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The Triassic rocks are widespread in China, and both marine and terrestrial strata are well developed. The Triassic stratigraphic architecture of China is very complex in both spatial variation of the so-called "South Marine and North Continental", i.e. the southern areas of China occupied mostly by marine facies while the northern China by terrestrial facies during the Triassic Period, and temporal transition of the "Lower Marine and Upper Continental", i.e. the lower part of the Triassic System composed mainly of marine facies and the upper part of terrestrial strata especially in South China. Although the Global Stratotype Section and Point (GSSP) of the Permian-Triassic boundary is located in South China, the Triassic of China except for some marine Lower-Middle Triassic depositions shows significantly local characteristics and is hardly correlated with the global chronostratigraphic chart. Consequently, the Triassic of China contains not only the international research hotspots but also difficult points in stratigraphic study. This paper aims to present a brief review of the Triassic in China, including chronostratigraphy, biostratigraphy, magnetostratigraphy and chemostratigraphy, and summarize an integrated Triassic stratigraphic framework of China. Accordingly, a stratigraphic correlation is proposed for the lithostratigraphic sequences among the three tectono-paleogeographic stratigraphic regions. The comprehensive study indicates that ammonoids are the classic index fossils in Triassic biostratigraphy but conodonts are more advantageous in the study and definition of the Triassic chronostratigraphic boundaries. China still has the potential to optimize the GSSPs of the Induan-Olenekian boundary and Olenekian-Anisian boundary. The correlation of the Permian-Triassic boundary between marine and terrestrial facies might be achieved with the help of the Permian-Triassic "transitional bed" and its related biotic and environmental events in association with the biostratigraphic study of conchostracan, vertebrate and plant fossils. In addition, the carbon isotopes have been proved to be one of the powerful methods in marine Triassic stratigraphic study, whereas the oxygen and strontium isotopes may be additional important bridges to establish the correlation between the marine and terrestrial strata, but as yet lacking of relevant studies in terrestrial strata. Considering the most stratigraphic intervals of the Triassic and the terrestrial Triassic in China are difficult to be correlated to the global chart, the proposed Chinese (regional) Triassic chronostratigraphic chart of marine and terrestrial stages would be of importance to the study of Chinese Triassic stratigraphy and related aspects, but the stages must be conceptually in line with international standards and studied as soon as possible in order to finalize the definition. [ABSTRACT FROM AUTHOR]

Integrated River Basin Management (IRBM) has been a long discussed way to sustainably manage water and land resources; yet, very few examples of effective IRBM are found because there is a lack of sufficient scientific support, as well as institutional accommodation, to successfully implement it. This paper overviews the major challenges with IRBM, the promising scientific approaches for the implementation of IRBM, and the areas of needed research, with considerable issues and experiences from China. It is expected that novel research will draw together disparate disciplines into an integrated scientific framework, upon which better modeling tools, stakeholder involvement, and decision-making support can be built. Cutting-edge new technologies will bring ideas of IRBM forward to theory and finally to practice. The paper will prompt scientists to undertake research to fill in the gaps in the current IRBM knowledge base and provide practitioners guidance on how to incorporate scientifically based information within the IRBM decision process. [ABSTRACT FROM AUTHOR]

Since climatic condition is the important foundation for human subsistence and development and the key factor in sustainable development of economy and society, climate change has been a global issue attracting great attentions of politicians, scientists, governments, and the public alike throughout the world. Existing climate regionalization in China aims to characterize the regional differences in climate based on years of the mean value of different climate indexes. However, with the accelerating climate change nowadays, existing climate regionalization cannot represent the regional difference of climate change, nor can it reflect the disasters and environmental risks incurred from climate changes. This paper utilizes the tendency value and fluctuation value of temperature and precipitation from 1961 to 2010 to identify the climate change quantitatively, and completes the climate change regionalization in China (1961-2010) with county administrative regionalization as the unit in combination with China's terrain feature. Level-I regionalization divides China's climate change (1961-2010) into five tendency zones based on the tendency of temperature and precipitation, which are respectively Northeast China-North China warm-dry trend zone, East China-Central China wet-warm trend zone, Southwest China-South China dry-warm trend zone, Southeast Tibet-Southwest China wet-warm trend zone, and Northwest China-Qinghai-Tibet Plateau warm-wet trend zone; level-II regionalization refers to fourteen fluctuation regions based on level-I regionalization according to the fluctuation of temperature and precipitation. [ABSTRACT FROM AUTHOR]

Terrestrial vegetation is one of the most important components of the Earth's land surface. Variations in terrestrial vegetation directly impact the Earth system's balance of material and energy. This paper describes detected variations in vegetation activity at a national scale for China based on nearly 30 years of remote sensing data derived from NOAA/AVHRR (1982-2006) and MODIS (2001-2009). Vegetation activity is analyzed for four regions covering agriculture, forests, grasslands, and China's Northwest region with sparse vegetation cover (including regions without vegetation). Relationships between variations in vegetation activity and climate change as well as agricultural production are also explored. The results show that vegetation activity has generally increased across large areas, especially during the most recent decade. The variations in vegetation activity have been driven primarily by human factors, especially in the southern forest region and the Northwest region with sparse vegetation cover. The results further show that the variations in vegetation activity have influenced agricultural production, but with a certain time lag. [ABSTRACT FROM AUTHOR]

Hypotheses concerning the origins of modern humans have been intensively debated, and two competing models, the recent 'Out-of-Africa' and 'Multiregional Evolution' paradigms, have dominated research and discussions for decades. Evidence from China has played a fundamental role in this debate: regional continuity and replacement by populations in-migrated from Africa have both been suggested and supported mainly by paleoanthropologists and geneticists, respectively. As more evidence has accumulated, new results obtained, and more scholars from various disciplines become involved, supporters of the recent 'Out-of-Africa' model agree more or less with the 'Multiregional Evolution' model regarding the complex history of modern humans and their interbreeding with other archaic populations (e.g., Neandertals). Recent discoveries of new human fossils, Paleolithic archaeological materials, and ancient DNA evidence in China have yielded a large body of information regarding the formation and development of modern humans in this region. However, controversies continue, including that most molecular biologists insist on the replacement of archaic populations by modern humans dispersed from Africa, while most paleoanthropologists and archaeologists propose an enhanced 'Continuity with Hybridization' model. In this paper, we compile new results and progress in China and present the current debates and issues on the origins of modern humans. Finally, we offer several suggestions for future studies. [ABSTRACT FROM AUTHOR]

Waterlogging is one of the major water issues in most cities of China and directly restricts their urbanization processes. The construction of Sponge City is an effective approach to solving the urban water issues, particularly for the waterlogging. In this study, both the urban issues emerged at the stage of rapid urbanization in China and the demands as well as problems of Sponge City construction related with the water issues were investigated, and the opportunities and challenges for the Sponge City construction in the future were also proposed. It was found that the current stormwater management focused on the construction of gray infrastructures (e.g., drainage network and water tank) based on the fast discharge idea, which was costly and hard to catch up with the rapid expansion of city and its impervious surface, while green infrastructures (e.g., river, lake and wetland) were ignored. Moreover, the current construction of Sponge City was still limited to low impacted development (LID) approach which was concentrated on source control measures without consideration of the critical functions of surrounding landscapes (i.e., mountain, river, wetland, forest, farmland and lake), while application of the integrated urban water system approach and its supported technologies including municipal engineering, urban hydrology, environmental science, social science and ecoscape were relatively weak and needed to be improved. Besides, the lack of special Sponge City plan and demonstration area was also a considerable problem. In this paper, some perspectives on Good Sponge City Construction were proposed such as the point that idea of urban plan and construction should conform to the integral and systematic view of sustainable urban development. Therefore, both the basic theoretical research and the basic infrastructure construction such as monitoring system, drainage facility and demonstration area should be strengthened, meanwhile, the reformation and innovation in the urban water management system and the education system should also be urgently performed. The study was expected to provide a deeper thinking for the current Sponge City construction in China and to give some of suggestions for the future directions to urban plan and construction, as well as urban hydrology discipline. [ABSTRACT FROM AUTHOR]

