Structural-territorial changes of the demographic situation in the Irkutsk region

The structural and territorial changes of the components of the demographic situation in the Irkutsk region are considered: population dynamics, natural increase (decrease), and age structure for 1994-2004 against 1979-1989. Use is made of the methods of conjugate-cartographic analysis and construction of matrix tables for the transition of the object under study from one state to the other. The study established a high dynamicity of the demographic situation, an enhancement of the influence of complicating factors, the formation of a new vast area of a stressed demographic situation, and significant shifts in territorial structure. The combination of complicating components was used to identify four types of demographic situation, the spatial distribution of which is shown on the map.     

Wavelet analysis of quasi-3-year temperature oscillations in China in last 50 years, and predicted changes in the next 20 years

The wavelet analysis method is used to analyze the annual and winter temperature data of 98 observation stations in China in eight climate zones during the last 50 years （1961-2009）. The periodicities of temperature changes are investigated, and the possible temperature change trends in China in the next 20 years （2012-2029） are also predicted. Our results show that in the inter-annual temperature variability there are pervasive quasi-3- to quasi-4-year cycles, and these cycle changes are relatively steady. The periodic characteristics of the annual temperature changes are clearly different between northern and southern China, and our period superimposition extrapolation shows that both annual and winter temperatures in China will continue to increase in the next 20 years, more so in northern China and in the Qinghai-Xizang Plateau （QXP） than in the southern region, except in the southwest. If temperatures follow historic increasing linear trends, the overall temper- ature is expected to increase by 1℃ between 2010 and 2029.     

Spatiotemporal changes in agricultural land cover in Nepal over the last 100 years

In order to advance land use and land cover change (LUCC) research in Nepal, it is essential to reconstruct both the spatiotemporal distribution of agricultural land cover as well as scenarios that can explain these changes at the national and regional levels. Because of rapid population growth, the status of agricultural land in Nepal has changed markedly over the last 100 years. Historical data is used in this study, encompassing soils, populations, climatic variables, and topography. Data were revised to a series of 30 m grid cells utilized for agricultural land suitability and allocation models and were analyzed using a suite of advanced geographical tools. Our reconstructions for the spatiotemporal distribution of agricultural land in Nepal reveal an increasing trend between 1910 and 2010 (from 151.2 × 10² km² to 438.8 × 10² km²). This expanded rate of increase in agricultural land has varied between different eco, physiographic, and altitudinal regions of the country, significantly driven by population changes and policies over the period of this investigation. The historical dataset presented in this paper fills an existing gap in studies of agricultural land change and can be applied to other carbon cycle and climate modeling studies, as well as to impact assessments of agricultural land change in Nepal.     

近40 a新疆土地利用及其绿洲动态变化

利用1972-2015年Landsat MSS/TM/OLI以及CBERS遥感影像数据,得到近40 a新疆土地利用时空数据,综合分析新疆土地利用及其绿洲的动态变化与动因。结果表明：新疆土地不断开垦、耕地面积不断扩大,已达到了相当的数量规模;土地的开垦与撂荒成为新疆乃至我国西北干旱地区土地利用变化最重要的特征,耕地撂荒与土地开垦的比率逐期下降,土地利用效率不断提高;城镇居民建设用地持续扩大;近40 a里,绿洲面积逐步扩大,面积占比由8.18%上升到9.93%;人工绿洲面积及占比也逐步增大,目前一半以上的绿洲面积为人工绿洲。气候的暖湿变化,以及政策、人口、社会经济、科技等要素成为新疆土地利用变化的动因。本文还提出了在关注各类土地数量变化的同时进一步开展土地开发的质量变化与评估研究。     

近600年来北极与中国气候变化的对比

A compilation of paleoclimate records from lake sediments, trees, ice cores, and historical documents provide a view of China and Arctic environmental changes in the last 600 years. Many of these changes have also been identified in sedimentary and geochemical signatures in deep-sea sediment cores from the North Atlantic Ocean, Arctic and Greenland and ice cores from the Qinghai-Tibet Plateau, confirming the linkage of environmental changes of different time scales between the Arctic and China. It is shown that the changes of precipitation, temperature and sea ice cover in Arctic were correlated with climate changes in China. This paper also developed a comparative research on the climate changes between Arctic and China both during the Little Ice Age (LIA) and the instrumental observation period. Cycles and trend of temperature variations during LIA and temperature and precipitation during the instrumental observation period are performed. We found some similarities and differences of environmental changes between Arctic and China.     

