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Based on statistical physics and graph theory, the research paradigm of a complex network, which has sprung up in the last decade, provides us with new global perspective to discuss the topic of international trade. In this paper, we engage in the issue of countries' roles and positions in international trade using the latest complex network theories. On a mid-level structure, countries are classified into three communities that reflect the structure of the “core/periphery” using the weighted extremal optimisation algorithm and the coarse graining process. On a micro-level, countries' rankings are provided with the aid of network's node centralities, which presents world trade as a closed, imbalanced, diversified and multi-polar development. Further, we firstly introduce the improved bootstrap percolation to simulate cascading influences following the breaking down of bilateral trade relations. We find that the breakdown of EU's export relations can more easily form a cascading reaction, which would result in a global collapse of world trade. All the results highlight the important positions of the EU, USA and Japan in the international trade system, which plays a positive role in promoting the world economy.

The Chinese government started implementation of the Grain for Green Project (GGP) in 1999, aiming to convert cropland to forestland to mitigate soil erosion problems in areas across the country. Although the project has generated substantial environmental benefits, such as erosion reduction, carbon sequestration and water quality improvements, the magnitude of these benefits has not yet been well quantified due to the lack of location-specific data describing the afforestation efforts. Remote sensing is well suited to detect afforestation locations, a prerequisite for estimating the impacts of the project. In this study, we first examined the practicability of using the Moderate Resolution Imaging Spectroradiometer (MODIS) land cover product to detect afforestation locations; however, the results showed that the MODIS product failed to distinguish the afforestation areas of GGP. Then, we used a normalized difference vegetation index (NDVI) time series analysis approach for detecting afforestation locatio...

With rapid economic development and urbanization, land use in China has experienced huge changes in recent years; and this will probably continue in the future. Land use problems in China are urgent and need further study. Rapid land-use change and economic development make China an ideal region for integrated land use change studies, particularly the examination of multiple factors and global-regional interactions in the context of global economic integration. This paper presents an integrated modeling approach to examine the impact of global socio-economic processes on land use changes at a regional scale. We develop an integrated model system by coupling a simple global socio-economic model (GLOBFOOD) and regional spatial allocation model (CLUE). The model system is illustrated with an application to land use in China. For a given climate change, population growth, and various socio-economic situations, a global socio-economic model simulates the impact of global market and economy on land use, and quantifies changes of different land use types. The land use spatial distribution model decides the type of land use most appropriate in each spatial grid by employing a weighted suitability index, derived from expert knowledge about the ecosystem state and site conditions. A series of model simulations will be conducted and analyzed to demonstrate the ability of the integrated model to link global socioeconomic factors with regional land use changes in China. The results allow an exploration of the future dynamics of land use and landscapes in China.

In this paper the model outputs from the Coupled Model Intercomparison Project (CMIP) phase 5 (CMIP5) are used to examine the climatology and interannual variability of the East Asian winter monsoon (EAWM). The multimodel ensemble (MME) is able to reproduce reasonably well the circulation features of the EAWM. The simulated surface air temperature still suffers from a cold bias over East Asia, but this bias is reduced compared with CMIP phase 3 models. The intermodel spread is relatively small for the large-scale circulations, but is large for the lower-tropospheric meridional wind and precipitation along the East Asian coast. The interannual variability of the EAWM-related circulations can be captured by most of the models. A general bias is that the simulated variability is slightly weaker than in the observations. Based on a selected dynamic EAWM index, the patterns of the EAWM-related anomalies are well reproduced in MME although the simulated anomalies are slightly weaker than the observations. One general bias is that the northeasterly anomalies over East Asia cannot be captured to the south of 30°N. This bias may arise both from the inadequacies of the EAWM index and from the ability of models to capture the EAWM-related tropical–extratropical interactions. The ENSO–EAWM relationship is then evaluated and about half of the models can successfully capture the observed ENSO–EAWM relationship, including the significant negative correlation between Niño-3.4 and EAWM indices and the anomalous anticyclone (or cyclone) over the northwestern Pacific. The success of these models is attributed to the reasonable simulation of both ENSO’s spatial structure and its strength of interannual variability.

This study evaluates the performances of three global satellite datasets (Advanced Very High Resolution Radiometer (AVHRR), Moderate Resolution Imaging Spectroradiometer (MODIS) and Satellite pour l’ observation de la Terre (SPOT) of the Mongolian Plateau, where in situ observation is insufficient to assess vegetation dynamics on terrestrial systems. We give a comprehensive assessment of the historical changes in vegetation dynamics by using comparative and correlation methods on the three archives using two indices: the growing season’s Normalized Difference Vegetation Index (NDVI) and the Start of the Season Index (SOS). The main findings are: (1) MODIS and SPOT have generally better comparability and consistency in the spatial-temporal trends of NDVI and SOS than AVHRR in this area; (2) all the three archives exhibit better consistency in Inner Mongolia than in Mongolia; (3) integration data analysis of AVHRR (1982–1997) and SPOT (1998–2012) shows that the dynamics of vegetation growth has three distinct phases: enhanced before 1994; a flatter/slightly decreasing trend before 2001; and, then, a rapid recovery between 2001 and 2012 with remarkable spatial heterogeneity, with Inner Mongolia experiencing a significant greening in vegetation NDVI compared with no obvious changes in Mongolia; (4) the temporal average SOS showed no significant “earlier spring” onset during the past 31 years, on the middle and northern Mongolian Plateau.

