STATUS OF PACIFIC REGION IN GLOBAL CHANGE——An Analysis of the X VIII Pacific Science Congress

Last June more than one thousand scientists from over 50 countries in the Pacific and other regions of the world gathered in Beijing of China and participated in the ⅩⅤⅢ Pacific Science Congress. This was an international general academic congress which had involved natural science, social science, engineering science,

Delineation of eco-geographic regional system of China

Eco-geographic regionalization has been one of the most important topics in China's regionalization researches since the end of the 20th century. It is a major ecosystem in geographic zonality. A hierarchical system, which is formed by division or combination of natural features based on geographic relativity and comparison of major ecosystem factors (including biological and non-biological) and geographic zonality, is called eco-geographic regional system. This paper introduces process of China's regionalization development. The first level unit, temperature zone, is delineated with main criteria of temperature. The second level unit, humidity region, is based on criteria of water/moisture states. The third level unit, natural region, is divided according to medium geomorphologic units. Vegetation types and soils are applied as supplementary criteria to indicate temperature and water/moisture states. Mapping process from qualitative to quantitative and China's eco-geographic regional system are also explained in this paper.

Eco-geographic Environment and Regional Development in Xinjiang of China

The study on relationship between eco-geographic environment(EGE) and regional development(RD) is of theoretical and practical significance to promote the comprehensive study on nature and human factors and regional coordination development.Based on the evaluation index system and models of EGE and RD, Quadrant Analysis Method(QAM) and the Coordination Degree and Coordinated Development Degree Model(CDCDDM) were applied to studying the relationship between EGE and RD in Xinjiang in this paper.The results show that Xinjiang can be divided into four type regions according to the relationship between EGE and RD, namely high coordination region(HCR), overloading development region(ODR), low coordination region(LCR) and potential development region(PDR).Most areas of Xinjiang belong to LCR which can not bear a larger population and support large-scale economic development.HCR, ODR and PDR, which are mainly distributed in piedmont oases and take basin as unit, should be focused on in the development of Xinjiang.The EGE has great influence on RD, and there is serious contradiction between them.Relevant suggestions on development strategies were put forward according to the character of different type regions, and the key regions of macro-layout of RD in Xinjiang were pointed out.

Spatiotemporal Urban Land Use Changes in the Changzhutan Region of Hunan Province in China

The Changzhutan region in the north-central part of Hunan Province in China has experienced a rapid urbanization in the past few decades that has led to substantial changes in its environment. In 2007, the National Development and Reform Commission of China designated the metropolitan district of Changsha City, Zhuzhou City, and Xiangtan City of this region as the fourth National Demonstration Area where economic development should be implemented in harmony with resource-saving and environment-friendly land use practices. The research, focus of this article will be on quantifying the spatial pattern of urban land use change which not only can provide an assessments and predictions of future environmental effects, but also will serve as a scientific basis for the development of urban sustainability. This paper integrates historical Landsat TM imagery, geographical information system (GIS) and socioeconomic data to determine the spatiotemporal urban land use dynamics and conversion of land use in response to the rapid urbanization of a select group of cities in China from 1990 to 2007. The approach is based on Principle Component Analysis to determine and model the relationship between the socioeconomic factors and land use/cover change (LUCC) for identifying the driving forces. The results indicate that land cover of the Changzhutan region mainly consists of forestland and cropland which accounted for about 93% of the total land area. During the 1990-2007 study period, the urban areas and water bodies increased by 46,297 ha and 775 ha, respectively, while forestland, cropland, and grassland decreased appreciably by 22,580 ha, 21,808 ha, and 5618 ha, respectively. Moreover, the urban land area during the 2000-2007 period increased by five times as much as that during the 1990-2000 period. The land use dynamic degree of Changsha City is the largest one followed by that for Xiangtan and Zhuzhou Cities. During this study period, the land use comprehensive intensity index increased and followed the sequence Xiangtan > Changsha > Zhuzhou. The changes were attributed to economic development, population growth, infrastructure improvements and construction, and land use policies. To address the negative or eco-environmental deleterious effects of these changes, landscape ecology plan, population growth control, and the development of an ecological friendly agriculture were suggested.

