气候变化中下垫面作用的数值模拟

本文利用一个三维数值模式,对下垫面在气候变化中的作用进行了数值模拟.共做了两个均一土壤下垫面试验和一个非均一土壤下垫面试验.结果表明,东半球夏季季风气候区的基本气候特征,主要是由海陆分布和大地形的影响所产生.但是,细致的气候特征却受下垫面土壤物理性质和初始湿度的很大影响.而且,通过环流系统的相互作用,除对本地区天气气候产生影响外,还会影响周围地区.非洲撒哈拉大沙漠的形成很可能是长期受到海陆分布及高原地形所造成的基本气候场作用的结果.     

内蒙古的气候变化浅析

本文利用相关分析、回归方程，对内蒙古境内46个台站有记录以来的年平均气温、降水量和年平均相对湿度的年度变化进行了分析研究。得出初步结论，内蒙古不同区域的气候变化趋势不尽相同，变化速率也有差异。内蒙古绝大部分地区年均温有上升的趋势，年均相对湿度总趋势是减小，大部分地区年降水量没有明显的变化。     

延安地区近５０年气候变化的特征分析

摘要：通过对１９５７—２００５年延安地区气温、降水及相对湿度的变化特征分析,揭示了近５０ａ来延安气候变化特征,结果表明：延安地区平均气温具有明显的年变化趋势,总体呈线性上升趋势,趋势率为０.２４２℃/（１０ａ）,１９８６年发生明显跃变,跃变后春季增温明显;降水量年变化特征趋势不明显,趋势变化较平均气温复杂,波动性大,２１世纪以来降水量有所增加。总体上２０世纪９０年代后呈现减少趋势。在全球气候变暖的大背景下,延安地区降水量下降,气温升高,气候变化有暖干化发展的趋势。

     

延安地区近5O年气候变化的特征分析

通过对1957--2005年延安地区气温、降水及相对湿度的变化特征分析,揭示了近50a来延安气候变化特征,结果表明：延安地区平均气温具有明显的年变化趋势,总体呈线性上升趋势,趋势率为0．242℃／（10a）,1986年发生明显跃变,跃变后春季增温明显;降水量年变化特征趋势不明显,趋势变化较平均气温复杂,波动性大,21世纪以来降水量有所增加。总体上20世纪90年代后呈现减少趋势。在全球气候变暖的大背景下,延安地区降水量下降,气温升高,气候变化有暖干化发展的趋势。     

一次局地大暴雨过程的综合分析

利用常规气象监测资料,以及卫星、雷达、闪电定位、GPS／MET等精细化监测资料,对2010年8月18日-19日的暴雨天气过程进行了综合分析发现：边界层两条仅中尺度辐合线与两条暴雨带有很好的对应关系。暴雨期间,共有6个α中尺度对流云团在边界层中尺度辐合线上生成、发展与合并,特大暴雨由β中尺度对流云团合并形成的MCS所造成。分析结果表明,暴雨发生在副高西进北抬和冷空气东移南下的背景下;700hPa、850hPa和边界层中尺度辐合线是此次暴雨过程的主要影响系统;局地闪电频次峰值出现时间早于强降水峰值出现时间1h左右;GPS探测网对水汽探测的反应早于区域加密站的观测,PWV锋区出现时间较强降水出现时间有大于12h的提前量,且PWV锋区的出现时间和位置对暴雨落区预报有一定的参考价值,可以作为判断强降水出现的一个重要参考依据。     

气候变化对冬小麦播期的影响

对驻马店市冬小麦播种期1960～2000年气象资料分析结果表明：秋、冬季气温随时间升高，特别是冬小麦播种的适宜温度期逐渐推退；1990年以后，9月25日～10月15日降水量逐渐减少，10月15～30日降水量基本与20世纪80年代持平。因此，冬小麦必须调整播期，适当晚播。     

宁夏近百年来的气候变化及突变分析

以宁夏北部地区近百年来的降水量、气温距平资料以及全区各季有仪器观测以来的温度降水资料为基础，利用Mann-Kendall突变检验法和滑动t检验法，分析了宁夏近百年来气候变化的阶段性和突变特点。结果表明：近百年来宁夏气候大概经历了五个主要阶段；80年代中期年平均气温及秋冬季平均气温发生改变；60年代左右年降水量发生突变；70年代中后期全区秋季降水量出现突变。     

互助县气候变化特征及对农业生态的影响分析

本利用30a的气象资料对影响互助县生态环境主要气候因子的基本特征及其变化进行分析，并探讨自然灾害及人类经济活动对生态环境的影响，为生态环境的保护和建设提供参考依据。     

