基于分布式水文模型的小流域山洪预报方法与应用

降水是引发山洪灾害的最重要因素。本文应用2013年1月到2016年12月的全国山洪灾害数据、土壤含水量数据及历史降水量数据,分析全国及典型区域（云、贵、川、渝）的山洪灾害及暴雨时空演变特征,初步探讨了基于灾害前期1 h、6 h、12 h及24 h的降水与山洪灾害的关系,研究山区流域的暴雨特征及引发灾害的静态阈值计算方法,同时,结合灾害前期不同时段土壤含水量特征,以10~50 cm深度的土壤含水量推求雨量动态阈值,建立了山洪灾害动态降水阈值推求方程。同时,选取了一定数量的样本对该方程进行检验,结果表明,当灾害发生前一段时间的土壤含水量信息确定时,检验样本中对应时段的实测降水量的值大于本文建立的方程计算出的动态降水临界阈值的样本占总样本的73%以上,是较优的阈值雨量的判别方法。

     

Algorithms of automatic calibration of multi-parameter models used in operational systems of flash flood forecasting

In the second article of the serie, new tools of fast and effective automatic calibration of multi-parameter hydrological models are presented. In particular, it is shown that the basic method, the Stepwise Line Search (SLS), two its modifications (SLS-F and SLS-2L) and their combination (SLS-2LF) can be used in automated systems of operational flash flood forecasting where computational efficiency is critical due to a great number of catchments that should be calibrated. Results of implementation of the SLS-based calibration procedures for parametrization of the Sacramento Soil Moisture Accounting Model, which demonstrate their high effectiveness and efficiency, are shown.     

Basic principles of automatic calibration of multi-parameter models used in operational systems of flash flood forecasting

This paper initiates a series of three articles on automatic calibration of operational multi-parameter models used for flash flood forecasting in automated regime. The main point expressed in this series is that proper calibration of even a single model for a single basin is not a trivial problem, but in automated forecasting systems, when thousands or even millions of basins should be parametrized simultaneously, priorities change. Now the computational efficiency becomes the most critical; an implemented calibration procedure must be fast and efficient rather than giving “the best“ parameters yet computationally expensive. The first article of the series contains critical analysis of the “mainstream“ in hydrological models calibration and presents basic principles of the Stepwise Line Search algorithm and its modifications, practically feasible and robust parametrization approaches that would be suitable for automated systems used for flash flood forecasting.     

Applying a coupled hydrometeorological simulation system to flash flood forecasting over the Korean Peninsula

In flash flood forecasting, it is necessary to consider not only traditional meteorological variables such as precipitation, evapotranspiration, and soil moisture, but also hydrological components such as streamflow. To address this challenge, the application of high resolution coupled atmospheric-hydrological models is emerging as a promising alternative. This study demonstrates the feasibility of linking a coupled atmospheric-hydrological model (WRF/WRFHydro) with 150-m horizontal grid spacing for flash flood forecasting in Korea. The study area is the Namgang Dam basin in Southern Korea, a mountainous area located downstream of Jiri Mountain (1915 m in height). Under flash flood conditions, the simulated precipitation over the entire basin is comparable to the domain-averaged precipitation, but discharge data from WRF-Hydro shows some differences in the total available water and the temporal distribution of streamflow (given by the timing of the streamflow peak following precipitation), compared to observations. On the basis of sensitivity tests, the parameters controlling the infiltration of excess precipitation and channel roughness depending on stream order are refined and their influence on temporal distribution of streamflow is addressed with intent to apply WRF-Hydro to flash flood forecasting in the Namgang Dam basin. The simulation results from the WRF-Hydro model with optimized parameters demonstrate the potential utility of a coupled atmospheric-hydrological model for forecasting heavy rain-induced flash flooding over the Korean Peninsula.     

GIS-Amur system of flood monitoring,forecasting, and early warning

GIS-Amur system offlood monitoring, forecasting, and early warning was developed at the Hydrometcenter of Russia and Planeta Research Center for Space Hydrometeorology for the effective surveill ance of hydrological conditions in the Amur River basin. The system is based on the use of hydrometeorological information, that is, observational data from weather and gaging stations, data from hydrological forecasts, and satellite data. The GIS- and web-based GIS-Amur system provides high reliability, safety, and operational speed. During the operational practice in the spring and summer 2015, the system demonstrated the forecast accuracy and reliability, the timely delivery of output products to end users, and the great variety of the output product types and formats. The system provides near-real time access to all available hydrometeorological data in the Amur River basin that favors correct and timely decision-making for flood risk reduction.     