A comparison of climate changes between Arctic and China in the last 600 years

A compilation of paleoclimate records from lake sediments, trees, ice cores, and historical documents provide a view of China and Arctic environmental changes in the last 600 years. Many of these changes have also been identified in sedimentary and geochemical signatures in deep-sea sediment cores from the North Atlantic Ocean, Arctic and Greenland and ice cores from the Qinghai-Tibet Plateau, confirming the linkage of environmental changes of different time scales between the Arctic and China. It is shown that the changes of precipitation, temperature and sea ice cover in Arctic were correlated with climate changes in China. This paper also developed a comparative research on the climate changes between Arctic and China both during the Little Ice Age (LIA) and the instrumental observation period. Cycles and trend of temperature variations during LIA and temperature and precipitation during the instrumental observation period are performed. We found some similarities and differences of environmental changes between Arctic and China.     

石羊河流域近50年最高最低气温变化分析

选取石羊河流域具有代表性的气象站近50 a的年、月最高最低气温观测数据,对春季、夏季、秋季、冬季及年最高最低气温序列进行直线拟合,分析了年和季节的变化规律,并对最高最低气温时间序列进行了小波分析和突变分析,分析了时间序列变化的周期性和突变性。结果表明:近50 a来石羊河流域最高气温和最低气温在所有的季节都是增高的,最低气温的增温趋势明显高于最高气温,且冬季最高最低气温增温最强,年的最低气温和最高气温的增温趋势和变化幅度明显,升温率分别为0.53℃/10 a和0.199℃/10 a;最高气温以25 a,20 a周期为主周期,最低气温具有一致性,年和季节都以25 a周期为显著,春季和冬季的最高最低气温主周期都是25 a,夏季的最高最低气温主周期都是20 a;年最高气温没有检测到显著的突变性,而年最低气温在1984年发生了突变,春季和冬季的最高气温分别在2003年和1986年发生突变,春季和夏季的最低气温都在2001年发生突变,秋季最高气温、最低气温和冬季最低气温的突变都发生在20世纪90年代初。     

近50年黑河流域的冰川变化遥感分析

黑河流域作为中国西北地区第二大内陆流域,其景观类型完整、流域规模适中、社会生态环境问题典型,已成为寒区、旱区水文与水资源研究的热点地区。本研究结合1：5 万地形图、Landsat TM/ETM+遥感影像及数字高程模型数据,运用面向对象的图像信息自动提取方法,建立冰川信息提取知识规则,对近50 年黑河流域的冰川变化进行遥感分析。结果表明：（1）20 世纪60 年代黑河流域内的967 条冰川到2010 年左右,减少为800 条冰川,减少数量明显;冰川面积由361.69 km²退缩为231.17 km²,共减少130.51 km²,退缩率为36.08%,平均每条冰川面积退缩0.14 km²。（2）黑河流域冰川分布及变化存在显著的区域差异性,黑河冰川退缩率比北大河大16%左右;冰川末端主要分布在4300~4400 m、4400~4500 m和4500~4600 m海拔区间内。（3）与西部其他山地冰川相比,黑河流域冰川退缩率较高。（4）根据流域内6 个气象站资料分析表明,降水增加对冰川的补给无法弥补气温上升导致的冰川消融所带来的物质损失,是黑河流域冰川普遍萎缩的关键因素。     

Geographical differentiation of territorial structures of the economy in Pacific Russia