近50年来中国气候变化特征的再分析

利用国家气象中心最近整编的中国 74 0个站逐日资料 ,通过对中国温度、降水、湿度、风速、气压这 5个基本气象要素变化特征较为全面的分析 ,揭示了近 5 0a来中国气候变化的一些新特征。得到的新结果有 :(1)近 5 0a来 ,全国平均气温在 2 0世纪 80年代以后上升更为明显 ;西南低温区在 90年代以后温度也处于上升状态 ;夏季的长江中上游出现明显的降温趋势。 (2 )全国平均年总降水量波动略有减少 ,但 90年代以后夏季降水增加明显 ,尤其是长江以南地区 ,而华北、东北地区降水显著减少 ,体现了夏季风的减弱。 (3)全国平均相对湿度的变化和降水相似。(4 )中国几乎全部地区的风速都在显著减小 ,冬、春季和西北西部最明显 ,该区 90年代的年平均风速比 5 0年代减少约 2 9%。风速大幅减小主要是由于亚洲冬、夏季风的减弱。 (5 )全国平均的海平面气压在增高 ,尤其是北方的冬季 ,这和中国风速的大幅减小有关。     

一次局地大暴雨过程的数值模拟和诊断分析

采用中尺度数值模式MM5(V3)对2002年8月15-16日发生在江苏启东附近的一次局地大暴雨过程进行了数值模拟,较好地模拟出了本次过程的暴雨中心落区和降水量,以及相关的中尺度系统的发生、发展过程.探讨了中尺度涡旋、局地环流对这次暴雨过程的影响,结果表明,中尺度涡旋对暴雨的发生起了至关重要的作用,局地环流的存在,也有利于降水的发生.     

乌鲁木齐城市化进程对局地气候变化的影响研究

利用1976—2014年乌鲁木齐城区和郊区两个气象站的气温、降水、相对湿度和风速气象数据及1995—2014年乌鲁木齐市城市发展数据,运用线性趋势对比分析城区和郊区各气候要素的年际变化特征;采用相关分析法对城市化因子和气候要素进行了探讨。结果表明:城、郊区气温均呈明显的上升趋势,城区的年均气温高于郊区;城区降水量是郊区的3.93倍,增长速率是郊区的3.98倍;各年代城区相对湿度比郊区大,但呈下降趋势,郊区呈上升趋势;各年代郊区风速大于城区,郊区风速约为城区的2.35倍,均呈下降趋势。近20 a,乌鲁木齐城市化进程加快,对局地气候影响明显,其中对平均气温和相对湿度的影响最为显著。     

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.     

Constructing legitimacy for climate change planning: A study of local government in Denmark

Existing research on climate change planning has tended to adopt an overly simplistic approach to analyzing how agency and structure mediate local governments’ responses to climate change. This research contributes to scientific capacity to predict and explain patterns of climate change planning by focusing on the concept of legitimacy and examining its influence upon the dialectic between structure and agency. A conceptual framework foregrounding legitimacy is developed based upon new institutional theory. An initiative to institutionalize climate change planning in Aarhus Municipality, Denmark, is used as a case study to validate four propositions derived from existing research but filtered through the conceptual framework. Validation of the propositions evidences a hierarchy in the salience of different forms of legitimacy, with moral and ethical arguments for undertaking climate change planning having limited social traction in Denmark in the absence of significant extreme climatic events. The analysis also generates thicker, more nuanced explanations for real-world patterns of climate change planning. The findings thereby provide a corrective to a number of assertions made in the literature, notably in relation to the role of agency in the institutionalization of climate change planning.     

Perceptions of climate and climate change by Amazonian communities

The Amazon region has been undergoing profound transformations since the late ‘70s through forest degradation, land use changes and effects of global climate change. The perception of such changes by local communities is important for risk analysis and for subsequent societal decision making. In this study, we compare and contrast observations and perceptions of climate change by selected Amazonian communities particularly vulnerable to alterations in precipitation regimes. Two main points were analysed: (i) the notion of changes in the annual climate cycle and (ii) the notion of changes in rainfall patterns. About 72% of the sampled population reports perceptions of climate changes, and there is a robust signal of increased perception with age. Other possible predictive parameters such as gender, fishing frequency and changes in/planning of economic activities do not appear overall as contributing to perceptions. The communities’ perceptions of the changes in 2013–2014 were then compared to earlier results (2007–2008), providing an unprecedented cohort study of the same sites. Results show that climate change perceptions and measured rainfall variations differ across the basin. It was only in the southern part of the Amazon that both measured and perceived changes in rainfall patterns were consistent with decreased precipitation. However, the perception of a changing climate became more widespread and frequently mentioned, signalling an increase in awareness of climate risk.     

OK Boomer: A decade of generational differences in feelings about climate change

The emergence of concern about and evidence of climate change has been argued to create a cultural milieu unique to the Millennial generation (born between 1981 and 1996) and iGeneration (aka iGens or Generation Z born after 1997). The present research tested a) claims of unique angst about climate change among younger versus older generations, b) growing generational discrepancies over time in emotions about climate change, c) generational differences for several emotions about climate change, and d) the implications of these emotions for motivating people to discuss climate change with others, potentially aiding coping with climate change and facilitating action to address climate change. Survey data gathered from 2010 to 2019 of a representative sample of United States residents (N = 22,468) document greater increases in worry about climate change and, to a lesser degree, anger and guilt about climate change, within the two youngest generations relative to changes among Generation X, Baby Boomers, and the Silent and Greatest Generations. Although generational differences were small and suggest overstatements of unique effects for younger generations, increases in younger generations’ emotions transform into the two youngest generations reporting the strongest emotions in 2019. Over ten years, these differential shifts in emotions explain more substantial increases in the frequency of discussing climate in the youngest generations.     

