The most important climatological feature of the South Asian region is the occurrence of monsoons. With increasing concerns about climate change, the need to understand the nature and variability of such climatic conditions and to evaluate possible future changes becomes increasingly important. This paper deals with long-term above and below normal monsoon precipitation causing prolong meteorological droughts and floods in India. Five regions across India comprising variable climates were selected for the study. Apart from long-term trends for individual regions, long-term trends were also calculated for the Indian region as a whole. The results show that intra-region variability for monsoon precipitation is large and there are increasing numbers of meteorological summer droughts. Meteorological monsoon floods were found to have negative long-term trends everywhere except in the peninsular Indian region. The results overall suggest generic conclusions concerning the region-wide long-term trend of severity of monsoon droughts and floods in India and their spatial variability.
This study has investigated the influence of Arctic Oscillation (AO) on dust storm frequency in North China in spring seasons during 1961?2007. There is a significant linkage between dust storm frequency and AO; a negative (positive) AO phase is related to an increased (decreased) dust storm frequency in North China. This relationship is closely related to changes in the cold air activity in Mongolia. The cold air activity exerts large impacts on the dust storm frequency; the frequency of cold air activity over Mongolia not only positively correlates with the dust storm frequency in North China, but also shows a long-term decreasing trend that is an important reason for the long-term decreasing of dust storm frequency in North China. The AO has large influence on the frequency of cold air activity over Mongolia; a negative (positive) AO phase is highly related to an increased (decreased) frequency of cold air activity over Mongolia, which results in an increased (decreased) dust storm frequency in North China.
An abrupt ice and snow storm disaster which occurred in the spring of 2008 severely destroyed forests over a surprisingly large portion of southern China. A transect crossing Jinggang Mountain-Jitai Basin-Yushan Mountain-Wuyi Mountain was selected as the study area. The authors integrated field data collected in two field surveys to analyze the impacts of the disturbance on forests. The following results were obtained. (1) The extent of damage to plantations along the transect decreased in the order of slash pine > masson pine > mixed plantation > Chinese fir. Slash pine is an introduced species from southern America which is characterized by fast growth, low wood quality and rich oleoresin, and showed a damage rate of 61.3% of samples, of which 70.4% cannot recover naturally. Masson pine is the native pioneer species of forests with harder wood, and 52.5% were damaged due to turpentine, of which 60.9% cannot recovery naturally. Chinese fir is a local tree species and samples showed a rate of 46% and a relative rate of 32.5%, lower than the mixed plantation. (2) From west to east along the transect, we can see that evergreen broad-leaved forest of the western transect on Jinggang Mountain showed the lightest damage extent, and a Cryptomeria plantation at an altitude of 700 m was severely destroyed while Chinese fir showed light damage below 700 m and relatively severe damage above 900 m. Masson pine and slash pine in the central transect in Jitai Basin were damaged severely due to turpentine activities, and closed natural secondary deciduous broad-leaved forest was damaged severely due to high ice and snow accumulation on intertwined shrubs. Masson pine aerial-seeding plantations below 400 m along the eastern transect in Xingguo and Ningdu counties were nearly undamaged for small tree sizes, and Chinese fir at 500-900 m altitude showed a lighter damage extent. However, masson pine which was distributed above 400 m and planted in the 1960s, was severely damaged due to turpentine.
Based on the monthly precipitation data for the period 1960-2008 from 616 rainfall stations and the phenology data of main grain crops, the spatial characteristics of drought hazard in China were investigated at a 10 km×10 km grid-cell scale using a GIS-based drought hazard assessment model, which was constructed by using 3-month Standard Precipitation Index (SPI). Drought-prone areas and heavy drought centers were also identified in this study. The spatial distribution of drought hazard in China shows apparent east-west difference, with the eastern part of China being far more hazardous than the western part. High hazard areas are common in the eastern and central parts of Inner Mongolian Plateau, the central part of Northeast China Plain, the northern part of Heilongjiang, the southeastern part of Qinghai-Tibet Plateau, the central and southern parts of Loess Plateau, the southern part of North China Plain, the northern and southern parts of Yangtze River Plain, and Yunnan- Guizhou Plateau. Furthermore, obvious differences in drought hazard were found both within and between different agricultural zonings.