[1] Numerical model simulations provide a useful platform for investigating the interactions between the atmospheric dust cycle and environmental change in Asia. However, model validation is still limited by the scarcity of ground observations of past terrestrial dust deposition fluxes. Here we apply a regional atmosphere-chemistry/aerosol climate model to simulate Asian dust emissions, transport, and deposition over East Asia during the years 1996–1998 and compare the present-day deposition fluxes and dominant dust sources obtained from the numerical simulations to those measured in a high-resolution Holocene palaeodust peat record on the eastern Qinghai-Tibetan Plateau. The model was found to produce reasonable dust emission fluxes from the Chinese dust sources, with average annual emissions of 179 Mt y−1, and successfully reproduced both the dominant dust sources and average deposition fluxes to the peat core, with modeled and observed fluxes of 6.1 g m−2 y−1. Sensitivity tests show that modeled dust fluxes are sensitive to the parameterization of erodible surfaces, and future development of the regional model to simulate dust emissions in Asia should include an improved scheme for the soil surface properties. The results presented here suggest that the regional model holds the potential to study past and present dust cycles in Asia but evidence the need for both further refinement of the model's dust parameterizations in this region and more high-resolution terrestrial validation data sets such as peat archives. This study demonstrates how present-day simulations, for which reanalysis data is available as boundary conditions, are useful tools to explore the relationship between the dust cycle and environmental change during the Holocene.

The majority of African countries are stricken by food shortages and undernourishment, with much of the population lacking reliable access to food supplies and basic dietary requirements. In this paper, we analyze past trends of food production and consumption in Africa, both for the continent as a whole and for 52 individual countries within it. Fluctuations in the self-sufficiency ratio (SSR) are used to characterize the stability of a country’s capacity to sustain its own population, and GDP per capita is taken as representative of national purchasing power. Our study shows that Africa’s food self-sufficiency is lower today than it was throughout the entire study period. This is probably a result of demographic expansion, leading to a greater increase in food demand than in food production. At the national level, a decrease in SSR mainly occurred in Northern and Southern Africa, and high SSR fluctuations (i.e. low stability) always appeared in conjunction with low SSR levels. Although “low SSR-low GDP” countries face the most serious food insecurity conditions, both “low SSR-high GDP” and “high SSR-low GDP” countries also need attention.

Consumption of fossil fuel resources leads to global warming and climate change. Apart from the negative impact of greenhouse gases on the climate, the increasing emission of anthropogenic heat from energy consumption also brings significant impacts on urban ecosystems and the surface energy balance. The objective of this work is to develop a new method of estimating the global anthropogenic heat budget and validate it on the global scale with a high precision and resolution dataset. A statistical algorithm was applied to estimate the annual mean anthropogenic heat (AH-DMSP) from 1992 to 2010 at 1×1 km2 spatial resolution for the entire planet. AH-DMSP was validated for both provincial and city scales, and results indicate that our dataset performs well at both scales. Compared with other global anthropogenic heat datasets, the AH-DMSP has a higher precision and finer spatial distribution. Although there are some limitations, the AH-DMSP could provide reliable, multi-scale anthropogenic heat information, which could be used for further research on regional or global climate change and urban ecosystems.

China's land use has undergone many changes over the past 300 years due to the significant transformations caused by natural and human factors and their impact on regional climate and the environment. This comprehensive review of recent state-of-the-art studies of China's land-use changes during that period concentrates on cropland, forest, grassland and urban areas. While most small-scale studies have reconstructed information from historical archive data and focused on a specific time period, large-scale studies have tended to rely on inverse modeling techniques to interpret land-use change dynamics based on remote-sensing data for example, the global land-use products of the History Database of the Global Environment (HYDE) and Center for Sustainability and the Global Environment (SAGE) datasets. All studies have shown that the cropland areas in China increased between 1700 and 1950, although they indicate different magnitudes and rates. A decrease in forest coverage was also reported in all studies. Little information was available on urban and grassland areas over the same period. Rapid urbanization in China has been particularly evident in the past 50 years. Meanwhile, spatially explicit reconstructions of historical land-use change in China since 1700 remain highly uncertain due to the lack of reliable data. Extensive work on primary data collection is required, including land-use records and drivers for future change.

