气候变化背景下钙华退化影响因素及其保育措施研究进展

为厘清黄龙钙华退化受气候变化调控规律,探究影响钙华沉积的生物与非生物因素对气候变化产生的响应,通过对钙华相关研究的专著及文献进行分析,从直接影响气候变化的水文因素和大气二氧化碳浓度出发,探索其对钙华退化的影响,表明水文过程及气候变化引起的极端事件是导致钙华退化的主要原因:(1)适宜的气候加速钙华沉积,极端的气候则会引起...     

Global climate change and the effect of conservation practices in US agriculture

 Increase in the use of conservation practices by agriculture in the United States will enhance soil organic carbon and potentially increase carbon sequestration. This, in turn, will decrease the net emission of carbon dioxide. A number of studies exist that calibrate the contribution of various individual, site-specific conservation practices on changes in soil organic carbon. There is a general absence, however, of a comprehensive effort to measure objectively the contribution of these practices including conservation tillage, the Conservation Reserve Program, and conservation buffer strips to an change in soil organic carbon. This paper fills that void. After recounting the evolution of the use of the various conservation practices, it is estimated that organic carbon in the soil in 1998 in the United States attributable to these practices was about 12.2 million metric tons. By 2008, there will be an increase of about 25%. Given that there is a significant potential for conservation practices, which could lead to an increase in carbon sequestration, there are a number of policy options that can be pursued. These include education and technical assistance, financial assistance, research and development, land retirement, and regulation and taxes. Received: 27 December 1999 · Accepted: 14 March 2000     

Natural hazards and climate change are not drivers of disasters

Natural Hazards - Many nations face challenges in assessing, understanding, and responding to the time-dependent nature of disaster risk. Changes in the intensity of occurrences of extreme events...     

Hydrological impact of forest fires and climate change in a Mediterranean basin

Forest fire can modify and accelerate the hydrological response of Mediterranean basins submitted to intense rainfall: during the years following a fire, the effects on the hydrological response may be similar to those produced by the growth of impervious areas. Moreover, climate change and global warming in Mediterranean areas can imply consequences on both flash flood and fire hazards, by amplifying these phenomena. Based on historical events and post-fire experience, a methodology to interpret the impacts of forest fire in terms of rainfall-runoff model parameters has been proposed. It allows to estimate the consequences of forest fire at the watershed scale depending on the considered burned area. In a second stage, the combined effect of forest fire and climate change has been analysed to map the future risk of forest fire and their consequence on flood occurrence. This study has been conducted on the Llobregat river basin (Spain), a catchment of approximately 5,000 km² frequently affected by flash floods and forest fires. The results show that forest fire can modify the hydrological response at the watershed scale when the burned area is significant. Moreover, it has been shown that climate change may increase the occurrence of both hazards, and hence, more frequent severe flash floods may appear.     

Benefit analysis of flood adaptation under climate change scenario

Natural Hazards - Typhoon Morakot of 2009 caused the worst flooding in the history of Taiwan. Because research on climate change has indicated that similar extreme disasters are expected to become...     

Identifying vulnerable areas of aquifer under future climate change (case study: Hamadan aquifer,West Iran)

Groundwater is the main source of water in arid and semi-arid regions, so it is very important to recognize vulnerable parts of aquifer under future climate change conditions. In this research, 16 climate models were evaluated based on weighting approach. HADCM3 and CGCM2.3.2a models were selected for temperature and precipitation prediction, respectively. LARS-WG was used for downscaling AOGCMs outputs. Results show that temperature increase by 1.4 °C and precipitation changes between +10 and ?6 % under B1 and A2 emission scenario, respectively. Runoff volumes will decrease by ?39 % under A2 emission scenario whereas runoff volume will increase by +12 % under B1 emission scenario. Simulation of groundwater head variation by MODFLOW software indicates higher groundwater depletion rate under A2 scenario compared to B1 scenario. Groundwater model outputs indicate that the most vulnerable part of the aquifer is located in the southwest region. Large number of extraction wells and low aquifer transmissivity are the reasons for high vulnerability of the region.     

Approximate local confidence intervals under change of support

Approximate local confidence intervals are constructed from uncertainty models in the form of the conditional distribution of the random variable Z given values of variables [Z_i, i=1,...,n]. When the support of the variable Z is any support other than that of the data, the conditional distributions require a change of support correction. This paper investigates the effect of change of support on the approximate local confidence intervals constructed by cumulative indicator kriging, class indicator kriging, and probability kriging under a variety of conditions. The conditions are generated by three simulated deposits with grade distributions of successively higher degree of skewness; a point support and two different block supports are considered. The paper also compares the confidence intervals obtained from these methods using the most used measures of confidence interval effectiveness.     

