排序方式： 共有11条查询结果，搜索用时 15 毫秒
1.
Lucas O. Bianchi Juan Antonio Rivera Facundo Rojas Mauro Britos Navarro Ricardo Villalba 《水文科学杂志》2017,62(4):533-545
In the Central Andes of Argentina (30–37°S), snowmelt is the main source of freshwater, an essential natural resource for ~2.2 million people in the adjacent arid lowlands. In this region, Laguna Llancanelo collects the water inputs from the Malargüe endorheic basin. Previous studies concerning the annual and intra-annual variations of this lagoon and its relationship with regional climate are rare. We obtained a monthly record for the Laguna Llancanelo area (LLA, 1984–2013) using the modified normalized difference water index derived from Landsat images. Monthly LLA ranges between 35 km2 and 411 km2 and is significantly related to variations of the Río Malargüe, the main snow-fed tributary to the lagoon. There is no long-term relationship between LLA and local rainfall, but rapid increases in LLA result from heavy rainfall around the lagoon. Conversely, rapid reductions in LLA encompass periods with both reduced discharge from the Río Malargüe and low local rainfall. The LLA integrates moisture of both Pacific (snowfall in the upper Andes) and Atlantic (lowland rainfall) origins; therefore, we propose using LLA as an indicator of regional water balance. 相似文献
2.
为研究黄河流域水文气象要素变化规律,并揭示各要素与东亚夏季风之间的潜在关系,建立了全流域VIC水文模型、MK突变检验和MK相关检验。结果表明:从20世纪80年代中期开始,流域绝大部分地区气温上升趋势明显,而降水、蒸散发、径流深和土壤湿度呈整体减小趋势,且中游地区减幅最大。各要素与东亚夏季风相关密切,但空间差异性明显。气温与东亚夏季风强度普遍呈负相关,且宁蒙河段及内流区相关性显著;其他要素则相反,正相关显著区域主要位于河口镇到三门峡区间。研究还发现相比较降水,黄土高原径流深对夏季风强度变化更为敏感。因此,对东亚夏季风的研究可为预测黄河流域内水文过程及水资源的变化提供重要的科学参考。 相似文献
3.
Towards a better understanding of hydrological interactions between the land surface and atmosphere, land surface models are routinely used to simulate hydro-meteorological fluxes. However, there is a lack of observations available for model forcing, to estimate the hydro-meteorological fluxes in East Asia. In this study, Common Land Model (CLM) was used in offline-mode during the summer monsoon period of 2006 in East Asia, with different forcings from Asiaflux, Korea Land Data Assimilation System (KLDAS), and Global Land Data Assimilation System (GLDAS), at point and regional scales, separately. The CLM results were compared with observations from Asiaflux sites. The estimated net radiation showed good agreement, with r =0.99 for the point scale and 0.85 for the regional scale. The estimated sensible and latent heat fluxes using Asiaflux and KLDAS data indicated reasonable agreement, with r = 0.70. The estimated soil moisture and soil temperature showed similar patterns to observations, although the estimated water fluxes using KLDAS showed larger discrepancies than those of Asiaflux because of scale mismatch. The spatial distribution of hydro-meteorological fluxes according to KLDAS for East Asia were compared to the CLM results with GLDAS, and the GLDAS provided online. The spatial distributions of CLM with KLDAS were analogous to CLM with GLDAS, and the standalone GLDAS data. The results indicate that KLDAS is a good potential source of high spatial resolution forcing data. Therefore, the KLDAS is a promising alternative product, capable of compensating for the lack of observations and low resolution grid data for East Asia. 相似文献
4.
5.