A technically transparent and freely available reference sample set for validation of global land cover mapping was recently established to assess the accuracies of land cover maps with multiple resolutions. This sample set can be used to estimate areas because of its equal-area hexagon-based sampling design. The capabilities of these sample set-based area estimates for cropland were investigated in this paper. A 30-m cropland map for China was consolidated using three thematic maps (cropland, forest and wetland maps) to reduce confusion between cropland and forest/wetland. We compared three area estimation methods using the sample set and the 30 m cropland map. The methods investigated were: (1) pixel counting from a complete coverage map, (2) direct estimation from reference samples, and (3) model-assisted estimation combining the map with samples. Our results indicated that all three methods produced generally consistent estimates which agreed with cropland area measured from an independent national land use dataset. Areas estimated from the reference sample set were less biased by comparing with a National Land Use Dataset of China (NLUD-C). This study indicates that the reference sample set can be used as an alternative source to estimate areas over large regions. [ABSTRACT FROM AUTHOR]

Herbaceous marsh is the most widely distributed type of marsh wetland ecosystem, and has important ecological functions such as water conservation, climate regulation, carbon storage and fixation, and sheltering rare species. The carbon sequestration function of herbaceous marsh plays a key role in slowing climate warming and maintaining regional environmental stability. Vegetation biomass is an important index reflecting the carbon sequestration capacity of wetlands. Investigating the biomass of marsh vegetation can provide a scientific basis for estimating the carbon storage and carbon sequestration capacity of marshes. Based on field survey data of aboveground biomass of herbaceous marsh vegetation and the distribution data set of marsh in China, we analyzed the aboveground biomass and its spatial distribution pattern of herbaceous marsh on a national scale for the first time. The results showed that in China the total area of herbaceous marsh was 9.7×104 km2, the average density of aboveground biomass of herbaceous marsh vegetation was 227.5±23.0 g C m−2 (95% confidence interval, the same below), and the total aboveground biomass was 22.2±2.2 Tg C (1 Tg=1012 g). The aboveground biomass density of herbaceous marsh vegetation is generally low in Northeast China and the Tibetan Plateau, and high in central North China and coastal regions in China. In different marsh distribution regions of China, the average biomass density of herbaceous marsh vegetation from small to large was as follows: temperate humid and semi-humid marsh region (182.3±49.3 g C m−2)−2)−2)−2)−2). Due to the different area of herbaceous marsh, the total aboveground biomass of herbaceous marsh vegetation in different marsh distribution regions was the largest in the temperate humid and semi-humid marsh region (9.6±2.6 Tg C), and was the smallest in the coastal marsh region (1.1±0.1 Tg C). The spatial distribution of aboveground biomass of herbaceous marsh vegetation in China has obvious non-zonality characteristics, but also presents certain zonality in some regions. The aboveground biomass of herbaceous marsh vegetation in the Tibetan Plateau decreased with the increase of altitude. With the aggravation of drought, the aboveground biomass of herbaceous marsh vegetation in temperate humid and semi-humid regions and temperate arid and semi-arid regions decreased first and then did not obviously change. The aboveground biomass of herbaceous marsh vegetation in temperate humid and semi-humid regions was relatively larger in the regions with higher average annual temperature. The results can provide scientific basis for accurately evaluating the adjustment action of wetland ecosystems on climate, and provide decision support for adaptive management of wetland ecosystems. [ABSTRACT FROM AUTHOR]

Based on observations and historical simulations from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) archive, the contributions of human activities (including greenhouse gases (GHGs), anthropogenic aerosols (AAs), and land use (LU)) and external natural forcings (Nat) to climate changes in China over the past 50 years were quantified. Both anthropogenic and external natural forcings account for 95%-99% of the observed temperature change from 1951-1975 to 1981-2005. In particular, the temperature changes induced by GHGs are approximately 2-3 times stronger than the observed changes, and AAs impose a significant cooling effect. The total external forcings can explain 65%-78% of the observed precipitation changes over the past 50 years, in which AAs and GHGs are the primary external forcings leading to the precipitation changes; in particular, AAs dominate the main spatial features of precipitation changes in eastern China. Human activities also dominate the long-term non-linear trends in observed temperature during the past several decades, and, in particular, GHGs, the primary warming contributor, have produced significant warming since the 1960s. Compared to the long-term non-linear trends in observed precipitation, GHGs have largely caused the wetting changes in the arid-semiarid region since the 1970s, whereas AAs have led to the drying changes in the humid-semihumid region; both LU and Nat can impose certain impacts on the long-term non-linear trends in precipitation. Using the optimal fingerprinting detection approach, the effects of human activities on the temperature changes can be detected and attributed in China, and the effect of GHGs can be clearly detected from the observations in humid-semihumid areas. However, the anthropogenic effects cannot be detected in the observed precipitation changes, which may be due to the uncertainties in the model simulations and to other issues. Although some results in this paper still need improvement due to uncertainties in the coupled models, this study is expected to provide the background and scientific basis for climate changes to conduct vulnerability and risk assessments of the ecological systems and water resources in the arid-semiarid region of China. [ABSTRACT FROM AUTHOR]

Global climate change and its possible ecological consequences have become the focused issue (IPCC, 2007; Mann et al., 2008; Ding et al., 2009). The Holocene contains the analogous characteristic of future climatic change and the continuous agriculture activity, providing the ideal “similar pattern” for studying the climate change and human adaption and impact in the future. Based on the recent studies of stalagmite, ice core, ocean, and lake etc., the paper introduces the new progress in the Holocene climate and agriculture research in China as follows: (1) Discuss the variability, amplitude, and unstable characteristic of climate, as well as the abrupt events and mechanisms of climate. (2) Analyze the botanical index records for studying the early agriculture. (3) Review the agricultural origin, expanding, and development. (4) Reveal the style and intensity of early agriculture and understand the agricultural impact and adaption to the environmental changes. (5) Introduce ongoing research projects in China and emphasize the significance of increasing the dating precision and the indicative effectiveness of proxies. (6) Realize how the ecosystem and environmental factors respond to the increasing temperature process, understand how the human adapt to the rapid climate change, and provide the scientific basis for assessing the effects of climate change and the human adaption in the future. [ABSTRACT FROM AUTHOR]

The debates over the origin of modern humans have long been centered on two competing theories: the 'Out-of-Africa' (single-place origin) theory and the 'Multi-regional Evolution' theory. China is an extremely important region where many ancient human fossils were collected along with numerous associated faunal remains and artefacts. These cultural remains, unearthed from different areas in the country and covering a long time span, will help clarify the controversy. The study of cultural materials in China is expected to shed important light on biological evolutionary patterns and social and technical developments of those early humans as well as their environmental conditions. Based on the analysis of Chinese fossils and associated materials, in conjunction with some genetic studies, this paper aims at evaluating each of the two theories in order to stimulate more discussions. Our study suggests that the evolutionary model of 'Continuity with Hybridization' is most relevant in reflecting the current understanding of human evolutionary history in China. Furthermore, we propose that the concept of regional diversity of evolutionary models should be seriously considered to illustrate different evolutionary modes applied to different parts of the world. [ABSTRACT FROM AUTHOR]

As an important part of the regional environment, the wet-dry climate condition is determined by precipitation and potential evapotranspiration (expressed as ET ). Based on weather station data, this study first calculated ET by using the FAO56 Penman-Monteith model. Then, the dryness index K (ratio of ET to precipitation) was used to study the spatio-temporal variation of the wet-dry condition in China from 1961 to 2015; moreover, dominant climatic factors of the wet-dry condition change were discussed. The annual precipitation and ET of the Qinling-Huaihe line were close to a balance ( K≈1.0). The annual precipitation in most areas exceeded the ET in the south of this line and the east of Hengduan Mountains ( K<1.0), where the climate is wet. Furthermore, the precipitation in the northwest inland areas of China, where the climate is dry, was markedly lower than ET ( K≥4.0). The overall annual K of China fluctuated around the 55-year mean and its linear trend was not significant. However, a relatively wet period of about 10 yr (1987-1996) was recorded. The overall annual K of China showed strong cyclicality on the time scale of 3, 7-8, 11 and 26-28 yr, and regional differences of the annual K trends and cyclicality were large. The degrees of wetness in the Northwest China and western Qinghai-Tibet Plateau were substantially increased, whereas the degrees of dryness in the Yunnan-Guizhou Plateau, Sichuan Basin, and Loess Plateau were markedly increased. The linear trend of the annual K in most regions of China was not significant, and the annual K of most areas in China showed strong cyclicality on the 8-14 yr time scale. Precipitation was the dominant factor of wet-dry condition change in most areas, especially in North China, where the annual K change was highly correlated with precipitation. [ABSTRACT FROM AUTHOR]