Regional Differences and Characteristics of Soil Organic Carbon Density Between Dry Land and Paddy Field in China

Study on the regional characteristics of soil organic carbon （SOC） density in farmland will not only contribute greatly to the technique of soil productivity enhancement, but also give evidences of technique selection and policy making for carbon sequestration in soils. Based on the second national soil survey of China, the situation of SOC density in the plow layer of farmland was analyzed under different land use patterns. Results showed that SOC density in the plow layer was about 3.15 kg m^-2 in average ranging from 0.81 to 12.68 kg m^-2. The highest density was found in the southeastern region with an average of 3.63 kg ma, while the lowest occurring in the northwestern region with an average of 3.00 kg m^-2. The variation coefficient of SOC density in the plow layer of farmland was 57%, which was 35% lower than that of non-farmland soils. Compared to SOC density in the dry land, SOC density in paddy soils was 13% higher with a lower variation coefficient between different regions. In addition, the relationships between the climatic factors （annual average temperature and precipitation） and SOC density were lower in farmland than those in non-farmland soils, as well as lower in paddy soils than those in dry land of farmland. These results suggest that anthropogenic disturbances have great impacts on SOC density in farmland soils, especially in paddy soils, indicating that Chinese rice cropping may contribute greatly to the SOC stability and sequestration in paddy field.

Delineation of boundary between tropical/subtropical in the middle section for eco-geographic system of South China

This paper discusses division on tropical/subtropical boundary of middle section in South China. This discussion results in new understanding on eco-geographic regions and their boundaries, especially on gradual changes of natural conditions between eco-geographic regions. It analyzes results of the same area by other researchers, clarifies differences and causes of the differences for the results. Boundaries of eco-geographic regions cannot be drawn as a line as changes from tropical to subtropical are gradual. Therefore, for an eco-geographic region like tropical zone, definite boundaries must be mapped while gradual changes are considered. Temperature, vegetation and soil are the indexes to divide tropical and subtropical. After indexes of tropical zone are confirmed, data of annual average index reflect general state of the tropical zone. Line from such data is called “tropical boundary”. On the other hand, affected by the monsoon climate, some years are hotter and some are cooler. In hotter years, temperature of north area of tropical boundary reaches tropical state whereas in cooler years, such area moves southward. Boundary of the hottest year is called annual tropical line and that of the coolest year true tropical line. Temperatures in areas south to annual tropical line can probably reach tropical in some years. Temperatures in areas south to real tropical line reach tropical every year. The area from true tropical to annual tropical is called tropical fluctuating zone. Therefore, new concepts of tropical, annual tropical, true tropical and tropical fluctuating zone are formed to understand tropical area from a new point of view in the paper. Based on the indexes of climate, vegetation and soil, boundaries of tropical, annual tropical, true tropical and tropical fluctuating zone of the study area are established. The tropical fluctuating zone explains different locating of different researchers. The paper also puts forward a new method to display boundary for eco-geographic regions.

Research Agenda for Understanding Transboundary Ecosystem Changes and Eco-security in Southwestern China

