Erratum to: Methodology for the analysis of causes of drought vulnerability on the River Basin scale

An inclinometer is a high-precision instrument used to detect displacement along sliding zones. From the time the inclinometer pipe is embedded to inclinometer calibration and to measured data collection and processing, many errors or misjudgments can occur that affect the measurement data. The most important objective for correctly using the observation results is the accurate interpretation of the horizontal displacement profiles obtained from the observation. This study combines existing inclusive data accumulated by a monitoring system on a test sloping site in a campus. It focuses on a comprehensive interpretation of the displacement relationships among different monitoring instruments. This study uses data interpretation principles, categorizes different mechanisms, and performs quantitative analysis and discussion in order to determine the significance presented by various types of monitored information in terms of slope sliding. In addition, in this study, stairwells in a campus building are used, an inclinometer is set up, and calibration equipment for the experiment is added in order to simulate various configurations and observe patterns for displacement curves. The examples for the various conditions include empty holes in the backfill around the pipe, connection points falling off, pipe torsion, relative sliding between layers reaching an extreme condition and leading to stuck pipes, multi-layered sliding, and different thicknesses in sliding zones. The experiment illustrates changes in behavior in terms of environmental factors. The results can be used for instrument calibration and measurement, and as a reference for disaster warning and prevention in hazardous areas with slopes.     

Assessment of drought hazard,exposure, vulnerability,and risk for rice cultivation in the Mun River Basin in Thailand

Natural Hazards - When assessing drought risk, most studies focus on hazard and vulnerability, paying less attention to exposure. Here, we propose a comprehensive drought risk assessment scheme...     

Research on eco-environmental vulnerability evaluation of the Anning River Basin in the upper reaches of the Yangtze River

The Anning River Basin is located in the transitional zone of the Qinghai-Tibet Plateau, Yunnan-Kweichow Plateau and Sichuan Basin. This transitional zone is an important ecological barrier of the upper reaches of the Yangtze River and plays a significant role in the ecological security and ecological construction of Sichuan Province. However, the innate vulnerability of the eco-environment combined with the unreasonable development and use of minerals, hydropower, agriculture and animal husbandry resources contribute to prominent eco-environmental problems. In support of remote sensing and geographical information system, this study uses the spatial principal component analysis (SPCA) method to build the evaluation model for the vulnerability evaluation and analysis of the eco-environment in the Anning River Basin. The following indicators are selected for the SPCA: elevation, slope, vegetation index, land use, soil type, soil erosion, precipitation, temperature, and population density. Thereafter, the first four principal components are selected and their corresponding weights are determined. The eco-environmental vulnerability comprehensive index of the Anning River Basin is calculated by using these data. According to the calculated results, the eco-environmental vulnerability of the Anning River Basin is divided into five levels, namely, potential vulnerability, slight vulnerability, light vulnerability, moderate vulnerability, and high vulnerability. Eco-environmental changes for the past 20 years (from 1990 to 2010) are discussed and analyzed as well as the driving forces. The analysis shows that the eco-environmental vulnerability of the Anning River Basin is at the moderate level, and exhibits obvious vertical distribution characteristics. The main reasons that cause eco-environmental changes are mainly human factors, socioeconomic factors, and environmental protection policies like “Natural Forests Protection” and “Grain-for-Green”. Based on the vulnerability classification results, the Anning River Basin is divided into three partitions for different degrees of eco-environmental reconstruction and protection, which provides foundation for the local eco-environmental reconstruction so as to reconstruct in order of the importance and urgency.     

Assessment on agricultural drought vulnerability in the Yellow River basin based on a fuzzy clustering iterative model

Drought is one of the major natural disasters occurring in China and causes severe impacts on agricultural production and food security. Therefore, agricultural drought vulnerability assessment has an important significance for reducing regional agricultural drought losses and drought disaster risks. In view of agricultural drought vulnerability assessment with the characteristics of multiple factors and uncertainty, we applied the fuzzy comprehensive evaluation framework to agricultural drought vulnerability model. The agricultural drought vulnerability assessment model was constructed based on the multi-layer and multi-index fuzzy clustering iterative method, which can better reveal the drought vulnerability (including sensitivity and adaptation capacity). Furthermore, the cycle iterative algorithm was used to obtain the optimal index weight vector of a given accuracy by setting the objective function. It provides a new approach to weight determination of agricultural drought vulnerability assessment. In this study, agricultural drought vulnerability of 65 cities (as well as leagues and states) in the Yellow River basin was investigated using a fuzzy clustering iterative model and visualized by using GIS technique. The results showed clear differences and regularities among the spatial distribution of agricultural drought vulnerability of different regions. A large number of the regions in the basin consisted of those exhibiting high to very high vulnerability and were mainly distributed throughout Qinghai, Gansu, northern Shaanxi, and southern Shanxi, accounting for 46 % of the total assessment units. However, the regions exhibiting very high vulnerability were not significantly affected by droughts. Most of the regions exhibiting moderate vulnerability (21.5 % of the assessment units) were mainly concentrated among agricultural irrigation areas, where agriculture is highly sensitive to droughts, and drought occurrence in these regions will likely cause heavy losses in the future. The regions exhibiting slight to low vulnerability were relatively concentrated, accounting for 32.3 % of the assessment units, and were mainly distributed in the plains of the lower reaches of the Yellow River, where the economy was rather well developed and the agricultural production conditions were relatively stronger.     

