鄱阳湖流域1960～2018年极端气温变化及其与大气环流的关系

为进一步揭示鄱阳湖流域极端气温事件变化及其影响因素,基于鄱阳湖流域24个气象站点连续59年观测资料,选取8个极端气温指数,分析鄱阳湖流域极端气温动态变化,并探讨了大气环流与极端气温变化的联系.结果表明:(1)鄱阳湖流域极端气温暖指数(暖昼天数、暖夜天数和夏日天数)及极值指数(日最低气温最小值和日最高气温最大值)均呈增加趋势;冷指数(冷昼天数、冷夜天数和霜冻天数)均呈逐渐减少趋势.(2)从空间分布来看,极端气温空间变化趋势与年际变化一致,极端气温暖指数和极值指数呈增加趋势,冷指数均呈减少趋势,但在不同地区变化趋势存在差异.流域各站点霜冻天数和冷昼天数均呈显著下降趋势,但在赣北地区下降趋势最显著.大部分站点(23/24)暖夜天数、夏日天数和日最低气温最小值均呈显著增加趋势;(3)鄱阳湖流域极端气温指数的变化与大气环流的变化存在相关性,其中西太平洋副高强度指数、夏季东亚季风指数、亚洲区极涡强度指数和北极涛动指数对极端气温事件影响显著.研究结果可为极端气候风险评估、灾害预警提供参考.     

Typical patterns of smallholder vulnerability to weather extremes with regard to food security in the Peruvian Altiplano

Smallholder livelihoods in the Peruvian Altiplano are frequently threatened by weather extremes, including droughts, frosts and heavy rainfall. Given the persistence of significant undernourishment despite regional development efforts, we propose a cluster approach to evaluate smallholders’ vulnerability to weather extremes with regard to food security. We applied this approach to 268 smallholder households using information from two existing regional assessments and from our own household survey. The cluster analysis revealed four vulnerability patterns that depict typical combinations of household attributes, including their harvest failure risk, agricultural resources, education level and non-agricultural income. We validated the identified vulnerability patterns by demonstrating the correlation between them and an independently reported damage: the purchase of food and fodder resulting from exposure to weather extremes. The vulnerability patterns were then ranked according to the different amounts of purchase. A second validation aspect accounted for independently reported mechanisms explaining smallholders’ sensitivity and adaptive capacity. Based on the similarities among the households, our study contributes to the understanding of vulnerability beyond individual cases. In particular, the validation strengthens the credibility and suitability of our findings for decision-making pertaining to the reduction of vulnerability.     

汉江流域1960~2014年降雨极值时空变化特征

深入研究降雨极值的时空变化规律和特点，有助于提高应对极端灾害的能力。通过构建PDS/GP模型，并引入降雨极值变化指标，结合统计检验分析汉江流域15个气象站点1960~2014年春、夏、秋季以及全年月降雨超定量系列的年际变化特征；利用复杂网络理论的聚类系数和节点度，结合各站点在典型年份春、夏和秋季的降雨极值变化指标，分析月降雨极值的空间分布特征。分析结果表明：从时间上看，汉江流域月降雨极值年际变化的季节性差异较大，近55 a没有明显的一致性变化趋势。受季风气候影响，夏季的月降雨极值年际变化与春、秋季相反，而秋季的变异指标年际波动最大。从空间上看，受季风气候、下垫面条件和人类活动等多种因素的综合作用，中下游月降雨极值变化的差异性要高于上游。随着相关阈值的增大，流域站网总体关联度有所降低。相同阈值下的结果表明空间上相邻的站点其关联性差异较大，部分相距较远的站点具有更大的关联性，分析结果可为降雨极值的空间插值提供参考。     

经验正交函数方法和TRMM数据对长江流域降水模式与极端水文过程的研究

气候变化加剧了极端天气和水文事件的发生，降水是区域干旱与洪水事件最直接驱动因素。以TRMM/PR月累积降水反演遥感数据为基础，利用经验正交函数EOF（Empirical Orthogonal Function）方法对长江流域降水时空变化模式进行提取，并对比分析了主要模式振幅强弱与极端水文事件的对应关系。结果表明在流域尺度上EOF方法及TRMM/PR数据可以较好地识别降水主要模式，通过时空尺度变换成功揭示主要降水模式强弱与流域极端水文事件的对应关系。鉴于日益丰富的巨量水文气象时空数据，EOF方法在模式提取、水文模拟、极端事件预估及灾害适应性研究等方面具有应用潜力     

