Remote Sensing of Mangrove Change Along the Tanzania Coast

This article contributes to the understanding of the changes in distribution and total area of mangrove forests along the mainland Tanzania coast over the past decade. Mangroves are recognized as critical coastal habitat requiring protection and special attention. The Tanzania coastline forms a suitable habitat for establishment of mangrove forests. Mangrove forests are distributed from Tanga in the north to Mtwara in the south covering approximately 109,593 hectares from 1988-1990 and about 108,138 hectares in 2000. The largest continuous mangrove stands are found in the districts of Rufiji, Kilwa, Tanga-Muheza, and Mtwara. Comparison of data between these two time periods shows that the geographic coverage of mangroves has no dramatic change in the past decade. The Tanzania Mangrove Management Project and other closely related programs and efforts pertaining to mangrove conservation contribute to direct restoration and natural regeneration of mangroves. This study documents the changes of mangroves and demonstrates that remote sensing and GIS offer important data and tools in the advancement of coastal resource management and ecosystem monitoring. Application of geographic information technologies is critical for improved coastal resources management and decision making for sustainable development in Tanzania.     

中国土地利用变化遥感研究的回顾与展望——基于陈述彭学术思想的引领

20世纪80年代以来中国社会经济快速发展带来的工业化、城市化正深刻影响着中国土地利用空间格局并影响到区域和国家生态与环境状况。在陈述彭先生指导下,1992年以来中国科学院建立起了完整的土地利用/覆盖变化遥感监测与数据分析技术路线,以及独特的分类体系和动态区划体系,奠定了中国LUCC信息平台的基础。本文在系统回顾陈述彭学术思想指导中国LUCC研究的基础上,面向国家需求与国际科技前沿梳理了我国LUCC研究的核心科学问题,并总结了中国科学院团队在最近20年LUCC研究取得的成果,包括土地利用/覆盖动态时空表征与分析模型、土地利用/覆盖变化过程及驱动机制、基于大数据和云计算的土地利用/覆盖变化探测方法、城市土地利用变化的区域气候/生态效应、气候变化与土地利用变化对农田生态系统的影响、林业活动的区域气候/生态效应,在此基础上对未来LUCC研究的前景进行了展望。     

How to construct future IDF curves,under changing climate,for sites with scarce rainfall records?

Optimal designs of stormwater systems rely very much on the rainfall Intensity–Duration–Frequency (IDF) curves. As climate has shown significant changes in rainfall characteristics in many regions, the adequacy of the existing IDF curves is called for particularly when the rainfall are much more intense. For data sparse sites/regions, developing IDF curves for the future climate is even challenging. The current practice for such regions is, for example, to ‘borrow’ or ‘interpolate’ data from regions of climatologically similar characteristics. A novel (3‐step) Downscaling‐Comparison‐Derivation (DCD) approach was presented in the earlier study to derive IDF curves for present climate using the extracted Dynamically Downscaled data an ungauged site, Darmaga Station in Java Island, Indonesia and the approach works extremely well. In this study, a well validated (3‐step) DCD approach was applied to develop present‐day IDF curves at stations with short or no rainfall record. This paper presents a new approach in which data are extracted from a high spatial resolution Regional Climate Model (RCM; 30 × 30 km over the study domain) driven by Reanalysis data. A site in Java, Indonesia, is selected to demonstrate the application of this approach. Extremes from projected rainfall (6‐hourly results; ERA40 Reanalysis) are first used to derive IDF curves for three sites (meteorological stations) where IDF curves exist; biases observed resulting from these sites are captured and serve as very useful information in the derivation of present‐day IDF curves for sites with short or no rainfall record. The final product of the present‐day climate‐derived IDF curves fall within a specific range, +38% to +45%. This range allows designers to decide on a value within the lower and upper bounds, normally subjected to engineering, economic, social and environmental concerns. Deriving future IDF curves for Stations with existing IDF curves and ungauged sites with simulation data from RCM driven by global climate model (GCM ECHAM5) (6‐hourly results; A2 emission scenario) have also been presented. The proposed approach can be extended to other emission scenarios so that a bandwidth of uncertainties can be assessed to create appropriate and effective adaptation strategies/measures to address climate change and its impacts. Copyright © 2013 John Wiley & Sons, Ltd.     

五台山积雪变化趋势及其影响因素

基于MODIS积雪产品与微波遥感数据,分析五台山2000—2019水文年积雪时空分布、变化趋势及与影响因素的Pearson相关性,结果表明：（1）五台山积雪期为10月至翌年4月,年内呈单峰型变化趋势,积雪集中于西北部。（2）积雪面积和积雪日数的年际变化呈显著减少趋势（p<0.05）。（3）积雪面积和积雪日数与海拔正相关,积雪面积在北坡高于南坡。（4）积雪面积与气温相关程度高于降水量,积雪面积在年内与气温和降水量日值呈显著负相关（p<0.05）,在年际与气温年均值呈显著负相关（p<0.05）。     

Evidence of a phase shift to Epizoanthus gabrieli Carlgreen, 1951 (Order Zoanthidea) and loss of coral cover on reefs in the Southwest Atlantic

There is at present a ‘coral reef crisis’; one of the more drastic consequences of this is a phase shift, in which reef‐building corals are replaced by non‐reef building benthos such as macroalgae and soft corals. Previous studies have principally focused on the shift to macroalgae. Our goal was to investigate whether the dominance of the zoanthid Epizoanthus gabrieli on some reefs of Todos os Santos Bay, Brazil, represented a non‐algal phase shift. In 2003, we identified a high cover of this species on two reefs (52% and 70%), but only in 2007 was it possible to confirm a reduction in coral cover. This dominance has persisted for over 9 years, characterizing a true phase shift. This loss of coral cover may be a result of anthropogenic disturbances within the bay; however, given the large number of human impacts, further studies are needed to identify specific causes of this shift. Although there are some reports of phase shift involving species pertaining to the Class Anthozoa, this is the first report of this phenomenon involving the order Zoanthidea.     

