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631.
利用Argo剖面浮标分析上层海洋对台风“布拉万”的响应 总被引:9,自引:2,他引:7
In situ observations from Argo profiling floats combined with satellite retrieved SST and rain rate are used to investigate an upper ocean response to Typhoon Bolaven from 20 through 29 August 2012. After the passage of Typhoon Bolaven, the deepening of mixed layer depth(MLD), and the cooling of mixed layer temperature(MLT) were observed. The changes in mixed layer salinity(MLS) showed an equivalent number of increasing and decreasing because the typhoon-induced salinity changes in the mixed layer were influenced by precipitation, evaporation, turbulent mixing and upwelling of thermocline water. The deepening of the MLD and the cooling of the MLT indicated a significant rightward bias, whereas the MLS was freshened to the left side of the typhoon track and increased on the other side. Intensive temperature and salinity profiles observed by Iridium floats make it possible to view response processes in the upper ocean after the passage of a typhoon. The cooling in the near-surface and the warming in the subsurface were observed by two Iridium floats located to the left side of the cyclonic track during the development stage of the storm, beyond the radius of maximum winds relative to the typhoon center. Water salinity increases at the base of the mixed layer and the top of the thermocline were the most obvious change observed by those two floats. On the right side of the track and near the typhoon center when the typhoon was intensified, the significant cooling from sea surface to a depth of 200×104 Pa, with the exception of the water at the top of the thermocline, was observed by the other Iridium float. Owing to the enhanced upwelling near the typhoon center, the water salinity in the near-surface increased noticeably. The heat pumping from the mixed layer into the thermocline induced by downwelling and the upwelling induced by the positive wind stress curl are the main causes for the different temperature and salinity variations on the different sides of the track. It seems that more time is required for the anomalies in the subsurface to be restored to pretyphoon conditions than for the anomalies in the mixed layer. 相似文献
632.
In August 2009,Typhoon Morakot brought a large amount of rainfall with both high intensity and long duration to a vast area of Taiwan.Unfortunately,this resulted in a catastrophic landslide in Hsiaolin Village,Taiwan.Meanwhile,large amounts of landslides were formed in the Jiaopu Stream watershed near the southeast part of the Hsiaolin Village.The Hsiaolin Village access road(Provincial Highway No.21 and Bridge No.8) was completely destroyed by the landslide and consequent debris flow.The major scope of this study is to apply a debris flow model to simulate the disaster caused by the debris flow that occurred in the Jiaopu Stream during Typhoon Morakot.According to the interviews with local residents,this study applied the destruction time of Bridge No.8 and Chen's house to verify the numerical debris flow model.By the spatial rainfall distributions information,the numerical simulations of the debris flow are conducted in two stages.In the first stage(before the landslide-dam failure),the elevation of the debris flow and the corresponding potential damages toward residential properties were investigated.In the second stage(after the landslidedam failure),comparisons of simulation results between the longitudinal and cross profiles of the Jiaopu Stream were performed using topographic maps and satellite imagery.In summary,applications of the adopted numerical debris flow model have shown positive impact on supporting better understanding of the occurrence and movement of debris flow processes. 相似文献
633.
Reservoir sedimentation data and sediment yields from Taiwanese rivers show increased soil erosion in response to both 20th century changes in land use and a more recent increase in typhoon frequency and intensity. Decadal variations of up to 5- to 20-fold in suspended-sediment rating curves demonstrate supply-limited transport and correspond to increased sediment delivery from hillslopes due to changes in land use, regional ground shaking during the Chi-Chi earthquake, and post-2000 changes in typhoon frequency and intensity. While accelerated erosion in central Taiwan after the Chi-Chi earthquake has been documented previously, our results show that periods of increased upland erosion also occurred earlier, in response to 20th century changes in land use. Analyses of rainfall records and typhoon frequency for the period 1900–2009 further point to an island-wide increase in erosion rates corresponding to increased typhoon frequency and intensity after 1990. 相似文献
634.
An extensive land cover change was triggered by a series of typhoons, especially Typhoon Morakot in 2009 in Taiwan. The normalized difference vegetation index (NDVI) series from multiple satellite images were applied to monitor the change processes of land cover. This study applied spatiotemporal analysis tools, including empirical orthogonal functions (EOF), and multiple variograms in analyzing space–time NDVI data, and detected the effects of large chronological disturbances in the characteristics of land cover changes. Spatiotemporal analysis delineated the temporal patterns and spatial variability of NDVI caused by these large typhoons. Results showed that mean of NDVI decreased but spatial variablity of NDVI increased after typhoons in the study area. The EOF can clarify the major component of NDVI variations and identify the core area of the NDVI changes. Various approaches showed consistent results that Typhoon Morakot significantly lowered the NDVI in land cover change process. Furthermore, the spatiotemporal analysis is an effective monitoring tool, which advocates the use of the index for the quantification of land cover change and resilience. 相似文献
635.
随着网络技术的发展,网络舆情分析在应对突发事件中发挥的作用日益显著。自然灾害发生后,准确把握舆情信息传播特征并分析其影响因素有助于应急管理部门及时采取有效的应急救援措施。本文以台风“利奇马”为例,基于“新浪舆情通”系统搜集的相关微博、微信、论坛、网站等全网舆情数据,探究台风灾害全过程舆情信息的时空分布特征,开展灾害舆情信息影响因素相关性分析。研究表明:① 相比于灰色EGM(1, 1)模型,ARIMA模型对于舆情的短时预测具有较高的适用度,所预测的舆情信息的时序变化与利奇马台风的生命周期相符;② 舆情的空间分布具有聚集性,其分布与受灾程度呈正相关关系,但同时受灾区经济状况和网络普及率影响;③ 灾情严重程度与原创舆情信息的相关性高于转发舆情信息,原创舆情信息更能反映受灾地区的实际受灾情况。研究内容为应急管理部门及时掌握舆情走势并调整应急救助决策提供了指导价值。 相似文献
636.
637.
台风活动对青藏高原东北侧干旱的影响 总被引:24,自引:11,他引:13
应用1959 ̄1996的青藏高原东北侧58个站历年逐月降水量资料,历年(1950 ̄1996年)逐月西太平洋台风资料及500hPa高度格点资料,分析了台风活动对高原东北侧干旱的影响。结果指出:少台风活动年与干旱环流流型及高原东北侧干旱之间,多台风活动年与多雨环流流型及高原东北侧多雨之间,均存在着对应关系。 相似文献
638.
639.
9806号台风异常移动特征的初步分析 总被引:2,自引:0,他引:2
9806号台风在其生命史中,共发生了7次突然左折和1次突然加速,形成了典型的倒抛物线型路径。本文初步分析了其异常移动的特征和原因,并详细比较了目前主要的业务预报方法对该台风的预报性能。为进一步揭示该类台风移动的物理机制积累经验,也为正确把握和使用各主要业务预报方法对该类台风预报结果的参考价值提供科学依据。 相似文献
640.
对在浙江省温岭登陆的“9711”号台风的风暴潮预报过程作了回顾, 总结了预报成功的经验, 探讨了对海门站预报误差较大的原因。预报实践证明, 正确的气象预报是台风暴潮预报的基础,密切关注风暴的增水变化,随时调整预报值是风暴潮预报的关键。与实测资料比较,“9711”号台风高潮位的预报是及时、准确的,它为进一步提高风暴潮的预报精度和时效积累了经验 相似文献