In recent years, the socio-economic impacts of winter extreme climate events have underscored the importance of winter climate anomalies in Southwest China (SWC). The spatio-temporal variability of surface air temperature (SAT) and precipitation in SWC and their possible causes have been investigated in this paper based on observational data from 1961 to 2010. The results indicate that SAT anomalies in SWC have two dominate modes, one is homogenous, and the other a zonal dipole. The former is caused by the anomalies of East Asian winter monsoon; the latter arises from the anomalies of both subtropical west Pacific high and regional cold air in lower troposphere. The most dominant mode of precipitation anomalies in SWC is homogenous and it has a high correlation with northern hemisphere annular mode (NAM，AO). Neither NAM nor ENSO has significant impacts on SAT in SWC. The anomalies of NAM are associated with the anomalies of tropical circulations, and therefore precipitation over the SWC. When NAM is in positive (negative) phase, the winter precipitation is more (less) than normal in SWC. Winter precipitation increase over the whole SWC is associated with the El Ni?o. However, during La Ni?a winter, the pattern is not uniform. There is an increase in precipitation over the central parts and a decrease in western and eastern parts of SWC. The severe drought in SWC in winter 2010 is more likely caused by anomalies of NAM, not El Ni?o.
Based on the statistics of glacier area variation measured in the Chinese Tianshan Mountains since 1960, the response of glacier area variation to climate change is discussed systematically. As a result, the total area of the glaciers has been reduced by 11.5% in the past 50 years, which is a weighted percentage according to the glacier area variations of 10 drainage basins separated by the Glacier Inventory of China (GIC). The annual percentage of area changes (APAC) of glaciers in the Chinese Tianshan Mountains is 0.31% after the standardization of the study period. The APAC varies widely for different drainage basins, but the glaciers are in a state of rapid retreat, generally. According to the 14 meteorological stations in the Chinese Tianshan Mountains, both the temperature and precipitation display a marked increasing tendency from 1960 to 2009 at a rate of 0.34℃·(10a)-1 and 11 mm·(10a)-1, respectively. The temperature in the dry seasons (from November to March) increases rapidly at a rate of 0.46℃·(10a)-1, but the precipitation grows slowly at 2.3 mm·(10a)-1. While the temperature in the wet seasons (from April to October) grows at a rate of 0.25 ℃·(10a)-1, but the precipitation increases at 8.7 mm·(10a)-1. The annual and seasonal climatic trends accelerate the retreat of glaciers.
Scenario modelling and the risk assessment of natural disasters is one of the hotspots in disaster research. However, up until now, urban natural disaster risk assessments lack common procedures and programmes. This paper selects rainstorm waterlogging as a disaster to research, which is one of the most frequently occurring hazards for most cities in China. As an example, we used a small-scale integrated methodology to assess risks relating to rainstorm waterlogging hazards in the Jing’an District of Shanghai. Based on the basic concept of disaster risk, this paper applies scenario modelling to express the risk of small-scale urban rainstorm waterlogging disasters in different return periods. Through this analysis of vulnerability and exposure, we simulate different disaster scenarios and propose a comprehensive analysis method and procedure for small-scale urban storm waterlogging disaster risk assessments. A grid-based Geographical Information System (GIS) approach, including an urban terrain model, an urban rainfall model and an urban drainage model, was applied to simulate inundation area and depth. Stage-damage curves for residential buildings and contents were then generated by the loss data of waterlogging from field surveys, which were further applied to analyse vulnerability, exposure and loss assessment. Finally, the exceedance probability curve for disaster damage was constructed using the damage of each simulated event and the respective exceedance probabilities. A framework was also developed for coupling the waterlogging risk with the risk planning and management through the exceedance probability curve and annual average waterlogging loss. This is a new exploration for small-scale urban natural disaster scenario simulation and risk assessment.