Inter-city mobility is one of the most important issues in the UN Sustainable Development Goals, as it is essential to access the regional labour market, goods and services, and to constrain the spread of infectious diseases. Although the gravity model has been proved to be an effective model to describe mobility among settlements, knowledge is still insufficient in regions where dozens of megacities interact closely and over 100 million people reside. In addition, the existing knowledge is limited to overall population mobility, while the difference in inter-city travel with different purposes is unexplored on such a large geographic scale. We revisited the gravity laws of inter-city mobility using the 2.12 billion trip chains recorded by 40.48 million mobile phone users' trajectories in the Jing-Jin-Ji Region, which contains China's capital Beijing. Firstly, unlike previous studies, we found that non-commuting rather than commuting is the dominant type of inter-city mobility (89.3%). Non-commuting travellers have a travel distance 42.3% longer than commuting travellers. Secondly, we developed more accurate gravity models for the spatial distribution of inter-city commuting and non-commuting travel. We also found that inter-city mobility has a hierarchical structure, as the distribution of inter-city travel volume follows Zipf's law. In particular, the hierarchy of non-commuting travel volume among the cities is more in line with an ideal Zipf distribution than commuting travel. Our findings contribute to new knowledge on basic inter-city mobility laws, and they have significant applications for regional policies on human mobility. [ABSTRACT FROM AUTHOR]

Understanding the stability of terrestrial carbon sinks (S-TCS) contributes to more accurate prediction of the terrestrial carbon sink (TCS) in the context of future global change and helps inform climate change mitigation policies. Here, focusing on China, we analyzed the spatial distribution and driving mechanisms for the S-TCS, quantified by the interannual variability of the TCS, using three independent approaches (atmospheric inversions, ecosystem carbon cycle models, and machine learning models based on flux tower observations). We found that the interannual variability of the TCS in China is relatively small compared with the conterminous United States and geographic Europe, indicating a generally stable TCS in China. Spatially, the S-TCS is lower in the North China Plain, Northeast China Plain, and western Yunnan-Guizhou Plateau than in other regions, with varying underlying mechanisms. Large interannual variations in precipitation and high TCS sensitivities to precipitation fluctuations explain the low S-TCS in the North China Plain and Northeast China Plain, while high TCS sensitivities to temperature variations drive the low S-TCS in the western Yunnan-Guizhou Plateau. Our findings highlight the importance of considering local contexts for stabilizing and enhancing China's TCS in a changing environment. [ABSTRACT FROM AUTHOR]

Reconstructing historical land use and land cover change using explicit temporal, quantitative, and spatial information is not only the prerequisite for simulating long-term climate change and ecological effects but is also a scientific basis for comprehensively understanding the process and mechanism of anthropogenic land use alterations. Considering changes in historical borders and administrative divisions, a provincial cropland area dataset for China over the past millennium was created on the basis of existing estimations since the Song Dynasty. Land suitability for cultivation was then assessed by incorporating altitude, slope, soil texture, and the maximum potential productivity of climate. Subsequently, a gridding allocation model for cropland was constructed, and the provincial cropland area for 24 years over the past millennium was allocated into grids with a resolution of 10 km. The cropland area in China increased from 3.71×107 ha in AD 1000 to 12.92×107 ha in AD 1999, with a peak of 13.50×107 ha in AD 1980. The total cropland area in China showed fluctuating increasing trends that can be divided into three phases: fluctuation without notable net change for AD 1000–1290, slow increase for AD 1290–1661, and rapid increase for AD 1661–1999. Spatially, cropland intensified in the middle-lower reaches of the Yellow and Yangtze Rivers and expanded to mountainous and frontier areas over the last millennium. Specifically, over the entire period, the fractional cropland areas (FCAs) in the middle-lower reaches of the Yellow and Yangtze Rivers increased by 1.4 and 0.8 times, respectively. Since the mid-Qing Dynasty, large-scale land reclamation expanded to areas of low reclamation in southwest and northeast China. The FCAs for southwest and northeast China increased from 2.13% and 0.55% in AD 1661 to 18.00% and 26.61% in AD 1999, respectively. For AD 1661–1999, the proportion of cropland increased by 55% in the hills and low mountains and 27% in the middle and high mountains. The comparison with remote sensing cropland data shows that the grid cells with absolute differences of 0–10% accounted for 70.35% of all grid cells, while grids with differences exceeding 60% accounted for only 0.83%. This finding indicates that the reconstruction method is feasible, and the reconstruction results objectively reveal the historical spatiotemporal changes in cropland. [ABSTRACT FROM AUTHOR]

Ammonia (NH3) can interact with other trace chemicals in the atmosphere, significantly impacting atmospheric chemistry and global climate change. China is a largely agricultural country with high consumption of nitrogen fertilizer and large livestock herds, resulting in high NH3 emissions. In this study, a comprehensive county-level inventory of Chinese NH3 emissions from 2013 to 2018 was compiled. Based on previous research, an estimate of NH3 emissions from household coal combustion was added to the inventory. The estimation of emissions from open biomass burning was improved by using a method based on fire radiative energy (FRE). The total NH3 emissions in China increased from 2013 (9.64 Tg) to 2015 (9.75 Tg), and then decreased to 9.12 Tg in 2018. Emissions from fossil fuels reached a peak value in 2018, accounting for 8.4% of total emissions, while fertilizer application and livestock waste were responsible for fewer emissions than in previous years, accounting for 27.7% and 49.9% of the total from non-fossil fuel sources, respectively. The highest emission rates were in central and southwestern China. Seasonally, NH3 emissions peaked in spring and summer. The inventory had a 1-km spatial resolution and a monthly temporal resolution, which confirmed its suitability for global and regional air quality simulations. [ABSTRACT FROM AUTHOR]

China announced its national goal to reach the peak of carbon emission by 2030 and achieve carbon neutrality by 2060, during the General Assembly of the United Nations in September 2020. In this context, the potential of the carbon sink in China's terrestrial ecosystems to mitigate anthropogenic carbon emissions has attracted unprecedented attention from scientific communities, policy makers and the public. Here, we reviewed the assessments on China's terrestrial ecosystem carbon sink, with focus on the principles, frameworks and methods of terrestrial ecosystem carbon sink estimates, as well as the recent progress and existing problems. Looking forward, we identified critical issues for improving the accuracy and precision of China's terrestrial ecosystem carbon sink, in order to serve the more realistic policy making in pathways to achieve carbon neutrality for China. [ABSTRACT FROM AUTHOR]

A robust tree-ring-width chronology was developed from two Pinus tabulaeformis sampling sites in the source of the Fenhe River, Shanxi Province, China. Based on the tree-ring-width indices, a 157-year long Palmer Drought Severity Index (PDSI) was reconstructed, which explains 53.7% of the variance of the modeled PDSI over the common period 1957-2008. The drought periods in the study area include 1914-1931 and 1970 to the present, whereas the wet periods were 1866-1892 and 1932-1969. The drought of 1914-1931 was a severe long-lasting drought with a low inter-annual variability, and the drought of 1970-2009 was an overall long-term drought with a high inter-annual variability. The period of 1866-1892 is a continuously wet period with a low inter-annual variability and the period of 1932-1969 is an overall long-term wet period with a high inter-annual variability. The reconstructed PDSI series in the source of the Fenhe River shows synchronous variations with the regional drought/wetness indices. Spatial correlation analyses indicate that the higher correlations lie exclusively in the Fenhe River Basin. This indicates that the reconstructed PDSI has regional representativeness and can represent the drought history of the entire Fenhe River Basin to some extent. Furthermore, the reconstructed PDSI matches with the variability of the per unit yield of summer grain crops in Shanxi Province very well and they have significant correlation. From a long-term perspective the reconstructed PDSI series could supply scientific and valuable information to the water resources management and then help the sustainable development in agricultural production, economic development, and ecosystem balance. [ABSTRACT FROM AUTHOR]