Changes in rice disasters across China in recent decades and the meteorological and agronomic causes

Both climate extremes and agricultural disasters have been reported to increase in recent decades; however, so far, we have little idea on the characteristics of agricultural disasters changes, as well as their meteorological and agronomic causes. Here, using the observed records on rice disasters at agro-meteorological stations across China and the meteorological indexes, we investigated the temporal and spatial changes of major rice disasters occurrence frequency and their relationships to climate change, climate extremes and agronomic practices from 1991 to 2009. We presented the temporal and spatial changes in occurrence frequency of major rice disasters, including droughts, floods, heat stress, chilling damage, insects and diseases, during the warmer period of 2000–2009, in comparison with the period of 1991–2000, based on both the observed records and the meteorological indexes. The results showed that changes in rice disasters could be largely ascribed to changes in climate extremes in recent decades. Floods, insects and diseases occurred more frequently at earlier growth stages; in contrast, chilling damage occurred more frequently at later growth stages in southwestern China during the period of 2000–2009, in comparison with the period of 1991–2000. Our findings highlighted the options should be taken timely and scientifically to reduce the disasters and to cope with ongoing climate change, based on the characteristics of agricultural disasters changes in recent decades.     

Mid-21st century climate and weather extremes in Cyprus as projected by six regional climate models

We present climate change projections and apply indices of weather extremes for the Mediterranean island Cyprus using data from regional climate model (RCM) simulations driven by the IPCC A1B scenario within the ENSEMBLES project. Daily time-series of temperature and precipitation were used from six RCMs for a reference period 1976–2000 and for 2026–2050 (‘future‘) for representative locations, applying a performance selection among neighboring model grid-boxes. The annual average temperatures of the model ensemble have a ±1.5°C bias from the observations (negative for maximum and positive for minimum temperature), and the models underestimate annual precipitation totals by 4–17%. The climatological annual cycles for the observations fall within the 1σ range of the 6-model average, highlighting the strength of using multi-model output. We obtain reasonable agreement between models and observations for the temperature-related indices of extremes for the recent past, while the comparison is less good for the precipitation-related extremes. For the future, the RCM ensemble shows significant warming of 1°C in winter to 2°C in the summer for both maximum and minimum temperatures. Rainfall is projected to decrease by 2–8%, although this is not statistically significant. Our results indicate the shift of the mean climate to a warmer state, with a relatively strong increase in the warm extremes. The precipitation frequency is projected to decrease at the inland Nicosia and at the coastal Limassol, while the mountainous Saittas could experience more frequent 5–15 mm/day rainfall. In future, very hot days are expected to increase by more than 2 weeks/year and tropical nights by 1 month/year. The annual number of consecutive dry days shows a statistically significant increase (of 9 days) in Limassol. These projected changes of the Cyprus climate may adversely affect ecosystems and the economy of the island and emphasize the need for adaptation strategies.     

Seasonal changes in daily precipitation extremes in mainland Portugal from 1941 to 2007

This study aims mostly at understanding seasonal variations in the intensity, frequency and duration of extreme precipitation events in mainland Portugal. For this purpose, selected precipitation indices that mainly focus on extremes were calculated at the seasonal scale for daily data recorded in the period 1941–2007 at 57 meteorological stations scattered across the area. These indices were explored for trends at the local and regional levels. The results show that there are marked changes in precipitation indices at the seasonal scale. Trends in spring and autumn precipitation have opposite signals. In spring, statistically significant drying trends are found together with a reduction in extremes. In autumn, wetting trends are detected for all indices, although overall they are not significant at the 5 % level. In addition, the relationship between seasonal extreme precipitation indices and atmospheric large-scale modes of low-frequency variability is analysed by means of a seasonal correlation analysis. Four modes of low-frequency variability are explored. Results confirm that, over mainland Portugal, the North Atlantic Oscillation is one of the most important teleconnection patterns in any season and the mode of variability that has the greatest influence on precipitation extremes in the area, particularly in the winter and autumn.     

