共查询到20条相似文献,搜索用时 73 毫秒
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本文利用淮河流域172个常规气象站的逐日降水资料、一日四次的NCEP再分析资料,从动力、热力、水汽三个方面对2013年7月3~7日淮河流域一次持续性强降雨过程的发生发展机理进行分析,进而为今后淮河流域的暴雨预报提供参考。一、降雨实况2013年7月3~7日,受高空槽、中低层低涡切变的共同影响,淮河流域发生了大范围的强降雨天气过程,并伴有大风、雷暴等强对流天气。 相似文献
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2007年7月初,嘉陵江流域发生强降雨过程,支流渠江控制站罗渡溪站出现了自1953年建站以来有实测资料的最大洪水,造成严重的洪涝灾害。介绍了“07.7”嘉陵江流域的降雨实况,分析了造成“07.7”洪水的天气成因和降雨特点,并对洪水的特点进行分析和总结,对以后的降雨、洪水预报有一定的参考价值。 相似文献
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采用统计学、天气学等方法分析了2005~2010年5~10月雅砻江流域水文站、气象站日雨量资料及气象要素资料。通过对期间217次降雨过程中雨带强度和位置变化特征的统计分析发现,影响雅砻江流域的过程性雨带有5种类型,其中以南压型雨带的发生率最高,降雨强度最大,对水情的影响程度最高。分析了影响雅砻江流域过程性降雨的天气系统以及其活动规律。从日常业务预报的角度,筛选出89个对应的致洪强降雨样本个例,分析提出致洪强降雨预报的天气学判据,即在强降雨发生前24 h,强降雨区附近有低值系统活动,且流层中低层天气要素呈现增温、增湿、气压降低等现象。 相似文献
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介绍2002年8月发生在长江中游的暴雨洪水的水雨情实况,分析了造成该次洪水的降水天气成因,并对洪水的特点进行一定总结和分析。有利于降雨的大尺度环流形势能不断诱导出降雨天气系统,形成持续的强降雨,易导致洪水发生;降雨特殊时空分布会造成洪水叠加,导致水位快速上涨。天气形势、天气系统、降雨的变化决定了洪水的形成、加剧、维持或消退。 相似文献
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鄱阳湖流域气候变化和人类活动对入湖水沙的影响 总被引:1,自引:0,他引:1
近些年鄱阳湖湖区季节性干枯问题频繁出现,有必要对鄱阳湖入湖水沙变化进行进一步研究。利用鄱阳湖流域"五河"基本水文站1961~2016年实测的水沙及流域降雨量资料,通过线性趋势、双累积曲线、经验统计法和统计系列对比法研究鄱阳湖入湖水沙演变过程及影响因素。结果表明:鄱阳湖流域降雨量、侵蚀性降雨量、降雨侵蚀力年际变化均呈不显著的上升趋势(P0.05)。入湖径流量年际变化趋势不显著,而入湖输沙量呈极显著的下降趋势(P0.01),且存在1985年和2000年两个突变点。影响入湖径流量和输沙量的关键降雨指标为年降雨量和降雨侵蚀力。以1961~1984年为基准期,1985~1999年经验统计法和系列对比法计算的水利水保工程减沙效应分别为41.8%和33.4%,在2000~2016年分别为70.6%和66.8%,水库拦沙是入湖输沙量减少的主要原因。 相似文献
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2020年6月底始,受持续强降雨和长江干流顶托倒灌影响,鄱阳湖水位暴涨,发生超历史纪录大洪水。基于水库、堤防、蓄滞洪区和非工程措施组成的鄱阳湖防洪体系现状,分析了2020年鄱阳湖洪水的雨情、水情和灾情特点,总结了鄱阳湖防洪体系在应对2020年洪水中取得的成效、存在的问题。提出要适应江湖自然节律,学会与洪水共生存,坚持束疏结合、重点防御、人力与技术防汛相结合、工程与非工程措施相结合,实施洪水风险管理,协调好湖泊治理与保护的关系等治水理念。 相似文献
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Local governance of Gunao Lake,Tikub Lake and Dagatan Lake: Small lakes of the Mount Banahaw–San Cristobal–Malepunyo Corridor,Philippines 下载免费PDF全文
B. B. C. Brillo 《Lakes & Reservoirs: Research and Management》2017,22(2):115-122
Although many lakes in the Philippines are threatened, the effectiveness of their governance has not received sufficient attention to date. This predicament is most severe in regard to small lakes as their localized governance has least been given consideration over the years. Predicated on this observation, this study explores the local governance of three small lakes (Gunao Lake; Tikub Lake; Dagatan Lake) situated between the Mount Banahaw–San Cristobal and Mount Malepunyo area. Specifically, it analyses the role of local governments in managing and developing the small lakes. Using data from interviews, observations and the few existing