Forest Cover Change in the Toledo District,Belize from 1975 to 1999: A Remote Sensing Approach*

Measuring land‐cover change is an essential part of sustainable conservation planning. This project uses Landsat MSS and ETM+ data to document forest cover change in the Toledo District, Belize, from 1975 to 1999 and provides an initial assessment of why these changes took place. Supervised and subpixel classification methods were employed. The results showed an aggregate forest loss of almost 10 percent, which is approximately 36,000 ha. Deforestation expanded significantly in the most populous Mayan areas of central Toledo District and along the Guatemalan border. Subpixel classification results showed that in 1999 the most densely forested areas were in northern Toledo District in the Maya Mountains.     

Spatio-temporal analysis of decadal-scale patterns in barrier island response to storms: Perdido Key,NW Florida

The ability to accurately quantify shoreline variability is essential in order to establish aggressive mitigation strategies, based on recent global climate change projections. This investigation employed a suite of coastal data (topographic maps, aerial photography, satellite imagery and lidar) to establish decadal trends of shoreline movement along Perdido Key, a sandy barrier island off Florida’s northwest coast. The technique used to detect morphologic change with time was a recently developed tool, Analyzing Moving Boundaries Using R. This innovative methodology improves our understanding of the evolution of coastal systems by modeling shoreline variance using a method that is sensitive to shoreline shape. Results show that the barrier shoreline is a highly dynamic feature with distinct zones of erosion and accretion that are pervasive over time. In general, the island is displaying a mechanism of rotational instability with the eastern half retreating, and the western portion advancing. The inflection point, around which this rotational shifting is taking place, lies at the center of a Pleistocene headland located along the island’s midpoint. The results of this study suggest that coastal evolution along the island may be meta-stable, with trends in shoreline variance corresponding mainly to discrete storm events in time.     

Assessing vulnerability to climate change and socioeconomic stressors in the Reef Islands group,Solomon Islands

This article assesses the vulnerability to climatic and socioeconomic stresses in the Reef Islands, Solomon Islands, an atoll island group in the Southwest Pacific. Climate change and the associated sea-level rise are often seen as the most pressing challenges to atoll communities, yet this study aims at critically re-assessing this view by placing climate in the context of a range of other internal and external stressors affecting local livelihoods, including population growth, inadequate land use practices, and lack of economic potential, as well as external factors such as poorly developed infrastructure, economic marginalization and weak governance of Solomon Islands. Findings suggest that some of these non-climatic stresses are currently – and in the short term – more important determinants of local vulnerability than climate change and sea-level rise. Certainly, these stresses are likely to be exacerbated by different elements of climate change in the short, medium and long term, but generally speaking climate change does not appear to be a major driver of the current changes in the islands. On the basis of these observations, the possible adaptation options, relevant to different time scales, are discussed.     

Settlement distribution and its relationship with environmental changes from the Neolithic to Shang-Zhou dynasties in northern Shandong, China

In this paper, the spatial and temporal distribution of the settlement sites of six periods from the Neolithic Age to the Shang and Zhou dynasties in northern Shandong was investigated using the ArcGIS program, and the relationship between settlement distribution and environmental changes was discussed, based on the proxy records of climatic and environmental change contained in the sediments from three sections at the Shuangwangcheng site and the previous work. The results show that the climate was warm and humid and the sea level was relatively high during the period of 8000-5000 a BP in the study area, and the ancient people lived in the relatively flat （slope of 〈2°） areas at high elevation （20-300 m above sea level）, such as diluvial tableland and alluvial plain. On the other hand, few archaeological sites in the low-lying plain in the west of the study area indicate that few people lived there during that period. This might be attributed to frequent flooding in the area. After 5000 years ago, the scope of human activity extended to the area close to the sea because the relatively colder and drier climate results in sea-level fall, meanwhile the low-lying plain in the west was occupied by the ancient people. The study area of this period was characterized by the rapid development of prehistoric culture, the intensified social stratification and the emergence of early city-states. However, around 4000 a BP, the abrupt change in climate and the increase in frequency and intensity of floods severely disrupted human activities, and eventually led to the decline of the Yueshi culture. During the Shang and Zhou dynasties, the climatic conditions gradually stabilized in a mild-dry state, which promoted the redevelopment and flourish of the Bronze Culture. The previous situation, which was characteristic of sparse human settlements due to freshwater shortage and unfitted conditions for sedentary agriculture, changed during the Shang and Zhou dynasties in northern coastal wetlands.Local residents effectively adapted themselves to the tough environmental conditions by producing sea-salt, which led to the rapid growth of human activities.     

