强降水事件的判定指标及评估研究          下载免费PDF全文

陈圣劼  张柳  康志明  刘梅  田心如 《气象科学》2023,43(4):505-514

以江苏1961—2020年夏季(6—9月)强降水事件的监测为例,分析评估了多种强降水事件的判定指标,如以百分位法、Gamma分布法和重现期法为代表的频率匹配阈值法及考虑偏离气候态程度的异常度法。结果表明,由于降水事件的区域差异和季节内变化特征,强(极端强)降水事件判定指标的设计应分区域分时段讨论,且能定量反映降水强度大、相对气候态异常显著且发生概率少(极少)的特点。不同判定方法所强调的强(极端强)降水事件的特点不同,如百分位法Type-Ⅱ强调了降水极值的极少发生,异常度法突出反映大幅度偏离气候态的程度。不同指标所确立的阈值大小也存在明显差别,如对于江苏夏季极端强降水事件的判定,百分位法Type-Ⅱ阈值最高,其次是异常度法,分别相当于20、10 a一遇最大降水量,百分位法Type-Ⅲ和Gamma分布法则相当于5 a一遇最大降水量。在与降水相关的服务工作中,不同地区需制定更详细的地方标准来明确强降水事件的定义,增强服务用语的规范性。  相似文献   

Improving extreme hydrologic events forecasting using a new criterion for artificial neural network selection     

Paulin Coulibaly  Bernard Bobe  Franois Anctil 《水文研究》2001,15(8):1533-1536

The issue of selecting appropriate model input parameters is addressed using a peak and low flow criterion (PLC). The optimal artificial neural network (ANN) models selected using the PLC significantly outperform those identified with the classical root‐mean‐square error (RMSE) or the conventional Nash–Sutcliffe coefficient (NSC) statistics. The comparative forecast results indicate that the PLC can help to design an appropriate ANN model to improve extreme hydrologic events (peak and low flow) forecast accuracy. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

乌鲁木齐极端天气事件及其与区域气候变化的联系   总被引：6，自引：0，他引：6  

杨霞  赵逸舟  李圆圆  赵克明 《干旱区地理》2009,32(6)

使用逐日观测资料,分析了乌鲁木齐极端天气事件的变化趋势及其与区域气候变暖的可能联系,结果表明:近30年来,乌鲁木齐的低温、大风和雷暴事件减少趋势明显,沙尘暴、大雾等事件呈略减少趋势;暴雨、高温和暴雪事件整体呈略增加的趋势。大雾、大风、低温、高温、雷暴等事件均具有较大的年际变化;暴雨、暴雪、沙尘暴、冰雹等事件的年际变化幅度均较小;各类极端天气事件均存在各自明显的周期性特征。乌鲁木齐年平均气温和高温、低温、沙尘暴等极端事件之间存在较强的相关性,这些与温度相关的极端天气事件的变化与区域气候变暖关系密切。  相似文献   

三塘湖盆地火山岩油气藏油气充注幕次及成藏年龄确定   总被引：2，自引：2，他引：0  

李华明  陈红汉  赵艳军 《地球科学》2009,34(5):785-791

油气藏油气充注幕次和成藏年龄确定一直是成藏过程研究的热点和核心问题.通过60块流体包裹体系统分析, 结合单井埋藏史投影方法, 分析了三塘湖盆地火山岩油气藏的油气充注幕次和成藏期次, 确定了其成藏年龄, 从而对其油气成藏过程进行了研究, 认为三塘湖盆地火山岩油气藏经历了石炭纪以来三期油气运聚的成藏过程.它们分别发生在259~230Ma、160~134Ma和70~0Ma, 其中早期(海西印支期)油气成藏对盆地深部油气勘探具有重要意义.   相似文献   

Paleoceanographic events of the southern Okinawa Trough during last 20 000 years   总被引：1，自引：0，他引：1  

Li Baohu  Zhao Quanhong  Wang Yongji  Jian Zhimin  Chen Ronghua 《海洋学报(英文版)》1998,17(4):519-530

Presentaddress:NanjingInstituteofGeologyandPaleontology,ChineseAcademyofSciences,Nanjing210008,ChinaINTRODUCTloNTheOkinawaTrough(NNE-SSW),thedeeperwaterbasinoftheEastChinaSea,liesbe-tween24'~3O"N,122"~13o'E(seeFig.l).Itssouthernpartiswideranddeeperthanthenorthernpart,withthemaximumwaterdepthof2719metersinthesouthwest.ThemostimPOrtanthydrographiccharacteristicinthisareaistheKuroshiocurrentwhichflowsalongthewestbankoftheokinawaTrough-(about2oo~5oometersindepth).Itinnu-encesthedep…  相似文献   

Meso-Cenozoic Tectonic Events Recorded by Apatite Fission Track in the Northern Longmen-Micang Mountains Region   总被引：2，自引：0，他引：2  

LEI Yongliang  JIA Chengzao  LI Benliang  WEI Guoqi  CHEN Zhuxin  SHI Xin 《《地质学报》英文版》2012,86(1):153-165