Pacific Russia is regarded as an aquaterritorial macroregion in the composition of the Far Eastern Federal District and the adjacent sea area within the 200-nautical mile Exclusive Economic Zone. The macroregion harbors enormous natural land and sea resource wealth potential and is endowed with possibilities of using the sea transport connecting Russia and Europe with countries of the Asia-Pacific Region. In Pacific Russia, two latitudinal zones, northern and southern, are identified; they include the territories of the constituent entities of the Far Eastern Federal District. Combinations of the kinds of activity for the constituent entities and latitudinal zones are treated as territorial structures of the economy. An assessment of the geographical differentiation of the economy in the latitudinal zones for the years 2004 and 2013 and its change was made from the differences of the homogeneous kinds of activity in the constituent entities measured in terms of the added value. Structural gradients of spatial (including latitudinal) differentiation of the homogeneous kinds of economic activity are suggested for neighboring constituent entities. The analysis made for the latitudinal zones can be useful in assessing the variants of investment in the economy of the constituent entities of Pacific Russia.     

150年来青藏高原南红山湖的介形类与环境变化

青藏高原西北部南红山湖2孔湖芯沉积物中的介形类动物群计有4属4种,据其分布特征划分出5个组合,各组合间的差异表现在介形类动物群丰度和每个种的丰度变化以及特征种的出现。通过分析介形类属种生态特征和组合变化对150年来的南红山湖环境变化进行了探讨。分析结果表明:1884年前为有缓慢水流注入的滨岸浅水期;1885～1970年间为湖水相对温暖期,在这期间湖泊环境仍有次一级的变化,其中,1885～1905年湖面迅速抬升,水深增大,水温也较高,1923～1944年为湖水温度另一个稍高期,1961～1969年湖面再次出现明显上升;1970年以来湖泊退缩、咸化。     

东北地区近百年降水时间序列变化规律的小波分析

利用1905~2005年东北地区哈尔滨、长春、沈阳和大连的降水时间序列资料,采用距平和Morlet小波分析方法,研究了东北地区降水变化的多时间尺度的周期性性变化规律,并对东北地区近期降水状况进行了预测。结果表明:近百年来东北地区年降水量呈现较显著下降趋势,整个东北地区降幅为-5.2mm/10a;长春为-12.7mm/10a;哈尔滨为-7.1mm/10a;大连为-2.7mm/10a;沈阳略为上升趋势为1.3mm/10a。东北地区的年降水量存在着区域性的多重时间尺度下的周期变化特征,2a~3a、5a~6a,10a和50a左右的长期振荡周期具有全域性;长春、哈尔滨年降水的主要控制周期是20a左右;5a~6a的短周期和50年的长周期变化也对年降水有较大影响。     

过去2000年亚洲气候变化(PAGES-Asia2k)集成研究进展及展望

介绍了国际过去全球变化研究计划(PAGES)过去2000年气候变化研究网络的设立背景、研究目的及亚洲在其中的独特性;总结了过去2000年亚洲气候变化(PAGES-Asia2k)集成研究的主要进展及中国的贡献,分析了当前在亚洲区域开展该项研究的主要问题及难点,并对未来研究进行了展望。亚洲历史悠久,高分辨率的代用资料丰富,是开展过去2000年气候变化研究的理想区域,但目前尚处于起步阶段。已有进展表明:在过去1200年中,亚洲830-1220年相对温暖,1340-1880年明显寒冷,20世纪则快速增暖;但亚洲气候类型多、变化过程复杂、区域差异大。因此,发展气候序列重建的新技术方法,提高重建序列的时、空分辨率、空间覆盖度和重建结果的精度,建立亚洲过去2000年气候代用资料数据库,集成重建过去2000年区域温度变化序列及干湿变化空间型,进而开展区域气候变化驱动机制与气候变化影响及适应研究,是该计划下一步的研究重点。     

