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991.
Weather forecasting in the Southern Ocean and Antarctica is a challenge above all due to the rarity of observations to be assimilated in numerical weather prediction(NWP)models.As observations are expensive and logistically challenging,it is important to evaluate the benefit that additional observations could bring to NWP.Atmospheric soundings applying unmanned aerial vehicles(UAVs)have a large potential to supplement conventional radiosonde sounding observations.Here,we applied UAV and radiosonde sounding observations from an RV Polarstern cruise in the ice-covered Weddell Sea in austral winter 2013 to evaluate the impact of their assimilation in the Polar version of the Weather Research and Forecasting(Polar WRF)model.Our experiments revealed small to moderate impacts of radiosonde and UAV data assimilation.In any case,the assimilation of sounding data from both radiosondes and UAVs improved the analyses of air temperature,wind speed,and humidity at the observation site for most of the time.Further,the impact on the results of 5-day-long Polar WRF experiments was often felt over distances of at least 300 km from the observation site.All experiments succeeded in capturing the main features of the evolution of near-surface variables,but the effects of data assimilation varied between different cases.Due to the limited vertical extent of the UAV observations,the impact of their assimilation was limited to the lowermost 1?2-km layer,and assimilation of radiosonde data was more beneficial for modeled sea level pressure and near-surface wind speed. 相似文献
992.
台风"杜鹃"的AMSU卫星微波探测资料分析 总被引:6,自引:7,他引:6
由于微波具有穿透云的能力,AMSU卫星探测资料得到了越来越广泛的应用。利用AMSU多个通道的资料,对2003年台风“杜鹃”过程进行了分析。通过比较AMSU-B(89GHz和150GHz)与GOES-9的台风结构图像可以发现微波具有较强的垂直探测能力;在AMSU-B的5个通道中,通道2(Ch2)亮温值的大小能够最好地反映热带气旋螺旋雨带冰晶层的深厚程度,从而判定螺旋雨带的强度;Ch2的亮温分布与雷达的强降水回波有较好的对应关系;利用AMSU-A温度反演资料能够清晰地揭示热带气旋的暖心结构、地面风速和中心气压与250hPa温度距平的关系,以及强降水的落区等。结果表明:AMSU资料作为一种新的卫星微波探测资料,在热带气旋的结构、螺旋雨带的强度及其降水强度的分析预报中具有一定的应用价值。 相似文献
993.
994.
为充分认识地磁观测环境中的各种干扰因素,提升台站观测人员对数据异常的识别能力,确保提供真实有效的高质量观测数据,以天津市徐庄子地震台地磁观测为例,阐述地磁观测中存在的多种干扰因素及形态特征和预处理方法。分析表明,徐庄子地震台地磁GM4磁通门磁力仪主要受高压直流输电、地铁运营、过往车辆、地电供电、GPS整点授时、磁扰以及雷电等因素的影响,干扰形态主要表现为尖峰、台阶、扰动等,并总结说明高压直流输电线路的干扰鉴定方式、幅度及干扰时段等。 相似文献
995.
996.
997.
H. Jochmann 《Astronomische Nachrichten》1989,310(6):435-442
Correlations between the geomagnetic field parameters and polar motion were explained using the hypothesis of an inner core motion. For a number of periodic constituents of both phenomena it could be proved that this model works well. Secular variations of polar motion caused by inner core dynamics are in the same order of magnitude as the secular variation of the pole derived from pole coordinates of the International Latitude Service (ILS). 相似文献
998.
In this paper we develop a statistical approach to resolve the transport problem for the tangential fluctuations of the geomagnetic field in the mantle. For the sake of simplicity we treat the mantle as a thick layer of vacuum and assume in addition that only a radial component of the magnetic field of the core penetrates through the core-mantle boundary. These assumptions allow us to find exact expressions for the tangential field components throughout the mantle. By using such expressions we construct a correlation tensor of tangential components and then, since the mantle is thick enough, study its asymptotic properties on the Earth surface. Incidentally, the correlation tensor trace happens to be equal to the correlation function of the radial component that was obtained by Pilipenko and Sokoloff (1992). Indeed, we provide a simple boundary problem which initially describes the diffusion functions. We also pay a special attention to transformation properties of the correlation tensor and find here some interesting analogies with secular variation data of the geomagnetic field 相似文献