The longitudinal range-gorge region (LRGR) in Southwestern China, characterized by longitudinal mountain ranges and deep valleys, includes the basins of four major international rivers: the Yuanjiang-Red, Lancang Mekong, Nujiang Salween and Irrawaddy. This region is classified as one of the world’s biodiversity hotspots, and provides an important ecological and economic corridor linking China and Southeast Asian countries. Over the past half century, it has served as a resource base for timber and minerals needed to fuel economic development, which resulted in rapid and drastic changes in ecosystem and species diversity. Proposed and ongoing development programs, such as China’s Great Western Development campaign, Greater Mekong Subregional Economic Cooperation (GMS) and China-ASEAN free trade zone development (“10+1”), threaten to bring unprecedented disturbance to the region’s ecosystems. Present and emerging threats to eco-security have caught tremendous attention worldwide. Therefore, studies on such problems are critical for enhancing ecosystem health and transboundary eco-security. This paper indicates several multi-disciplinary and cross-sector studies on transboundary resources in this region that will meet three major national needs: 1) identifying core scientific issues of ecological development and infrastructure construction in highplateau and mountainous areas for the Western Development campaign; 2) developing maintenance mechanisms and control methodologies for transboundary eco-security and resource base development; 3) providing scientific grounds for multi-lateral diplomacy, trade and economic cooperation, and conflict resolution as part of China’s opening-up to south Asia. The key subjects to be solved include dynamics and major drive forces of this area, ecological effects caused by major projects construction, and transboundary eco-security and its controlling. The research projects proposed in this article will develop theories on ecosystem change and transboundary eco-security, and provide a scientific basis for national and international development strategies.

Advancing Climate Dynamics Toward Reliable Regional Climate Projections

With a scientific consensus reached regarding the anthropogenic effect on global mean temperature, developing reliable regional climate projections has emerged as a new challenge for climate science. A national project was launched in China in 2012 to study ocean's role in regional climate change. This paper starts with a review of recent advances in the study of regional climate re-sponse to global warming, followed by a description of the Chinese project including the rationale, objectives, and plan for field ob-servations. The 15 research articles that follow in the special issue are highlighted, representing some of the initial results from the project.

Interlinkage Between Global Environmental Changes,Water Resources Availability and Quality in the East African Rift:Preliminary Analyses and Some Cases:The MaWARi Project(Kenya,Ethiopia,Djibouti,France)

The East African Rift extending across Djibouti, Ethiopia and Kenya is characterized by low level of economic development,high level of poverty,increasing population,scarce natural resources(land,water, and environment),complex and rich ecosystems, increasing desertification and degrading biodiversity, underdeveloped regional trade and market,water resources mainly stored in groundwater and

Water Resources of the South Asian Region in a Warmer Atmosphere

The global mean surface temperature may rise by about 0.3t per decade during the next few decades as a result o f anthropogenic greenhouse gas emissions in the earth's atmosphere. The data generated in the greenhouse warming simulations (Business-as-Usual scenario of IPCC) with the climate models developed at Max Planck Institute for Meteorology, Hamburg have been used to assess future plausible hydrological scenario for the South Asian region.The model results indicate enhanced surface warming (2.7) for summer and 3.6℃ for winter) over the land reginos of South Asia during the next hundred years. While there is no significant change in the precipitation over most of the land regions during winter, substantial increase in precipitation is likely to occur during summer. As a result, an increase in soil moisture is likely over central india, Bangladesh and South China during summer but a statistically significant decline in soil moisture is expected over central China in winter. A moderate decrease in surface runoff may occur over large areas of central China during winter while the flood prone areas of NE--India, Bangladesh and South China are likely to have an increase ill surface runoff during summer by the end of next century.

Regional changes in extreme heat events in China under stabilized 1.5℃ and 2.0℃ global warming

Extreme heat events(EHEs)have a significant impact on the social economy and human health.China is a country with a large population and diverse terrain,and it is necessary to project future extreme heat changes in the sub-regions.This study used a specially designed dataset,the Community Earth System Model(CESM)simulations,namely CESM low-warming,to investigate the EHEs in China under 1.5℃ and 2.0℃ global warming.The results indicate that the regional mean warming over China will exceed the global average,about 1.63℃ and 2.24℃ in 1.5℃ and 2.0℃ warmer futures.Compared to the present-day(1976–2005),the frequency and duration of the EHEs in South China are projected to increase the most among the sub-regions.For example,the frequency of EHEs in South China at 1.5℃ and 2.0℃ warming will exceed 3 and 3.5 times the present-day level.However,when global warming rises from 1.5℃ to 2.0℃,the increased impacts relative to the 1.5℃ warming level will be the lowest in South China(less than 40%),and the highest increased impacts are projected to appear in Northeast China(53%-84%)and Northwest China(53%–107%).The main reason for this situation is that compared with the 1.5℃ scenario,the upper zonal westerly in northern China weakens and the continental high pressure enhances under the 2.0℃ scenario.Therefore,limiting global warming at 1.5℃ instead of 2.0℃ is beneficial for eliminating extreme heat events,especially for Northeast China and Northwest China.