气候变化对澜沧江下游梯级电站发电及生态调度的影响

近年来伴随气候变化地表径流呈极端化分布，为水电生态调度带来了挑战。为探究气候变化对电站发电和生态调度的影响、发电和生态目标间协调关系对气候变化的响应，以澜沧江下游梯级电站为例，结合多模式多情景未来径流预估结果及水库发电调度模型，针对发电及生态效益目标实施了单/多目标最优化。结果表明：在气候变化影响下，未来澜沧江径流总量将有所增加，水文变率将显著增强，河道生态所受影响也将增大；电站发电保证率及生态流量破坏率指标受不同调度方案的影响程度较气候变化影响更高，未来发电和生态效益的冲突依然存在；气候变化导致的水文变率增强可加剧发电与生态效益间的冲突，导致保持现有发电效益的同时增大对河道生态的影响。     

气候变化对澜沧江下游梯级电站发电及生态调度的影响

近年来伴随气候变化地表径流呈极端化分布,为水电生态调度带来了挑战。为探究气候变化对电站发电和生态调度的影响、发电和生态目标间协调关系对气候变化的响应,以澜沧江下游梯级电站为例,结合多模式多情景未来径流预估结果及水库发电调度模型,针对发电及生态效益目标实施了单/多目标最优化。结果表明:在气候变化影响下,未来澜沧江径流总量将有所增加,水文变率将显著增强,河道生态所受影响也将增大;电站发电保证率及生态流量破坏率指标受不同调度方案的影响程度较气候变化影响更高,未来发电和生态效益的冲突依然存在;气候变化导致的水文变率增强可加剧发电与生态效益间的冲突,导致保持现有发电效益的同时增大对河道生态的影响。     

气候变化下淮河流域极端洪水情景预估

利用IPCC第4次评估公开发布的22个全球气候模式在A1B、A2和B1三种典型排放情景下的未来气温和降水预测结果,结合新安江月分布式水文模型,在对模型验证效果良好的基础上,参照集合预报方法,对未来90年(2010～2099年)气候变化下淮河流域的极端洪水进行预估。研究结果表明,从出现概率来看,淮河流域未来可能发生极端洪水年份的密集程度从大到小依次为A2情景、A1B情景、B1情景。A1B情景下,21世纪下半叶出现极端洪水的可能性增大,A2情景在2035～2065年以及2085年以后是极端洪水发生较为集中的时期。B1情景在21世纪70年代左右发生极端洪水的可能性较大。综合各种极端事件的定义方法,将极端洪水划定3个洪水量级。A2情景预估极端洪水的平均洪量在3种情景中最大,B1情景最小。3种情景未来一级极端洪水发生比例都比历史上偏大,A2情景下增加最多。二级极端洪水都较历史略有减少,三级极端洪水减少最显著。3种情景下各个量级极端洪水所占比例各不相同,A1B和A2情景二级以上极端洪水出现比例较大,B1情景下极端洪水量级多为三级,超1954年的一级极端洪水所占比例较小。     

Importance of climate,forest fires and human population size in the Holocene boreal forest composition change in northern Europe

The relative importance of climate, forest fires and human population size on long‐term boreal forest composition were statistically investigated at regional and local scales in Fennoscandia. We employ pollen data from lakes, reflecting regional vegetation, and small forest hollows, reflecting local vegetation, from Russia, Finland and Sweden to reconstruct the long‐term forest composition. As potential drivers of the Holocene forest dynamics we consider climate, generated from a climate model and oxygen isotope data, past forest fires generated from sedimentary charcoal data and human population size derived from radiocarbon dated archaeological findings. We apply the statistical method of variation partitioning to assess the relative importance of these environmental variables on long‐term boreal forest composition. The results show that climate is the main driver of the changes in Holocene boreal forest composition at the regional scale. However, at the local scale the role of climate is relatively small. In general, the importance of forest fires is low both at regional and local scales. The fact that both climate and forest fires explain relatively small proportions of variation in long‐term boreal vegetation in small forest hollow records demonstrates the complexity of factors affecting stand‐scale forest dynamics. The relative importance of human population size was low in both the prehistorical and the historical time periods. However, this is the first time that this type of data has been used to statistically assess the importance of human population size on boreal vegetation and the spatial representativeness of the data may cause bias to the analysis.     