苦海沉积物有机质反映的过去840年来青藏高原东部环境变化

青藏高原对全球气候变暖响应敏感,研究青藏高原近千年来环境演化过程、规律与驱动机制对预测其未来气候变化有重要意义。本文通过位于青藏高原东部的苦海沉积物总有机质相关指标(总有机碳(TOC)、总氮(TN)、总有机碳与总氮比值(TOC/TN)和总有机碳同位素(δ¹³Corg)的研究重建了该区域过去840年来环境演化过程。结果表明,苦海沉积物中的有机质主要来自于内源水生植物。由于暖期(冷期)时黄河上游径流量较高(低),苦海水位随之升高(降低),湖泊水动力增强(减弱),浅水区沉水植物对研究岩芯中的有机质贡献率提高(降低),导致沉积物TOC、TN、TOC/TN升高,δ¹³Corg值正(负)偏。人类活动导致的青藏高原近50年气候异常变暖可能是~1950 AD之后δ¹³Corg反映的黄河上游径流量变化与重建的中国温度记录之间的关系发生转变的原因。苦海沉积物δ¹³Corg记录与万象洞石笋δ¹⁸O记录和太阳总辐射强度记录变化特征的相似性说明青藏高原东部地区气候变化的控制因素为太阳辐射驱动下的季风降雨量变化。     

过去150年长江三角洲地区的春季物候变化(英文)

Based on phenological records extracted from Chinese historical dairies, spring phenological series in the Yangtze River Delta (YRD) of China since 1834 is reconstructed. Together with temperature and phenological observation data, the indicating significance of spring phenological series to temperature changes is also analyzed. The results are shown as follows. (1) From 1834 to 1893, spring phenodate in the YRD was fluctuated and gradually delayed, but, advanced greatly at the end of the 19th century. From 1900 to 1990, although the decadal variations were found, no clear multi-decadal trend was detected. From 1990 to 2010, spring phenodate showed significantly advance again. Compared with the mean value for 1977-1996, the latest phenodate occurred in 1893 with 27 days delayed while the earliest phenodate occurred in 2007 with 17 days advanced. (2) The correlation coefficients between spring phenodates and temperatures from December to March and from January to March exceeded -0.75 and -0.80, respectively, indicating that our phenodate series well presents the long-term changes of winter and early spring (especially from January to March) tem-peratures. These results provide important basic data for the long-term integrated tempera-ture reconstruction over China in the future work.     

湖北省近500年区域干湿序列重建及其比较分析

在历史旱涝记载资料可靠性检验的基础上,重建了湖北省3个区域近500年来的干湿气候变化序列,并比较分析了各区域干湿气候变化的趋势特征、准周期性及跃变现象。结果表明:在3个区域中,鄂东区1570~1770、1890~1950年两个时段偏湿,1470~1520、1790~1830年则偏干;鄂北区偏湿时期主要在1470~1530、1710~1750、1850~1910年三个时段,1470~1530、1770~1830年则偏干;鄂西南区有1550~1610、1650~1710、1830~1890、1930~1990年4个主要偏湿时期,而无明显的偏干时段。运用功率谱和小波分析对3个干湿序列研究后发现,3个区域干湿变化具有多个气象周期,区域间周期类型差异显著,但50~70年左右的周期在3个区域上均表现突出;采用滑动t检验方法辨识干湿气候跃变现象,在"世纪尺度"和 30年尺度上检测到各区域干湿变化存在多个跃变事件,且同一跃变事件对不同区域向干(或向湿)影响的趋势相同。     

Response of the St. Joseph River to lake level changes during the last 12,000 years in the Lake Michigan basin

The water level of the Lake Michigan basin is currently 177 m above sea level. Around 9,800 ¹⁴C years B.P., the lake level in the Lake Michigan basin had dropped to its lowest level in prehistory, about 70 m above sea level. This low level (Lake Chippewa) had profound effects on the rivers flowing directly into the basin. Recent studies of the St. Joseph River indicate that the extreme low lake level rejuvenated the river, causing massive incision of up to 43 m in a valley no more than 1.6 km wide. The incision is seen 25 km upstream of the present shoreline. As lake level rose from the Chippewa low, the St. Joseph River lost competence and its estuary migrated back upstream. Floodplain and channel sediments partially refilled the recently excavated valley leaving a distinctly non-classical morphology of steep sides with a broad, flat bottom. The valley walls of the lower St. Joseph River are 12–18 m tall and borings reveal up to 30 m of infill sediment below the modern floodplain. About 3 × 10⁸ m³ of sediment was removed from the St. Joseph River valley during the Chippewa phase lowstand, a massive volume, some of which likely resides in a lowstand delta approximately 30 km off-shore in Lake Michigan. The active floodplain below Niles, Michigan, is inset into an upper terrace and delta graded to the Calumet level (189 m) of Lake Chicago. In the lower portion of the terrace stratigraphy a 1.5–2.0 m thick section of clast-supported gravel marks the entry of the main St. Joseph River drainage above South Bend, Indiana, into the Lake Michigan basin. This gravel layer represents the consolidation of drainage that probably occurred during final melting out of ice-marginal kettle chains allowing stream piracy to proceed between Niles and South Bend. It is unlikely that the St. Joseph River is palimpsest upon a bedrock valley. The landform it cuts across is a glaciofluvial-deltaic feature rather than a classic unsorted moraine that would drape over pre-glacial topography. This is the fifth in a series of ten papers published in this special issue of Journal of Paleolimnology. These papers were presented at the 47th Annual Meeting of the International Association for Great Lakes Research (2004), held at the University of Waterloo, Waterloo, Ontario, Canada. P.F. Karrow and C.F.M. Lewis were guest editors of this special issue.     