ANALYSIS ON SPATIAL DIFFERENCE OF LAND USECHANGE BASED ON PHYSICAL AND CULTURALLANDSCAPE ATTRIBUTES──A Case Study at Mongolian AutonomousCounty of Qian Gorlos, Jilin Province

Land use changes are regarded as landscape pattern change driven by many interactive natural and social-economic factors. Different combination of physical geographical elements induced the difference of spatio-temporal pattern of land use change. There are four physical geographical regions in Mongolian Autonomou County of Qian Gorlos of Jilin Province. Based on spatial analysis and statistical analysis, we conclude that the primary pattern of land use and the tendency of land use changes are all different in four physical geographical regions. During 1987 - 1996, the dominant land use change processes were from grassland or forest to arableland, from unused land to paddy and grassland to unused land. Though land use change is mainly affected by social and economic condition in short period, the composite characters of physical geographical elements controls land use dynamic process. The relationship between land use dynamic process and the character of physical geographical units differ in different regions. Possible human impacts on land use change are explored with application of buffer areas of series distance along main roads and radius around main settlements. A few models are built to describe the relationship between land use spatial change rates and distance to road and settlements. According to our result, the relationship with the proximity to roads was a negative liner function, with the change rate decreasing rapidly when moving away from roads. Within a distance of less 7. skin from main traffic lines, land use changes occur red more. The bulk of grassland was apt to be opened up for cultivation around the settlements and the transformation from dryland to paddy occurred within the distance of 1km away from settlements.

皖江城市带近20年土地利用变化及其生态环境效应

分析区域土地利用变化及其对生态环境的影响,能为区域土地利用结构优化及生态环境保护提供理论依据.以皖江城市带为例,基于2000年、2010年、2020年土地利用数据集,运用土地利用转移矩阵模型,分析了该地区土地利用时空变化特征;同时结合生态环境质量指数、网格单元分析方法及土地利用转型的生态贡献率,探究了土地利用变化的生态环境效应.结果表明:(1)皖江城市带土地利用转移主要为耕地和森林之间的相互转移,以及人造地表对耕地的侵占;(2)皖江城市带森林的生态价值重要性最大,最高达到55.29%,人造地表用地的变动对该区域的生态影响较大,生态价值贡献率为28.20%;(3)皖江城市带生态环境质量指数稳定且有下降趋势,区域生态环境质量指数呈现“南高北低”的空间格局;(4)耕地向森林及草地的转换是导致生态环境改善的主要原因,森林转向耕地及耕地转向人造地表是导致生态环境恶化的主要原因.