Annual land use land cover (LULC) change information at medium spatial resolution (i.e. at 30 m) is required in numerous subjects, such as biophysical modelling, land management and global change studies. Annual LULC information, however, is usually not available at continental or national scale due to reasons such as insufficient remote sensing data coverage or lack of computational capabilities. Here we integrate high temporal resolution and coarse spatial resolution satellite images (i.e., Moderate Resolution Imaging Spectroradiometer (MODIS) and Global Inventory Modelling and Mapping Studies (GIMMS) normalized difference vegetation index (NDVI)) with high spatial resolution datasets (China's Land-Use/cover Datasets (CLUDs) derived from 30-meter Landsat TM/ETM+/OLI) to generate reliable annual nominal 30 m LULC maps for the whole of China between 1980 and 2015. We also test the performance of a statistical based change detection algorithm (Breaks for Additive Seasonal and Trend), originally designed for tracking forest change, in classifying all-type LULC change. As a result, a nominal 30 m annual land use/land cover datasets (CLUD-A) from 1980 to 2015 was developed for the whole China. The mapping results were assessed with a change sample dataset, a regional annual validation sample set and a three-year China sample set. Of the detected change years, 75.61% matched the exact time of conversion within ±1 year. Annual mapping results provided a detail process of urbanization, deforestation, afforestation, water and cropland dynamics over the past 36 years. The consistent characterization of land change dynamics for China can be further used in scientific research and to support land management for policy-makers. [ABSTRACT FROM AUTHOR]

We surveyed the occurrence of tropical cyclone (TC) tornadoes in China from 2006 to 2018. There were 64 cataloged TC tornadoes, with an average of five per year. About one-third of the landfalling TCs in China were tornadic. Consistent with previous studies, TC tornadoes preferentially formed in the afternoon shortly before and within about 36 h after landfall of the TCs. These tornadoes mainly occurred in coastal areas with relatively flat terrains. The maximum number of TC tornadoes occurred in Jiangsu and Guangdong provinces. Most of the TC tornadoes were spawned within 500 km of the TC center. Two notable characteristics were found: (1) TC tornadoes in China mainly occurred in the northeast quadrant (Earth-relative coordinates) rather than the right-front quadrant (TC motion-relative coordinates) of the parent TC circulation; and (2) most tornadoes were produced by TCs with a relatively weak intensity (tropical depressions/storms), in contrast with the United States where most tornadoes are associated with stronger TCs. Further analyses showed that TC tornadoes in China tend to be spawned in an environment with large low-level storm relative helicity and large convective available potential energy taking entrainment effects into account. TC tornadoes were particularly active in 2018, with 24 reported tornadoes accounting for 37.5% of the total surveyed samples. The first recorded tornado outbreak in the modern history of China occurred in the envelope of TC Yagi (2018), in which 11 tornadoes were reported in association with significant midlevel intrusions of dry air and the interaction of Yagi with an approaching midlatitude midlevel trough. [ABSTRACT FROM AUTHOR]

Sediment source fingerprinting apportions the sources of sediment produced by water erosion by linking sampled sediment mixtures and landscape source materials using diagnostic and conservative fingerprints. Using this approach, the nature and location of active sediment sources across the catchment can be elucidated, generating information which is a key prerequisite for the design and implementation of catchment management strategies. The science of sediment source fingerprinting continues to attract much research globally, but to date, there have been relatively few fingerprinting studies in China. Here, there remain major challenges for the fingerprinting approach arising from the uniqueness of Chinese landscapes, including for instance, the complex land use configuration with highly fragmented or mosaic patches and the highly dynamic land use conversion rates, generating a need to test the physical basis for the discriminatory power and environmental behavior of both traditional and novel tracers. Future research is needed to investigate the applicability of tracer properties in different physiographic settings and to evaluate the potential strategic utility of the approach for supporting the improved management of soil and water sustainability. Here, the strategic availability of independent observation data for different components of catchment sediment budgets and well-maintained research infrastructure for plots, micro-catchments and drainage basins provides immediate opportunity for testing the approach and refining procedures. Such detailed testing across scales would be invaluable for promoting sediment source fingerprinting as both a scientific and management tool for informing soil and water conservation practices in China. [ABSTRACT FROM AUTHOR]

The formation and evolution of permafrost in China during the last 20 ka were reconstructed on the basis of large amount of paleo-permafrost remains and paleo-periglacial evidence, as well as paleo-glacial landforms, paleo-flora and paleofauna records. The results indicate that, during the local Last Glacial Maximum (LLGM) or local Last Permafrost Maximum (LLPMax), the extent of permafrost of China reached 5.3×106−5.4×106 km2, or thrice that of today, but permafrost shrank to only 0.80×106−0.85×106 km2, or 50% that of present, during the local Holocene Megathermal Period (LHMP), or the local Last Permafrost Minimum (LLPMin). On the basis of the dating of periglacial remains and their distributive features, the extent of permafrost in China was delineated for the two periods of LLGM (LLPMax) and LHMP (LLPMin), and the evolution of permafrost in China was divided into seven periods as follows: (1) LLGM in Late Pleistocene (ca. 20000 to 13000−10800 a BP) with extensive evidence for the presence of intensive ice-wedge expansion for outlining its LLPMax extent; (2) A period of dramatically changing climate during the early Holocene (10800 to 8500−7000 a BP) when permafrost remained relatively stable but with a general trend of shrinking areal extent; (3) The LHMP in the Mid-Holocene (8500−7000 to 4000−3000 a BP) when permafrost degraded intensively and extensively, and shrank to the LLPMin; (4) Neoglaciation during the late Holocene (4000−3000 to 1000 a BP, when permafrost again expanded; (5) Medieval Warming Period (MWP) in the late Holocene (1000−500 a BP) when permafrost was in a relative decline; (6) Little Ice Age (LIA) in the late Holocene (500−100 a BP), when permafrost relatively expanded, and; (7) Recent warming (during the 20th century), when permafrost continuously degraded and still is degrading. The paleo-climate, geography and paleopermafrost extents and other features were reconstructed for each of these seven periods. [ABSTRACT FROM AUTHOR]

Scientific assessment of the accounting over carbon in the terrestrial ecosystem in the process land use/land cover changes caused by human activities will help reduce the uncertainty in estimating carbon emissions from the terrestrial ecosystem. This study employs a bookkeeping model to estimate the carbon emissions from farmland reclamation in China during the past 300 years based on the annual rate of land use changes (derived from historical natural vegetation, farmland data), preset carbon density and coefficients of disturbance curves. We find out that: (1) there was a net increase of 79.30×104 km2 in national farmland; about 65% of reclaimed farmland had been forest land and 26% of that had been grass land previously; (2) the total amount of carbon emissions from farmland expansion in China had been between 2.94 and 5.61 Pg with the median 3.78 Pg during the past 300 years; specifically, carbon emissions of vegetation were 1.58 Pg while those of soil ranged from 1.35 Pg to 4.03 Pg with the median 2.20 Pg; (3) carbon emissions vary greatly across various ecosystems: the emissions were most from forest land, and then grass land and swamps, and the least from shrubs; deserts functioned more likely to be carbon stock in the process of land reclamation; (4) along the time line, carbon emissions had decreased first and then increased while the peak emissions occurred in the first half of 20th century; and spatially, carbon emissions were most released in Northeast and Southwest China; Northwest China was of the minimum carbon emissions. [ABSTRACT FROM AUTHOR]

Cretaceous strata are widely distributed across China and record a variety of depositional settings. The sedimentary facies consist primarily of terrestrial, marine and interbedded marine-terrestrial deposits, of which marine and interbedded facies are relatively limited. Based a thorough review of the subdivisions and correlations of Cretaceous strata in China, we provide an up-to-date integrated chronostratigraphy and geochronologic framework of the Cretaceous system and its deposits in China. Cretaceous marine and interbedded marine-terrestrial sediments occur in southern Tibet, Karakorum, the western Tarim Basin, eastern Heilongjiang and Taiwan. Among these, the Himalayan area has the most complete marine deposits, the foraminiferal and ammonite biozonation of which can be correlated directly to the international standard biozones. Terrestrial deposits in central and western China consist predominantly of red, lacustrine-fluvial, clastic deposits, whereas eastern China, a volcanically active zone, contains clastic rocks in association with intermediate to acidic igneous rocks and features the most complete stratigraphic successions in northern Hebei, western Liaoning and the Songliao Basin. Here, we synthesise multiple stratigraphic concepts and charts from southern Tibet, northern Hebei to western Liaoning and the Songliao Basin to produce a comprehensive chronostratigraphic chart. Marine and terrestrial deposits are integrated, and this aids in the establishment of a comprehensive Cretaceous chronostratigraphy and temporal framework of China. Further research into the Cretaceous of China will likely focus on terrestrial deposits and mutual authentication techniques (e.g., biostratigraphy, chronostratigraphy, magnetostratigraphy and cyclostratigraphy). This study provides a more reliable temporal framework both for studying Cretaceous geological events and exploring mineral resources in China. [ABSTRACT FROM AUTHOR]

