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Syed Nizamuddin 《Pure and Applied Geophysics》1984,122(1):86-88
Potential gradients were measured in the valley of the Simhachalam hills and near the top. They were found to be higher at the top than in the valley, where they increased in the forenoon. It was the reverse at the top of the hills. The valley winds were found to play an important role in the variation of potential gradient. 相似文献
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流域地理景观的GIS数据三维可视化 总被引:17,自引:1,他引:16
应用以"GIS"为核心的空间信息技术,是开展"数字流域"工程建设自然和最佳的选择。结合"清江流域水文水情与洪水演进仿真系统"的具体研制,分析流域地理数据特点及传统GIS在"数字流域"建设中的优缺点,在应用传统GIS二维方式展示形式管理和预处理先期各类基础流域地理空间数据及其相应属性数据的基础上,为满足仿真系统系列三维可视化要求,建立面向流域空间实体对象的数据模型,定义流域地理空间对象数据结构,将流域地理常规的GIS数据以三维形式展示,在实际的系统开发过程中,取得较好的三维可视化效果,并可满足"数字清江"建设各阶段综合处理、分析、评价、决策以及可视化等方面的需求。 相似文献
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Massimiliano Burlando Emilia Georgieva Corrado F. Ratto 《Boundary-Layer Meteorology》2007,125(2):389-397
The planetary boundary-layer (PBL) parameterization is a key issue for the definition of initial wind flow fields in diagnostic
models. However, PBL theories usually treat separately stable, neutral, and convective stability conditions, so that their
implementation in diagnostic wind models is not straightforward. In the present paper, an attempt is made to adopt a comprehensive
PBL parameterisation, covering stable/neutral and unstable atmospheric conditions, which appears suitable to diagnostic models.
This parameterisation is implemented into our diagnostic mass-consistent code. A validation of the consistency between the
implemented PBL parameterisations has been checked through an analysis of the sensitivity of the vertical wind profiles to
atmospheric stability. 相似文献
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O.?NovotnyEmail author J.?Jansky V.?Plicka H.?Lyon-Caen 《Studia Geophysica et Geodaetica》2008,52(1):123-131
The western part of the Gulf of Corinth attracts attention due to its seismically active fault system and considerable seismic
hazard. Detailed studies of the seismic activity of the region have been carried out especially as part of the so-called Corinth
Rift Laboratory (CRL) Project. For standard earthquake locations, the CRL uses the HYPO algorithm and a special structural
model that is composed of homogeneous layers (Rigo et al., 1996). This model was derived from a passive seismic experiment
in a broader area around the western part of the Gulf. A significant part of the seismic activity is concentrated close to
the town of Aigion, which was damaged by a strong earthquake in 1995. A sequence of smaller earthquakes occurred to the south
of this town in the year 2001. In the present paper, we have used this sequence to derive an improved structural model for
the region in the vicinity of the town of Aigion. This new model is based on the minimization of travel-time residuals. In
particular, we used arrival times from a subset of 88 events recorded by at least 5 stations of the southern part of the CRL
network, had magnitudes of over 2.3, and were recorded at the nearest station (station code AIO). A variant of the method
of conjugate gradients has been used for this purpose. In comparison with the model derived by Rigo et al. (1996), the new
model is characterized by a higher νP/νS velocity ratio and by higher velocities to a depth of about 7 km. The new model was derived with the aim to get more accurate
locations of future events in the vicinity of the town of Aigion. 相似文献
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The results of a research study of the carbon monoxide concentration from California to 90° S, Antarctica are presented. The data both extend and support other research studies of the latitudinal distribution of carbon monoxide in that higher concentrations are evident over the Northern Hemisphere than over the Southern Hemisphere. Carbon monoxide concentrations range between 50 to 60 ppb with a few peaks into the 60s in the latitudinal area south of the ITCZ and values of 80 ppb or higher at latitudes north of Hawaii. A comparison is also made of carbon monoxide and ozone concentrations along the flight tract between California and Antarctica, over the Ellsworth Mountains of Antarctica, and between 78° S and the South Pole. These ozone-carbon monoxide data show statistically significant negative correlations in the upper troposphere and lower stratosphere over Antarctica. It is believed that this is a good indication of mixing across the tropopause. 相似文献