The evolution analysis of flood and drought in Huai River Basin of China based on monthly precipitation characteristics

Based on the daily precipitation data of 38 weather stations in the Huai River Basin from 1961 to 2010, this study used SPI index, P-III curve to determine the flood/drought years, under what situations for droughts and floods easily happen, and to analyze the evolution law of flood and drought during inter-annual and intra-annual based on the characteristic of monthly precipitation. The results showed that: (1) annual rainfall of the Huai River Basin presented decreasing trend, maximum rainfall appeared from June to August, and multi-year average precipitation increased gradually from north to south; (2) the variation of monthly precipitation during flood years was more severe than other typical years, and precipitation in drought years showed nearly 50 % decline compared with normal years; (3) high rainfall of flood years was mainly caused by the increase in rainfall in flood season, and the strategy of flood control and drought relief was “short-term flood prevention and long-term drought relief”; (4) while precipitation of most months in drought year was reduced, the relevant strategies “annual basin-wide of long-term drought prevention” should be carried out; (5) combination events of floods and droughts occurred frequently. Persistent drought dominated in spring and summer while droughts and floods that happened alternately were mainly in summer and autumn.     

Social vulnerability to floods: a case study of Huaihe River Basin

Since ancient times, floods occurred frequently in Huaihe River with significant casualties and economic losses. In developing measures for disaster prevention or emergency response for disaster relief, the study of social vulnerability to floods in Huaihe River Basin should be strengthened. Based on the latest socioeconomic data, the index system of social vulnerability to floods was constructed from three dimensions: population, economy, and flood prevention. Sensitive indexes were identified from the original indexes by principal component analysis, and the social vulnerability index for floods was calculated for Huaihe River Basin. The results described the characteristics of the spatial distribution. It also demonstrated that vulnerability manifests itself as a regional phenomenon, with significant changes from city to city across the Huaihe River Basin. Understanding the impacts of changes in vulnerability was crucial in developing measures to prevent floods.     

Effects of human activities on hydrological drought patterns in the Yangtze River Basin,China

Natural Hazards - As an extremely important region for the socioeconomic development of China, the Yangtze River Basin (YRB) is vulnerable to climate change and natural disasters. In recent...     

Assessment of precipitation and drought variability in the Weihe River Basin,China

The amount and distribution of precipitation play crucial roles in the occurrence of drought in the Weihe River Basin (WRB), China. Using the precipitation data (1960–2010) of 21 meteorological stations, the spatial and temporal characteristics of short-, medium-, and long-term droughts on 3-, 6-, and 12-month time scales, respectively, were examined using the theory of runs and the Standardized Precipitation Index (SPI). The trends of the drought characteristics were analyzed by a modified Mann-Kendall (MMK) test method. Furthermore, comparative analysis of the SPI at different time scales was conducted. The results showed that (1) the main drought type was moderate drought, which occurred frequently in July and October; (2) the drought intensity and frequency were highest in the 1990s, and the drought severity and drought duration in the northwest was more serious than that in the east; (3) an increasing trend of short droughts appeared mainly in the spring and fall; an increasing trend of medium droughts mainly occurred in the 1990s and that of long-term droughts were mainly presented in the northwest region of the WRB; (4) SPI-3 can better reflect precipitation in the current month, SPI-6 has an advantage in characterizing drought persistence, and SPI-12 performs well in capturing extraordinary droughts; and (5) it was also observed that there is a strong relation between the precipitation distribution and drought zones in the basin, and the drought conditions changed continuously with the seasons depending upon the amount and spatial distribution of precipitation .     