2002-2017年千岛湖浮游植物群落结构变化及其影响因素 总被引：2，自引：0，他引：2
为认识大型水库中浮游植物群落结构的演替特征及其驱动机制，以钱塘江流域新安江水库（下称"千岛湖"）为例，基于2002-2017年16年的水库浮游植物数据，结合同期千岛湖水质与水文气象资料，分析了千岛湖浮游植物结构及优势属的长期变化特征，探讨了影响浮游植物群落结构变化的主要因素.结果表明：2002-2017年千岛湖共鉴定出浮游植物7门93属，主要由硅藻门、绿藻门、蓝藻门及隐藻门种类组成.16年间，浮游植物年均丰度和群落结构经历了4个阶段：2008年前丰度持续低值且蓝藻不是主要类群，2009-2012年丰度较高且蓝藻成为主要类群，及2013-2015丰度降低且蓝藻占比降低，2016-2017年丰度增加且蓝藻再次成为主要类群.浮游植物门类变化的同时伴随着优势属的变化：浮游植物年优势属从2002-2008年的小环藻属（Cyclotella）、隐藻属（Cryptomonas）和蓝隐藻属（Chroomonas）转变为2009-2012年的颤藻属（Oscillatoria）、小球藻属（Chlorella）、小环藻属和蓝隐藻属，2013-2017年又转变为鱼腥藻属（Anabaena）、束丝藻属（Aphanizomenon）、小环藻属、针杆藻属（Synedra）、直链藻属（Melosira）、栅藻属（Scenedesmus）和蓝隐藻属.冗余分析表明，气温、风速、水位、入库流量等气象水文因子和总氮浓度、电导率、氮磷比、透明度等水质因子与浮游植物群落结构变化关系密切.研究结果表明，在千岛湖这种大型贫-中营养水库，浮游植物群落结构不仅受来水营养盐负荷的影响，还在很大程度上受水文、气象条件的影响，给水库藻类水华等生态风险的预测以及水库水质管理带来了挑战. 相似文献
6.
ABSTRACTTurbulence is considered to generate and drive most geophysical processes. The simplest case is isotropic turbulence. In this paper, the most common three-dimensional power-spectrum-based models of isotropic turbulence are studied in terms of their stochastic properties. Such models often have a high order of complexity, lack stochastic interpretation and violate basic stochastic asymptotic properties, such as the theoretical limits of the Hurst coefficient, when Hurst-Kolmogorov behaviour is observed. A simpler and robust model (which incorporates self-similarity structures, e.g. fractal dimension and Hurst coefficient) is proposed using a climacogram-based stochastic framework and tested over high-resolution observational data of laboratory scale as well as hydro-meteorological observations of wind speed and precipitation intensities. Expressions of other stochastic tools such as the autocovariance and power spectrum are also produced from the model and show agreement with data. Finally, uncertainty, discretization and bias related errors are estimated for each stochastic tool, showing lower errors for the climacogram-based ones and larger for power spectrum ones. 相似文献
7.
George Papaioannou George Varlas Anastasios Papadopoulos Athanasios Loukas Petros Katsafados Elias Dimitriou 《水文研究》2021,35(4):e14151
A common source of uncertainty in flood inundation forecasting is the hydrograph used. Given the role of sea-air-hydro-land chain processes on the water cycle, flood hydrographs in coastal areas can be indirectly affected by sea state. This study investigates sea-state effects on precipitation, discharge, and flood inundation forecasting implementing atmospheric, ocean wave, hydrological, and hydraulic-hydrodynamic coupled models. The Chemical Hydrological Atmospheric Ocean wave System (CHAOS) was used for coupled hydro-meteorological-wave simulations ‘accounting’ or ‘not accounting’ the impact of sea state on precipitation and, subsequently, on flood hydrograph. CHAOS includes the WRF-Hydro hydrological model and the WRF-ARW meteorological model two-way coupled with the WAM wave model through the OASIS3-MCT coupler. Subsequently, the 2D HEC-RAS hydraulic-hydrodynamic model was forced by the flood hydrographs and map the inundated areas. A flash flood event occurred on 15 November 2017 in Mandra, Attica, Greece, causing 24 fatalities, and damages was selected as case study. The calibration of models was performed exploiting historical flood records and previous studies. Human interventions such as hydraulic works and the urban areas were included in the hydraulic modelling geometry domain. The representation of the resistance caused by buildings was based on Unmanned Aerial System (UAS) data while the local elevation rise method was used in the urban-flood simulation. The flood extent results were assessed using the Critical Success Index (CSI), and CSI penalize. Integrating sea-state affected the forecast of precipitation and discharge peaks, causing up to +24% and from −8% to +36% differences, respectively, improving inundation forecast by 4.5% and flooding additional approximately 70 building blocks. The precipitation forcing time step was also highlighted as significant factor in such a small-scale flash flood. The integrated multidisciplinary methodological approach could be adopted in operational forecasting for civil protection applications facilitating the protection of socio-economic activities and human lives during similar future events. 相似文献
8.