An Innovative Method of Model Integration to Forecast Spatial Patterns of Shoreline Change: A Case Study of Nags Head,North Carolina*

Many coastal erosion models are designed to be used at transects or discrete points but they produce valid results only for locations that meet a set of well-defined criteria. Results obtained from these models are difficult to generalize, since adjoining areas may not meet these requirements. In this paper, a GIS-based methodology is described for combining the results from two two-dimensional coastal erosion models and a three-dimensional static inundation model to forecast the possible response of a coastline to several alternative sea level rise scenarios. These shoreline forecasts are unique in that they integrate results obtained from several different models and allow graphical representations of these alternative future shorelines to be produced. Coastal planners may use these integrated shoreline forecasts to assess the possible impact of sea level rise on a given region. To demonstrate this methodology a case study was conducted for Nags Head, North Carolina.     

广西涠洲岛海域珊瑚礁现状及其保护策略研究

通过对2005年涠洲岛珊瑚礁生态调查,结合对以往资料和数据的分析,对比1984年和1964年2次调查结果,掌握涠洲岛珊瑚礁的现状.同时讨论了涠洲岛珊瑚礁区面临的生存威胁,提出保护和管理涠洲岛珊瑚礁的建议,以期建立可持续的生态旅游开发与新型的生态保护生态管理体系.     

山东北部地区聚落遗址时空分布与环境演变的关系

利用GIS软件对山东北部地区聚落遗址时空分布特征进行分析,并结合双王城剖面沉积环境分析和前人研究成果探讨了聚落时空分布与环境演变之间的关系。结果表明:距今8000-5000 年间,在气候温暖湿润和海面相对较高的环境背景下,人类活动主要集中在海拔相对较高(20~200 m),地形较为平坦(坡度< 2°)的洪积台地和冲积平原上;西部平原地区由于地势低洼,容易积水而发生水患,因而很少有遗址分布。距今5000 年之后,气候暖湿程度降低,海平面持续下降,人类活动范围明显向海扩展;西部低洼地区在气候变干和海面降低的双重影响下,自然环境得到改善,也开始被古人广泛开发利用。这一时期区域文化繁荣发展,逐渐形成社会结构复杂、城邦林立的初期文明。然而距今4000 年左右,由于气候变化和洪患灾害加剧,史前文化开始明显衰落。商周时期气候环境趋于稳定,文化发展再次兴盛。北部滨海平原地区随着生产技术的进步,人类适应区域资源环境条件,在早期农业人群难以定居的滩涂地上形成以盐业生产为主要经济活动的聚落群。     

Dynamics of shoreline and land reclamation from 1985 to 2015 in the Bohai Sea,China

Journal of Geographical Sciences - Extraction and analysis of the shoreline and land reclamation patterns are important for studies on topics such as the dynamics of coastal wetland ecological...     