Carbon transfer via international trade affects the spatial pattern of global carbon emissions by redistributing emissions related to production of goods and services. It has potential impacts on attribution of the responsibility of various countries for climate change and formulation of carbon-reduction policies. However, the effect of carbon transfer on climate change has not been quantified. Here, we present a quantitative estimate of climatic impacts of carbon transfer based on a simple CO2 Impulse Response Function and three Earth System Models. The results suggest that carbon transfer leads to a migration of CO2 by 0.1–3.9 ppm or 3–9% of the rise in the global atmospheric concentrations from developed countries to developing countries during 1990–2005 and potentially reduces the effectiveness of the Kyoto Protocol by up to 5.3%. However, the induced atmospheric CO2 concentration and climate changes (e.g., in temperature, ocean heat content and sea-ice) are very small and lie within observed interannual variability. Given continuous growth of transferred carbon emissions and their proportion in global total carbon emissions, the climatic effect of traded carbon is likely to become more significant in the future, highlighting the need to consider carbon transfer in future climate negotiations.

This paper discussed the analysis of the survey on sustainability of bioenergy conducted in the Philippines, India and China. It acquired general perceptions of the people by asking them (a) specific questions about their level of familiarity with bioenergy; (b) relationship of their work to bioenergy; and (c) their opinion on contribution of various feedstock on the economy and impact of bioenergy production on food security. In addition to these questions, we estimated preference weights of various feedstock based on the conjoint choices on bioenergy’s contribution to social stability, social welfare and ecological balance. The estimates revealed significant trade-offs not only among these three dimensions of sustainability but also the relative importance of energy security, food security and ecosystem capacity to other economic, social and environmental objectives. The types of first generation feedstock that are currently used for biofuel production in the respective countries and those that offer alternative household use are perceived as important to the economy and preferred bioenergy feedstock. Based on the results of the study, the preferred role of bioenergy for sustainable development reflects the social and economic concerns in the respective Asian countries, e.g., energy security in China, food security in India, and ecosystem degradation in the Philippines.

A realistic simulation of snow cover and its thermal properties are important for accurate modelling of permafrost. We analyze simulated relationships between air and near-surface (20 cm) soil temperatures in the Northern Hemisphere permafrost region during winter, with a particular focus on snow insulation effects in nine land surface models and compare them with observations from 268 Russian stations. There are large across-model differences as expressed by simulated differences between near-surface soil and air temperatures, (ΔT), of 3 to 14 K, in the gradients between soil and air temperatures (0.13 to 0.96 °C/°C), and in the relationship between ΔT and snow depth. The observed relationship between ΔT and snow depth can be used as a metric to evaluate the effects of each model's representation of snow insulation, and hence guide improvements to the model’s conceptual structure and process parameterizations. Models with better performance apply multi-layer snow schemes and consider complex snow processes. Some models show poor performance in representing snow insulation due to underestimation of snow depth and/or overestimation of snow conductivity. Generally, models identified as most acceptable with respect to snow insulation simulate reasonable areas of near-surface permafrost (12–16 million km2). However, there is not a simple relationship between the quality of the snow insulation in the acceptable models and the simulated area of Northern Hemisphere near-surface permafrost, likely because several other factors such as differences in the treatment of soil organic matter, soil hydrology, surface energy calculations, and vegetation also provide important controls on simulated permafrost distribution.

Argonaute proteins (Ago) are core components of the RNA Induced Silencing Complex (RISC) that load and utilize small guide nucleic acids to silence mRNAs or cleave foreign DNAs. Despite the essential role of Ago in gene regulation and defense against virus, the molecular mechanism of guide-strand loading into Ago remains unclear. We explore such a mechanism in the bacterium Thermus thermophilus Ago (TtAgo), via a computational approach combining molecular dynamics, bias-exchange metadynamics, and protein-DNA docking. We show that apo TtAgo adopts multiple closed states that are unable to accommodate guide-DNA. Conformations able to accommodate the guide are beyond the reach of thermal fluctuations from the closed states. These results suggest an induced-fit dominant mechanism for guide-strand loading in TtAgo, drastically different from the two-step mechanism for human Ago 2 (hAgo2) identified in our previous study. Such a difference between TtAgo and hAgo2 is found to mainly originate from the distinct rigidity of their L1-PAZ hinge. Further comparison among known Ago structures from various species indicates that the L1-PAZ hinge may be flexible in general for prokaryotic Ago's but rigid for eukaryotic Ago's.

Based on the natural disaster analysis theory, the spatial characteristics of agricultural drought risk in China were investigated at 10 × 10 km grid scale. It shows that agricultural drought risk in China has a clear southeast–northwest spatial pattern. High and very high risk mainly occur in the eastern part of Northeast Plain, the central of Inner Mongolian Plateau, the Loess Plateau, north Xinjiang, the north and south of Yangtze Plain, and Yunnan-Guizhou Plateau. Statistics also show that 19.5 % of the main crop planting area is exposed to low risk, 35.1 % of the area to moderate risk, 39.8 % of the area to high risk, and 5.6 % of the area to very high risk. Further investigation shows that 23 % of total wheat growing areas is located in high and very high risk class; corn and rice are 16 % and 14 % respectively. Comprehensive analysis shows that severely affected areas by drought in the history are mainly located in the high and very high risk areas.

