Kalman滤波风暴潮数值预报四维同化模式研究进展   总被引：1，自引：1，他引：1  

于福江  张占海 《海洋预报》2002,19(1):105-112

本文首先介绍了Kalman滤波在风暴潮数值预报中的应用，特别介绍了近年来国际上发展的一些在实际中可行的次优化Kalman滤波算法。并通过一个稳态Kalman滤波风暴潮数值预报模式的实例表明，使用资料同化可以明显改进风暴潮后报结果；资料同化能够提供更为合理的预报初始场，对风暴潮的短期预报有较明显的改进。一旦没有资料同化到模式中去，预报结果很快接近确定性模式。  相似文献   

渤海局部海域风暴潮漫滩的数值模拟   总被引：9，自引：2，他引：9       下载免费PDF全文

史峰岩  孙文心 《海洋与湖沼》1993,24(1):16-23

在Johns变边界模型的基础上,提出了一种嵌套式变边界数值模型,应用于渤海风暴潮的数值计算。分别模拟得到了1964年和1969年两次渤海风暴潮黄河三角洲一带的最大淹水范围和水位过程曲线。模拟过程中考虑了天文潮与风暴潮的非线性耦合效应。模拟结果分别与实测值和固定边界模型的结果进行了比较,从而证实了变边界模型不仅能计算出最大淹水范围,而且得到的风暴潮水位值也更加符合实际。  相似文献   

Modeling of storm-induced coastal flooding for emergency management   总被引：3，自引：0，他引：3  

K. F. Cheung  A. C. Phadke  Y. Wei  R. Rojas  Y. J. -M. Douyere  C. D. Martino  S. H. Houston  P. L. -F. Liu  P. J. Lynett  N. Dodd  S. Liao  E. Nakazaki 《Ocean Engineering》2003,30(11):1353-1386

This paper describes a model package that simulates coastal flooding resulting from storm surge and waves generated by tropical cyclones. The package consists of four component models implemented at three levels of nested geographic regions, namely, ocean, coastal, and nearshore. The operation is automated through a preprocessor that prepares the computational grids and input atmospheric conditions and manages the data transfer between components. The third generation spectral wave model WAM and a nonlinear long-wave model calculate respectively the wave conditions and storm surge over the ocean region. The simulation results define the water levels and boundary conditions for the model SWAN to transform the storm waves in coastal regions. The storm surge and local tides define the water level in each nearshore region, where a Boussinesq model uses the wave spectra output from SWAN to simulate the surf-zone processes and runup along the coastline. The package is applied to hindcast the coastal flooding caused by Hurricanes Iwa and Iniki, which hit the Hawaiian Island of Kauai in 1982 and 1992, respectively. The model results indicate good agreement with the storm-water levels and overwash debris lines recorded during and after the events, demonstrating the capability of the model package as a forecast tool for emergency management.  相似文献   

Development of a model-based high-resolution extreme surface wind climatology for Switzerland   总被引：1，自引：0，他引：1  

Stéphane Goyette 《Natural Hazards》2008,44(3):329-339

An innovative methodology aimed at establishing a numerical model-based high-resolution climatology of extreme winds over Switzerland is described, that makes use of the Canadian Regional Climate Model where a new windgust parameterization has been implemented. Self-nesting procedures allow windstorms to be studied at resolution as high as 2-km. The analysis of ten major windstorms concludes that the average spatial pattern and magnitude of the simulated windspeeds are well captured, and the areas that experienced extreme winds correspond well with observations and to the location where forest damage was reported following the last two of these storms. This climatology would eventually serve to form risk assessment maps based on the exceedance of windspeed thresholds. There is, however, a need for further investigations to encompass the full range of potential extreme wind cases. The ultimate goal of this methodology is to assess the change in the behaviour of extreme winds for a climate forced by enhanced greenhouse gas concentrations, and the impact of future windstorms over the Alpine region at high resolution.  相似文献   