金沙江下游近40年来土壤侵蚀变化--以云南彝良为例

云南金沙江流域是我国水土流失最为严重的区域之一，尤其以金沙江下游区最为突出。为揭示该区域土壤侵蚀动态变化的基本规律，为今后水土保持和土地资源可持续利用提供依据，选择该区域较为典型的彝良县作为研究实例，采用航片判读、实地调查、GIS等方法编制了1960、1980和2000年土壤侵蚀图，据此分析该县1960～2000年的土壤侵蚀变化特点，并应用马尔柯夫模型预测在当前土地利用方式下土壤侵蚀动态变化趋势，为该县制定水土保持措施和土地利用规划提供了重要依据。     

1960-2012年西藏林芝气温和降水变化

基于1960-2012年日平均气温和日降水量数据,利用小波分析和Mann-Kendall突变分析方法,分析了西藏林芝气温和降水的变化特征。结果表明：林芝年平均气温增长速率0.028℃·a^-1;年平均气温受3~4 a尺度波动的影响,无明显主周期;年平均气温序列有3个突变点,分别是1972-1973年、1975-1976年和1977-1978年。年降水量增长率1.218 mm·a^-1;年降水量受4 a、10 a和20 a尺度波动的影响;有两个主周期,分别为2 a、19 a;年降水量序列有4个突变点,分别为1960-1961年、1965-1966年、1977-1978年、1982-1983年。     

1960—2019年西北地区气候变化中的Hiatus现象及特征

1998—2012年全球地表平均温度发生变暖停滞（Hiatus）,然而Hiatus现象是否在全球各地均存在尚有争议,其在西北地区的表现及特征缺乏深入研究。本文基于1960—2019年气温地面观测数据,利用累积距平曲线、Mann-Kendall突变检验、滑动t检验及Yamamoto检验进行气候突变分析,结合线性倾向估计进行气候变化趋势分析,对西北地区气候变化中的Hiatus现象及其特征进行了探讨。结果表明：① 西北地区年均气温在1986年、1996年和2012年分别突变,1996年突变升温后在1998—2012年间保持高位震荡;② 1998—2012年间西北地区年均温变化率为-0.20 ℃/10a,呈现明显Hiatus现象,分季节看,冬季降温幅度最大,夏季仍保持升温,春季均温比秋、冬季提前1年开始和结束停滞期,从空间上看,西北地区东南部降温最显著,青藏高原不存在Hiatus;③ 2012年Hiatus结束后西北地区气温普遍快速升高,季节上以冬季升温最快,空间上以南疆升温最快。综合来看,1998—2012年的Hiatus现象在除青藏高原外的西北地区表现明显,停滞后的快速升温值得高度关注。     

基于SPI的1960~2012年西南地区水稻生长季干旱时空特征分析

基于1960~2012年逐月降水资料,选取标准化降水指数（SPI）为干旱衡量指标,将SPI1与水稻各生长阶段（Growth Period of Rice,GPR）相结合,研究西南地区近53 a来整体和水稻（Oryza sativa）4个生长阶段的干旱时空演变特征。结果表明：整体上,西南地区历年干旱站次比均高于50%,全域性干旱特征显著。水稻不同生长阶段干旱时空分布特征差异显著。① GPR1和GPR2阶段以全域性干旱为主,GPR3和GPR4阶段则呈现局域性干旱>区域性干旱>全域性干旱的特征;② 生长阶段内干旱连续性特征明显,尤其是GPR2 阶段,易发生周期为2~6 a的全域性干旱和区域性干旱。③ 轻旱高值区呈现由东北向西南转移的趋势;中旱高发区呈现出明显的从北部向南部移动的趋势;重旱高发区各阶段空间分布差异较大。④ 水稻在GPR1和GPR2阶段主要受轻旱和中旱影响;GPR3和GPR4阶段重旱发生频率上升,影响范围增大。     

Copenhagen,Climate Science and the Emotional Geographies of Climate Change

The Pacific island nation-state of Tuvalu featured significantly at the Copenhagen Conference of Parties (COP) 15 climate change negotiations, where the vulnerability of Tuvalu to sea level rise and emotional outpourings of the Tuvaluan delegation contributed to the nation's prominence. In this paper we discuss the likely impacts for Tuvalu of a 1.5°C versus 2°C global warming target and explore sadness and discomfort surrounding discussion of these targets during COP 15. We highlight tensions between science and emotion, arguing that affective encounters can be significant in climate change decision-making. Weeping by a member of the Tuvalu delegation evoked discomfort in the conference plenary. This discomfort briefly unsettled the apparently stable boundaries of convention and protocol that seek to separate emotion from science and politics. We argue that possibilities for change arise when emotions enter climate change negotiations, even though (or perhaps because) these are arenas that privilege rational exchange. Our conclusion urges that more attention be paid to how climate science and emotion are intertwined in climate change politics.     