As an important indicator of cropping intensity, Cropping Index (CI) is defined as the number of peaks in the Vegetation Index (VI) time-series curve in a year. The existing CI mapping algorithms (e.g., the cross-fitting and the second order difference algorithm) are vulnerable to noise contained in the VI time series and need a priori knowledge and some extra constraints which could not be directly derived from the VI time-series data. In this paper, a shape-matching method is developed which can map CI directly from the preprocessed VI time-series data without the de-noising processes. This shape-matching method utilizes a decision-making process to find out the true peaks in the VI time-series curve based on a rank order mathematical morphology algorithm. The processing procedure involves five steps: (a) determination of the temporal moving window size, (b) detection of local maximum/minimum points, (c) exclusion of false maximum/minimum points, (d) determination of the threshold for the minimum growth amplitude, and (e) mapping of CI. This shape-matching method only needs two input parameters, the temporal moving window size and the threshold for the minimum growth amplitude, which can be both directly derived from the VI time-series data with some selected test pixels. Moreover, the response of the shape-matching method is relatively insensitive to the exact values of its design parameters, making it more flexible and effective in adapting to other regions. This new method is applied to map the CIs in Jiangsu Province, China, in 2010, based on the Enhanced Vegetation Index (EVI) time-series data derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) product. The overall CI mapping accuracy for the shape-matching method is 80 percent, which is much higher than the CI mapping accuracy of 60 percent for the second order difference algorithm. This shape-matching method can be further applied to other regions with a grid-search for its optimal parameters using some test pixels.

At the United Nations Framework Convention on Climate Change Conference in Cancun, in November 2010, the Heads of State reached an agreement on the aim of limiting the global temperature rise to 2 °C relative to preindustrial levels. They recognized that long-term future warming is primarily constrained by cumulative anthropogenic greenhouse gas emissions, that deep cuts in global emissions are required, and that action based on equity must be taken to meet this objective. However, negotiations on emission reduction among countries are increasingly fraught with difficulty, partly because of arguments about the responsibility for the ongoing temperature rise. Simulations with two earth-system models (NCAR/CESM and BNU-ESM) demonstrate that developed countries had contributed about 60–80%, developing countries about 20–40%, to the global temperature rise, upper ocean warming, and sea-ice reduction by 2005. Enacting pledges made at Cancun with continuation to 2100 leads to a reduction in global temperature rise relative to business as usual with a 1/3–2/3 (CESM 33–67%, BNU-ESM 35–65%) contribution from developed and developing countries, respectively. To prevent a temperature rise by 2 °C or more in 2100, it is necessary to fill the gap with more ambitious mitigation efforts.

The aim of our study was to determine an optimal slice thickness that was efficient in revealing bronchial imageology of pulmonary nodules (PNs) on multi-slice spiral computed tomography (MSCT) images preliminarily. Fifty-four patients with 62 PNs (diameter ≤ 3 cm) underwent multidetector-row computed tomography of the chest in a single-breath-hold technique. The raw data were acquired with a collimation of 0.625 mm. Three sets of contiguous images were reconstructed with 1-, 2-, and 5-mm slice thickness, respectively. Bronchial imageology of SPNs on the CT images presented in 1-, 2-, and 5-mm slice thickness was compared. Using the 1-mm sections as the gold standard, an optimal slice thickness in revealing bronchial imageology of PNs was determined. Bronchial imageology of PNs on the CT images presented in 1 mm slice thickness involved 85 bronchi (35 second-fourth generation bronchi; 50 fifth-eighth generation bronchi). Bronchial imageology on 2-mm-thick sections was as same as that on 1-mm-thick sections in 34 second-fourth generation bronchi. No statistically significant difference in number of second-fourth generation bronchi with same bronchial imageology was found between that on 2-mm-thick images and 1-mm-thick images (P = 0.836 > 0.05). Bronchial imageology on 5-mm-thick sections was as same as that on 1-mm-thick sections in 24 second-fourth generation bronchi. There was statistically significant difference in number of second-fourth generation bronchi with same bronchial imageology between that on 5-mm-thick images and 1-mm-thick images (P = 0.026 < 0.05). Bronchial imageology on 2-mm-thick sections was as same as that on 1-mm-thick sections in 38 fifth-eighth generation bronchi. There was statistically significant difference in number of fifth-eighth generation bronchi with same bronchial imageology between that on 2-mm-thick images and 1-mmthick images (P = 0.029 < 0.05). Bronchial imageology on 5-mm-thick images was as same as that on 1-mm-thick images in 31 fifth-eighth generation bronchi. There was statistically significant difference in number of fifth-eighth generation bronchi with same bronchial imageology between that on 5-mm-thick sections and 1-mm-thick sections (P = 0.001 < 0.05). It is suggested that the use of 2-mm slice thickness is suitable in revealing second-fourth generation bronchi and the use of 1-mm slice thickness is suitable in revealing fifth-eighth generation bronchi.