Archaeological evidence for pastoralist land-use and settlement in Namaqualand over the last 2000 years

Despite the extreme aridity of the region, there is good evidence that sheep were being herded in small numbers in Namaqualand up to 2000 years ago. Archaeological research at Spoegrivier Cave on the Atlantic coast confirms the presence of sheep at 2100 years ago. Increasing aridity in Namaqualand around 1300 years ago lead to the abandonment of the cave. Jakkalsberg on the banks of the Orange River in the Richtersveld was occupied around 1300 BP by people who were herding sheep rather than hunting game. People with sheep and goats were herding their livestock at Bethelsklip, in central Namaqualand, between 800 and 360 BP. The archaeological evidence clearly supports a long tradition of herding in the region. The question is whether these early herder groups are the ancestors of the Namaqua Khoekhoen pastoralists who occupied Namaqualand during historical times?Historical records from the 17 to 20th centuries testify to the seasonal transhumance of the Namaqua with cattle, sheep and goats between the Kamiesberg Mountains and the plains. On occasions pastoralist groups also moved to the interior plateau of Bushmanland to make use of the seasonal grasses after summer thunderstorms. Traditional land-use practices have a long history in the region and a study of these land-use patterns may assist in interpreting the archaeological record and in developing a sustainable land-use policy for the region.     

Sediment source changes over the last 250 years in a dry-tropical catchment, central Queensland, Australia

Rivers draining to the Great Barrier Reef are receiving increased attention with the realisation that European land use changes over the last  150 years may have increased river sediment yields, and that these may have adversely affected the reef environment. Mitigation of the effects associated with such changes is only possible if information on the spatial provenance and dominant types of erosion is known. To date, very few field-based studies have attempted to provide this information. This study uses fallout radionuclide (¹³⁷Cs and ²¹⁰Pb_ex) and geochemical tracing of river bed and floodplain sediments to examine sources over the last  250 years for Theresa Creek, a subcatchment of the Fitzroy River basin, central Queensland, Australia. A Monte Carlo style mixing model is used to predict the relative contribution of both the spatial (geological) sources and erosion types. The results indicate that sheetwash and rill erosion from cultivated basaltic land and channel erosion from non-basaltic parts of the catchment are currently contributing most sediment to the river system. Evidence indicates that the dominant form of channel erosion is gully headcut and sidewall erosion. Sheetwash and rill erosion from uncultivated land (i.e., grazed pasture/woodland) is a comparatively minor contributor of sediment to the river network. Analysis of the spatial provenance of floodplain core sediments, in conjunction with optical dating and ¹³⁷Cs depth profile data, suggests that a phase of channel erosion was initiated in the late nineteenth century. With the development of land underlain by basalt in the mid-twentieth century the dominant source of erosion shifted to cultivated land, although improvements in land management practices have probably resulted in a decrease in sediment yield from cultivated areas in the later half of the twentieth century. On a basin-wide scale, because of the limited spatial extent of cultivation, channel sources are likely to be the largest contributor of sediment to the Fitzroy River. Accordingly, catchment management measures focused on reducing sediment delivery to the Great Barrier Reef should focus primarily on decreasing erosion from channel sources.