Global historical land use datasets are widely used in global environmental change studies; however, uncertainties in the included pasture data have not been evaluated. In this study, using trend, relative difference ratio (RDR), and spatial comparisons, we evaluated the accuracy of China pasture data in the HYDE (versions 3.1 and 3.2), SAGE, and PJ datasets using historical document-based reconstructions, including the land use datasets for China covering 1935-1997 (hereafter Ge-dataset) and Northeast China covering the 1700s-2000 (hereafter Ye-dataset), and the satellite-based China’s Land-Use/cover Datasets (CLUDs) for 1980-2015. Four important results were obtained. (1) China pasture area in the HYDE, SAGE, and PJ datasets and grassland area in the Ge-dataset, Ye-dataset, and CLUDs show both disparate trends and large differences in absolute values. (2) Spatially, 50.9%, 52.8%, and 63.0% pasture/grassland grids in 2000 had RDRs greater than 60% between HYDE3.1, HYDE3.2, and SAGE datasets, and CLUDs, respectively. The percentage of grids with RDRs less than 20% were 24.9%, 26.7%, and 16.0%, respectively. (3) Based on HYDE3.2, the spatial distribution of pasture in Northeast China over the last 300 year has expanded, which is in contrast to the results from the Ye-dataset, which shows the spatial distribution of grassland shrinking because of human reclamation activities. (4) The large contrasts between the global datasets and Chinese native datasets are due to differences in pasture/grassland definitions, land use practices, and spatial reconstruction methods. [ABSTRACT FROM AUTHOR]

Phenology is a reliable biological indicator for reflecting climate change. An examination of changes in crop phenology and the mechanisms driving them is critical for guiding regional agricultural activities in attempts to adapt to climate change. Due to a lack of records based on continuous long-term observation, studies on changes in multiple consecutive phenological stages throughout a whole growing season on a national scale are rarely found, especially with regard to the spatiotemporal differentiation of phenological changes. Using a long-term dataset (1981-2010) of wheat phenology collected from 48 agro-meteorological stations in China, we qualified the spatiotemporal changes of 10 phenological stages as well as the length of wheat growth phases. Results showed that climate and wheat phenology changed significantly during the growing seasons from 1981 to 2010. On average, on a national scale, dates of sowing (0.19 d a-1), emergence (0.06 d a-1), trefoil (0.05 d a-1), and milk ripe (0.06 d a-1) showed a delaying trend, whereas dates of tillering (-0.02 d a-1), jointing (-0.15 d a-1), booting (-0.21 d a-1), heading (-0.17 d a-1), anthesis (-0.19 d a-1), and maturity (-0.10 d a-1) showed an advancing trend. Furthermore, the vegetative growth phase and growing season were shortened by 0.23 and 0.29 d a-1, respectively, whereas the reproductive growth phase was lengthened by 0.06 d a-1. Trends in dates of phenological stages or length of growing phases varied across wheat-planting regions. Moreover, spatiotemporal differentiation of sensitivity in growing season length (GSL) to variations in climatic factors during the growing season between spring and winter wheat were remarkable. The GSL of spring (winter) wheat decreased (increased) with an increase in average temperature during the growing season. In all wheat-planting regions, the GSL increased with the increasing of total precipitation and sunshine duration during the growing season. In particular, the sensitivity of GSL to precipitation for spring wheat was weaker than for winter wheat, while the sensitivity of GSL to sunshine duration for spring wheat was stronger than for winter wheat. Recognition of the spatiotemporal differentiation of phenological changes and their response to various climatic factors will provide scientific support for decision-making in agricultural production. [ABSTRACT FROM AUTHOR]

Fourteen countries share about 22000 km land border with China, but not much is known about the variation in vegetation in such a large diverse area. By employing the remotely-sensed vegetation indices the vegetation greenness along the border was discussed. Our results show that since the early 21st century, similar trends in vegetation greenness have occurred along most of China's border, but differences occurred on either side of the border. Along the border with North Korea and South Asian nations, greater increasing trend in vegetation greenness occurred inside China's border, suggesting that China's vegetation protection programs have been successful. Spatial and temporal variations in vegetation greenness trends were observed along China's border with Russia, Mongolia, and Central Asian nations. Vegetation variation was lower inside China, along the Russian border, and China's eastern border with Mongolia. Along most borders with Central Asian nations, rates of vegetation change inside China's border during the growing season were higher than the rates outside the border. The results suggest that social customs, resource exploitation patterns, and national environmental conservation programs may profoundly affect vegetation greenness. [ABSTRACT FROM AUTHOR]

Based on multi-temporal topographic maps, remote sensing images and field surveys covering the entire coastal zone of mainland China, the coastlines of six periods since the early 1940s were extracted. Coastline changes over the last 70 years were then analyzed in terms of coastline structure, coastline fractals, coastline change rates, land-sea patterns, and bay areas. The results showed that mainland coastline structure changed dramatically, and due to the significant coastline artificialization mainly driven by sea reclamation and coastal engineering, the remaining natural coastline merely accounts for less than one third at present. Coastline fractal dimension represented an overall spatial pattern of 'north < entirety < south'; however, the discrepancy between the north and south coast was apparently narrowed due to dramatic coastline artificialization of northern China which in turn altered the whole pattern. Patterns and processes of land-sea interchange along the mainland coast were complex and varied spatially and temporally, with over 68% advancing toward sea and 22% retreating toward land. The net growth of land area was nearly 14.2 ×10 km with an average growth rate of 202.82 km a; and coast retreat was characterized by area decrease of 93 bays with a magnitude of 10.1 ×10 km and an average shrinking rate up to 18.19% or an average shrinking speed up to 144.20 km a, among which the total area of Bohai shrunk by 7.06%, with an average annual loss amounting to 82 km. The dramatic coastline changes along mainland China have brought about kinds of challenges to the coastal environment, therefore the integrated management, effective environment protection and sustainable utilization of coastlines is urgent. [ABSTRACT FROM AUTHOR]

Five General Circulation Model (GCM) climate projections under the RCP8.5 emission scenario were used to drive the Variable Infiltration Capacity (VIC) hydrologic model to investigate the impacts of climate change on hydrologic cycle over continental China in the 21st century. The bias-corrected climatic variables were generated for the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR5) by the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP). Results showed much larger fractional changes of annual mean Evapotranspiration (ET) per unit warming than the corresponding fractional changes of Precipitation (P) per unit warming across the country, especially for South China, which led to a notable decrease of surface water variability (P-E). Specifically, negative trends for annual mean runoff up to −0.33%/year and soil moisture trends varying between −0.02% to −0.13%/year were found for most river basins across China. Coincidentally, interannual variability for both runoff and soil moisture exhibited significant positive trends for almost all river basins across China, implying an increase in extremes relative to the mean conditions. Noticeably, the largest positive trends for runoff variability and soil moisture variability, which were up to 0.41%/year and 0.90%/year, both occurred in Southwest China. In addition to the regional contrast, intra-seasonal variation was also large for the runoff mean and runoff variability changes, but small for the soil moisture mean and variability changes. Our results suggest that future climate change could further exacerbate existing water-related risks (e.g., floods and droughts) across China as indicated by the marked decrease of surface water amounts combined with a steady increase of interannual variability throughout the 21st century. This study highlights the regional contrast and intra-seasonal variations for the projected hydrologic changes and could provide a multi-scale guidance for assessing effective adaptation strategies for China on a river basin, regional, or as a whole. [ABSTRACT FROM AUTHOR]