There is a cross-cutting relationship between the E-W trending structures and the NE-trending structures in the northern Longmen-Micang Mountains region,which reflects possible regional tectonic transi...  相似文献   

Pronounced increase in slope instability linked to global warming: A case study from the eastern European Alps     

Sara Savi  Francesco Comiti  Manfred R. Strecker 《地球表面变化过程与地形》2021,46(7):1328-1347

In recent decades, slope instability in high-mountain regions has often been linked to increase in temperature and the associated permafrost degradation and/or the increase in frequency/intensity of rainstorm events. In this context we analyzed the spatiotemporal evolution and potential controlling mechanisms of small- to medium-sized mass movements in a high-elevation catchment of the Italian Alps (Sulden/Solda basin). We found that slope-failure events (mostly in the form of rockfalls) have increased since the 2000s, whereas the occurrence of debris flows has increased only since 2010. The current climate-warming trend registered in the study area apparently increases the elevation of rockfall-detachment areas by approximately 300 m, mostly controlled by the combined effects of frost-cracking and permafrost thawing. In contrast, the occurrence of debris flows does not exhibit such an altitudinal shift, as it is primarily driven by extreme precipitation events exceeding the 75th percentile of the intensity-duration rainfall distribution. Potential debris-flow events in this environment may additionally be influenced by the accumulation of unconsolidated debris over time, which is then released during extreme rainfall events. Overall, there is evidence that the upper Sulden/Solda basin (above ca. 2500 m above sea level [a.s.l.]), and especially the areas in the proximity of glaciers, have experienced a significant decrease in slope stability since the 2000s, and that an increase in rockfalls and debris flows during spring and summer can be inferred. Our study thus confirms that “forward-looking” hazard mapping should be undertaken in these increasingly frequented, high-elevation areas of the Alps, as environmental change has elevated the overall hazard level in these regions.  相似文献   

Early post-release survival of stranded Cape fur seal pups at Black Rocks,Algoa Bay,South Africa     

《African Journal of Marine Science》2013,35(3):463-468

The small and isolated Cape fur seal Arctocephalus pusillus pusillus rookery at Black Rocks, Algoa Bay, South Africa, is an important component of the marine biota of the Addo Elephant National Park. Although little is known of the demographics of this rookery, it is believed to be declining in abundance. The pupping season for this population coincides with summer storms that often wash pups from Blacks Rocks. In the past, many that washed up on the mainland were rescued and returned to their colony. However, the necessity and value of this exercise has been questioned. The displacement of 200 pups from their rookery following a severe storm in December 2008 presented an opportunity to follow the early survival of rescued pups that were returned to Black Rocks. Tag resightings of those that were adequately tagged (n = 52) were obtained during five visits to Black Rocks over a period of 3½ months. The results indicated that about one-quarter of tagged pups survived. This is the first study to demonstrate substantial short-term survival of otariid pups following rehabilitation and return to the wild.  相似文献   

全新世胶州湾海侵及大沽河古河口湾的形成和演变   总被引：4，自引：0，他引：4  

刘志杰  庄振业  韩德亮  祁兴芬 《海岸工程》2004,23(1):5-12

晚更新世盛冰期低海面时,胶州湾为陆地,大沽河流于其上,河口在黄海陆架边缘。全新世海侵时,海水沿古河道侵入,约在9．6kaB．P．左右,胶州湾地区被海水淹没,并于湾顶西北侧形成196km^2的大沽河溺谷型河口湾,当时大沽河河口退缩至今谈家庄一沽河镇(李哥庄)一带。随后,河流泥沙在该河口湾快速淤积,形成十余米厚的水下冲积扇和1～2m厚的冲积层,将溺谷湾充填。约在4kaB．P．左右大沽河河口外延至现今营海码头村、三角底一带。  相似文献   

华北晚古生代海平面变化及其层序地层响应   总被引：5，自引：0，他引：5       下载免费PDF全文

吕大炜李增学  刘海燕郭建斌刘彬彬  孟召磊 《中国地质》2009,36(5):1079-1086

依据沉积学、煤地质学、层序地层学、古生物学等多学科综合方法,对华北地区晚古生代地层进行层序地层分析,并研究了相对海平面升降和其层序地层学响应,研究结果表明:研究区晚古生代地层存在着8种层序界面,主要包括古构造运动面、古生物间断面、大面积泥炭化沼泽化界面、陆表海低水位砂体底界、盆地转换界面、大范围冲刷面、大面积暴露面和硅质海绵岩等;依据界面的划分原则可以将研究区地层划分出1个盆地充填层序、3个构造层序(相当于二级层序)和7个三级层序;分析发现,基于层序格架下的相对海平面升降可以分为层序1-层序3的短期大规模海侵阶段及长时间海退阶段和层序4-层序7的长时期的海退阶段.在此基础上,依据海平面变化曲线及其层序地层响应特征发现华北晚古生代海平面变化具有周期性与复合性和高频性与事件性等特点.  相似文献