中国北方气候变化特征及其对岩溶水的影响

在气候变化的大背景下,近数十年来随着北方岩溶区降水量的趋势性下降和气温的不断升高,岩溶水补给资源量大幅度衰减,气候变化成为引发一系列岩溶水文地质环境问题的原因之一。针对这一问题,以岩溶水系统为单元,采用大量气象系列资料研究北方岩溶区降水变化与分布特征,分析了气候变化发展趋势及成因,从区域角度出发,估算了气候变化对岩溶水资源的影响。     

The impact of ENSO and macrocirculation patterns on precipitation under climate change

The possible impact of El Niño-Southern Oscillation (ENSO) and macrocirculation patterns (CPs) on local precipitation are examined and analyzed here under climate change conditions. First the relationship between the input and output variables under present conditions is established using two models, a fuzzy rule-based model (FRBM) and a multivariate linear regression model (MLRM), then this historical relationship is extended under climate change conditions. The input variables for these models consist of lagged ENSO-data (represented by the Southern Oscillation Index, SOI) and 500 hPa height data clustered into macrocirculation patterns over the western United States, while the output is an estimate of monthly local precipitation at selected Arizona stations. To overcome the lack of SOI data under climate change, several scenarios are constructed by perturbing the historical SOI data in a design of experiments framework. The results of the experimental design show that, in general, the precipitation amount seems to decrease under climate change. While the stations and months have differences, as expected, the perturbed scenarios do not show significant differences.     

Assessment of potential risks induced by increasing extreme precipitation under climate change

Natural Hazards - A warmer climate has caused more extreme climate events like the heatwave or extreme precipitation, which has led to a large number of lives and economic losses. In this study, we...     

Impact of water demand on hydrological regime under climate and LULC change scenarios

The present study focuses on an assessment of the impact of future water demand on the hydrological regime under land use/land cover (LULC) and climate change scenarios. The impact has been quantified in terms of streamflow and groundwater recharge in the Gandherswari River basin, West Bengal, India. dynamic conversion of land use and its effects (Dyna-CLUE) and statistical downscaling model (SDSM) are used for quantifying the future LULC and climate change scenarios, respectively. Physical-based semi-distributed model Soil and Water Assessment Tool (SWAT) is used for estimating future streamflow and spatiotemporally distributed groundwater recharge. Model calibration and validation have been performed using discharge data (1990–2016). The impacts of LULC and climate change on hydrological variables are evaluated with three scenarios (for the years 2030, 2050 and 2080). Temperature Vegetation Dyrness Index (TVDI) and evapotranspiration (ET) are considered for estimation of water-deficit conditions in the river basin. Exceedance probability and recurrence interval representation are considered for uncertainty analysis. The results show increased discharge in case of monsoon season and decreased discharge in case of the non-monsoon season for the years 2030 and 2050. However, a reverse trend is obtained for the year 2080. The overall increase in groundwater recharge is visible for all the years. This analysis provides valuable information for the irrigation water management framework.     

Hierarchy evaluation of water resources vulnerability under climate change in Beijing,China

Rapid population growth and increased economic activity impose an urgent challenge on the sustainability of water resources in Beijing. Water resources system is a complex uncertain system under climate change which is of vulnerability. But water resources system vulnerability research is relatively weak. In this study, we present a multifunctional hierarchy indicator system for the performance evaluation of water resources vulnerability (WRV) under climate change. We established an evaluation model, i.e., analytic hierarchy process combining set pair analysis (AHPSPA) model, for assessing WRV, in which weight is determined by the analytic hierarchy process (AHP) method and the evaluation degrees are determined by the set pair analysis (SPA) theory. According to the principle of scientificalness, representative, completeness and operability, the index systems and standard of water resources vulnerability evaluation are established based on the analysis of sensibility and adaptability which include five subsystems: climate change, water resources change, social and economic infrastructure, water use level and water security capability. The AHPSPA model is used to assess water resource vulnerability in Beijing with 26 indexes under eight kinds of future climate change scenarios. Certain and uncertain information quantity of the WRV is calculated by connection numbers in the AHPSPA model. Results show that the WRV of Beijing is in the middle vulnerability (3 or III) under above-mentioned different climate change scenarios. The uncertain information is between 37.77 and 39.99 % in the WRV evaluation system in Beijing. Compared with present situation, the WRV will become better under scenario I and III and will become worse under scenario II, scenario IV, scenario representative concentration pathways (RCP)2.6, scenario RCP4.5, scenario RCP6.0 and scenario RCP8.5. In addition, we find that water resources change and water use level factors play more important role in the evaluation system of water resource vulnerability in Beijing. Finally, we make some suggestions for water resources management of Beijing.

     

气候变化情景下青藏工程走廊融沉灾害风险性区划研究

气候变暖会加剧青藏工程走廊多年冻土区融沉灾害的发生,威胁重大工程的安全运营. 选取冻土体积含冰量和活动层厚度变化量为指标,借助ArcGIS软件,采用融沉指数模型对青藏工程走廊融沉灾害做出了区划. 结果表明：在未来50 a,青藏工程走廊内融沉灾害在A1B和A2情景下主要为中高风险性,在B1情景下主要为中低风险性. 高风险区主要分布在楚玛尔河高平原、五道梁和开心岭等高温高含冰量冻土区.