Soil visible-near infrared diffuse reflectance spectroscopy (vis-NIR DRS) has become an important area of research in the fields of remote and proximal soil sensing. The technique is considered to be particularly useful for acquiring data for soil digital mapping, precision agriculture and soil survey. In this study, 1581 soil samples were collected from 14 provinces in China, including Tibet, Xinjiang, Heilongjiang, and Hainan. The samples represent 16 soil groups of the Genetic Soil Classification of China. After air-drying and sieving, the diffuse reflectance spectra of the samples were measured under laboratory conditions in the range between 350 and 2500 nm using a portable vis-NIR spectrometer. All the soil spectra were smoothed using the Savitzky-Golay method with first derivatives before performing multivariate data analyses. The spectra were compressed using principal components analysis and the fuzzy k-means method was used to calculate the optimal soil spectral classification. The scores of the principal component analyses were classified into five clusters that describe the mineral and organic composition of the soils. The results on the classification of the spectra are comparable to the results of other similar research. Spectroscopic predictions of soil organic matter concentrations used a combination of the soil spectral classification with multivariate calibration using partial least squares regression (PLSR). This combination significantly improved the predictions of soil organic matter ( R = 0.899; RPD = 3.158) compared with using PLSR alone ( R = 0.697; RPD = 1.817). [ABSTRACT FROM AUTHOR]

The primary objective of this work is to develop an operational snow depth retrieval algorithm for the FengYun3B Microwave Radiation Imager (FY3B-MWRI) in China. Based on 7-year (2002-2009) observations of brightness temperature by the Advanced Microwave Scanning Radiometer-EOS (AMSR-E) and snow depth from Chinese meteorological stations, we develop a semi-empirical snow depth retrieval algorithm. When its land cover fraction is larger than 85%, we regard a pixel as pure at the satellite passive microwave remote-sensing scale. A 1-km resolution land use/land cover (LULC) map from the Data Center for Resources and Environmental Sciences, Chinese Academy of Sciences, is used to determine fractions of four main land cover types (grass, farmland, bare soil, and forest). Land cover sensitivity snow depth retrieval algorithms are initially developed using AMSR-E brightness temperature data. Each grid-cell snow depth was estimated as the sum of snow depths from each land cover algorithm weighted by percentages of land cover types within each grid cell. Through evaluation of this algorithm using station measurements from 2006, the root mean square error (RMSE) of snow depth retrieval is about 5.6 cm. In forest regions, snow depth is underestimated relative to ground observation, because stem volume and canopy closure are ignored in current algorithms. In addition, comparison between snow cover derived from AMSR-E and FY3B-MWRI with Moderate-resolution Imaging Spectroradiometer (MODIS) snow cover products (MYD10C1) in January 2010 showed that algorithm accuracy in snow cover monitoring can reach 84%. Finally, we compared snow water equivalence (SWE) derived using FY3B-MWRI with AMSR-E SWE products in the Northern Hemisphere. The results show that AMSR-E overestimated SWE in China, which agrees with other validations. [ABSTRACT FROM AUTHOR]

Phanerozoic chronostratigraphic units can only be defined through their lower boundary stratotypes. The lowermost stage of the Paleocene of China, which mainly consists of terrestrial deposits, can only be defined through its lower boundary stratotype, i.e. the continental Cretaceous/Paleogene boundary stratotype. There is no section yet found which contains continuous terrestrial deposits and biostratigraphic records of the Cretaceous-Paleogene transition in Nanxiong, Guangdong and Jiayin, Heilongjiang, there is no evidence for establishing the continental stratotype of the Cretaceous/Paleogene boundary in either area. Therefore, both the 'Shanghuan stage' and 'Furaoan stage' are not good candidates for the lowermost stage of the Paleocene of China. From the viewpoint of charophytes, the outcrop section of the Dangyang, Hubei Province (Central China) contains the most continuous, abundant and diverse terrestrial biostratigraphic records of the Cretaceous-Paleogene transition, in particular the early Paleocene, known so far in the world. The biostratigraphic records of ostracods in the transition are also continuous, rich, and diverse. The Dangyang outcrop section is the only section known so far in China that is a possible candidate for a continental stratotype of the Cretaceous/Paleogene boundary in China and the section is the only potential section identified to date for establishing the regional lowermost stage of the Paleocene, Paleogene and Cenozoic in China or stratotype section for the stage. [ABSTRACT FROM AUTHOR]

This study investigates water vapor isotopic patterns and controls over China using high-quality water vapor δD data retrieved from the Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) observations. The results show that water vapor δD values on both annual and seasonal time-scales broadly exhibit a continental effect, with values largely decreasing northwestward from coastal lowlands to high-elevation mountainous regions. However, region-specific analysis reveals spatially distinct patterns of water vapor δD between seasons. In the monsoon domain (e.g., China south of 35°N), depletion in D in the summer and fall seasons is closely tied to monsoon moisture sources (the Indian and Pacific oceans) and subsequent amount effect, but higher δD values in winter and spring are a result of isotopically-enriched continental-sourced moisture proceeded by less rainout. In contrast, farther inland in China (non-monsoon domain), moisture is derived overwhelmingly from the dry continental air masses and local evaporation, and δD values are largely controlled by the temperature effect, exhibiting a seasonality with isotopically enriched summer and depleted winter/spring. The observation that the spatial pattern of water vapor δD is the opposite to that of precipitation δD in the summer season also suggests that partial evaporation of falling raindrops is a key driver of water vapor isotope in the non-monsoon domain. This study highlights the importance of non-Rayleigh factors in governing water vapor isotope, and provides constraints on precipitation isotope interpretation and modern isotope hydrological processes over China. [ABSTRACT FROM AUTHOR]

By the end of the year 2010, a total of 15 large tight gas fields have been found in China, located in the Ordos, Sichuan, and Tarim basins. The annual production and total reserves of these fields in 2010 were 222.5×10 and 28657×10 m, respectively, accounting for 23.5% and 37.3%, respectively, of the total annual production and reserves of natural gases in China. They took a major part of all natural gas production and reserves in China. According to the analyses of 81 gas samples, the stable carbon and hydrogen isotopic compositions of tight gases in China have following characteristics: (1) Plots of δC- δC- δC, δC-C/C and δC- δC demonstrate the coal-derived origin of tight gases in China; (2) For the primary alkane gases, both carbon and hydrogen isotopic values increase with increasing molecular mass, i.e., δC< δC< δC< δC and δH< δH< δH; (3) The isotopic differences of δC- δC, δC- δC, δH- δH and δH- δH decrease with increasing R (%) and C/C; (4) There are seven causes for the carbon and hydrogen isotopic reversal, however, the carbon and hydrogen isotopic reversal of tight gases in China is caused mainly by multiple stages of gas charge and accumulation. [ABSTRACT FROM AUTHOR]

On the basis of new paleontological data, the sequence and distributions of the Middle Devonian-Tournaisian rocks on Hainan Island have been sorted out for the first time. The Devonian rocks include the Middle Devonian Jinbo Formation and the Upper Devonian Changjiang Formation, which are distributed in northwestern Hainan Island. The Jinbo Formation is represented by 631 m of littoral facies deposits, and was intruded by the Yanshanian granite in the base. The presence of chitinozoans Eisenackitina caster, Funsochitina pilosa, and Lagenochitina amottensis indicates the Givetian in age. The Changjiang Formation is made up of 140 m of neritic facies rocks, and contains the Famennian conodonts Palmatolepis gracilis sigmoidalis, Polygnathus germanus, and corals Cystophrentis kalaohoensis. The Devonian-Tournaisian transition beds, the lower part of the Jishi Formation, are composed of 61-129 m sandstone and siltstone, with gastropods Euomphalus spp. and brachiopods, and marked by conglomerate with the underlying Devonian rocks. The middle-upper part of the Tournaisian Jishi Formation consists of 100-251 m clastic and carbonate rocks, containing abundant corals Pseudoularinia irregularis, conodonts Siphonodella isosticha, trilobites Weberiphillipsia linguiformis, and brachiopods. On the basis of the occurrence of Xinanosprifer flabellum and Homotoma sp., the Nanhao Formation in southern Hainan Island is now regarded as the Lower Silurian, instead of the previously designated Lower Carboniferous. It is confirmed that no Carboniferous rocks occurred in the area south to the Gancheng-Wanning Fault. [ABSTRACT FROM AUTHOR]