Objective The aim of this study was to determine an optimal slice thickness that was efficient in revealing lobulation of malignant solitary pulmonary nodules (SPNs) on multi-slice spiral computed tomography (MSCT) images preliminarily.

The China–Russia gas deal will play an important role in reducing greenhouse-gas emissions and air pollution in China.

Using 1958–2002 NCEP/NCAR reanalysis data, we investigate stationary and transient planetary wave propagation and its role in wave-mean flow interaction which influences the state of the polar vortex (PV) in the stratosphere in Northern Hemisphere (NH) winter. This is done by analyzing the Eliassen-Palm (E-P) flux and its divergence. We find that the stationary and transient waves propagate upward and equatorward in NH winter, with stronger upward propagation of stationary waves from the troposphere to the stratosphere, and stronger equatorward propagation of transient waves from mid-latitudes to the subtropics in the troposphere. Stationary waves exhibit more upward propagation in the polar stratosphere during the weak polar vortex regime (WVR) than during the strong polar vortex regime (SVR). On the other hand, transient waves have more upward propagation during SVR than during WVR in the subpolar stratosphere, with a domain of low frequency waves. With different paths of upward propagation, both stationary and transient waves contribute to the maintenance of the observed stratospheric PV regimes in NH winter.

We report the investigation on the adsorption behaviors of CO on the rutile TiO2(110)-1 × 1 surface with preadsorbed O adatoms using scanning tunneling microscopy (STM) joint with density functional theory (DFT) calculations. The STM experimental results show that the diffusive CO molecules tend to adsorb at the site close to the O adatoms, forming CO−O and CO−O−CO complexes. These complexes are quite stable against the high bias voltages and UV illumination. DFT calculations give an activation energy barrier of 0.56 eV for CO oxidation through the CO−O complex to produce CO2. Our experimental and theoretical results both indicate that the dissociative O2, that is, the O adatoms on Ti4+, may not be directly responsible for the catalytic oxidation at low temperature.

The aim of this study was to evaluate the efficacy of three-phase contrast material-enhanced MRI in assessing no-surgical treatment response in peripheral bronchogenic carcinoma preliminarily. Twenty-two patients with bronchogenic carcinoma after no-surgical treatment underwent three-phase contrast material-enhanced MRI. Three scans were obtained at 25 s, 120 s and 180 s respectively after nonionic contrast material was administrated via the antecubital vein at a rate of 2 mL/s by using an autoinjector. Precontrast and postcontrast signal intensity on every scan was recorded. Peak Height (PH) and Maximum Enhancement (Emax) were calculated. Enhancement pattern was evaluated on the images obtained at 120 s and 180 s after injection of contrast medium. Precontrast signal intensity, postcontrast signal intensity at 120 s and 180 s were 478 ± 108, 926 ± 209 and 1050 ± 252. PH (571 ± 225) and Emax (119 ± 49) of bronchogenic carcinoma after no-surgical treatment were significantly lower than those of bronchogenic carcinoma without any therapy (mean PH 655, mean Emax 150) (t = 2.178, P = 0.005 < 0.05, t = 4.196, P = 0.001 < 0.05). Six cases among 22 appeared homogeneous enhancement at 180 s. At 120 s, there were 4 cases with inhomogeneous enhancement, 1 case with homogeneous enhancement, 1 case with peripheral enhancement among the 6 cases. Bronchogenic carcinoma after no-surgical treatment shows a gradual increase to the PH after administration of contrast material. Three-phase contrast material-enhanced MRI can reflect the blood supply of bronchogenic carcinoma and might be effective approach for evaluation of no-surgical treatment response in bronchogenic carcinoma.

Objective The aim of the study was to evaluate the efficacy of contrast material-enhanced computed tomography (CT) in assessing no-surgical treatment response in bronchogenic carcinoma.

This paper investigates the response of the land surface and the lowest section of the atmospheric surface layer to rainfall events and through the subsequent drying out period. The impacts of these sequences of rainfall and drying events in controlling near-surface temperatures are put into the context of malaria transmission modeling using temperature controls on the survivability of mosquitoes that are developing the malaria parasite. Observations using measurements from a dwelling hut, constructed to a local design at Wankama near Niamey, Niger, show that as the atmosphere gets moister and colder following rainfall, there is a potentially higher risk of malaria transmission during the rainy days. As the atmosphere gets warmer and drier during the drying period, there is a potentially decreasing rate of malaria transmission as the increasing temperature reduces the survivability of the mosquitoes. A numerical weather prediction model comparison shows that the high-resolution limited-area model outperforms the global-scale model and shows good agreement with the observations. Statistical analysis from the model results confirms that the findings are not restricted to a single location or single time of the day. It was also found that air temperatures over forest areas do not change as much during the study period, since the longer memory of the soil moisture means there is relatively little influence from single rainfall events.