Field-based monitoring of sediment runoff from natural gas well sites in Denton County,Texas, USA     

H. F. L. Williams  D. L. Havens  K. E. Banks  D. J. Wachal 《Environmental Geology》2008,55(7):1463-1471

This study evaluates sediment runoff from gas well development sites in Denton County, Texas. The magnitude of sediment runoff was investigated by intercepting sediment in traps and weirs at the periphery of each gas well site and by measuring the growth of debris lobes that formed down slope from two sites. Four debris lobes formed at one gas well site and one formed at a second site. Debris lobes ranged in size from 30 to 306 square meters. Sediment from one site entered local creek channels, either as a component of storm water runoff or, in one case, as a debris lobe that flowed into a channel. The study findings suggest that sediment movement is significantly diminished once areas disturbed by gas well construction become naturally re-vegetated. Based on estimates of debris lobe volumes, sediment loading rates of about 54 metric tonnes per hectare per year were calculated for one site. It is concluded that gas well development sites in areas similar to those studied, especially where vegetation has been removed and terrain has relatively steep slopes (greater than 6%), generate sediment runoff comparable to small construction sites and should therefore be considered for regulations requiring erosion and sediment control measures.  相似文献   

Tropical Storm Gamma and the Mosquitia of eastern Honduras: a little-known story from the 2005 hurricane season     

David M Cochran Jr  Carl A Reese  Kam-biu Liu 《Area》2009,41(4):425-434

The 2005 Atlantic hurricane season was unprecedented in terms of storm activity in the United States, Mexico, Central America and Caribbean. Given the impacts of hurricanes Katrina and Rita, the Honduran Mosquitia sparked little attention despite being hit by two hurricanes and a tropical storm in 2005. This article recounts the history of these storms in the Afro-Caribbean community of Batalla, drawing from public weather advisories and testimony of local residents obtained through participatory research. We contextualise this local history with results from the first paleotempestological study undertaken in the Mosquitia to shed light on long-term risk of catastrophic storms in the region and to demonstrate the value of integrating these two research approaches. Our findings contribute to recent ethnographic research on hazards by describing how a coastal people understand and respond to tropical cyclones and how landscape change influences the vulnerability of a coastal area. Although residents have not witnessed a storm as intense as those documented in the paleotempestological record, their knowledge and perceptions show how tropical cyclones can be disasters while leaving behind no sedimentary records. The paleotempestological evidence, however, reminds us that catastrophic hurricanes have struck the Mosquitia in the past and will do so again in the future. Understanding the interactions between contemporary human perceptions and responses and long-term hurricane risk provides insight for emergency managers and local stakeholders to better prepare for such a catastrophic event.  相似文献   

Storm surges and coastal impacts at Mar del Plata,Argentina     

Mónica M.E. Fiore  Enrique E. D’Onofrio  Jorge L. Pousa  Enrique J. Schnack  Germán R. Bértola 《Continental Shelf Research》2009

Positive storm surges (PSS) lasting for several days can raise the water level producing significant differences between the observed level and the astronomical tide. These storm events can be more severe if they coincide with a high tide or if they bracket several tidal cycles, particularly in the case of the highest astronomical tide. Besides, the abnormal sea-level elevation near the coast can cause the highest waves generated to attack the upper beach. This combination of factors can produce severe erosion, threatening sectors located along the coastline. These effects would be more serious if the storm surge height and duration increase as a result of a climatic change. The Mar del Plata (Argentina) coastline and adjacent areas are exposed to such effects. A statistical characterization of PSS based on their intensity, duration and frequency, including a surge event classification, was performed utilizing tide-gauge records over the period 1956–2005. A storm erosion potential index (SEPI) was calculated from observed levels based on hourly water level measurements. The index was related to beach profile responses to storm events. Also, a return period for extreme SEPI values was calculated. Results show an increase in the average number of positive storm surge events per decade. Considering all the events, the last decade (1996–2005) exhibits an average 7% increase compared to each one of the previous decades. A similar behavior was found for the decadal average of the heights of maximum annual positive storm surges. In this case the average height of the last two decades exceeds that of the previous decades by approximately 8 cm. The decadal average of maximum annual duration of these meteorological events shows an increase of 2 h in the last three decades. A possible explanation of the changes in frequency, height and duration of positive storm surges at Mar del Plata would seem to lie in the relative mean sea-level rise.  相似文献   