Evaluation of CHIRPS and its application for drought monitoring over the Haihe River Basin,China

To establish the drought index objectively and reasonably and evaluate the hydrological drought accurately, firstly, the optimal distribution was selected from nine distributions (normal, lognormal, exponential, gamma, general extreme value, inverse Gaussian, logistic, log-logistic and Weibull), then the Optimal Standardized Streamflow Index (OSSI) was calculated based on the optimal distribution, and last, the spatiotemporal evolution of hydrological drought based on the OSSI series was investigated through the monthly streamflow data of seven hydrological stations during the period 1961–2011 in Luanhe River basin, China. Results suggest: (1) the general extreme value and log-logistic distributions performed prominently in fitting the monthly streamflow of Luanhe River basin. (2) The main periods of hydrological drought in Luanhe River basin were 148–169, 75–80, 42–45, 14–19 and 8–9 months. (3) The hydrological drought had an aggravating trend over the past 51 year and with the increase in timescale, the aggravating trend was more serious. (4) The lower the drought grade was, the broader the coverage area. As for the Luanhe River basin, the whole basin suffered the mild and more serious drought, while the severe and more serious drought only cover some areas. (5) With the increase in time step, the frequency distribution of mild droughts across the basin tended to be concentrated, the frequency of extreme droughts in middle and upper reaches tended to increase and the frequency in downstream tends to decrease. This research can provide powerful references for water resources planning and management and drought mitigation.     

IMERG卫星降水数据在嘉陵江流域的干旱监测效用评估

针对嘉陵江流域存在雨热同期,水旱灾害频发的现象,为快速且准确地把握流域内降水与干旱情况,利用覆盖范围广且分辨率高的网格化IMERG卫星降水数据对嘉陵江流域进行多时空尺度反演,并基于卫星降水数据采用标准化降水指数(SPI)对流域实行干旱监测。结果表明：1)根据分类指标与统计指标的计算结果,三种卫星降水数据中的IMERG-F能更准确地反映流域内的日降水量,与地面降水数据CC达0.737,整体高估地面降水2.6%,具有在干旱监测方面的应用潜力。2)三种卫星降水数据驱动的SPI指数在干旱监测方面存在一定的差异,IMERG-F驱动的SPI指数与地面降水数据驱动的SPI指数保持较高的一致性(CC>0.9),较近实时产品IMERG-F更能准确地呈现出流域的干湿特征。3)卫星识别降水与干旱监测的能力受地形地貌的影响,IMERG卫星降水数据在平原丘陵地带具有较好的适用性。     

Spatial and temporal evolution characteristics and causes of drought and flood in the Henan section of the Yellow River

Natural Hazards - Under the background of global warming, it is very important to explore the spatial–temporal evolution and causes of regional drought/flood for the realization of drought...     

Analysis of the landscape change at River Basin scale based on SPOT and TM fusion remote sensing images: a case study of the Weigou River Basin on the Chinese Loess Plateau

Eco-environmental changes which generally manifest as the ecological landscape changes are mainly affected by natural and human factors. Through complex interaction, natural factors and human activities alter the landscape structure and decide the service function of regional ecosystem. With the development of geographical information system (GIS) and satellite remote sensing (RS) techniques, the researches on quantitative analysis of landscape changes have made great strides forward. In this paper, the landscape change dynamics in the Weigou River basin have been investigated by the combined use of high-resolution RS images and GIS techniques. The objectives are to determine the landscape transition rates among landscape types and to quantify changes of various landscape indexes using FRAGSTATS, one of the spatial pattern analysis programs for categorical maps. Under man–machine interactive interpretation method, all of the 10-m resolution SPOT + TM images are classified into six primary types (farmland, forest, grassland, water, construction area and desert) and 12 sub-types based on the interpretation key which was established based on 1947 filed pictures in the Weigou River basin. A field check on the data accuracy shows that the total interpretation accuracy approaches 97.53%. Significant land-use change has taken place in the Weigou River basin over the six years from 1998 to 2004 due to rehabilitation measures. The results show that there has been a notable decrease in farmland mainly due to conversion to forest and grassland, the landscape heterogeneity and evenness has increased, and there is a greater connectivity. The dominance of farmland patch has decreased. And hence the ecological environment has started to develop in a reversing direction. The study of the integration of high-resolution RS images and GIS technique is an effective approach to analyze the landscape changes at river basin scale.     