documents on these lakes, this study contends that the main feature of governance regarding the three lakes is the Municipal Governments’ commitment and determination, which is consequential in their development over time. For Gunao Lake, the failure of the Municipal Government of Dolores to link the development of the lake with the tourism agenda in the Mount Banahaw area has resulted in its lack of tourism development. For Tikub Lake, the consistent push of the Municipal Government of Tiaong for its tourism agenda is key in the incremental improvement and preservation of the lake. For Dagatan Lake, the persistence of the Municipal Government of San Antonio in pursuing the restoration project and searching for a patron to finance the endeavour is crucial in the revival of the lake. Overall, this study highlights the distinct praxis of local governance regarding each of these small lakes, extends scholarship in regard to lake governance and offers a broad template for managing the many existing small lakes in the country. 相似文献
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Nitrate (NO3?) levels in Lake Superior have increased from historic levels of about 5?μM to its current concentration of about 25?μM. The atmosphere makes a substantial contribution to the nitrogen budgets for Lake Superior and Lake Michigan. This study provides a more well-defined estimate of nitrogen dry deposition rates derived from the measurement of over-water concentrations, and in situ meteorological measurements, which were input into the Resistance Model. We obtained a nitrogen dry deposition rate of [(3.41?±?2.26)?×?107?kg?N/yr; (5.90?±?3.91)?kg?N/ha/yr] over Lake Michigan, and [(1.54?±?1.06)?×?107?kg?N/yr; (1.87?±?1.27)?kg?N/ha/yr] over Lake Superior. Nitric acid (HNO3), which originates from the combustion of fossil fuels, contributes 84% of the total nitrogen dry deposition to Lake Michigan; and 66% to Lake Superior. Ammonia (NH3), which originates from agricultural activities and gasoline combustion, is the second highest contributor of nitrogen dry deposition to both lakes: contributing 13% to Lake Michigan and 32% to Lake Superior. The nitrogen dry deposition is approximately 68% of the nitrogen wet deposition over Lake Superior, and approximately 80% of wet deposition over Lake Michigan. The over-water dry deposition velocity of HNO3 and NH3 were also evaluated. We obtained morning deposition velocities of 0.099?cm/s for NH3 and 0.095?cm/s for HNO3; and afternoon values of 0.137?cm/s for NH3 and 0.132?cm/s for HNO3. Another key finding is that the atmospheric concentrations of nitrogen compounds near Lake Michigan and Lake Superior have decreased since 2003. 相似文献