We present the investigations of hydroxylated TiO2 (110)−1 × 1 surfaces using scanning tunneling microscopy (STM). It is observed that in topographic images the protrusions of hydroxyls (OH) on TiO2 (110) surfaces are dependent on the tip−sample distance in STM measurements at room temperature. In comparison with those of the fivefold coordinated Ti atoms and the oxygen vacancies, the relative apparent height of OHs becomes smaller and smaller with decreasing tip−sample distance by changing the imaging conditions. The OHs even become invisible in much shorter tip−sample distances. Reversibly, the OHs are almost completely recovered when the imaging conditions are restored. It suggests that the OHs may be identified by varying the imaging conditions in STM measurement.

Objective To evaluate the efficacy of double-phase contrast material-enhanced computed tomography (CT) in assessing no-surgical treatment response in bronchogenic carcinoma preliminarily.

This paper reviews the land cover changes on the Tibetan Plateau during the last 50 years partly caused by natural climate change and, more importantly, influenced by human activities. Recent warming trends on the plateau directly influence the permafrost and snow melting and will impact on the local ecosystem greatly. Human activities increased rapidly on the plateau during the last half century and have significant impacts on land use. Significant land cover changes on the Tibetan Plateau include permafrost and grassland degradation, urbanization, deforestation and desertification. These changes not only impact on local climate and environment, but also have important hydrological implications for the rivers which originate from the plateau. The most noticeable disasters include the flooding at the upper reaches of Yangtze River and droughts along the middle and lower reaches of Yellow River. Future possible land cover changes under future global climate warming are important but hard to assess due to the deficits of global climate model in this topographically complex area. Integrated investigation of climate and ecosystems, including human-beings, are highly recommended for future studies.

Regional climate models are major tools for regional climate simulation and their output are mostly used for climate impact studies. Notes are reported from a series of numerical simulations of summer rainfall in China with a regional climate model. Domain sizes and running modes are major foci. The results reveal that the model in forecast mode driven by “perfect” boundaries could reasonably represent the inter-annual differences: heavy rainfall along the Yangtze River in 1998 and dry conditions in 1997. Model simulation in climate mode differs to a greater extent from observation than that in forecast mode. This may be due to the fact that in climate mode it departs further from the driving fields and relies more on internal model dynamical processes. A smaller domain in climate mode outperforms a larger one. Further development of model parameterizations including dynamic vegetation are encouraged in future studies.

[Departement_IRSTEA]Eaux [TR1_IRSTEA]ARCEAU; International audience; A realistic simulation of snow cover and its thermal properties are important for accurate modelling of permafrost. We analyse simulated relationships between air and near-surface (20 cm) soil temperatures in the Northern Hemisphere permafrost region during winter, with a particular focus on snow insulation effects in nine land surface models, and compare them with observations from 268 Russian stations. There are large cross-model differences in the simulated differences between near-surface soil and air temperatures (ΔT; 3 to 14 °C), in the sensitivity of soil-to-air temperature (0.13 to 0.96 °C °C−1), and in the relationship between ΔT and snow depth. The observed relationship between ΔT and snow depth can be used as a metric to evaluate the effects of each model's representation of snow insulation, hence guide improvements to the model's conceptual structure and process parameterisations. Models with better performance apply multilayer snow schemes and consider complex snow processes. Some models show poor performance in representing snow insulation due to underestimation of snow depth and/or overestimation of snow conductivity. Generally, models identified as most acceptable with respect to snow insulation simulate reasonable areas of near-surface permafrost (13.19 to 15.77 million km2). However, there is not a simple relationship between the sophistication of the snow insulation in the acceptable models and the simulated area of Northern Hemisphere near-surface permafrost, because several other factors, such as soil depth used in the models, the treatment of soil organic matter content, hydrology and vegetation cover, also affect the simulated permafrost distribution.

We perform a land-surface model intercomparison to investigate how the simulation of permafrost area on the Tibetan Plateau (TP) varies among six modern stand-alone land-surface models (CLM4.5, CoLM, ISBA, JULES, LPJ-GUESS, UVic). We also examine the variability in simulated permafrost area and distribution introduced by five different methods of diagnosing permafrost (from modeled monthly ground temperature, mean annual ground and air temperatures, air and surface frost indexes). There is good agreement (99 to 135 × 104 km2) between the two diagnostic methods based on air temperature which are also consistent with the observation-based estimate of actual permafrost area (101 × 104 km2). However the uncertainty (1 to 128 × 104 km2) using the three methods that require simulation of ground temperature is much greater. Moreover simulated permafrost distribution on the TP is generally only fair to poor for these three methods (diagnosis of permafrost from monthly, and mean annual ground temperature, and surface frost index), while permafrost distribution using air-temperature-based methods is generally good. Model evaluation at field sites highlights specific problems in process simulations likely related to soil texture specification, vegetation types and snow cover. Models are particularly poor at simulating permafrost distribution using the definition that soil temperature remains at or below 0 °C for 24 consecutive months, which requires reliable simulation of both mean annual ground temperatures and seasonal cycle, and hence is relatively demanding. Although models can produce better permafrost maps using mean annual ground temperature and surface frost index, analysis of simulated soil temperature profiles reveals substantial biases. The current generation of land-surface models need to reduce biases in simulated soil temperature profiles before reliable contemporary permafrost maps and predictions of changes in future permafrost distribution can be made for the Tibetan Plateau.

