2017年辽宁省春夏季精细化气象干旱监测评估     

李晶  王婉昭  刘东明  黄岩  王莹  李荣平 《气象与环境学报》2019,35(3):100-105

基于辽宁省1114个国家级和区域级地面台站1961年以来的逐日气温和降水观测资料,利用距离平方反比法差值生成了1717个乡镇的气象资料序列,采用气象干旱综合监测指数统计分析了辽宁省2017年4—8月精细化到乡镇的气象干旱特征。结果表明:2017年辽宁省春夏季异常高温,同时降水异常偏少,致使气象干旱不断发展;干旱在4月5日前从中部和北部开始,4月末扩展到西部,5—6月再向东南发展,波及88%的乡镇,7月以来气象干旱程度开始减轻;气象干旱持续时间长的乡镇主要集中在中部和北部,最长持续时间153d;受气温偏高和降水过程的影响,中度以上气象干旱面积呈阶段性变化,且极端干旱的发展伴随高温时段。由于气象干旱不同于农业干旱,在开展为农服务时要因地制宜采取应对措施。  相似文献   

Spatio-temporal Distribution of Three Kinds of Flash Droughts over Agricultural Land in China from 1983 to 2015   总被引：1，自引：0，他引：1  

Xiang Zhang  Nengcheng Chen  Chuli Hu  Xiaoting Peng 《地球科学进展》2018,33(10):1048-1057

At present, flash drought occurs globally and regionally and causes a lot of socio-economic loss in a very short time. Therefore, flash drought has been regarded as one of the hottest issues in drought research. However, flash drought monitoring, prediction and decision-making have encountered a lot of challenges due to its multiple driven factors and complex spatio-temporal process. Aiming at this problem, this paper focused on the agricultural land in China, and analyzed the spatio-temporal distribution of three kinds of flash droughts (i.e., precipitation-deficit, high-temperature, and composite flash droughts) from 1983 to 2015. We studied the occurrences, duration, spatial distribution, temporal distribution, and trend of all three kinds of flash droughts. Our results demonstrated that, the occurrences of flash drought agricultural land in China increased year by year, among which high-temperature flash drought increased dramatically; duration of flash droughts had different trends, but the variations were relatively smooth; Northeast China was identified as a vulnerable area of flash drought, indicating more flash drought events and longer duration; flash droughts in China were found to concentrate in spring (high-temperature drought) and summer seasons (precipitation-deficit drought). This study is helpful for building new flash drought monitoring method and system, and it is also valuable for flash drought preparedness on regional scale.  相似文献   

The terrestrial fauna of the Late Triassic Pant-y-ffynnon Quarry fissures,South Wales,UK and a new species of Clevosaurus (Lepidosauria: Rhynchocephalia)     

Emily Keeble  David I. Whiteside  Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2018,129(2):99-119

Pant-y-ffynnon Quarry in South Wales yielded a rich cache of fossils in the early 1950s, including articulated specimens of new species (the small sauropodomorph dinosaur Pantydraco caducus and the crocodylomorph Terrestrisuchus gracilis), but no substantial study of the wider fauna of the Pant-y-ffynnon fissure systems has been published. Here, our overview of existing specimens, a few described but mostly undescribed, as well as freshly processed material, provides a comprehensive picture of the Pant-y-ffynnon palaeo-island of the Late Triassic. This was an island with a relatively impoverished fauna dominated by small clevosaurs (rhynchocephalians), including a new species, Clevosaurus cambrica, described here from a partially articulated specimen and isolated bones. The new species has a dental morphology that is intermediate between the Late Triassic Clevosaurus hudsoni, from Cromhall Quarry to the east, and the younger C. convallis from Pant Quarry to the west, suggesting adaptive radiation of clevosaurs in the palaeo-archipelago. The larger reptiles on the palaeo-island do not exceed 1.5?m in length, including a small carnivorous crocodylomorph, Terrestrisuchus, and a possible example of insular dwarfism in the basal dinosaur Pantydraco.  相似文献   

