Probabilistic depth–damage curves for assessment of flood-induced building losses

Natural Hazards - To investigate the propagation of meteorological droughts to agricultural and hydrological droughts, the relationship between droughts was analyzed using observed precipitation...     

Spatiotemporal meteorological drought assessment: a case study in south-east Australia

Natural Hazards - An understanding on different aspects of droughts is crucial for effective water resources management. Australia has experienced notable droughts in recent years. The present...     

Spatiotemporal variability of vegetation due to drought dynamics (2012–2017): a case study of the Upper Paraíba River basin,Brazil

Natural Hazards - Vegetation indices have been widely used for monitoring the spatiotemporal variables of vegetation and characterizing droughts, primarily in semiarid regions. Drought is a...     

Evaluation of time scale of meteorological,hydrological and agricultural drought indices

Natural Hazards - The present study was carried out to characterize drought in the Marathwada region of Maharashtra, which experiences recurring droughts, through meteorological, hydrological and...     

Spatio-temporal variability of dry and wet conditions over East Africa from 1982 to 2015 using quantile regression model

Natural Hazards - Precipitation and temperature are critical climatic variables that drive catastrophic climatic events including droughts and floods. These variables continue to fluctuate, thereby...     

An overview of US state drought plans: crisis or risk management?

Natural Hazards - Recent severe drought events across the nation have raised our concerns over society’s changing and increasing vulnerability to droughts. All levels of governments have...     

A multifractal cross-correlation investigation into sensitivity and dependence of meteorological and hydrological droughts on precipitation and temperature

Natural Hazards - Several studies have been conducted on droughts, precipitation, and temperature, whereas none have addressed the underlying relationship between nonlinear dynamic properties and...     

Investigation of spatio-temporal patterns of seasonal streamflow droughts in a semi-arid region

Natural Hazards - Spatio-temporal patterns of seasonal streamflow droughts were investigated for the semi-arid Karkheh watershed, located in western Iran with an area of 41,470 km2,...     

Assessing the effect of future landslide on ecosystem services in Aqabat Al-Sulbat region,Saudi Arabia

Natural Hazards - Co-occurrence events of droughts and heatwaves characterized by abnormal low soil moisture (SM) and high temperatures may cause more significant impacts on society and natural...     

ENSO-induced drought hazards and wet spells and related agricultural losses across Anhui province,China

Natural Hazards - Using daily precipitation data from 25 meteorological stations for a period of 1961–2014, spatiotemporal features of wet spells and droughts and related impacts on...     

Spatio‐temporal trend analysis of drought in the GAP Region,Turkey

Natural Hazards - Drought is considered to be one of the most devastating natural disasters. In recent years, determination of historical droughts has gained more importance. This can be attributed...     

Wetland loss and degradation in the Yellow River Delta, Shandong Province of China

Environmental degradation of wetlands is a major issue in the Yellow River Delta of China. Natural threats and human activities, such as flow cut-off of the Yellow River and droughts, population growth and urbanization, cause wetlands degradation of the delta during the last century, especially in the recent 50?years. Wetland degradation in the Yellow River Delta was investigated and its causation was analyzed. The results indicated that landscape changes of wetlands were mostly tremendous in the whole delta, namely loss of wetland area, surface water and groundwater pollution. Some new degradation control measures based on traditional and scientific knowledge must be used to reverse the wetlands degradation in the Yellow River Delta.     

云南干旱“常态化”的分析

近年来云南持续发生严重干旱,云南干旱是否日趋"常态化"成为社会各界关心的一个热点问题,相关报道不断见诸媒体。本文从水文的角度对云南省的历史干旱、水文要素以及趋势预测等方面进行了深入的分析。在历史依据和现代气象水文观测数据的支撑下,考察近100年来全球增暖可能导致部分地区干旱化的可能,从而认为近年来提出的云南干旱"常态化"存在科学依据;但干旱"常态化"仅能局限于近现代时期这一时间范畴,对于今后更长时期云南省干旱发展趋势,依据现有技术手段及研究成果尚难以判断把握。     

近1 000年长江中下游旱涝与气候变化关系

文章利用旱涝灾害历史记载与现代器测降水资料重建长江中下游旱涝灾害等级序列 ,并通过相关分析与波谱分析、交叉谱分析等分别探讨了长江中下游旱涝灾害发生与东太平洋海水表面温度 (SST)以及太阳活动 (太阳黑子数 )的关系。结果表明 ,长江中下游涝灾多发生于气候过渡期 ,即涝灾在气候由一种气候状态向另一种气候状态转变时期多发。谱分析与交叉谱分析结果表明 ,长江中下游旱涝灾害等级序列在 10～ 11年周期上与太阳黑子数存在相关 ,但两者有近 1年的滞后性。长江中下游旱涝灾害与SST的相关关系分析表明 ,SST正距平年份 ,往往对应着长江中下游的涝灾 ;而SST负距平年份往往对应着长江中下游旱灾。因而可以认为 ,SST与太阳活动变化(太阳黑子数量变化 )在不同周期频度上对长江中下游旱涝灾害具有明显影响。     

Copula-based evaluations of drought variations in Guangdong, South China

Changing characteristics of hazardous weather-related events have been arousing considerable public interest in recent years. Guangdong is an economically developed province in China and is prone to natural hazards. Using monthly precipitation data covering a period of 1956?C2008 from 127 rain gauge stations, the probabilistic behaviors of SPI-based droughts were investigated with copulas functions. Results indicated a higher risk of droughts along the coastal regions and the western Guangdong, particularly the Pearl River Delta (PRD) region. Joint probabilities of droughts with higher intensity and longer duration were found to have relatively even geographical distribution across Guangdong. The northern parts of Guangdong are higher in altitude and have a lower risk of droughts. Identification of regions characterized by droughts of different severity and durations across Guangdong is important for scientific management of water resource and agricultural activities and also the development of social resilience under the influence of climate changes.     