The hydrological impact of forest removal on the southeast Tibetan Plateau during the second half of the last century is investigated in this study using an atmospheric general circulation model. The effects of deforestation are investigated by examining the differences between the forest replacement and control experiments. Model results demonstrate that deforestation of the southeast Tibetan Plateau would influence the local and the remote climate as well. It would lead to decreased transpiration and increased summer precipitation in the deforested area and a wetter and warmer climate on the Tibetan Plateau in summer. This may produce more runoff into the rivers originating from the Tibetan Plateau and worsen flooding disasters in the downstream areas. The numerical experiments also show that deforestation would remotely impact Asian climate, and even global climate, although the statistical significance is small. A strong drought is found at middle and lower reaches of the Yellow River, where livelihoods and economics have suffered from recent droughts. Ecosystem research on the Tibetan Plateau is a relatively new topic and needs further interdisciplinary investigation.

This study investigates the capability of the regional climate model REMO to simulate the summer monsoonal rainfall distribution and evolution on the Tibetan Plateau. The model is performed for summer 1998 driven by “perfect boundaries” in a one-way double-nesting system, with a 55 km grid point intermediate mother domain encompassing East Asia and a 18 km grid point spacing nested domain covering almost the whole Tibetan Plateau. By comparison with in situ observations, the model results demonstrate that the higher resolution run out-performs the lower one. At a horizontal resolution of 18 km, REMO could reproduce the major precipitation events at daily scale and simulate the spatial differences. The evolution and spatial distribution of the monsoonal rainfall in the model are reasonable and comparable to observations.

Devastating floods due to Atlantic hurricanes are relatively rare events. However, the frequency of the most intense storms is likely to increase with rises in sea surface temperatures. Geoengineering by stratospheric sulfate aerosol injection cools the tropics relative to the polar regions, including the hurricane Main Development Region in the Atlantic, suggesting that geoengineering may mitigate hurricanes. We examine this hypothesis using eight earth system model simulations of climate under the Geoengineering Model Intercomparison Project (GeoMIP) G3 and G4 schemes that use stratospheric aerosols to reduce the radiative forcing under the Representative Concentration Pathway (RCP) 4.5 scenario. Global mean temperature increases are greatly ameliorated by geoengineering, and tropical temperature increases are at most half of those temperature increases in the RCP4.5. However, sulfate injection would have to double (to nearly 10 teragrams of SO2 per year) between 2020 and 2070 to balance the RCP4.5, approximately the equivalent of a 1991 Pinatubo eruption every 2 y, with consequent implications for stratospheric ozone. We project changes in storm frequencies using a temperature-dependent generalized extreme value statistical model calibrated by historical storm surges and observed temperatures since 1923. The number of storm surge events as big as the one caused by the 2005 Katrina hurricane are reduced by about 50% compared with no geoengineering, but this reduction is only marginally statistically significant. Nevertheless, when sea level rise differences in 2070 between the RCP4.5 and geoengineering are factored into coastal flood risk, we find that expected flood levels are reduced by about 40 cm for 5-y events and about halved for 50-y surges.

We investigate the spectroscopy and photoinduced electron dynamics within the conduction band of reduced rutile $\mathrm{Ti}{\mathrm{O}}_{2}(110)$ surface by multiphoton photoemission $(\mathrm{mPP})$ spectroscopy with wavelength tunable ultrafast $(\ensuremath{\sim}20\phantom{\rule{0.16em}{0ex}}\mathrm{fs})$ laser pulse excitation. Tuning the $\mathrm{mPP}$ photon excitation energy between 2.9 and 4.6 eV reveals a nearly degenerate pair of new unoccupied states located at $2.73\ifmmode\pm\else\textpm\fi{}0.05$ and $2.85\ifmmode\pm\else\textpm\fi{}0.05$ eV above the Fermi level, which can be analyzed through the polarization and sample azimuthal orientation dependence of the $\mathrm{mPP}$ spectra. Based on the calculated electronic structure and optical transition moments, as well as related spectroscopic evidence, we assign these resonances to transitions between $\mathrm{Ti}\phantom{\rule{0.16em}{0ex}}3d$ bands of nominally ${t}_{2g}$ and ${e}_{g}$ symmetry, which are split by crystal field. The initial states for the optical transition are the reduced $\mathrm{T}{\mathrm{i}}^{3+}$ states of ${t}_{2g}$ symmetry populated by formation oxygen vacancy defects, which exist within the band gap of $\mathrm{Ti}{\mathrm{O}}_{2}$. Furthermore, we studied the electron dynamics within the conduction band of $\mathrm{Ti}{\mathrm{O}}_{2}$ by three-dimensional time-resolved pump-probe interferometric $\mathrm{mPP}$ measurements. The spectroscopic and time-resolved studies reveal competition between 2PP and 3PP processes where the ${t}_{2g}\text{\ensuremath{-}}{e}_{g}$ transitions in the 2PP process saturate, and are overtaken by the 3PP process initiated by the band-gap excitation from the valence band of $\mathrm{Ti}{\mathrm{O}}_{2}$.