新疆天山山区干旱灾害综合风险评估与区划     

吴秀兰  张婧莉  余行杰  玛依拉&#  买买提艾力 《气象与环境学报》2022,38(4):161-167

以自然灾害风险四因子理论为基础,综合考虑研究区自然及社会经济情况,建立适合天山山区干旱灾害风险概念框架和指标体系,结合GIS技术进行了该地区干旱灾害风险评估与区划。结果表明：致灾因子危险性较高的区域是伊犁河谷及天山北坡一带,东疆地区和南疆西部危险性较低;承灾体脆弱性较高的区域为伊犁河谷和博州地区,吐鲁番、哈密及克州属于低脆弱区;孕灾环境敏感性较高地区主要分布在天山北坡的精河至吐鲁番一线、阿克苏地区西部、巴州北部等地,伊犁河谷、巴州北部、哈密市北部、南疆西部山区属低敏感区;防灾减灾能力整体表现为中东部高于西部区域;新疆天山山区干旱综合风险整体呈现出中部高、两端低的趋势,即中部的天山南北两侧干旱风险高于南疆西部和东疆地区。构建的评估模型总体反映了研究区旱灾综合风险水平,可为新疆天山草原灾害风险管理、应对气候变化、抗旱减灾行动提供参考。  相似文献   

Identifying future climate change and drought detection using CanESM2 in the upper Siem Reap River,Cambodia     

《Dynamics of Atmospheres and Oceans》2021

Cambodia is one of the most vulnerable countries to climate change impacts such as floods and droughts. Study of future climate change and drought conditions in the upper Siem Reap River catchment is vital because this river plays a crucial role in maintaining the Angkor Temple Complex and livelihood of the local population since 12th century. The resolution of climate data from Global Circulation Models (GCM) is too coarse to employ effectively at the watershed scale, and therefore downscaling of the dataset is required. Artificial neural network (ANN) and Statistical Downscaling Model (SDSM) models were applied in this study to downscale precipitation and temperatures from three Representative Concentration Pathways (RCP 2.6, RCP 4.5 and RCP 8.5 scenarios) from Global Climate Model data of the Canadian Earth System Model (CanESM2) on a daily and monthly basis. The Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI) were adopted to develop criteria for dry and wet conditions in the catchment. Trend detection of climate parameters and drought indices were assessed using the Mann-Kendall test. It was observed that the ANN and SDSM models performed well in downscaling monthly precipitation and temperature, as well as daily temperature, but not daily precipitation. Every scenario indicated that there would be significant warming and decreasing precipitation which contribute to mild drought. The results of this study provide valuable information for decision makers since climate change may potentially impact future water supply of the Angkor Temple Complex (a World Heritage Site).  相似文献   

基于MCI指数的福建省干旱气候特征     

庄瑶  鲍瑞娟  张容焱  何金海  汪澜 《气象与环境学报》2021,37(5):93-99

采用目前国家干旱监测业务实行的MCI指数,利用Morlet小波、经验正交函数（EOF）等方法,分析了福建省1961—2019年全省66个气象站MCI指数表征的干湿状况和干旱变化特征。结果表明：福建省存在明显的干湿气候特征,具有显著的6—8 a和22 a的周期振荡,内陆山区干湿变化周期比沿海长,在季节尺度上各季均存在多时间尺度和地域差异化的特点;其空间变化具有3种典型模态,反映了季风降水多寡和地形差异。MCI表征的干旱过程时空分布与历史干旱事件相吻合,秋季和冬季是福建省干旱发生频率最高的季节,春季和夏季是干旱强度最强的季节;闽江口以南沿海地区干旱发生率明显高于内陆地区,全省出现同步干旱的机率较小（12%）。  相似文献   

升温1.5℃和2.0℃情景下中亚地区干旱耕地暴露度研究     

王安乾  陶辉  方泽华 《气候变化研究进展》2022,18(6):695-706

基于CMIP5中的5个全球气候模式统计降尺度的降水、最高和最低气温等数据,利用标准降水蒸发指数（SPEI）和强度-面积-持续时间（IAD）方法识别全球升温1.5℃与2.0℃情景下中亚地区干旱事件,结合30 m分辨率土地利用数据,探讨中亚干旱事件的演变及耕地暴露度变化。结果表明：相比基准期（1986—2005年),中亚地区的降水和潜在蒸发量均有所增加;全球升温1.5℃与2.0℃情景下,中亚地区的干旱事件频次、强度和面积均将增加,其中重旱和极旱事件的频次和影响面积大幅上升,而中旱事件的频次和影响面积持续下降;1986—2005年中亚地区年均干旱耕地暴露度约11.5万km2,全球升温1.5℃和2.0℃情景下,干旱耕地暴露度将分别上升到17.9万km2和28.6万km2,且暴露在极旱下的耕地面积增加最明显。全球升温1.5℃与2.0℃情景下,增加的干旱事件将会严重威胁当地农业生产和粮食安全,中亚地区需对干旱事件采取长期的减缓与适应措施。  相似文献   