The main old lands in China include the North China Block (NCB), South China Block (SCB) and Tarim Block (TRB), all of which have individual tectonic evolving histories. The NCB experienced complex geological evolution since the early Precambrian onwards, and carries important records from the old continental nuclei, giant crustal growth episode and cratonization (stabilitization), then to the Paleoproterozoic rifting-subduction-accretion-collision with imprints of the Great Oxygen Event (GOE), and to the Late Paleoproterozoic-Neoproterozoic multi-stage rifting representing North China platform tectonic features. The TRB has two-layer basement of the Early Precambrian metamorphic complexes and Neoproterozoic sedimentary sequences. Three till sheets have been reported. The SCB consists of the Yangtze Block (YZB) and Cathaysia Block (CTB) that were cohered in the Neoproterozoic. The YZB recorded tectonic processes of the Early Precambrian crustal growth, 1.0-0.9 Ga and 0.8-0.6 Ga metamorphic-magmatic events, and two Neoproterozoic glaciations. The CTB consists of ca. 1.8 Ga, 1.0 to 0.9 Ga and ca. 0.8 Ga granitic gneisses and metamorphic rocks, indicating there was a vast Precambrian basement. The Neoproterozoic sedimentary rocks overlie partly on the basement. That the YZB and CTB have a Neoproterozoic uniform cover layer illustrates the SCB should form, at least, during 1.0-0.9 Ga, corresponding to the Rodinia Supercontinent. The Central Chinese Orogenic System with high-ultra-high-pressure metamorphic rocks supports a suggestion that the above-mentioned three old lands were collided to assemble a unified Chinese Continent during the Pangea orogenic period. [ABSTRACT FROM AUTHOR]

Soil respiration is an important process in terrestrial carbon cycle. Concerning terrestrial ecosystems in China, quantifying the spatiotemporal pattern of soil respiration at the regional scale is critical in providing a theoretical basis for evaluating carbon budget. In this study, we used an empirically based, semi-mechanistic model including climate and soil properties to estimate annual soil respiration from terrestrial ecosystems in China from 1970 to 2009. We further analyzed the relationship between interannual variability in soil respiration and climatic factors (air temperature and precipitation). Results indicated that the distribution of annual soil respiration showed clear spatial patterns. The highest and lowest annual soil respiration rates appeared in southeastern China and northwestern China, respectively, which was in accordance with the spatial patterns of mean annual air temperature and annual precipitation. Although the mean annual air temperature in northwestern China was higher than that in some regions of northeastern china, a greater topsoil organic carbon storage in northeastern China might result in the higher annual soil respiration in this region. By contrast, lower temperature, less precipitation and smaller topsoil organic carbon pool incurred the lowest annual soil respiration in northwestern China. Annual soil respiration from terrestrial ecosystems in China varied from 4.58 to 5.19 Pg C a between 1970 and 2009. During this time period, on average, annual soil respiration was estimated to be 4.83 Pg C a. Annual soil respiration in China accounted for 4.93%-6.01% of the global annual soil CO emission. The interannual variability in soil respiration depended on the interannual variability in precipitation and mean air temperature. In order to reduce the uncertainty in estimating annual soil respiration at regional scale, more in situ measurements of soil respiration and relevant factors (e.g. climate, soil and vegetation) should be made simultaneously and historical soil property data sets should also be established. [ABSTRACT FROM AUTHOR]

The concentrations of PAHs in the surface waters from seven river basins in China were summarized from literature published from 2000-2010. Subsequently, the risks from individual PAHs and ΣPAHs in the surface waters of China were quantified by comparing the overlap between the probability distributions of exposure concentrations with the probability distributions of toxicity data. The results show that the concentrations of 15 PAHs in the surface waters ranged from 3.09 to 38139.00 ng L, with a geometric mean of 474.93 ng L. The significantly higher concentrations of the 15 PAHs occurred in the surface waters from northern China when compared with those from southern China. The concentrations of the 15 PAHs in Chinese surface waters were higher than those in other waters worldwide. The MOS (margin of safety) values were calculated at 90th percentile values of exposure concentrations and 10th percentile values of toxicity data, with 5.75, 0.17, 2.33, 0.30, 0.57, 1.74, 1.05, and 0.11 for Ace, Ant, Flu, BaP, Flua, Nap, Phe, and Pyr, respectively. The probabilities of the individual PAH concentrations exceeding the 10th percentile value of the toxicity data were 6.06%, 2.07%, 9.51%, and 2.07% for Nap, Ace, Phe, and Flu, respectively, suggesting minimal risk to aquatic organisms; however, the probabilities of BaP, Ant, Flua, and Pyr exceeding this value were 19.49%, 25.46%, 15.15%, and 30.50%, respectively, indicating potential risks. Among the individual PAHs, the ecological risk from Pyr was the highest, followed by, in descending order of risk, Ant, Bap, Flua, Phe, Nap, Flu, and Ace. Additionally, the combined ecological risk of ΣPAH8 in Chinese surface waters was significantly higher than any that of individual PAHs alone. The MOS values in the river basins were < 1, except for the Haihe River Basin, suggesting a potential combined risk from ΣPAH8 in the other six river basins. The probabilities calculation indicate that low to high ecological risk from ΣPAH8 for all aquatic species was reported in the Liaohe River Basin (65.58%), Huaihe River Basin (57.15%), Songhua River Basin (46.49%), Pearl River Basin (38.41%), Yangtze River Basin (25.98%), Yellow River Basin (15.92%), and Haihe River Basin (5.22%). [ABSTRACT FROM AUTHOR]

Using 24 proxy temperature series, the rates of temperature change in China are analyzed at the 30- to 100-year scales for the past 2000 years and at the 10-year scale for the past 500 years. The results show that, at the 100-year scale, the warming rate for the whole of China in the 20th century was only 0.6±1.6°C/100 a (interval at the 95% confidence level, which is used hereafter), while the peak warming rate for the period from the Little Ice Age (LIA) to the 20th century reached 1.1±1.2°C/100 a, which was the greatest in the past 500 years and probably the past 2000 years. At the 30-year scale, warming in the 20th century was quite notable, but the peak rate was still less than rates for previous periods, such as the rapid warming from the LIA to the 20th century and from the 270s-290s to 300s-320s. At the 10-year scale, the warming in the late 20th century was very evident, but it might not be unusual in the context of warming over the past 500 years. The exact timing, duration and magnitude of the warming peaks varied from region to region at all scales. The peak rates of the 100-year scale warming in the AD 180s-350s in northeastern China as well as those in the 260s-410s and 500s-660s in Tibet were all greater than those from the mid-19th to 20th century. Meanwhile, the rates of the most rapid cooling at scales of 30 to 100 years in the LIA were prominent, but they were also not unprecedented in the last 2000 years. At the 10-year scale, for the whole of China, the most rapid decadal cooling in the 20th century was from the 1940s to 1950s with a rate of −0.3±0.6°C/10 a, which was similar to rates for periods before the 20th century. For all regions, the rates of most rapid cooling in the 20th century were all less than those for previous periods. [ABSTRACT FROM AUTHOR]

Here we report the first discovery of a relatively complete skull of Choerolophodon from the late early Miocene Dalanggou quarry of Linxia Basin, Gansu Province in China. The skull is low and elongated, with two enamel-less and outward-and-upward curved incisors and the choerolophodont molars. These characters indicate that the new specimen can be assigned to the genus Choerolophodon, as it is quite distinct from other common gomphotheres in northern China such as Gomphotherium, Platybelodon, and Sinomastodon. The skull is also primitive in possessing laterally-expanded zygomatic arches, anteriorly-positioned orbits, weakly-developed cheek teeth cement, and retention of a P4. Prior to this discovery, Choerolophodon was found primarily from the middle-late Miocene of Africa, Eastern Europe, and western and southern Asia. The discovery of this new material expands the known temporal and spatial distributions of this taxon and helps us better understand the phylogeny, evolution, and adaptive radiation of gomphotheres in early Miocene of China. [ABSTRACT FROM AUTHOR]

Trends of the tropical cyclones (TCs) influence on China and its four subregions, namely the South China (SC), East China (EC), Northeast China (NEC), and China's inland area (CI), are detected by applying quantile regression to the CMA-STI tropical cyclone best track and related severe wind and precipitation observation datasets. The results indicate that in the past 50 years, the number of TCs affecting China and its four subregions has remained steady, except that the frequency in extremely active years has decreased not only in China as a whole, but also in NEC. In addition, TC activity is found to have weakened over the northwest South China Sea, Guangdong, and Shandong Peninsula. However, the most important changes in seasonality are found in the first quartiles of the number of days of TCs affecting CI. While the extreme values of sustained winds all have decreasing trends, the extreme values of wind gusts are completely different not only among different orders of extreme values, but also among different subregions. However, the trends of extreme TC rainfall, namely the maximum storm precipitation and the maximum 1-h precipitation, are not significant. [ABSTRACT FROM AUTHOR]