Model projected heat extremes and air pollution in the eastern Mediterranean and Middle East in the twenty-first century

The eastern Mediterranean and Middle East, a region with diverse socioeconomic and cultural identities, is exposed to strong climatic gradients between its temperate north and arid south. Model projections of the twenty-first century indicate increasing hot weather extremes and decreasing rainfall. We present model results, which suggest that across the Balkan Peninsula and Turkey climate change is particularly rapid, and especially summer temperatures are expected to increase strongly. Temperature rise can be amplified by the depletion of soil moisture, which limits evaporative cooling, prompted by the waning of large-scale weather systems that generate rain. Very hot summers that occurred only rarely in the recent past are projected to become common by the middle and the end of the century. Throughout the region, the annual number of heat wave days may increase drastically. Furthermore, conditions in the region are conducive for photochemical air pollution. Our model projections suggest strongly increasing ozone formation, a confounding health risk factor particularly in urban areas. This adds to the high concentrations of aerosol particles from natural (desert dust) and anthropogenic sources. The heat extremes may have strong impacts, especially in the Middle East where environmental stresses are plentiful.     

Role of climate risks and socio-economic factors in influencing the impact of climatic extremes: a normalisation study in the context of Odisha,India

Economic costs imposed by climatic extremes have been increasing over the years and are expected to follow a similar trend in the coming years as well. Such costs are incurred due to two factors: (1) natural climate variability and anthropogenic climate change and (2) exposure and vulnerability of socio-economic factors. The impact of these factors as identified separately through a ‘normalisation technique’ is analysed in the existing normalisation studies conducted mostly in developed country contexts; these have produced mixed results. However, one needs to enquire about the influence of the above two factors in a developing country context where the anticipated impacts of climate extremes are significant. This study, therefore, makes an attempt to adjust impact data, in terms of the reported population affected and economic damages of three extreme events, namely cyclones, floods and droughts, together for societal changes between 1972 and 2009 in Odisha in eastern India. Further, the second component is analysed in two ways: (1) assuming that exposed socio-economic factors are equally vulnerable similar to the other normalisation studies, i.e. no adaptation and (2) incorporating adaptation in the existing normalisation methods—which has attracted less attention so far in the literature. The results suggest that: (a) both the natural climate variability and the socio-economic factors influence the increasing damages in the recent decades, and (b) when adaptation is introduced in the normalisation model, economic losses have reduced significantly compared to the estimates using the existing normalisation models.     

洞庭湖主要生态环境问题变化分析

通过对近几十年来洞庭湖水情、泥沙、污染和湿地生态等不同方面问题的回顾分析，认为在三峡工程建设、洞庭湖退田还湖和极端天气事件影响下，洞庭湖主要生态环境问题发生了一些变化。由于气候干旱化，加之三峡水库蓄水影响，导致洞庭湖入湖水量季节性减少，湖区水位下降，干旱期延长。模拟显示2006和2009年三峡秋季蓄水使洞庭湖出口水位平均下降2.03和2.11 m；由于三口来沙急剧减少，入湖泥沙打破了以淤积为主的模式，2006年洞庭湖第一次出现从拦蓄泥沙变成向长江净输出泥沙。低水位运行不仅对洲滩演进和湖泊水质带来影响，也加速了对湖滩的开发利用，外来物种的发展威胁了湖泊湿地生物多样性和动物栖息地的稳定。同时，湖区复合型水污染威胁加重，洞庭湖水质从2008年的Ⅳ类水下降为Ⅴ类水。洞庭湖在缺水与洪涝矛盾中，正从单一洪灾为主转向矛盾的两个方面共存。这些变化一方面与气候变化有关，也是流域生产由传统农业转向农、林、水、工的综合发展，以及湖泊与流域关系改变的结果。     

‘Subjective resilience’: using perceptions to quantify household resilience to climate extremes and disasters

How should we measure a household’s resilience to climate extremes, climate change or other evolving threats? As resilience gathers momentum on the international stage, interest in this question continues to grow. So far, efforts to measure resilience have largely focused on the use of ‘objective’ frameworks and methods of indicator selection. These typically depend on a range of observable socio-economic variables, such as levels of income, the extent of a household’s social capital or its access to social safety nets. Yet while objective methods have their uses, they suffer from well-documented weaknesses. This paper advocates for the use of an alternative but complementary method: the measurement of ‘subjective’ resilience at the household level. The concept of subjective resilience stems from the premise that people have an understanding of the factors that contribute to their ability to anticipate, buffer and adapt to disturbance and change. Subjective household resilience therefore relates to an individual’s cognitive and affective self-evaluation of their household’s capabilities and capacities in responding to risk. We discuss the advantages and limitations of measuring subjective household resilience and highlight its relationships with other concepts such as perceived adaptive capacity, subjective well-being and psychological resilience. We then put forward different options for the design and delivery of survey questions on subjective household resilience. While the approach we describe is focused at the household level, we show how it has the potential to be aggregated to inform sub-national or national resilience metrics and indicators. Lastly, we highlight how subjective methods of resilience assessment could be used to improve policy and decision-making. Above all, we argue that, alongside traditional objective measures and indicators, efforts to measure resilience should take into account subjective aspects of household resilience in order to ensure a more holistic understanding of resilience to climate extremes and disasters.     