渭河流域一次致洪暴雨过程的中尺度滤波分析

利用常规高空观测资料和NCEP/NCAR 1°×1°的再分析资料以及25点低通滤波技术,对2003年8月28—29日发生在渭河流域的一次致洪暴雨进行了中尺度分析和探讨,分析出中尺度环流演变特征,总结了渭河流域致洪暴雨的概念模型,认为这次暴雨过程中在以西南气流为主的平均气流场上隐藏着尺度较中尺度平均流场小得多的涡旋,其移动方向和发展程度决定了强降水落区及其强度;高空西风风速脉动与低层南风风速脉动耦合形成了中尺度次级环流圈,其上升支为强降水提供了足够的动力抬升机制;而850 hPa低空急流、700 hPa中尺度低涡、南风脉动以及高空西风风速脉动等条件的合理配置是中尺度次级环流形成的必备因素;地面中尺度辐合线是本次暴雨的触发机制。     

南大4km预报系统对新疆夏季降水预报的评估

南大4 km预报系统(WRF＿NJU)是南京大学自2013年起每年夏季每日两次对中国地区进行的4 km分辨率的48 h实时预报。将该系统、欧洲中期天气预报中心(EC)、中国气象局(CMA)和日本气象厅(JMA)在2016—2018年夏季6—8月对新疆北疆和南疆地区降水的预报与自动站观测资料进行对比分析。结果表明：Gilbert技巧评分(GSS)一般EC最高,WRF＿NJU次之,JMA最低。空间上,EC在南、北疆的预报都最接近观测,WRF＿NJU预报降水平均偏低,CMA和JMA明显偏高。WRF＿NJU预报降水的日变化趋势与观测一致,峰值时段基本相同,稍有1～2 h偏差。量级上总体偏高,在峰值时段尤为明显。降水过程发展方面,WRF＿NJU对大多数降水过程模拟效果较好。通过个例分析,发现高空急流和低层水汽输送的预报效果直接影响着降水的预报效果。     

The 12–13 November 1999 flash flood in southern France

The flash flood that occurred on 12–13 November 1999 in meridional France is documented. This event caused 35 fatalities and severe damage to property as rainfall totals locally exceeded 550 mm in 24 h and 620 mm in 48 h.The main issue of the present study is to discuss how realistically the spatial and temporal rainfall distribution of this flash flood event can be represented with present state-of-the-art operational and research modeling frameworks. The predictability of the present event for different forecast ranges is investigated and sensitivity studies are conducted in order to discuss the influence of model physics (convection, microphysics), atmospheric moisture analysis and Mediterranean sea surface temperature forcing on the quality of the results. It is shown that the present event could be reasonably predicted on forecast ranges of 2–3 days as it was essentially determined by strong moisture advection from the Mediterranean coupled with frontal and orographical lifting. However, precipitation scores show significant sensitivity to both analysis errors and model physics.     

Long-range forecasting of forest fire danger based on the SLAV model seasonal ensemble forecasts

Developed is a scheme of the long-range forest fire danger (FD) forecasting based on the computation of the Nesterov??s index and on hydrodynamic forecasts of air temperature and precipitation of the SLAV model. The satellite information on the climatic distribution of the snow cover was taken into account for the forecast issuance. It is proposed to express the FD index not using traditional classes of fire danger but in ??above the norm,?? ??norm,?? and ??below the norm?? gradations. Presented are the results of author??s trials of the method based on the retrospective model data for six years. Discussed are the approaches to the improvement of the method of long-range fire danger forecasting.     

