Search

Study on pattern and change on land cover stands an important aspect to global change. The spatial characteristics of ecological system show some familiar or disfamiliar principle with up-scaling or down-scaling process, which can be defined as spatial autocorrelation. In this paper, four typical parameters of ecological features, say Gross Primary Product (GPP), Net Primary Product (NPP), Normalized Difference Vegetation Index (NDVI), and Enhanced Vegetation Index (EVI), are selected to investigate the spatial variability on vegetative features in Longitudinal Range-Gorge Region (LRGR), Southwest China. Moran coefficient (MC) is calculated for spatial autocorrelation degree, and semivariance function is used for spatial variability and spatial heterogeneity analysis. The results show that: (1) the ecological features show negative autocorrelation in the whole region. The higher anisotropy is on north-south direction, and then on southeast-northwest direction. (2) The spatial variability scale is great on vegetative features in the whole region. (3) The autocorrelation distance on north-south direction is the greatest, then on southwest-northeast direction. Through the above analysis it can be found that the vegetative features are consistent with direction of landform in LRGR, which is shown on higher auto-correlation on south-north direction, and lower on west-east direction. [ABSTRACT FROM AUTHOR]

Four wetland maps for all China have been produced, based on Landsat and CBERS-02B remote sensing data between 1978 and 2008 (1978, 1990, 2000 and 2008). These maps were mainly developed by manual interpretation and validated by substantial field investigation in 2009. Based on these maps, we analyzed the 2008 wetland distribution in China and discussed wetland changes and their drivers over the past 30 years. (i) There were about 324097 km of wetlands in 2008, for which inland marshes or swamps were the most common wetland type (35%), with lakes (26%) second. Most of the wetlands were in Heilongjiang, Inner Mongolia, Qinghai and Tibet, occupying about 55% of the national wetland area. (ii) From 1978 to 2008, China's wetland area continually and significantly decreased, by about 33% based on changes in the wetland map. This was in sharp contrast to the increase in artificial wetlands, which increased by about 122%. Inland marshes accounted for the main loss of total wetlands from 1978 to 2000. From 2000 through 2008, riverine and lacustrine wetlands constituted the main wetland loss. Fortunately however, the rate of wetland loss decreased from 5523 to 831 km/a. (iii) The change ratio of lost natural wetlands (including inland and coastal wetlands) to non-wetlands has decreased slightly over the past 30 years. From 1978 to 1990, nearly all natural wetlands (98%) lost were transformed into non-wetlands. However, the ratio declined to 86% from 1990 to 2000, and to 77% from 2000 to 2008. (iv) All Chinese provinces were divided into three groups according to patterns of wetland changes, which could relate to the driving forces of such changes. Tibet was completely different from other provinces, as it was one representative example in which there was a net wetland increase, because of global warming and decreased human activity since 1990. Increased economic development caused considerable wetland loss in most eastern provinces, and artificial wetlands increased. [ABSTRACT FROM AUTHOR]

Meta-analysis is a quantitative synthetic research method that statistically integrates results from individual studies to find common trends and differences. With increasing concern over global change, meta-analysis has been rapidly adopted in global change research. Here, we introduce the methodologies, advantages and disadvantages of meta-analysis, and review its application in global climate change research, including the responses of ecosystems to global warming and rising CO2 and O3 concentrations, the effects of land use and management on climate change and the effects of disturbances on biogeochemistry cycles of ecosystem. Despite limitation and potential misapplication, meta-analysis has been demonstrated to be a much better tool than traditional narrative review in synthesizing results from multiple studies. Several methodological developments for research synthesis have not yet been widely used in global climate change researches such as cumulative meta-analysis and sensitivity analysis. It is necessary to update the results of meta-analysis on a given topic at regular intervals by including newly published studies. Emphasis should be put on multi-factor interaction and long-term experiments. There is great potential to apply meta-analysis to global climate change research in China because research and observation networks have been established (e.g. ChinaFlux and CERN), which create the need for combining these data and results to provide support for governments' decision making on climate change. It is expected that meta-analysis will be widely adopted in future climate change research. [ABSTRACT FROM AUTHOR]

Xinjiang Autonomous Region is located in the arid area of westerly of China and there are many arguments about the changes of past temperature and moisture. Most of the lakes on the plain in northern Xinjiang are sealed lakes and terminal lakes. They can evidently reflect the changes in palaeoclimate. The palaeoenvironmental changes of some plain lakes in northern Xinjiang during the late Holocene will be analysed mainly based on the data of pollen, sedimentary facies, loss on ignition (LOl), susceptibility and grain size from the Sichang Lake, Dongdaohaizi Lake and Aibi Lake. Results reveal an assembled pattern of temperature and moisture dominated by cold-wet and warm-dry. In addition, the impact factor will be discussed. [ABSTRACT FROM AUTHOR]

On 20 March, 2002, a super dust storm attacked Beijing, which was stronger than any dust storm ever recorded. The concentration of total suspended particulates (TSP) reached 10.9 mg · m-3, 54 times as high as the national air quality standard. The concentrations of major crustal elements, such as Ca, Al, Fe, Na, Mg and Ti, were 30-58 times higher than those in non-dust storm days. The concentrations of pollution elements, such as Zn, Cu, Pb, As, Cd and S, were also about several or even nearly ten times higher than those in normal days. The enrichment factors of Pb, As, Cd and S in PM2.5 were as high as 12.7, 29.6, 43.5, 28.4, indicating that these pollutants came from the mixing of mineral aerosol with pollution aerosol emitted by pollution sources on the way of dust storm's long-range transport. The overlap of invaded air mass from dust with pollution air mass from Beijing local area was another reason for the enhancement of pollutants. During dust storm, fine particles (PM2.5) accounted for 30% of TSP and pollutants in PM2.5 accounted for even as high as 45%-69% of TSP. The increase of pollutants after dust storm proved further that mineral aerosol, especially the fine particles from dust storm favored the transformation and accumulation of pollutants. It must be noted that Fe (II) was detected again in this dust storm, which provided new evidence for the mechanism of coupling and feedback between iron and sulfur in the atmosphere and the ocean. The increase of both pollutants and nutrient, Fe(II), during dust storm illuminated that dust storm is an important factor affecting the global environment change. [ABSTRACT FROM AUTHOR]