2011年长江中下游春旱的气候特征分析

利用我国高分辨率逐日降水资料，从降水量、无降水日数、连续无降水日数、气象干旱指数（CI）等指标对2011年春季长江中下游地区发生的气象干旱进行了分析评估。结果表明，2011年春季长江中下游地区降水量为近60 a同期最少，无降水日数、气象干旱影响范围均为近60 a同期最大，重度以上气象干旱日数为近几十年来同期罕见。此次严重气象干旱具有强度强、持续时间长、干旱范围广、影响程度重等特点，为近60 a来长江中下游地区春季发生的最严重的气象干旱，对水资源、水产养殖业、农业生产等造成了重大影响。还从大气环流、水汽输送角度对气象干旱的成因进行了初步分析，认为2011年冬春季北方冷空气势力强大，向南扩张明显，南方热带对流系统不活跃，向长江中下游地区水汽输送弱，是造成此次气象干旱的主要原因     

Statistical downscaling for climate change projections in the Mediterranean region: methods and results

Besides dynamical downscaling by regional climate models, statistical downscaling (SD) is a major tool to derive climate change projections on regional or even local scales. For the Mediterranean area, an increasing number of downscaling studies based on different statistical techniques have been published in the last two decades with a broad range of sometimes differing results relating to different variables and regional domains. This paper gives a short review of these Mediterranean downscaling studies mainly considering the following two aspects: (1) what kind of progress has been realized in this field since the early 1990s? The review addresses the inclusion of extremes in downscaling assessments, the development of probabilistic approaches, the extension of predictor sets, the use of ensembles for both dynamical model simulations and statistical model assessments, the consideration of non-stationarities in the predictor–predictand relationships, and some advances related to synoptic downscaling. (2) What are the main regional climate change signals in the Mediterranean area, considering agreed and controversial points also with respect to dynamical models? Best accordance among future projections can be found in seasonal temperatures with lower rates of warming in winter and spring, and, in most cases, higher ones in summer and autumn. Different results are obtained for the intra-annual range of extreme temperatures, but high-temperature conditions are generally expected to increase. Regarding seasonal precipitation, predominant reductions are indicated for spring, summer, and autumn. For winter, however, projections are distinctly different (GCMs: rainfall decrease; RCMs: increase only in the northernmost parts of the Mediterranean region; SD: widespread increases in the northern and western parts in several studies). Different results are obtained for rainfall extremes, but the entire precipitation distribution tends to shift towards higher and lower values. Apart from some sub-regional deviations, there is a predominant increase in future dry period durations. For near-surface winds, only a few studies are available, and they project some decline mainly for the winter season.     

Climate change perceptions and adaptations of smallholder farmers in Eastern Kenya

Several studies have indicated the importance of understanding farmers’ perceptions of risks associated with climate change, the adaptation strategies they employ and factors that affect adaptive capacity. This study aimed to understand smallholder farmers’ perceptions of climate change, adaptation strategies and adaptive capacity in the semiarid Matungulu Sub-County, Eastern Kenya. A participatory approach, using three climate roundtables, was conducted to enhance community participation and understanding of climate change issues. The study showed that farmers’ perceptions concerning climate change are influenced by past experiences of weather extremes that have affected production levels and farm incomes. The farmers have made strategic responses to manage risks posed by climate change. However, they face several challenges in adaptation such as inadequate technical knowledge, low financial resources and inadequate land size. Further, the study showed that climate roundtables is a successful participatory approach that can give effective insights for smallholder farmers to understand agricultural vulnerability, climate change and their adaptation strategies.     

Resilience and adaptation to extremes in a changing Himalayan environment

Human communities inhabiting remote and geomorphically fragile high-altitude regions are particularly vulnerable to climate change-related glacial hazards and hydrometeorological extremes. This study presents a strategy for enhancing adaptation and resilience of communities living immediately downstream of two potentially hazardous glacial lakes in the Upper Chenab Basin of the Western Himalaya in India. It uses an interdisciplinary investigative framework, involving ground surveys, participatory mapping, comparison of local perceptions of environmental change and hazards with scientific data, identification of assets and livelihood resources at risk, assessment of existing community-level adaptive capacity and resilience and a brief review of governance issues. In addition to recommending specific actions for securing lives and livelihoods in the study area, the study demonstrates the crucial role of regional ground-level, community-centric assessments in evolving an integrated approach to disaster risk reduction and climate change adaptation for high-altitude environments, particularly in the developing world.     