基于AREM 模式的贝叶斯洪水概率预报试验

为提高预见期内洪水预报精度,选取湖北省漳河水库2006 —2008 年汛期逐小时流域降水量、流量资料以及武汉暴雨研究所提供的相应时段AREM 模式预报的00 —60 h 逐小时降水预报产品作为研究资料,引入贝叶斯概率统计模型对AREM 模式的降水预报进行订正,并分别对订正前后的预报降水进行对比分析;其后,进一步将AREM 模式预报订正前后的降水预报值分别输入新安江水文模型进行洪水预报试验。结果表明,订正后的预报降水比订正前的精度有所提高,均方根误差减小幅度小于10 % ;检验期场次洪水的平均确定性系数提高10 .66 % ,平均洪峰相对误差减小3.05 % ,洪水预报精度在一定程度上有所提高。     

基于QPE和QPF的遗传神经网络洪水预报试验

以湖北省清江上游水布垭控制流域为例,利用分组Z-I关系并结合地面雨量站资料对雷达估算降水进行校准,计算出流域实况平均面雨量;再利用遗传算法和神经网络相结合的方法建立订正AREM预报降水的模型;最后,将订正前后的AREM预报降水输入新安江水文模型进行洪水预报试验。结果表明：订正后AREM预报降水能明显提高过程的累计降水量预报精度,平均相对误差减小幅度在60%以上,对逐小时过程降水预报精度也有一定提高,但与实况相比仍有一定差距;订正前后AREM预报降水的洪水预报试验的确定性系数的场次平均从-32.6%提高到64.38%,洪峰相对误差从39%减小到25.04%,确定性系数的提高效果优于洪峰相对误差,整体上洪水预报精度有所提高。     

北京市暴雨积涝风险等级预警方法及应用

使用2007—2010 年汛期(6—8 月)北京市200 多个自动气象站逐小时降雨量数据、北京市政府防汛抗旱指挥部办公室每日发布的汛情通报、北京市暴雨积涝综合风险区划指数以及降雨量短时临近预警产品,对北京市出现的积水个例与同期降水强度进行相关统计分析,找出道路积水临界预警指标;基于北京市暴雨积涝综合风险区划指数和道路积水临界预警指标,建立暴雨积涝风险等级预警模型,制作暴雨积涝风险等级预警服务产品,该产品经2011—2012 年汛期(6—8月)试用表明,道路积水临界预警指标和预警模型均具有一定的参考价值。     

An experience of the humidity forecasts verification and assessment of their applicability in forecasting of the aircraft icing zones

Results of verification of the relative humidity forecasting performed by using a number of numerical models are presented. Efficiency of forecasting of possible conditions combinations that cause the aircraft icing, such as negative temperature and high relative humidity, is assessed. The best results are demonstrated by the NCEP global model and semi-Lagrangian model with varying resolution. Significant discrepancies in the humidity initial fields modeled by using different models are revealed.     

数值模式降水评分对分辨率的敏感性初探

传统的降水检验中多采用TS评分等分类检验方法,这些方法由于使用点对点的比较方式,使得降水评估受到空间及时间微小差异所带来的\     

对流尺度集合预报中模式地形扰动对其预报技巧的影响研究

基于ARPS3DVAR+WRF（Advanced Regional Prediction and 3-dimensional variational System）快速同化模式对西南地区近几年发生的4次强降水过程进行模拟试验,对12 h降水预报结果采用升尺度方法,计算邻域平均预报、站点概率预报,最终形成邻域概率预报,并细致分析了这三种预报的特点与效果,讨论了升尺度窗区尺度给不同量级降水带来的影响,最后结合AROC评分与邻域空间检验FSS讨论业务概率预报应用的最佳尺度。结果表明：升尺度邻域平均预报在小雨与大暴雨量级降水上表现不稳定,对中雨的预报提高不明显,但是对大雨与暴雨预报有较好的改善效果;站点概率预报具有一定的误导性,而邻域概率预报可以弥补其缺憾,越高分辨率的模式有更多的降水样本,在降水不确定性上能给出更好的概率分级信息;相对邻域平均的升尺度预报TS检验结果,基于邻域概率的FSS和AROC分析有更好的预报技巧指导意义;36 km升尺度窗区既能消除一定程度的强降水预报不确定性,同时也可以保留适当的对流尺度特征,为最佳升尺度窗区。

     