Using energy consumption and land use data of each region of China in 2007, this paper established carbon emission and carbon footprint model based on energy consumption, and estimated the carbon emission amount of fossil energy and rural biomass energy of different regions of China in 2007. Through matching the energy consumption items with industrial spaces, this paper divided industrial spaces into five types: agricultural space, living & industrial-commercial space, transportation industrial space, fishery and water conservancy space, and other industrial space. Then the author analyzed the carbon emission intensity and carbon footprint of each industrial space. Finally, advices of decreasing industrial carbon footprint and optimizing industrial space pattern were put forward. The main conclusions are as following: (1) Total amount of carbon emission from energy consumption of China in 2007 was about 1.65 GtC, in which the proportion of carbon emission from fossil energy was 89%. (2) Carbon emission intensity of industrial space of China in 2007 was 1.98 t/hm2, in which, carbon emission intensity of living & industrial-commercial space and of transportation industrial space was 55.16 t/hm2 and 49.65 t/hm2 respectively, they were high-carbon-emission industrial spaces among others. (3) Carbon footprint caused by industrial activities of China in 2007 was 522.34×106 hm2, which brought about ecological deficit of 28.69×106 hm2, which means that the productive lands were not sufficient to compensate for carbon footprint of industrial activities, and the compensating rate was 94.5%. As to the regional carbon footprint, several regions have ecological profit while others have not. In general, the present ecological deficit caused by industrial activities was small in 2007. (4) Per unit area carbon footprint of industrial space in China was about 0.63 hm2/hm2 in 2007, in which that of living & industrial- commercial space was the highest (17.5 hm2/hm2). The per unit area carbon footprint of different industrial spaces all presented a declining trend from east to west of China.
International trade is an important impact factor to the carbon emissions of a country. As the rapid development of Chinese foreign trade since its entry into the WTO in 2002, the effects of international trade on carbon emissions of China are more and more significant. Using the recent available input-output tables of China and energy consumption data, this study estimated the effects of Chinese foreign trade on carbon emissions and the changes of the effects by analyzing the emissions embodied in trade between 2002 and 2007. The results showed a more and more significant exporting behavior of embodied carbon emissions in Chinese international trade. From 2002 to 2007, the proportion of net exported emissions and domestic exported emissions in domestic emissions increased from 18.32% to 29.79% and from 23.97% to 34.76%, respectively. In addition, about 22.10% and 32.29% of the total imported emissions were generated in processing trade in 2002 and 2007, respectively, which were imported and later exported emissions. Although, most of the sectors showed a growth trend in imported and exported emissions, sectors of electrical machinery and communication electronic equipment, chemical industry, and textile were still the biggest emission exporters, the net exported emissions of which were also the largest. For China and other developing countries, technology improvement may be the most favorable and acceptable ways to reduce carbon emissions at present stage. In the future negotiations on emissions reduction, it would be more fair and reasonable to include the carbon emissions embodied in international trade when accounting the total emissions of an economy.
Dynamic urban expansion simulation at regional scale is one of the important research methodologies in Land Use/Cover Change (LUCC) and global environmental change influenced by urbanization. However, previous studies indicate that the single urban expansion simulation for future scenarios at local scale cannot meet the requirements for characterizing and interpreting the interactive mechanisms of regional urbanization and global environmental change. This study constructed a regional Dynamic Urban Expansion Model (Reg-DUEM) suitable for different scenarios by integrating the Artificial Neural Network (ANN) and Cellular Automaton (CA) model. Firstly we analyzed the temporal and spatial characteristics of urban expansion and acquired a prior knowledge rules using land use/cover change datasets of Beijing-Tianjin-Tangshan metropolitan area. The future urban expansion under different scenarios is then simulated based on a baseline model, economic models, policy models and the structural adjustment model. The results indicate that Reg-DUEM has good reliability for a non-linear expansion simulation at regional scale influenced by macro-policies. The simulating results show that future urban expansion patterns from different scenarios of the metropolitan area have the tremendous spatio-temporal differences. Future urban expansion will shift quickly from Beijing metropolis to the periphery of Tianjin and Tangshan city along coastal belt.