Relict nebkhas (pimple mounds) record prolonged late Holocene drought in the forested region of south-central United States

The origin and significance of pimple mounds (low, elliptical to circular dune-like features found across much of the south-central United States) have been debated for nearly two centuries. We cored pimple mounds at four sites spanning the Ozark Plateau, Arkansas River Valley, and Gulf of Mexico Coastal Plain and found that these mounds have a regionally consistent textural asymmetry such that there is a significant excess of coarse-grained sediment within their northwest flanks. We interpret this asymmetry as evidence of an eolian depositional origin of these mounds and conclude they are relict nebkhas (coppice dunes) deposited during protracted middle to late Holocene droughts. These four mounds yield optically stimulated luminescence ages between 2400 and 700 yr that correlate with well-documented periods of eolian activity and droughts on the southern Great Plains, including the Medieval Climate Anomaly. We conclude vegetation loss during extended droughts led to local eolian deflation and pimple mound deposition. These mounds reflect landscape response to multi-decadal droughts for the south-central U.S. The spatial extent of pimple mounds across this region further underscores the severity and duration of late Holocene droughts, which were significantly greater than historic droughts.     

Long karst spring discharge time series and droughts occurrence in Southern Italy

A series of long karst spring discharges have been analysed to determine trends, fluctuations and relationship to rainfall. Data come from aquifers in southern Italy, and in some cases cover more than one hundred years of records. Based on yearly discharge data, hydrological series show the drop of the discharge after 1986, which has been interrupted by the recent wet years of 2009 and 2010. This drop is connected to the decrease in annual rainfall, but other factors also seem to contribute to this phenomenon. Based on monthly scale data series, the relationship between meteorological and hydrological droughts has been analyzed, using the standard precipitation index (SPI). As karst systems are large reservoirs, only longer meteorological droughts induce groundwater droughts, and the start, duration and time-lag of the hydrological droughts have been evaluated.     

Groundwater-dependent ecology of the shoreline of the subtropical Lake St Lucia estuary

The ecology of the St Lucia estuary in South Africa is of unique international importance. During droughts the estuary experiences high salinities, with values above that of seawater. Ion-poor groundwater flowing into the estuary from prominent sand aquifers along its eastern shoreline forms low-salinity habitats for salt-sensitive biota. During droughts, plants and animals can take refuge in the groundwater discharge zone until the condition in the estuary regains tolerable salinity. Simulations of the groundwater discharge indicate that the flow can persist during droughts over at least a decade, and be of great important for the resilience of the estuary. Anthropogenic activities have reduced the river inflow and made the St Lucia estuary more sensitive to droughts. The groundwater has thereby become increasingly important for the estuary’s ecology. Protection of the groundwater discharge along the shoreline itself and actions to increase the groundwater recharge are therefore important management tasks.     

SPI-based evaluation of drought events in Xinjiang, China

Daily precipitation data for 1957?C2009 from 53 stations in the Xinjiang, China, are analyzed, based on the Standardized Precipitation Index (SPI) with the aim to investigate spatio-temporal patterns of droughts. The Mann?CKendall trend test is used to detect the trends in the SPI values of monthly drought series, drought severity and drought duration. The frequencies of moderate, severe and extreme droughts are higher in the North Xinjiang, while mild droughts occur more often in the South Xinjiang. A decreasing frequency of droughts in the North Xinjiang is found in winter, but a drying tendency is detected in the western parts of the North Xinjiang during spring, summer and autumn, which may be harmful for agriculture. The South Xinjiang seems to be getting wetter in summer, while the south parts of the South Xinjiang seem to be getting drier in spring. The middle of the East Xinjiang is identified to be in a slightly dry tendency. The drought severity is decreasing and drought duration is getting shorter in the North Xinjiang, while both of them increase in the southern parts of the South Xinjiang. In addition, droughts in the middle parts of the East Xinjiang are intensifying.     

干旱频率分析研究进展

从干旱定义与识别、点干旱频率分析和区域干旱频率分析3个方面系统阐述了干旱频率分析研究进展和存在问题,归纳了适用于干旱频率分析的干旱定义,干旱识别存在的主要问题以及区域干旱频率分析研究的3种途径。提出综合利用研究区域水文气象特性、干旱成因、旱情、旱灾,并结合前期的大气环流条件等信息来描述和识别干旱,重点开展对干旱特征变量的理论分布、干旱事件重现期公式和经验频率公式等基本理论的研究,关注区域干旱频率分析,注重对径流、土壤水、地下水和供水系统的干旱特性分析。