystem in dynamic balance. In addition, the effect of these adaptation measures always has an inertia that may induce a longer and deeper impact on the region, which is considered when making adaptation strategies. Rainfed areas are considered to be the most sensitive and unstable to environment change. This study reveals the mechanism of adaptation from a macroscopic perspective and may provide some references on measures and strategies for drought adaptation in other rainfed areas.

Currently, multiple leaf area index (LAI) products retrieved from remote sensing data are widely used in crop growth monitoring, land-surface process simulation and studies of climate change. However, most LAI products are only retrieved from individual satellite observations, which may result in spatial-temporal discontinuities and low accuracy in these products. In this paper, a new method was developed to simultaneously retrieve multiscale LAI data from satellite observations with different spatial resolutions based on an ensemble multiscale filter (EnMsF). The LAI average values corresponding to the date of satellite observations were calculated from the multi-year Moderate Resolution Imaging Spectroradiometer (MODIS) LAI product and were used as a priori knowledge for LAI in order to construct an initial ensemble multiscale tree (EnMsT). Satellite observations obtained at different spatial resolutions were then applied to update the LAI values at each node of the EnMsT using a two-sweep filtering procedure. Next, the retrieved LAI values at the finest scale were used as a priori knowledge for LAI for the new round of construction and updating of the EnMsT, until the sum of the difference of LAI values at each node of the EnMsT between two adjacent updates is less than a given threshold. The method was tested using Thematic Mapper (TM) or Enhanced Thematic Mapper Plus (ETM+) surface reflectance data and MODIS surface reflectance data from five sites that have different vegetation types. The results demonstrate that the retrieved LAI values for each spatial resolution were in good agreement with the aggregated LAI reference map values for the corresponding spatial resolution. The retrieved LAI values at the coarsest scale provided better accuracy with the aggregated LAI reference map values (root mean square error (RMSE) = 0.45) compared with that obtained from the MODIS LAI values (RMSE = 1.30).

During chlorine disinfection of drinking water, chlorine may react with natural organic matter (NOM) and bromide ion in raw water to generate halogenated disinfection byproducts (DBPs). To mitigate adverse effects from DBP exposure, granular activated carbon (GAC) adsorption has been considered as one of the best available technologies for removing NOM (DBP precursor) in drinking water treatment. Recently, we have found that many aromatic halogenated DBPs form in chlorination, and they act as intermediate DBPs to decompose and form commonly known DBPs including trihalomethanes and haloacetic acids. In this work, we proposed a new approach to controlling drinking water halogenated DBPs by GAC adsorption of intermediate aromatic halogenated DBPs during chlorination, rather than by GAC adsorption of NOM prior to chlorination (i.e., traditional approach). Rapid small-scale column tests were used to simulate GAC adsorption in the new and traditional approaches. Significant reductions of aromatic halogenated DBPs were observed in the effluents with the new approach; the removals of total organic halogen, trihalomethanes, and haloacetic acids by the new approach always exceeded those by the traditional approach; and the effluents with the new approach were considerably less developmentally toxic than those with the traditional approach. Our findings indicate that the new approach is substantially more effective in controlling halogenated DBPs than the traditional approach.