Projecting Spatial Patterns of Flood Hazard: Recent Climate and Future Changes over Yangtze River Basin

Projection of hazard changes in climate extremes is critical to assessing the potential impacts of climate change on human and natural systems. Using simulations of providing regional climates for impacts studies, five indicators (rainstorm days, maximum 3-day precipitation, elevation, gradient and distance from river or lake) were selected to project the spatial patterns of flood hazard over Yangtze River Basin for the baseline period (1961– 1990) and future (2011–2100) under SRES B2 scenario. The results ...     

Radon: exploring the log-normal mystery

The term “log-normal mysticism” has been coined by Tóth et al. (2006) for the so far unexplained observation that indoor radon concentration data from geographical surveys very often appear to be quite accurately log-normally distributed. In this contribution, I try to verify the statement with the dataset of the Austrian indoor radon survey and data from the ongoing European indoor radon mapping project. It appears that, with some limitations, an approximate log-normality is present for a large scale of spatial ranges. Investigation of the frequency of outliers points to the systematic presence of a “fat tail” in Rn frequency distribution, i.e. of extremes which disturb log-normality. “Local log-normality”, i.e. within a neighbourhood, possibly restricted to geological units, is an important assumption in certain radon mapping approaches.     

Vulnerability of Inuit food systems to food insecurity as a consequence of climate change: a case study from Igloolik, Nunavut

This paper develops a conceptual model to examine the vulnerability of Inuit food systems to food insecurity as a consequence of climate change. The model illustrates that food system vulnerability is determined by the exposure and sensitivity of the food system to climate-related risks and its adaptive capacity to deal with those risks. The model is empirically applied using a case study from Igloolik, Nunavut. Specifically, the paper focuses on how extreme climate-related conditions in 2006 interacted with the food system to affect food security, using 2006 as a lens to identify and characterize some of the processes and conditions shaping vulnerability, and establishing a baseline for identifying and characterizing processes that are likely to shape future vulnerability. There is a high level of adaptive capacity among Igloolik Inuit, with food sharing mechanisms, hunting flexibility, and store-food access moderating the impact of climatic-risks on food security. However, high fuel and commodity prices, the increasing economic burden of adapting to back-to-back years with unfavorable climatic conditions, underlying community vulnerabilities, and the nature to the climate extremes in 2006, overwhelmed the adaptive capacity of many community members. Those dependent on traditional foods and having limited access to financial resources were particularly vulnerable.     

Metaphors for the War (or Race) against Climate Change

Despite overwhelming scientific consensus, millions of Americans fail to view climate change as a pressing threat. How can we address this disconnect between science and public opinion? In the present study, we investigated the role of metaphorical framing in shaping attitudes toward climate change. Participants read a brief article that metaphorically described US efforts to reduce carbon emissions as a war or race against climate change, or non-metaphorically described it as the issue of climate change. We further manipulated whether these emission-reduction goals emphasized the relatively near or distant future. We found that, compared to the race frame, the war metaphor made people perceive more urgency and risk surrounding climate change and express a greater willingness to increase conservation behavior, irrespective of the time horizon. Those who read the non-metaphorical report tended to respond in between these two extremes. We discuss the implications of these findings for climate communications.     

三江源地区1961~2005年气温极端事件变化

利用三江源地区11个气象台站1961~2005年逐日最高气温和最低气温资料，分析了三江源地区极端高温和极端低温的变化趋势。研究表明：近45年来，白天和夜间温度极端偏高的日数明显增多，分别以26 d/10 a和44 d/10 a速度在增加;白天和夜间温度极端偏低的日数显著减缓，分别以41 d/10 a和85 d/10 a的速度显著减少;年极端低温和极端高温分别以042℃/10 a和029℃/10 a的速度增加;白天和夜间温度极端偏高的日数增加主要发生在冬季和夏季，而白天和夜间温度极端偏低的日数减少主要发生在春季和秋季，夜间温度极端偏低的日数减少趋势最为明显;长江源地区极端气温变化对区域增温的响应更为敏感。