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为了分析鄱阳湖区降雨量的变化特征,按照相关标准对年降雨日数和降雨量进行分级,深入研究各级雨日(量)的年际变化特征和年内分配规律。利用鄱阳湖区都昌站1953—2012年逐日降雨资料,采用趋势突变检验、Hurst指数、集中度和集中期等方法对鄱阳湖区年和季节分级雨日(量)的变化特征进行分析。研究结果表明:①鄱阳湖区年平均降雨日数为134 d,其中,小雨日数、中雨日数、大雨日数和暴雨日数所占雨日的比例分别为70.9%,18.66%,8.2%,2.98%;过去几十年,年总雨日数、小雨日数和暴雨日数均呈现显著减少的趋势并可能持续减少,年总雨日数在1978年发生突变,突变后雨日数减少了14 d;季节性降雨中,春、夏2季以大雨暴雨为主,秋、冬2季以小雨、中雨为主。②鄱阳湖区年平均降雨量为1 335.66 mm,小雨、中雨、大雨和暴雨占年降雨的比例分别为20.74%,29.50%,27.35%,22.41%;过去几十年,年降雨量呈显著减少趋势并可能继续减少,并在1976年发生突变,突变后年平均降雨量减少了301.26 mm。③鄱阳湖区降雨集中度平均为0.4,但受降雨年内分配的影响,降雨集中度年际差异较大;降雨集中期主要集中在3月中旬—6月中旬,其中,4月中旬—5月中旬占了71.43%。鄱阳湖区降雨日数的减少主要是由小雨日数减少引起的,降雨量的减少是各级雨量共同减少造成的;降雨集中度的大小与大雨和暴雨量所占年降雨量的比例密切相关,且与降雨不均匀系数显著正相关。研究结果可为进一步认识鄱阳湖湿地水文情势变化特征提供依据。 相似文献
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Distribution and carbon isotope composition of lipid biomarkers in Lake Erhai and Lake Gahai sediments on the Tibetan Plateau 总被引:1,自引:0,他引:1
Lipid biomarkers and carbon isotopes of n-alkanes, n-fatty acids, and n-alkan-2-ones were used to determine organic carbon sources to surface sediments in lakes Erhai and Gahai on the Tibetan Plateau. All sediment samples contained n-fatty acids with lower concentrations of n-alkanes and n-alkan-2-ones. Long chain n-alkanes in lake sediments were characteristic of a source mixture of epicuticular waxes of higher plants and submerged littoral zone plants while n-fatty acids sources were bacteria and floating and/or submergent macrophytes; the n-alkan-2-ones had a possible source in epicuticular waxes of higher plants and/or grass from catchment which entered the lake and were reworked by the microorganisms. Sediment samples examined from Lake Erhai had heavier δ13C values of bulk organic carbon and specific carbon compounds than samples from Lake Gahai and meadow soil. This heavier isotopic composition can be best interpreted by the enhanced productivity occurring in Lake Erhai due to its lower salinity and possibly to limited CO2 concentrations; for the latter, this may have enriched 13C in the dissolved inorganic carbon pool of the lake water. 相似文献
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水利工程建设对洞庭湖及鄱阳湖湿地的影响 总被引:1,自引:0,他引:1
随着三峡水利工程建成运行以及长江上游干流梯级 水库的规划建设,水利工程对两湖(洞庭湖、翻阳湖)湿地的叠加累积影响正逐步显露,其主 要表现为泥沙对两湖湿地演化的影响,水文变化对两湖生物、生境的影响。对生物及生境的 影响,两湖湿地表现较为一致,为此,主要论述了对滩地、植被、越冬珍稀水鸟、鱼类的影 响等。大型水利工程建设对湿地演化的影响,两湖湿地表现出的差异性则较大:对洞庭湖, 长江干流水利工程减缓了湿地正向演化的速度,但却加重了湿地正向演化最终的萎缩程度; 对鄱阳湖,长江干流水利工程破坏了现有的泥沙冲淤准动态平衡过程,大大加速了湿地的正 向演化的速度,此外鄱阳湖控制工程将使鄱阳湖湿地迅速萎缩。 相似文献
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洪泽湖是我国第四大淡水湖,是一典型的过水性湖泊,无论是洪水(水灾)或是枯水(旱灾)均应当引起同等重要的关注,泄与蓄要兼顾兼施,必须从资源水利的角度来审视和研讨洪泽湖的治理和改造,因此,开辟了海水道是治理淮河与洪泽湖的根本举措,蓄泄兼施,淮水在湖外分流;清淤掘底,增加蓄水量;整治湖口,淮河洪水畅流入湖,防治污染,保护水环境。 相似文献