澜沧江—湄公河流域跨界含水层研究

跨界含水层由位于不同国家的含水层组成,是地下水资源系统的重要组成部分。妥善管理并公平合理地利用跨界含水层,对促进可持续发展及国家之间的睦邻友好关系有着重要意义。通过分析澜沧江—湄公河流域水文地质条件,划定流域的跨界含水层系统,并对地下水资源与环境问题进行探索,提出跨界含水层综合评价指标体系,结合澜沧江—湄公河流域4个跨界含水层相关的指标进行了综合评价。本次研究,对管理澜沧江—湄公河流域跨界含水层,建设和谐的东南亚国际环境有着重要意义。     

Assessment of physical vulnerability to agricultural drought in China

Food security has drawn great attention from both researchers and practitioners in recent years. Global warming and its resultant extreme drought events have become a great challenge to crop production and food price stability. This study aimed to establish a preliminary theoretical methodology and an operational approach for assessing the physical vulnerability of two wheat varieties (“Yongliang #4” and “Wenmai #6”) to agricultural drought using Environmental Policy Integrated Climate model (EPIC). Drought hazard index was set up based on output variables of the EPIC water stress (WS), including the magnitude and duration of WS during the crop-growing period. The physical vulnerability curves of two wheat varieties to drought were calculated by the simulated drought hazard indexes and loss ratios. And the curve’s effect on drought disaster risk was defined as A, B and C sections, respectively. Our analysis results showed that (a) physical vulnerability curves varied between two wheat varieties, which were determined by genetic parameters of crops; (b) compared with spring wheat “Yongliang 4#” winter wheat “Wenmai 6#” was less vulnerable to drought under the same drought hazard intensity scenario; (c) the wheat physical vulnerability curve to drought hazard displayed a S shape, suggesting a drought intensity–dependent magnifying or reducing effect of the physical vulnerability on drought disasters; (d) the reducing effect was mainly in the low-value area of vulnerability curve, whereas the magnifying effect was in the middle-value area, and the farming-pastoral zone and the Qinling Mountain–Huaihe River zone formed important spatial division belts.     

Measuring individual vulnerability to floods in the lower and middle Grijalva River Basin,Tabasco, Mexico

Natural Hazards - We built an easy-to-interpret individual vulnerability index to floods that is amenable for empirical testing and may be adapted to any perceived hazard or ecological setting. An...     

基于文献记录的黑河流域历史时期旱涝特征分析

流域的旱涝灾害特征及其变化规律是流域水资源演变研究的重要内容。利用历史文献资料重建了西北内陆河黑河流域公元0-1949年的旱涝灾害等级序列,结合滑动平均、小波变换处理等方法,探讨了流域历史时期旱涝等级的频数特征、旱涝变化的周期特征及其与气候冷暖和人类活动之间的关系。对公元1000年以后的旱涝灾害规律进行分析,结果表明：流域存在5个旱灾高发阶段（1230-1270年、1430-1530年、1640-1760年、1860-1890年、1900-1940年）,3个涝灾高发期（1650-1690年、1730-1790年、1830-1910年）,并呈现出旱涝灾害频发的态势;1000-1949年期间,流域旱涝灾害存在4个准周期变化,对比发现这与太阳黑子活动等环境变化周期有紧密的联系;1580年以前,气候冷暖是影响旱涝灾害发生的主要因子,但16世纪以后,旱涝灾害交替频发,很可能是人类活动加剧了该现象。所以,定量辨析自然因素和人类活动对流域旱涝灾害的影响将是未来研究的重点方向。     

Assessment of regional drought vulnerability and risk using principal component analysis and a Gaussian mixture model

Due to the complex characteristics of drought, drought risk needs to be quantified by combining drought vulnerability and drought hazard. Recently, the major focus in drought vulnerability has been on how to calculate the weights of indicators to comprehensively quantify drought risk. In this study, principal component analysis (PCA), a Gaussian mixture model (GMM), and the equal-weighting method (EWM) were applied to objectively determine the weights for drought vulnerability assessment in Chungcheong Province, located in the west-central part of South Korea. The PCA provided larger weights for agricultural and industrial factors, whereas the GMM computed larger weights for agricultural factors than did the EWM. The drought risk was assessed by combining the drought vulnerability index (DVI) and the drought hazard index (DHI). Based on the DVI, the most vulnerable region was CCN9 in the northwestern part of the province, whereas the most drought-prone region based on the DHI was CCN12 in the southwest. Considering both DVI and DHI, the regions with the highest risk were CCN12 and CCN10 in the southern part of the province. Using the proposed PCA and GMM, we validated drought vulnerability using objective weighting methods and assessed comprehensive drought risk considering both meteorological hazard and socioeconomic vulnerability.

     

Geographic perspectives on vulnerability analysis

This special issue of GeoJournal is centered on geographic approaches to vulnerability analysis. Six papers addressing several core areas of active research in vulnerability analysis are included in this volume of work. In particular, network analysis methods, geographic data acquisition and use, measurement of vulnerability, evaluation of spatial and temporal variability in vulnerability, as well as related theoretical and policy issues are examined in detail.