We present the preparation of C54 TiSi 2 nanoislands on Si (1 1 1) with a method of the pulsed laser deposition of titanium oxide thin films. The TiO 2 thin films with nominal thicknesses of 1 nm on Si (1 1 1) were annealed at 850 °C for about 4 h in situ. The X-ray diffraction patterns and the X-ray photoelectron spectra indicate that the nanoislands are in C54 TiSi 2 phase. The characterization using a scanning tunneling microscope shows that the nanoislands with triangular, polygonal and rod-like shapes on Si (1 1 1) exhibit the Volmer–Weber growth mode. The sizes of the polygonal islands distribute in two separated ranges. For the small islands, they have a narrow lateral size distribution centered at 4 nm and a height range in 0.6–3.6 nm, while for the large islands, their lateral sizes are in the range of 12–40 nm and the heights in the range of 4–9 nm. The sizes of the well-shaped triangular islands are intermediate with the lateral sizes in range of 5–20 nm and the heights of 2–3.5 nm. The rod-like islands are about 50–200 nm in length, 5 nm in height and about 15–20 nm in width. The origination of the various shapes of the nanoislands is attributed to the symmetry of Si (1 1 1) substrate and the lattice mismatch between the C54 TiSi 2 and the Si (1 1 1) surface.

A general atmospheric circulation model (ECHAM5) has been applied to investigate the impact of land use changes on the Tibetan Plateau (TP) on local and global climate. The “control” simulation with current land cover reasonably represents the large-scale circulation and state of the atmosphere over the Tibetan Plateau and the surrounding region. Modifying the land cover to a hypothetical non-anthropogenically-influenced vegetation cover shows significant modifications to the local and remote climate. Compared to this scenario, the TP is warmer and drier under present conditions. The Indian summer monsoon is intensified and the East China summer monsoon is weakened due to human-induced land cover change on the TP. The mean global temperature has almost no variation, whereas precipitation slightly increases. Our study indicates that human-induced land use changes on the Tibetan Plateau have had a significant impact on local to regional, and to a lesser extent global, climate.

We present the growth of textured TiO2 thin films on muscovite mica using pulsed laser deposition. Atomic force microscopy, scanning electron microscopy, X-ray photoemission spectroscopy, and transmission electron microscopy were used to characterize the TiO2 films. Quasi-periodic wavy and comb-like buckles were observed. Below a critical thickness of about 25 nm, TiO2 films were relatively smooth, and buckles began to form when the nominal thickness of TiO2 films was larger than 25 nm. Co-existence of wavy and comb-like quasi-periodic buckles was observed when the nominal thickness of TiO2 films was larger than 100 nm. The film stress is compressive due to the competition of the tensile stress from the lattice mismatch and the growth stress. The buckle delamination occurred when the compressive stress overcome the adhesion strength of the TiO2 films on mica. A value of adhesion strength around 0.9 MPa for TiO2 on mica is obtained. The symmetric domains of buckles are assigned to the anisotropic lattice mismatch for TiO2 on mica.

Tin oxide (SnO 2 ) nanowires have been synthesized in bulk quantities at lower temperature (680 °C) by thermal evaporation of SnO powder. These as-synthesized SnO 2 nanowires are single crystals with [3 0 1] growth axis, with diameters ranging from 10 to 190 nm and lengths extending to tens of micrometers. The growth of SnO 2 nanowires synthesized by lower-temperature evaporation is dominated by a self-catalytic vapor–liquid–solid (VLS) mechanism. The self-catalytic effect in VLS process has been described.

Multiphoton photoemission (MPP) from metal surfaces with energy, momentum, time, and resolution enables probing the electronic structure, optical response, and electron dynamics at metal surfaces. We discuss recent progress in understanding of the MPP excitation process for Ag(111) and Cu(111) surfaces using tunable femtosecond laser excitation and photoelectron E(k) imaging.

This paper explores land use change in China using a global, parsimonious land use model (PLUM). The model links drivers of population growth and socio-economic development to agricultural yield changes and alternative national and international environmental policies. Comparison with historic data (over the past 30 years) suggests that the model is reasonably good at reproducing changes in food consumption in China and consequent crop production with prescribed population, GDP and yield data. The model simulates a decline in forest area, which results from the increased demand for arable land in response to higher production demand. This is different from the observed trend of increasing forest area partly because the model excludes new plantation, the main resource of new forest in China. Application of a simple business as usual scenario suggests that PLUM could be used to project future land use change at the country level from global level consideration of human environment interactions.