Mechanisms for the land/sea warming contrast exhibited by simulations of climate change

The land/sea warming contrast is a phenomenon of both equilibrium and transient simulations of climate change: large areas of the land surface at most latitudes undergo temperature changes whose amplitude is more than those of the surrounding oceans. Using idealised GCM experiments with perturbed SSTs, we show that the land/sea contrast in equilibrium simulations is associated with local feedbacks and the hydrological cycle over land, rather than with externally imposed radiative forcing. This mechanism also explains a large component of the land/sea contrast in transient simulations as well. We propose a conceptual model with three elements: (1) there is a spatially variable level in the lower troposphere at which temperature change is the same over land and sea; (2) the dependence of lapse rate on moisture and temperature causes different changes in lapse rate upon warming over land and sea, and hence a surface land/sea temperature contrast; (3) moisture convergence over land predominantly takes place at levels significantly colder than the surface; wherever moisture supply over land is limited, the increase of evaporation over land upon warming is limited, reducing the relative humidity in the boundary layer over land, and hence also enhancing the land/sea contrast. The non-linearity of the Clausius–Clapeyron relationship of saturation specific humidity to temperature is critical in (2) and (3). We examine the sensitivity of the land/sea contrast to model representations of different physical processes using a large ensemble of climate model integrations with perturbed parameters, and find that it is most sensitive to representation of large-scale cloud and stomatal closure. We discuss our results in the context of high-resolution and Earth-system modelling of climate change.     

光伏电站对局地气候的影响研究进展

清洁能源的快速发展有效降低了人类对传统化石能源的依赖,并为缓解全球气候变暖做出显著贡献。随着各地光伏装机规模的不断扩大,光伏电站这一人工设施对气候环境的影响日益引起人们的关注。针对这一问题,国内外学者自2000年陆续开展了相关研究。综合国内外现有研究成果,对研究方法、影响机理及光伏电站对气候的影响等方面进行总结。大量研究表明：光伏电站布设会在荒漠地区产生“光伏热岛效应”,从而引起局部区域气温上升,在城市地区布设能够在降低能源消耗的同时减少“城市热岛效应” 。此外,光伏组件还会对反照率、地表辐射平衡等产生影响,进而对局地甚至全球气候产生作用,其影响范围和程度尚无准确结论,还需要进一步深入探索。     

People as sensors: Mass media and local temperature influence climate change discussion on Twitter

This study examined whether people living in the US connect their sensory experiences with local temperature to climate change and whether mass media influences the process. We used the volume of Twitter messages containing words “climate change” and “global warming” as the indicator of attention that public pays to the issue. Specifically, the goals were: (1) to investigate whether people immediately notice substantial local weather anomalies such as deviations from long-term mean temperatures and connect them to climate change by contributing to climate change discourse on Twitter and (2) to examine the role of mass media in this process. Over 2 million tweets were collected for a two-year period (2012–2013) and were assigned to 157 urban areas in the continental US. The rate of tweeting on climate change was regressed on the time variables, number of climate change publications in the mass media, and a number of temperature variables. The analysis was conducted at the two levels of aggregation – national and local. The high significance of the mass media and temperature variables in the majority of regression models suggests that both the weather and mass media coverage control public interest to the topic. However, no convincing evidence was found that the media acts as a mediator in the relationship between local weather and climate change discourse. Overall, the findings confirmed that the public recognize extreme temperature anomalies and connect these anomalies to climate change.     

Learning and climate change

Abstract

Learning—i.e. the acquisition of new information that leads to changes in our assessment of uncertainty—plays a prominent role in the international climate policy debate. For example, the view that we should postpone actions until we know more continues to be influential. The latest work on learning and climate change includes new theoretical models, better informed simulations of how learning affects the optimal timing of emissions reductions, analyses of how new information could affect the prospects for reaching and maintaining political agreements and for adapting to climate change, and explorations of how learning could lead us astray rather than closer to the truth. Despite the diversity of this new work, a clear consensus on a central point is that the prospect of learning does not support the postponement of emissions reductions today.     

The impact of local temperature volatility on attention to climate change: Evidence from Spanish tweets

Variability in local weather patterns has long been suggested as a major barrier impeding laypeople from recognizing long-term climate trends. However, as humans are able to detect and interpret rapid signal fluctuations, it seems psychologically plausible to assume that they are able to integrate short-term variations of weather variables into their mental representations of climate change. Using a combined analysis of social media and weather station data, here we investigated the impact of the short-term volatility of local temperature on climate change-related tweets from 2014 to 2017. We found a nonlinear hockey stick relationship between weekly temperature volatility and climate change-related tweets, a volatility rise of 1 °C corresponds to an 82% increase in climate change tweets when volatility is above 3.5 °C. This volatility effect was observed from 2016 onwards, suggesting a recent change in people’s mental representations of climate change. This study provides empirical evidence illustrating that in the public mind, climate change may not be represented as a mere temperature increase any more, but as a disruption of the climate system in general.