近50年塔克拉玛干沙漠和古尔班通古特沙漠及其周边地区气候变化特征的对比分析

利用塔克拉玛干沙漠及古尔班通古特沙漠及其周边地区（包括平原和山区）76个气象站1961-2010年的逐日地面观测资料,对比分析了两个沙漠及其周边地区气温和降水变化特征。结果表明：塔克拉玛干沙漠及其周边地区年平均气温明显高于古尔班通古特沙漠及其周边地区,但是升温速率低于古尔班通古特沙漠,两大沙漠及其周边地区年平均气温的差值在缩小,塔克拉玛干沙漠周边山区上升速率接近或者大于大部分平原地区,而古尔班通古特沙漠周边山区上升速率与平原地区相比总体偏小,塔克拉玛干沙漠及其周边地区年平均气温的突变时间在1989-1993年,古尔班通古特沙漠及其周边地区的突变时间在1994-1995年,同时均存在8～9a振荡周期;古尔班通古特沙漠及其周边地区年降水量是塔克拉玛干沙漠及其周边地区的2.5倍,增加速率高于塔克拉玛干沙漠及其周边地区,增加相对幅度小于塔克拉玛干沙漠及其周边地区,两大沙漠及其周边地区年降水量的差值进一步加大但加大的速度在减缓,塔克拉玛干沙漠及其周边地区的突变时间在1984年,古尔班通古特沙漠及其周边地区的突变时间在1983-1986年,塔克拉玛干沙漠及其周边地区存在5a、7～8a和18a的振荡周期,古尔班通古特沙漠及其周边地区存在2～4a、6～8a、18a的振荡周期。     

Land cover changed object detection in remote sensing data with medium spatial resolution

Land cover change information is crucial to analyse the process and the change patterns of environments and ecological systems. Recent studies have incorporated object-based image analysis for its ability to generate meaningful geographical objects into studies of change detection. In this research, we developed a systematic methodology to realise multi-type land cover changed object detection with medium spatial resolution remote sensing images in Beijing, China. Optimum index factor (OIF) was applied to determine the best change indicators and the chi-square transformation was carried out to determine the change threshold of the 4 classes of changed object. The clustering change vectors in the feature space were proposed to discriminate the change types. According to the accuracy assessment, the overall accuracy of changed/unchanged object detection was approximately 93.9% with an overall kappa of 0.824, and the change type discrimination also achieved an overall accuracy of 81.67%, indicating the effectiveness of the proposed method.     

The interpretation of culture in nature: Landscape transformation and vegetation change during two centuries at Hystad,SW Norway

In Norway, on-site biological surveys precede the designation of nature reserves. Although many nature conservation areas have been affected by past human use (e.g. cattle grazing, timber harvesting), a typical biological survey may fail to portray the extent of human influence on biodiversity and vegetation dynamics. In 1984, Hystad forest (western Norway) was made a nature reserve after botanists interpreted the ecosystem 'close to untouched'. It was thought best to leave the forest alone, so no management plan was developed. It was later realized that the vegetation was changing, but the reason was not obvious. I gathered and analyzed further biological data plus information on land-use history from varied sources (e.g. cadastral maps, archive material and oral histories). The area has undergone a series of transformations since the 17th century. The present forest is no more than 100 years old, and extensive parts are much younger. The initial survey underestimated the extent of cultural impact and failed to predict vegetation change subsequent to reserve establishment, whereas a historical-geographical approach reveals that the vegetation is in a state of transition, driven primarily by a change from active farming to farm abandonment. Planning for conservation must recognize past as well as present human use of the landscape to anticipate consequent land cover responses.     

南海季风爆发与风向改变指数关系初探

通过定义一个风向改变指数,探讨了该指数与南海夏季风爆发之间的关系,得到以下主要结论:利用Yamamoto突变检验,定义了南海关键区,南海季风爆发时,850 hPa上的风场在该关键区确有突变发生;南海夏季风爆发时的风场突变是全球风场突变的一部分;分析了南海关键区上该指数的空间分布和时间演变,发现30～300 hPa平均于5月初风场开始反向,其早于低层风场反向约2周,这对预报南海季风爆发具有启示意义.     

Intellectual property rights and low carbon technology transfer: Conflicting discourses of diffusion and development

Intellectual property rights (IPRs) and the transfer of low carbon technologies to developing countries have been the focus of sustained disagreement between many developed and developing country Parties to the United Nations Framework Convention on Climate Change (UNFCCC). We argue that this disagreement stems from two conflicting political discourses of economic development and low carbon technology diffusion which tend to underpin developing and developed countries’ respective motivations for becoming party to the Convention. We illustrate the policy implications of these discourses by examining empirical evidence on IPRs and low carbon technology transfer and highlight how the two discourses are based on an incomplete understanding of the role of technological capacity in either economic development or technology diffusion. This has important implication for the success of post-2012 international climate agreements.