Analysing the relationship between drought and soil erosion using vegetation health index and RUSLE models in Godavari middle sub-basin,India     

《地学前缘(英文版)》2022,13(2):101312

Drought is a natural phenomenon posing severe implications for soil, groundwater and agricultural yield. It has been recognized as one of the most pervasive global change drivers to affect the soil. Soil being a weakly renewable resource takes a long time to form, but it takes no time to degrade. However, the response of soil to drought conditions as soil loss is not manifested in the existing literature. Thus, this study makes a concerted effort to analyze the relationship between drought conditions and soil erosion in the middle sub-basin of the Godavari River in India. MODIS remote sensing data was utilized for driving drought indices during 2000–2019. Firstly, we constricted Temperature condition index (TCI) and Vegetation Condition Index (VCI) from Land Surface Temperature (LST) and Enhanced Vegetation Index (EVI) derived from MODIS data. TCI and VCI were then integrated to determine the Vegetation Health Index (VHI). Revised Universal Soil Loss Equation (RUSLE) was utilized for estimating soil loss. The relationship between drought condition and vegetation was ascertained using the Pearson correlation. Most of the northern and southern watersheds experienced severe drought condition in the sub-basin during 2000–2019. The mean frequency of the drought occurrence was 7.95 months. The average soil erosion in the sub-basin was estimated to be 9.88 t ha^?1 year^?1. A positive relationship was observed between drought indices and soil erosion values (r value being 0.35). However, wide variations were observed in the distribution of spatial correlation. Among various factors, the slope length and steepness were found to be the main drivers of soil erosion in the sub-basin. Thus, the study calls for policy measures to lessen the impact of drought and soil erosion.  相似文献   

渤海湾盆地南堡凹陷南部深层沙一段优质碎屑岩储层特征及成因机制     

赵晓东  时阳  文雯  李亮  张博明  陈刚强 《地质论评》2021,67(3):67040015-67040015

利用岩芯、薄片、扫描电镜和分析化验等资料,对南堡凹陷南部深层古近系沙一段（沙河街组一段）优质碎屑岩储层特征进行了分析并揭示其成因机制。研究表明：①南堡凹陷南部沙一段优质碎屑岩储层属于低孔中渗储层,发育原生孔隙、次生孔隙和微裂缝;②沙一段沉积期处于强水动力沉积环境,辫状河三角洲前缘水下分流河道砂体普遍发育,岩性主要为中粗砂岩、含砾砂岩和砂砾岩等粗岩性,岩石类型主要为岩屑长石砂岩,石英、岩浆岩岩屑等刚性组分含量高,储层在强压实作用下仍保留了局部原生残余粒间孔,部分刚性组分强压条件下形成微裂缝;③沙一段与东三段为区域不整合接触,大气水的酸性流体在成岩初期以及烃源岩成熟之后产生的有机酸在成岩后期通过油源断裂和不整合面进入储层,造成长石、易溶碎屑等组分溶蚀形成次生孔隙,溶蚀作用不仅增加孔隙空间,而且扩大喉道宽度。结论认为：粗岩性和高刚性颗粒含量为原生孔隙的保存提供了物质基础;油源断层、不整合面为酸性流体的进入提供路径,促进了次生孔隙发育。  相似文献   

On the linkage between changes in cloud cover and precipitation extremes over Central India     

《Dynamics of Atmospheres and Oceans》2019

In this study, linkage between changing characteristics of precipitation extremes and cloud covers over Central India is explored during summer monsoon period using Satellite data (1998–2015). This is a first attempt to relate the changes in cloud cover to the changes in precipitation extremes. Non-rainy cirrus clouds are excluded from this study. Results show that heavy rainfall (≥ 60 mm/day) is associated with cold cloud tops (Tb≤220 K) while moderate rainfall (<60 mm/day and ≥20 mm) occurs mostly with middle clouds (Tb>220 K and ≤245 K). Low level clouds (Tb> 245 K) are responsible for light rainfall (<20 mm/day). Increases in top 20%, 10%, 5% and 1% heavy precipitation relate well with the increases in very deep convective, deep convective and convective cloud cover. Among these relations, increase in top 5% heavy precipitation relates best with increase in very deep convective cloud cover. Decrease in bottom 30% low precipitation relates with decrease in low level cloud cover. The results reported in this study fit into the framework of how weather extremes respond to climate change.  相似文献