气候变化对中国西南地区主要桦木科乔木树种潜在地理分布的影响

依据收集的中国西南地区8种主要桦木科(Betulaceae)乔木树种分布数据、37个环境因素数据,选取19个生物气候因素、15个土壤因素、3个地形因素,应用最大熵模型(MaxEnt)构建中国西南地区主要桦木科乔木树种分布区预测模型,预测当前(1971—2000年)及未来2070年(2061—2080年)3种气候环境(SSPs126、SSPs245、SSPs585)时中国西南地区主要桦木科乔木树种的潜在地理分布;采用地理信息系统软件(ArcGIS10.8),将8种桦木科乔木树种当前气候环境潜在分布区数据与2000年土地利用(有林地)数据结合,将未来气候环境时8种桦木科乔木树种各潜在分布区数据与2020年土地利用(有林地)数据相融合,分析各桦木科乔木树种的适生区范围、变化趋势及影响桦木科乔木树种分布的主要环境因素。结果表明:①最大熵模型预测的模型精度值均大于0.8,模型预测结果具有高精度和可信度。②影响高山桦(Betula delavayi)潜在地理分布的主要环境因素为温度季节性变化标准差(贡献率37%)、等温性(贡献率23.6%)、坡度(贡献率17.6%)、表层土基础饱和度(贡献率16.6%),累计贡献率为94.8%;影响其他7种桦木科乔木树种潜在地理分布的主要环境因素为年降水量(贡献率36.1%)、温度季节性变化标准差(贡献率18.7%)、海拔(贡献率16.3%)、最冷月最低温(贡献率14.9%),累计贡献率达86.0%。③8个树种主要分布于长江以南地区,其中白桦(Betula platyphylla)、糙皮桦(Betula utilis)、高山桦的潜在地理分布,延伸至陕西、山西、甘肃南部、河北北部、辽宁东部等地。④未来3种气候环境时,川滇桤木(Alnus ferdinandi-coburgii)、高山桦、白桦潜在地理分布,适生区总面积减少1.3%~50.6%;尼泊尔桤木(Alnus nepalensis)、亮叶桦(Betula luminifera)、糙皮桦的潜在地理分布,适生区总面积增加0.2%~13.0%;红桦(Betula albosinensis)、云贵鹅耳枥(Carpinus pubescens)潜在地理分布,适生区总面积在SSPs126、SSPs585环境时呈减少趋势(减少0.7%~4.9%),在SSPs245环境时分别增加2.6%、5.4%。⑤未来气候环境时,各乔木树种适生分布区均向北扩张;其中,川滇桤木、红桦、高山桦、糙皮桦的高度适生区,向北迁移至四川中部、云南北部、西藏东南部地区;尼泊尔桤木、亮叶桦、白桦、云贵鹅耳枥的高度适生区,向东北方向迁移至贵州、重庆、山西、湖北西部、甘肃南部、云南东部等地。

Effect of land use and land cover change on soil erosion and the spatio-temporal variation in Liupan Mountain Region,southern Ningxia,China

The Liupan Mountains are located in the southern Ningxia Hui Autonomous Region of China,that forms an important divide between landforms and biogeographic regions.The populated part of the Liupan Mountain Region has suffered tremendous ecological damage over time due to population pressure,excessive demand and inappropriate use of agricultural land resources.To present the relationship between land use/cover change and spatio-temporal variation of soil erosion,data sets of land use between the late 1980s and 2000 were obtained from Landsat Thematic Mapper(TM)imagery,and spatial models were used to characterize landscape and soil erosion conditions.Also,soil erosion in response to land use and land cover change were quantified and analyzed using data from geographical information systems and remote sensing.Soil erosion by water was the dominant mode of soil loss,while soil erosion by wind was only present on a relatively small area.The degree of soil erosion was classified into five severity classes:slight,light,moderate,severe,and very severe.Soil erosion in the Liupan Mountain Region increased between the late 1980s and 2000,both in terms of acreage and severity.Moderate,severe,and very severe eroded areas accounted for 54.86%of the total land area.The lightly eroded area decreased,while the moderately eroded area increased by 368817 ha(22%)followed by severe erosion with 146552 ha(8.8%),and very severe erosion by 97067.6 ha(5.8%).Soil loss on sloping cropland increased with slope gradients.About 90%of the cropland was located on slopes less than 15°.Most of the increase in soil erosion on cropland was due to conversion of steep slopes to cropland and degradation of grassland and increased activities.Soil erosion was severe on grassland with a moderate or low grass cover and on dry land.Human activities,cultivation on steep slopes,and overgrazing of pastures were the main reasons for the increase in erosion severity.