1961—2012年甘肃省干湿变化特征及其影响因子

基于1961—2012年甘肃省和青海省祁连山区54个气象站逐日气象数据,分析了甘肃省地表湿润指数的时空变化特征及各气象要素对不同区域干湿变化的影响程度.结果表明:近52年,以黄河为界,甘肃东、西部呈现出不同的干湿变化趋势,河东地区趋于干旱,尤其是陇中和陇东部分地区;河西部分区域趋于湿润,尤其是祁连山中部地区.河东变干主要是秋季显著变干,其中9月最突出;河西变湿主要是冬季变湿,尤其是在12月和1月.敏感性和贡献度分析表明,除降水量外,地表湿润指数对空气相对湿度的敏感性最高,其次是日照时数,再次是最高温度和平均风速,对最低温度的敏感性最低.近52年地表湿润指数-30％～30%的相对变化量中,降水量的贡献最大,贡献量在-30%～25%;其次是风速,贡献量在-4％～12%,最高温度、最低温度、日照时数以及相对湿度的贡献较小,在-4％～4%.     

近40年来金沙江南岸干热河谷区的土地利用变化及其土壤侵蚀治理研究 ——以云南宾川县为例

云南金沙江流域生态环境极为脆弱,在人为作用下土地利用/土地覆被变化较为显著,水土流失严重,生态环境日益恶化,目前已被我国政府列为全国生态环境建设的重点区域。本文选择金沙江中游中山高原与干热河谷区较为典型的宾川县作为研究实例,采用航片判读、实地调查与GIS等方法编制1960、1980和2000年土地利用与土壤侵蚀图,据此分析了该县1960 ~ 2000年的土地利用/土地覆被变化及其引发的土壤侵蚀变化特征,重点揭示区域土地利用/土地覆被变化的基本规律及其引发的土壤侵蚀变化过程,并提出土壤侵蚀治理的工程与技术措施。     

长江源头湿地消长对气候变化的响应

位于青藏高原腹地唐古拉山以北的长江源头区域,由于受直接人类活动的影响程度较小,因此,从气候变化与湿地消长关系的强弱程度上可以看出其中的关键信息,能更真实地反映气候变化对长江源头湿地的影响.据灰色系统理论分析发现,蒸发量对湿地总面积的消长相对其他气候因子更具主导作用,其次为降水量的影响,且夏季各气候因子对湿地面积消长的影...     

2000-2012年祁连山植被覆盖变化及其与气候因子的相关性

研究祁连山地区植被覆盖变化及其与气候因子的响应关系对这一地区土地利用总体特征以及对区域及全球气候和环境变化都将产生深远的意义。利用2000-2012年美国国家航空航天局提供的MODIS NDVI数据并结合相应的气候资料,通过对逐像元信息的提取和分析,运用均值法、斜率分析法、相关分析法,研究了2000-2012年不同季节祁连山植被覆盖的时空变化及其与气候因子的相关性。结果表明:13 a来祁连山植被覆盖整体上呈增加趋势,其中春季植被改善最为明显,秋季次之;植被覆盖变化在不同季节都存在明显的空间差异;不同季节植被与气温、降水的时滞效应不尽相同;祁连山春季大部分地区NDVI与气温呈显著正相关,夏季NDVI与降水呈显著正相关,秋、冬季NDVI与降水、气温的相关性不明显。