GPT2w（global pressure and temperature 2 wet）是目前应用较为广泛的对流层延迟经验模型之一,可提供气压、温度、水汽压等气象参数。为验证和分析GPT2w模型在南极地区的精度,本文利用分布在南极区域的探空站数据和中国第33次南极科考期间的实测探空气球数据对模型气压、温度、水汽压参数进行分层精度检验。与探空站数据比较发现,在南极地区地面高度上,GPT2w模型精度较高,与全球其他区域精度较为一致;进一步通过对比1月和7月统计结果,发现Bias和RMS呈现出季节特性;同时发现模型在垂直方向存在较大误差,表现为随着高度的增加,精度随之下降并逐步趋于稳定。实测数据对比方面,首先利用ECMWF（European Centre for Medium-range Weather Forecasts）气压分层数据对实测数据的可靠性进行验证,结果显示,实测数据与ECMWF分层数据符合得较好;同时通过比对发现,GPT2w天内精度在地面高度上仍与月平均精度相当,但垂直方向随着高度的增加精度相比于暖季精度会有所下滑,说明未考虑日周期项变化对模型精度存在一定影响。用探空数据计算的对流层延迟（zenith tropospheric delay,ZTD）来分析GPT2w的计算精度,结果表明GPT2w在南极区域ZTD计算精度在厘米级,与全球其他位置计算精度相当。 相似文献
The Hongshishan chromitite deposits are situated to the north of the Beishan orogenic collage, in the southern part of the Central Asian Orogenic Belt. This study describes the mineral chemistry, Re-Os isotopes and platinum-group elements geochemistry of the Hongshishan chromitites for the purpose of constraining the origin, evolution and composition of their parental melts. The restricted ranges of Al2O3, Cr2O3 and Cr#-Mg# variation of chromite-cores ... 相似文献
Most previous studies on the quantitative risk assessment (QRA) of landslides focused on the probability of slope failure at the pre-failure stage and adopted empirical models for consequence analysis. The conventional approaches simplify the relationship between the pre-failure state and the post-failure behavior and cannot reasonably account for the effects of uncertainty on the entire landslide process. In this paper, an efficient QRA method that involves the direct simulation of the entire landslide process is proposed. A QRA formula that considers the probability of only those landslides that can impact the element at risk is used. The coupled Eulerian–Lagrangian method is used to simulate the entire landslide process and to identify slopes that can impact the element at risk and determine the failure consequences. The subset simulation method is adopted to efficiently estimate the probability of landslide impact, and parameter uncertainty is considered. Two case histories of landslides are investigated. First, the 2011 Baqiao loess landslide in Xi’an, China, is investigated, and the results of the proposed method are compared with those of the conventional approaches. Second, the proposed method is applied to assess the risk of the 2015 Ganjingzi landslide in the Three Gorges Reservoir. The effects of the risk mitigation works are also discussed.
The settlement of highway embankments can directly affect the structural safety of road pavement. Comprehensive assessment of the long-term settlement characteristics of highway embankments is important in highway safety management. The present study conducted long-term settlement monitoring in an embankment of the Xi’an-Xianyang Highway in Shaanxi Province, China, that was constructed with recycled construction and demolition waste. Variations in sectional settlement, cumulative settlement, differential settlement, and settlement rates were made in a barricade section and an arc-shaped protective slope section. The maximum settlement observed in the barricade section was 51.75 mm, with the embankment exhibiting “basin-shaped” settlement. The maximum settlement in the arc-shaped protective slope section was 42.22 mm, and the embankment exhibited “W-shaped” settlement. Furthermore, there were two stages of great increase in the settlement rate. Based on the results, control standards for the sectional settlement of embankments constructed with recycled construction and demolition waste are proposed. Finally, a model for predicting the long-term settlement in road embankments constructed with recycled construction and demolition waste is established based on a Weibull distribution probability density function.