全球治理视野下的国际经济秩序发展与法治化

党的二十大报告提出了中国如何实践全球经济治理的重大命题。随着国际体系中权力的扩散和转移,国际经济秩序也面临着新的挑战。国际经济秩序的法治化将国际经济发展中形成的规则体系化,国际硬法和软法的结合反映了法治化的灵活性和适应性特征。在多边主义模式面临困境的情况下,RCEP为亚洲区域主义提供了规范基础。全球治理的可持续发展目标也正在影响国际经济秩序。中国从全球治理的边缘走向中心,将持续推进全球经济治理规则民主化、法治化。

Effects of longitudinal range-gorge terrain on the eco-geographical pattern in Southwest China

China＇s southwestern special terrain pattern as parallel arrangement between lon- gitudinal towering mountains and deep valleys has significant effects on the differentiation of local natural environment and eco-geographical pattern in this region. The 1：50,000 Digital Elevation Model （DEM） data of Longitudinal Range-Gorge Region （LRGR）, meteorological observation data from the station establishment to 2010, hydrological observation data, Normalized Difference Vegetation Index （NDVI） and Net Primary Productivity （NPP） products of MOD13 and MOD17 as well as 1：1,000,000 vegetation type data were used. Moisture in- dices including surface atmospheric vapor content, precipitation, aridity/humidity index, sur- face runoff, and temperature indices including average temperature, annual accumulated temperature, total solar radiation were selected. Based on ANUSPLIN spline function, GIS spatial analysis, wavelet analysis and landscape pattern analysis, regional differentiation characteristics and main-control factors of hydrothermal pattern, ecosystem structure and function in this region were analyzed to reveal the effects of terrain pattern o~ regional dif- ferentiation of eco-geographical elements. The results show that： influenced by terrain pattern moisture, temperature and heat in LRGR have shown significant distribution cllaracteristics as intermittent weft differences and continuous warp extension. Longitudinal mountains and valleys not only have a north-south corridor function and diffusion effect on the transfer of major surface materials and energy, but also have east-west barrier function and blocking effect. Special topographic pattern has important influences on vegetation landscape diversity and spatiat pattern of ecosystem structure and function, which is the main-control factor on vegetation landscape diversity and spatial distribution of ecosystem. Wavelet variance analysis reflects the spatial anisotropy of environmental factors, NDVI and NPP, while wavelet consistency analysis reveals the control factors on spatial distribution of NDVI and NPP as well as the quantitative relationship with control degree. Special terrain pattern in LRGR is the major influencing factor on eco-geographical regional differentiation in this region. Under the combined effect of zonality and non-zonality laws with ＂corridor-barrier＂ functior as the main characteristic, special spatial characteristics of eco-geographical regional system in LRGR is formed.

近54年中国地面气温变化

采用国家基准气候站和基本气象站地面月平均气温资料,在严格质量控制和非均一性订正的基础上,分析了1951年以来中国大陆地区近地表年和季节平均气温演化的时间与空间特征。结果表明,我国近54年来年平均地表气温变暖幅度约为1.3℃,增温速率接近0.25℃/10a,比全球或半球同期平均增温速率高得多。全国大范围增暖主要发生在近20余年。气温变化的季节差异和空间特征与前人分析结论基本一致,冬季增温速率高达0.39℃/10a,春季为0.28℃/10a,秋季0.20℃/10a,夏季增温速率最小,但也达到0.15℃/10a。我国20世纪80年代初期开始的明显增暖主要表现在冷季,但进入90年代以来夏季增暖也日趋明显。从区域上看,中国大陆地区最明显的增温发生在北方和青藏高原地区,而西南的四川盆地和云贵高原北部仍维持弱的降温趋势。值得提出的是,作者给出的结果尚未考虑城镇化对地面气温观测记录的影响。

基于OMI卫星遥感数据的中国对流层NO2时空分布

基于2004年11月—2008年1月OMI卫星对流层NO2的垂直柱浓度数据,对我国8个自然地理分区对流层NO2垂直柱浓度的年均值、月均值的分布进行了分析,依据月均值变化建立正弦曲线拟合模型,依据该模型定量分析了各自然区对流层NO2垂直柱浓度的变化趋势、变化周期和变化幅度等特征.结果表明:拟合模型可较好地反映我国8个自然区对流层NO2垂直柱浓度的变化特征;证明了人类活动影响了对流层NO2垂直柱浓度的分布及其变化,这种影响主要体现在对流层NO2垂直柱浓度的高低、变化的周期性以及增长趋势等方面.