Charcoals collected from the middle-late Pliocene sediments of the Taigu Basin, Shanxi Province, China, have been identified as Ulmus sp. (Ulmaceae), Prunus sp., Maloidoxylon sp. (Rosaceae), and Maclura sp. (Moraceae). These taxa, along with the previously known fossils, indicate the occurrence of temperate climate and local wildfire at that time. Charcoals of trees and/or shrubs and the morphological changes of these charcoals demonstrate that crown fires and surface fires occurred in the Taigu Basin during the middle-late Pliocene. [ABSTRACT FROM AUTHOR]

Multi-decadal high resolution climate change simulations over East Asia were performed by using The Abdus Salam International Centre for Theoretical Physics (ICTP) Regional Climate Model (RegCM3), nested within the NASA/NCAR global model FvGCM/CCM3. Two sets of simulations were conducted at 20-km grid spacings, one for present day (1961-1990) and one for the future climate (2071-2100, IPCC A2 scenario). Simulations of present climate conditions over China by RegCM3 and FvGCM were compared against observations to assess the model performance. Results showed that both models reproduced the observed spatial structure of 500 hPa height, surface air temperature and precipitation. Compared with FvGCM, RegCM3 provided increasing spatial detail of surface variables. Furthermore, RegCM3 improved the simulation of monsoon precipitation over the region. Changes in the mean temperature and precipitation were analyzed and compared between the two models. Significant warming in the end of the 21st century was simulated by both models in December-January-February (DJF), June-July-August (JJA), and the annual mean. In DJF, greater warming was simulated by FvGCM over Northeast and Northwest China, as well as the Tibetan Plateau, compared with RegCM. In JJA, RegCM3 simulated greater warming over northern China, Inner Mongolia, Northwest China, and the Tibetan Plateau. Simulated changes in DJF precipitation showed similar spatial patterns between the two models. In JJA, while FvGCM projected a prevailing increase of monsoon precipitation over China, which is in agreement with other global models, RegCM3 projected extended areas of decreased precipitation. Changes in the variability for annual mean temperature and precipitation also are presented. [ABSTRACT FROM AUTHOR]

Based on 11004 satellite images from CBERS CCD and Landsat TM/ETM, changes in the spatial characteristics of all lakes in China were determined following pre-established interpretation rules. This dataset was supported by 6843 digital raster images (1:100000 and 1:50000), a countrywide digital vector dataset (1:250000), and historical literature. Comparative data were corrected for seasonal variations using precipitation data. There are presently 2693 natural lakes in China with an area greater than 1.0 km, excluding reservoirs. These lakes are distributed in 28 provinces, autonomous regions and municipalities and have a total area of 81414.6 km, accounting for ∼0.9% of China's total land area. In the past 30 years, the number of newly formed and newly discovered lakes with an area greater than 1.0 km is 60 and 131, respectively. Conversely, 243 lakes have disappeared in this time period. [ABSTRACT FROM AUTHOR]

The Cyathaxonia faunas are widely distributed in the Carboniferous and Permian strata in China. The fauna in China contains 12 families and 40 genera, and can be recognized as three episodes from Early Carboniferous to the end-Permian in terms of their occurrence and composition: 1) Mississippian; 2) Pennsylvanian-Early Permian; 3) Middle Permian-Late Permian. They were relatively abundant in episodes 1 and 2. A decrease of family Antiphyllidae and an increase of family Hapsiphyllidae can be observed from Early Carboniferous to the end-Permian. Two case studies are given to illustrate the bio-facies of the Cyathaxonia faunas, which are from the Mississippian of Baoshan, West Yunnan and the Mississippian of Chaohu, South Anhui. In both areas, Cyathaxonia faunas occur just below the large dissepimented solitary and compound coral assemblages in a continuous sequence in a single section, which implies that the occurrence of these small, non-dissepimented solitary corals is not strictly related with Gondwanan or Peri-gondwanan cold water environment, but might be controlled by such benthic conditions as deeper, mud-rich, quieter, and darker sedimentary environments. [ABSTRACT FROM AUTHOR]

Cranial morphological features of the stem-group sarcopterygian Guiyu oneiros Zhu et al., 2009 provided here include the dermal bone pattern and anatomical details of the ethmosphenoid. Based on those features, we restored, for the first time, the skull roof bone pattern in the Guiyu clade that comprises Psarolepis and Achoania. Comparisons with Onychodus, Achoania, coelacanths, and actinopterygians show that the posterior nostril enclosed by the preorbital or the preorbital process is shared by actinopterygians and sarcopterygians, and the lachrymals in sarcopterygians and actinopterygians are not homologous. The endocranium closely resembles that of Psarolepis, Achoania and Onychodus; however, the attachment area of the vomer possesses irregular ridges and grooves as in Youngolepis and Diabolepis. The orbito-nasal canal is positioned mesial to the nasal capsule as in Youngolepis and porolepiforms. The position of the hypophysial canal at the same level or slightly anterior to the ethmoid articulation represents a synapmorphy of the Guiyu clade. The large attachment area of the basicranial muscle indicates the presence of a well-developed intracranial joint in Guiyu. [ABSTRACT FROM AUTHOR]

Using NCEP/NCAR reanalysis and precipitation records of Chinese stations, we have investigated the relationship of interhemispheric oscillation of air mass (IHO) with global lower-level circulation and monsoon anomalies in boreal summer. Our results show that the summer IHO explains a greater portion of variance in the abnormal distribution of atmospheric mass over 30°S-60°N as well as the Antarctic. The IHO strongly correlates to the variations of sea level pressure (SLP) in these regions. It is shown that IHO has some influences on both atmospheric mass transports and water vapor fluxes over 30°S-60°N in association with three anomalous cyclonic circulations over land areas of the eastern hemisphere, which is in close relation to the changes in summer monsoon intensity in eastern Asia and western Africa. Composites of summer rainfall anomalies in China for high and low IHO-index years indicate that the eastern Asian summer monsoon is more intense, with positive precipitation anomaly centers in northern and northeastern parts of China, as opposed to the negative center over the mid-lower reaches of the Yangtze River (MLRYR) in stronger IHO years. In weak IHO years, a feeble summer monsoon appears in eastern Asia, leading to positive center of precipitation anomalies displaced into the MLRYR. Furthermore, a teleconnection in wind fields between the western African and eastern Asian monsoon regions was observed in the middle and higher troposphere in the scenario of IHO. The anomalous cyclonic (anticyclonic) circulations along the path of this Africa-East Asia teleconnection were found to be just over the diabatic heating (cooling) centers, suggesting that diabatic forcings are responsible for the formation of this Africa-East Asia teleconnection. [ABSTRACT FROM AUTHOR]

Although the early Pleistocene hominin fossils found in East Asia continent are widely recognized as the earliest hominins migrated from Africa, debates remain on the morphology and taxonomy of these fossils. In this study, dental crown shape of the three early Pleistocene hominin teeth (P, M, and M) found in Jianshi, Hubei Province of China was analyzed by means of geometric morphometrics. The comparative samples of fossil hominins from Africa, Asia, and Europe as well as those of modern humans ( N=257) were used. The results indicate that the contour, asymmetry, and cusp patterns of these three types of teeth differ obviously between the fossil hominins and modern humans. The crown shape of P in most fossil hominins including Australopithecus, African early Homo, and Asian Pleistocene hominins are asymmetric with their crown occlusal contours long and curving elliptic-shaped. The occlusal contour of the fossil hominin M is symmetric and rectangle-shaped with no marked cusp protrusion. The crown shape of fossil M is characterized by asymmetric contour with slightly projected metaconid and hypoconid. On the contrary, in modern Chinese and some European late Pleistocene hominins, the crowns of Ps show symmetric contours with buccal side wider than lingual side; the crown shape of M is asymmetric with lingual cusp distal-placed, especially for hypoconid; the M has symmetric and round crown contour. Our study reveals that Australopithecus has wide variations in its crown shape, whereas these dental morphospaces of Asian hominins are closely placed. The crown contour, symmetry, and cusp patterns of these three teeth of Jianshi hominin resemble those of Asian early and middle Pleistocene hominins. No marked difference in dental crown shape is shown between the Jianshi hominin and other Chinese Homo erectus, and there is also no evidence in support of the Jianshi hominin's closeness to Australopithecus and African early Homo members. [ABSTRACT FROM AUTHOR]