2009年黄海绿潮浒苔爆发与漂移的水文气象环境 总被引：1，自引：0，他引：1
2008年和2009年,黄海中西部局部海区均出现绿潮浒苔,但由于绿潮爆发时间不同和漂移路径不同,造成的影响大不相同。本文利用EOS卫星的多通道资料,采用通道合成的方法,给出了绿潮浒苔的分布和移动情况。利用卫星遥感的海面风场、降水、云中液态水含量、海表面温度(SST)、POM模式模拟的海流等资料,分析了2009年绿潮浒苔期间的水文气象条件、以及浒苔聚集和定向移动的原因,并与2008年的情况进行了对比。结果表明,前期降水的明显增多与绿潮爆发有密切关系,降水过后海水中营养盐类充足,而且降水后黄海上空降水和云中液态水含量偏少,日照比较充足,光合作用强,有利于海上浒苔迅速繁殖。2009年黄海西部降水明显增多的时间较2008年晚15 d左右,是2009年绿潮浒苔爆发比2008年晚15 d左右的重要原因。风力是浒苔在海洋中移动的主要强迫力,强劲持续的的东风或者东南风是导致2008年浒苔在青岛沿海登陆的主要外界强迫力,而2009年西南风使浒苔向东北方向漂移。SST变化对浒苔爆发的影响不显著。定量分析表明,浒苔密集区的移动更倾向于与盛行风向一致,向下风方偏右5~40(°)方向漂移,浒苔密集区的移速与海流速度更加一致,约为海流速度大小的0.8倍。 相似文献
9.
Turgay Partal 《水文科学杂志》2013,58(13):2455-2464
ABSTRACTThis study focuses on the variability of lake evaporation and also the periodic relationships among hydro-meteorological variables. The monthly hydro-meteorological data of Lake Keban were investigated by wavelet transforms. The results show that the main periodicity is on an annual scale. This periodicity is weaker for precipitation and wind speed but higher for evaporation, temperature, runoff and relative humidity. In addition to this, the continuous wavelet figures show some weak periodicities on the almost 10-year scale level but they are not continuous over time. Also, strong events on a short-term monthly scale are seen for evaporation, precipitation and runoff in 1988. This event in 1988 may be explained by the 1988 La Niña event, which was one of the strongest on record. Also, the periodicities on the 2–8-month scales in the precipitation data can be interpreted as being connected with the strong El Niño events of 1982 and 1992.
Editor D. Koutsoyiannis; Associate editor A. Carsteanu 相似文献
10.
Regional warming and modifications in precipitation regimes has large impacts on streamflow in Norway, where both rainfall and snowmelt are important runoff generating processes. Hydrological impacts of recent changes in climate are usually investigated by trend analyses applied on annual, seasonal, or monthly time series. None of these detect sub-seasonal changes and their underlying causes. This study investigated sub-seasonal changes in streamflow, rainfall, and snowmelt in 61 and 51 catchments respectively in Western (Vestlandet) and Eastern (Østlandet) Norway by applying the Mann–Kendall test and Theil–Sen estimator on 10-day moving averaged daily time series over a 30-year period (1983–2012). The relative contribution of rainfall versus snowmelt to daily streamflow and the changes therein have also been estimated to identify the changing relevance of these driving processes over the same period. Detected changes in 10-day moving averaged daily streamflow were finally attributed to changes in the most important hydro-meteorological drivers using multiple-regression models with increasing complexity. Earlier spring flow timing in both regions occur due to earlier snowmelt. Østlandet shows increased summer streamflow in catchments up to 1100 m a.s.l. and slightly increased winter streamflow in about 50% of the catchments. Trend patterns in Vestlandet are less coherent. The importance of rainfall has increased in both regions. Attribution of trends reveals that changes in rainfall and snowmelt can explain some streamflow changes where they are dominant processes (e.g., spring snowmelt in Østlandet and autumn rainfall in Vestlandet). Overall, the detected streamflow changes can be best explained by adding temperature trends as an additional predictor, indicating the relevance of additional driving processes such as increased glacier melt and evapotranspiration. 相似文献