气候变化对重庆农业的影响及对策研究

本文分析了重庆市气候特点及其对重庆农业的影响;并在全球气候变暖的大气候背景下,分析了重庆气候的变化趋势,并就气候变化对重庆农业可能造成的影响进行了初步的探讨;提出了重庆农业应对气候变化的适应性战略和技术措施。     

Climate change and fluvial flood risk in the UK: more of the same?

The potential impact of climate change on fluvial flooding is receiving considerable scientific and political interest thanks to evidence from climate model projections and a widely held belief that flood risk may be increasing at European levels. This review compares published work on historical trends in UK rainfall and river flow records with high‐resolution regional climate change projections, and attempts to reconcile apparent differences between the two. Attention is focused on the techniques used for climate change detection and attribution, as well as the potential confounding effects of land‐use change. International and domestic efforts to build adaptive capacity rest on improved quantification of uncertainty in flood risk at very local, catchment and regional scales. This will involve further research to better integrate climate and land‐management interactions, to understand changes in the dependence between different flood generating mechanisms, and to improve the characterization and communication of uncertainty at all stages of analysis. Resources are also needed to ensure that latest, but still uncertain, science is presented in an appropriate form to underpin policy development and is translated into sensible guidance for practitioners. Copyright © 2007 John Wiley & Sons, Ltd.     

Decadal trend of climate in the Tibetan Plateau—regional temperature and precipitation

The Tibetan Plateau has one of the most complex climates in the world. Analysis of the climate in this region is important for understanding the climate change worldwide. In this study, climate patterns and trends in the Tibetan Plateau were analysed for the period from 1961 to 2001. Air temperature and precipitation were analysed on monthly and annual time scales using data collected from the National Meteorological Centre, China Meteorological Administration. Nonlinear slopes were estimated and analysed to investigate the spatial and temporal trends of air temperature and precipitation in the Tibetan Plateau using a Mann–Kendall method. Spatial analysis of air temperature and precipitation variability across the Tibetan Plateau was undertaken. While most trends are local in nature, there are general basinwide patterns. Temperature during the last several decades showed a long‐term warmer trend, especially the areas around Dingri and Zogong stations, which formed two increasing centres. Only one of the stations investigated exhibited decreasing trend, and this was not significant. Precipitation in the Tibetan Plateau has increased in most regions of the study area over the past several decades, especially in the eastern and central part, while the western Tibetan Region exhibited a decreased trend over the same period. Copyright © 2007 John Wiley & Sons, Ltd.     

气候变化背景下珠江流域极端洪水事件的变化趋势

根据1951-2010年珠江流域23个典型断面流量资料,用P-III型分布曲线拟合洪水系列进行频率计算,分析了珠江流域极端洪水事件的变化趋势。结果表明：1980年以来,珠江流域极端洪水事件发生的频次明显增加,尤其是自1990年以来增加趋势显著;1981-2010年较1951-1980年珠江流域约70%典型断面极端洪水事件呈增加趋势,主要分布在西江、北江、粤西;而近30%的典型断面呈减少趋势,主要分布在东江和桂南。     

Politics eclipses climate extremes for climate change perceptions

Whether or not actual shifts in climate influence public perceptions of climate change remains an open question, one with important implications for societal response to climate change. We use the most comprehensive public opinion survey data on climate change available for the US to examine effects of annual and seasonal climate variation. Our results show that political orientation has the most important effect in shaping public perceptions about the timing and seriousness of climate change. Objective climatic conditions do not influence Americans’ perceptions of the timing of climate change and only have a negligible effect on perceptions about the seriousness of climate change. These results suggest that further changes in climatic conditions are unlikely to produce noticeable shifts in Americans’ climate change perceptions.     

土地利用和气候变化对区域净初级生产力的影响

应用以遥感观测数据驱动的GLO-PEM模式模拟估计的中国北方20年的NPP数据同其20年气候数据结合,同时利用通过遥感宏观调查所得的两期土地利用数据,分析20年气候和土地利用变化对区域净初级生产力 (Net Primary Productivity,NPP) 的影响的时空特征。分析结果表明,20年来研究区域年均温度显著增加 (年均增温0.064 ^oC),年降水量明显减少 (年降水减少率为1.49 mm/年),NPP以减少趋势为主 (年减少率6.9 TgC)。研究区域NPP的变化受旬 (月) 均温和旬 (月) 降水量和季节温度和季节降水的变化影响显著。季节NPP同季节降水和温度的相关性在空间上同植被覆盖表现出高度的一致性,其相关系数大小随着不同植被覆盖类型变化而变化。通过分析可见,就整个研究区来说,发生土地利用变化的区域仅占整个研究区域的5.45%, 气候对整个研究区域NPP的影响占主导地位 (占了总影响量的90%);土地利用发生区域土地利用的作用占了绝对地位,土地利用的影响占了约97%。整个研究区域近20年来因为降水明显减少,温度显著升高,导致NPP明显下降,在两期土地利用间隔时间段内 (约10年) 因气候影响NPP减少了78 (±0.6) TgC。因为土地利用的变化导致NPP减少9 (±0.2) TgC。气候和土地利用共同作用是研究区域的NPP减少87 (±0.8) TgC。     