Valley economy is a new mode in mountainous area development that is defined by various characters of valley development, and is a distinguishing economical geographic pattern for mountainous area development. The special spatial coupling relations in the distribution of different mountainous elements in valleys are new subjects for the mountain development studies, and such studies are meaningful both for researches and practices. Based on the long term researches on mountainous area development and following a brief exploration into the connotations and the spatial organizing process of valley economy, the authors analyzed the present situations of the development of valley economy in Beijing’s mountainous areas, studied the characteristics and the impacts of the spatial structural changes of the valley economy in Beijing’s mountainous areas, and finally proposed a rational arrangement of the spatial structure of the valley economy in Beijing’s mountainous areas. It is considered in this study that valley economy plays an important role in the development and functional transformation in Beijing’s mountainous areas in the new epoch. Firstly, valley economy is not outlined by the administrative boundaries, and it connects most of the villages in the mountainous areas roughly along the major transportation lines. Therefore, valley economy can exert positive influence on the development in the mountainous areas, at least in the aspects such as the rearrangement of industrial structure in the mountainous areas and the coordinated development of rural and urban areas. In addition, it is found that the valley economy in Beijing’s mountainous areas is evolved in a spatial organizing stage of secondary concentration, which is characterized by resource-saving, ecological protection and industrial optimization. Therefore, the development of valley economy will be helpful to the coordination between ecological protection and economic development in the mountainous areas, and will promote the integrated development of the mountainous areas. The developing mode of the valley economy in Beijing’s mountainous areas will provide the basis for the decision-making in the transformation of the functional roles of Beijing’s mountainous areas, and on the other hand, will present experiences for the studies in the mountainous areas outside of Beijing.
To explore geographical differences in quantitative characteristics and spatial pattern of human settlements environmental suitability (HSES) in the Three Gorges Reservoir Area (TGRA), terrain, climate, hydrology, vegetation and other natural factors were selected to build the livable environmental evaluation, and the quantitative analysis was conducted through Remote Sensing(RS) and Geographic Informational System (GIS) to reveal geographical characteristics and spatial patterns of HSES. The results are obtained as follows: (1) inhabitants of the TGRA of Chongqing are concentrated in the area with moderate high HSES, which is 78% of the total population distributed in 48% of the study area; (2) the HSES is closely related to the terrain, and it forms an arc-banded spatial succession pattern: relatively low in the northeast and the southeast while comparatively high in the west and the south; (3) large numbers of people are distributed in the area with low suitability (with higher population density than the average of the western China), but economic development level in these areas is quite low. Moreover, these areas are ecological sensitive and fragile, many kinds of eco-environmental problems have been caused by human activities. Therefore, population migration and layout are reasonable options for the development of these areas.
In recent years, the role of human activities in changing sediment yield has become more apparent for the construction of hydraulic engineering and water conservation projections in the Upper Yangtze River, but it has not been evaluated at the macro scale. Taking Sichuan Province and Chongqing City as an example, this paper studies the relationship between socio-economic factors and sediment yield in the Upper Yangtze River based on section data in 1989 and 2007. The results show that sediment yield is significantly correlated with population density and cultivated area, in which the former appears to be more closely related to sediment yield. Moreover, in the relation of sediment yield vs. population density, a critical value of population density exists, below which the sediment yield increases with the increase of population density and over which the sediment yield increases with the decrease of population density. The phenomenon essentially reflects the influence of natural factors, such as topography, precipitation and soil property, and some human activities on sediment yield. The region with a higher population density than critical value is located in the east of the study area and is characterized by plains, hills and low mountains, whereas the opposite is located in the west and characterized by middle and high mountains. In the eastern region, more people live on the lands with a low slope where regional soil erosion is slight; therefore, sediment yield is negatively related with population density. In contrast, in the western region, the population tends to aggregate in the areas with abundant soil and water resources which usually lead to a higher intensity of natural erosion, and in turn, high-intensity agricultural practices in these areas may further strengthen local soil erosion. It is also found that population tends to move from the areas with bad environment and high sediment yield to the areas with more comfortable environment and less sediment yield. The natural factors have greater influence on sediment yield of western region than that of eastern region. Generally, the natural factors play a dominant role on sediment yield in the Upper Yangtze River.
The geomorphological environment is one of the most fundamental variables affecting the development of human society. The mission of geomorphological environment research is to explore the most basic environment and features of our Earth’s surface morphology. The results can be applied to resource evaluation, environmental protection and reducing and preventing geological disasters. Thus, it can serve to help achieve sustainable development. This paper examines the Shenzhen east coastal zone as a case strongly influenced by urban expansion. We use modern geomorphological theory and methods, along with GIS and RS techniques, to reveal key characteristics of the geomorphological environment and landform classification. Furthermore, coastal ecosystem evaluation and regional resources sustainable utilization should be considered relative to the corresponding geomorphological environment. Based on this study, we conclude that modern geomorphological theory and methods, supported by “3S” techniques including GIS, RS and GPS, can play an important role in resolving the environment, resources and population problems as well as sustainable development challenges facing humankind at present.