Beach recovery after 2004 Indian Ocean tsunami from Phang-nga, Thailand     

Montri Choowong  Sumet Phantuwongraj  Thasinee Charoentitirat  Vichai Chutakositkanon  Sombat Yumuang  Punya Charusiri 《Geomorphology》2009,104(3-4):134-142

The 2004 Indian Ocean tsunami devastated the coastal areas along the Andaman western coast of Thailand and left unique physical evidence of its impact, including the erosional landforms of the pre-tsunami topography. Here we show the results from monitoring the natural recovery of beach areas at Khuk Khak and Bang Niang tidal channels of Khao Lak area, Phang-nga, Thailand. A series of satellite images before and after the tsunami event was employed for calculating the beach area and locating the position of the changed shoreline. Field surveys to follow-up the development of the post-tsunami beach area were conducted from 2005 to 2007 and the yearly beach profile was measured in 2006. As a result, the scoured beach areas where the tidal channel inlets were located underwent continuous recovery. The return of post-tsunami sediments within the beach zone was either achieved by normal wind and wave processes or during the storm surges in the rainy season. Post-2004 beach sediments were derived mainly from near offshore sources. The present situation of the beach zone has almost completed reversion back to the equilibrium stage and this has occurred within 2 years after the tsunami event. We suggest these results provide a better understanding of the geomorphological process involved in beach recovery after severe erosion such as by tsunami events.  相似文献   

磁暴期间亚极光区极化流（SAPS）的DMSP观测与RAM模拟的比较研究          下载免费PDF全文

王慧  马淑英  A.J.Ridley 《地球物理学报》2009,52(6):1419-1428

亚极光区极化流（Subauroral Polarization Streams, SAPS）为快速流动的西向等离子体流,位于昏侧-子夜前亚极光区,是磁层-电离层-热层耦合的重要过程之一.本文利用密西根大学的RAM （Ring current-Atmosphere Interaction Model）模型对一次典型磁暴期间发生的SAPS事件进行了模拟,并与DMSP卫星观测值进行了比较.结果表明：模拟结果能大致反映观测现象;模拟得到的SAPS峰值速度所在纬度随磁暴时间的变化与观测值有较大差别;SAPS速度观测值在约18∶00 UT和约20∶00 UT左右出现两个峰值,而模拟值只有一个峰值,出现在约18∶00 UT,主要原因是模型对亚暴过程的模拟存在不足.  相似文献   

Design and routing of storm flows in an urbanized watershed without surface streams     

David E. Schaad  Jon Farley  Criss Haynes   《Journal of Hydrology》2009,375(3-4):334-344

In the karst geologic setting of Greenbrier County, West Virginia, USA, the drainage network in the watersheds do not support surface streams, but depend entirely on sinkholes, solution cavities, or injection wells as discharge points for accumulated storm water. By providing a systematic framework for designing and routing storms in this geologic setting, functioning retention and attenuation structures have been developed which are protective of water quality while still safely discharging storm water in a controlled manner to the subsurface. This article provides a rationale for the design methodology and then examines the successful implementation of an attenuation and storm water retention design to manage the surface discharges for an entire watershed. By examining the pre-development flows and evaluating future land use patterns (i.e., installation of impermeable surfaces over large areas), as well as sinkhole conveyance capabilities, it was necessary to examine alternative disposal options for collected storm water as well as devise a basin-wide management strategy to coordinate future development of the watershed. Additionally, innovative water quality measures were implemented to help prevent contamination from preferentially infiltrating into the subsurface as a result of these land development activities.  相似文献