Seasonal variability in free-living marine nematode community structure in a sandy beach of the Taiping Bay of Qingdao, China

Nematode assemblage composition, trophic structure and biodiversity were followed over an annual cycle in a sandy beach of the Taiping Bay of Qingdao, China. Nematode assemblage in the sandy beach maintained a high genus diversity （75 genera）. Mlero- laimus and Bathylaimus were the dominant genus of the nematode assemblage, accounting for 66% of the total nematode abundance. The nematodes＇ dominant trophic structure changed seasonally as a response to the seasonal changes in food quality. Epigrowth-feeder nematodes （2A） were the dominant trophic groups in the trophic structure with the highest abundance in spring because of phytoplankton bloom, while the feeding type （ 1 B） showed higher abundance in summer that was due to the increasing of sediment detritus after spring bloom. Furthermore, species diversity and evenness calculated on nematodes identified to the genus level displayed significant temporal changes, which was also reflected by the index of trophic diversity. According to the cluster analysis, the nematode community structure of the whole year was clearly separated into two periods （A and B）. Biota-Envlron- ment matching （BIOENV） results showed that seawater temperature, sediment Chl a and grain size were responsible for the nema- tode community structure variation in spring and summer period （Period A）. However, seawater/interstitial water temperature, interstitial water dissolved oxygen concentration,interstitial water salinity, and sediment Ph a a were more important in constructing the autumn and winter period （Period B） nematode community structure.     

Application of Structure‐from‐Motion photogrammetry to river restoration

Structure‐from‐Motion (SfM) photogrammetry is now used widely to study a range of earth surface processes and landforms, and is fast becoming a core tool in fluvial geomorphology. SfM photogrammetry allows extraction of topographic information and orthophotos from aerial imagery. However, one field where it is not yet widely used is that of river restoration. The characterisation of physical habitat conditions pre‐ and post‐restoration is critical for assessing project success, and SfM can be used easily and effectively for this purpose. In this paper we outline a workflow model for the application of SfM photogrammetry to collect topographic data, develop surface models and assess geomorphic change resulting from river restoration actions. We illustrate the application of the model to a river restoration project in the NW of England, to show how SfM techniques have been used to assess whether the project is achieving its geomorphic objectives. We outline the details of each stage of the workflow, which extend from preliminary decision‐making related to the establishment of a ground control network, through fish‐eye lens camera testing and calibration, to final image analysis for the creation of facies maps, the extraction of point clouds, and the development of digital elevation models (DEMs) and channel roughness maps. The workflow enabled us to confidently identify geomorphic changes occurring in the river channel over time, as well as assess spatial variation in erosion and aggradation. Critical to the assessment of change was the high number of ground control points and the application of a minimum level of detection threshold used to assess uncertainties in the topographic models. We suggest that these two things are especially important for river restoration applications. Copyright © 2016 John Wiley & Sons, Ltd.     

Achieving additional emission reductions under a cap-and-trade scheme

Over the last decade, cap-and-trade emissions schemes have emerged as one of the favoured policy instruments for reducing GHG emissions. An inherent design feature of cap-and-trade schemes is that, once the cap on emissions has been set, no additional reductions beyond this level can be provided by the actions of those individuals, organizations and governments within the covered sectors. Thus, the emissions cap constitutes an emissions floor. This feature has been claimed by some to have undesirable implications, in that it discourages ethically motivated mitigation actions and preempts the possibility that local, state and national governments can take additional mitigation action in the context of weak national or regional targets. These criticisms have become prominent in Australia and the US within the public debate regarding the adoption of an emissions trading scheme (ETS). These criticisms and their potential solutions are reviewed. A set-aside reserve is proposed to automatically retire ETS permits, which would correspond to verified and additional emissions reductions. This minimizes the possibility that ethically motivated mitigation actions are discouraged, allows for additional action by other levels of government, while providing transparency to other market participants on the level of permit retirements.     

基于Brown-Forsythe检验的水文序列变异点识别

当前在水文序列变异点识别中常采用的几种统计方法都对数据有较多假设,当假设不满足时,识别结果通常并不理想。本文根据统计学方差分析的原理,建立了基于Brown-For-sythe检验的水文序列变异点识别方法,并采用该方法对新疆开都河大山口站近50年年平均径流序列进行了变异点识别。研究结果表明,该识别方法继承了Brown-Forsythe检验的优点,对数据不做过多假设,且易于进行多变异点识别,在一定程度上具有比当前所用统计方法更优越的性能。