暴雨集合预报-观测概率匹配订正法在四川盆地的应用研究

利用2015年6月1日至8月31日ECMWF集合预报系统（EPS）51个成员的降水预报结果,基于安徽省大别山区12个代表站点1~3 d的逐12 h降水观测资料,采用TS评分、箱须图、泰勒图等方法,研究ECMWF集合预报降水结果在安徽省大别山区降水分级预报中的应用效果。主要结论如下：ECMWF集合降水预报中,08时起报的24 h降水量和20时起报的48 h降水量可参考性较大;降水分级检验中,晴雨预报正确率在70%以上,小雨和中雨的空报率较高,对大雨以上量级的预报能力相对较差;大型降水过程中,暴雨以上量级的预报需关注不同预报时效下降水量预报的变化趋势,个别成员对极端降水的表现也值得关注。

     

台湾天气研究计划与绿岛中尺度实验简介

从1987年开始,台湾暴雨研究进入一个新纪元,由早期定性描述分析进入定量计算与模拟,其中包括新观测设施的建设与数值天气预报系统的建立。近年来,随着全球气候变暖,台湾极端降雨事件有所增加,其中不少极端降雨事件是由非台风暴雨所致,往往给当地社会经济和人民生命财产造成严重影响,这就迫切需要不断提高强降雨定量预报业务水平。本文通过对近30 a台湾在非台风暴雨研究发展方面取得的主要进展的回顾,重点介绍了台湾气象部门为了提高强降雨定量预报业务水平所做出的努力,同时对未来台湾非台风暴雨研究规划与方向作了简要介绍。

     

基于分布式水文模型的小流域山洪预报方法与应用

以2016—2017年清江流域2次大径流事件和3次小径流事件为研究对象,首先,分析了CMORPH卫星-地面自动站-雷达三源融合降水产品(CMPAS)、中国全球大气再分析产品(CRA)和雨量站降雨资料(Gauge)3种产品的降水时空分布特征;然后,基于径流事件实况与不同降水产品的特点,设计了两种径流模拟试验方案,对3种产品的降水数据输入WRF-Hydro模式的径流模拟结果进行分析。最后,结合降水时空分布差异,探讨3种降水产品在径流模拟中的应用效果。结果表明: (1)5次径流事件中,3种降水产品探测的降雨中心、雨带位置和走向大致相同,流域内面雨量随时间变化趋势较为一致。(2)两种试验方案下,3种降水产品均能模拟出各次径流事件。对大径流事件,CMPAS的模拟效果最优,相关系数均在0.76以上、纳什效率系数均在0.63以上;对小径流事件,Gauge的模拟效果最优,相关系数均在0.75以上,纳什效率系数均在0.48以上;CRA无论对大、小径流事件,其模拟效果相对都较差,但参数经重新率定后,其模拟效果明显改善。(3)3种降水产品经重新率定参数后(方案2),其在峰现、涨水、退水各时段的径流模拟效果改善不同。对小径流事件,相对涨水和退水时段,各产品在峰现时段的模拟效果改善较为明显,而对大径流事件,3种降水产品在各时段的模拟效果均无明显改善。

     

A study of gravity waves generated by convective systems in eta model forecasts

Summary Spectral filtering and visualization reveal a multitude of gravity waves in the fine mesh (29 km) Eta model output, extending into the large scale, masking the vertical motions associated with Rossby-modes. The 6 h forecast of the Eta model from 00 UTC 22 December 1994 initialization contains gravity waves recognizable over a broad spectrum of wavelengths as concentric circles radiating outward from centers of model convection. Contamination of the signal is therefore identifiable in any spectral range, as rings. Postprocessing techniques are presented to eliminate gravity wave contamination and to reveal the meteorologically significant signal. Low-pass filtering is found to be an effective means of extracting the Rossby signal, but with loss in Rossby signal that renders the results obtained with a high resolution model no better than what could have been obtained from a coarser resolution model. Time filtering, is suggested as a more effective method for eliminating the effects of fast modes while maintaining mesoscale details of the slow modes.With 9 Figures     

低频环流系统的一种统计预报方法

根据实时MICAPS资料,采用经验正交函数分解和滤波方法,统计分析了欧亚大陆上空700 hPa水汽输送通量流函数和势函数主要低频分量的分布特征。结果表明：存在流函数和势函数低频环流系统变化的关键区。根据关键区环流系统演变,确定了与上海地区未来10—30 d强降水过程相对应的预报指标。以上海地区2010年7月降水过程预报为例,概述了整个预报流程,并从物理机制上证明了低层（110°E,30°N）附近的辐合以及自低空至高空向东倾斜的上升运动是造成该次降水的主要成因。