无人机测绘在农村土地承包经营权确权中的应用

以粤北山区某县农村土地承包经营权确权登记项目为例,设计了无人机航空摄影及后续处理技术方案,生产了现势性高强、分辨率高的正射影像,并应用到了后续权属调查中,实践表明该方法有助于降低生产成本、提高工作效率。     

Performance Evaluation of the GRAPES Model in Wind Simulations Over South China

In the present study, the performance of the GRAPES model in wind simulation over south China was assessed. The simulations were evaluated by using surface observations and two sounding stations in south China. The results show that the GRAPES model could provide a reliable simulation of the distribution and diurnal variation of the wind. It showed a generally overestimated southerly wind speed especially over the Pearl River Delta region and the south of Jiangxi Province as well as the coastal region over south China. GRAPES also exhibited a large number of stations with the opposite surface wind directions over the east of Guangxi and the south of Jiangxi during the nocturnal- to-morning period, as well as an overall overestimation of surface wind over the coastal regions during the afternoon. Although GRAPES could simulate the general evolutional characteristics of vertical wind profile, it underestimated wind speed above 900 hPa and overestimated wind speed below 900 hPa. Though the parameterization scheme of gravity wave drag proved to be an effective method to alleviate the systematic deviation of wind simulation, GRAPES still exhibited large errors in wind simulation, especially in the lower and upper troposphere.     

广东省年度土地利用变更调查与遥感监测实施初探

土地变更调查是国土资源管理的重要基础性工作。本文结合广东省多年来积极探索建立的适应自身需求的变更调查工作机制,开展年度变更调查实践,总结项目组织实施、技术方法等方面的经验,特别是对重点变更类别提出了具体操作办法,对今后进一步高效、精确地开展土地调查具有一定的借鉴意义。     

基于高斯过程二元分类模型的溶洞规模预测方法

溶洞规模与其影响因素之间存在着复杂的非线性关系，如何根据影响因素有效预测溶洞规模是一类复杂的模式识别问题。基于高斯过程二元分类模型，提出一种溶洞规模的预测方法，该方法通过对样本的学习，建立溶洞规模与其影响因素之间复杂的非线性映射关系，对仅提供影响因素的预测样本进行具有概率意义的识别输出。研究结果表明，该方法除具有小样本、模型参数自适应确定、识别精度高等优点之外，还能够对预测结果给予概率意义的可信度，为实际工程有效预测溶洞规模提供了定量的依据，具有良好的应用前景。      

Improved Tropical Cyclone Forecasts with Increased Vertical Resolution in the TRAMS Model

The numerical simulation of typhoons has been found to be very sensitive to the vertical resolution of the model. During the updating of the TRAMS model from version 1.0 to 3.0, the horizontal resolution has been increased from 36 km to 9 km, while the vertical layer number only increased from 55 to 65 layers. The lack of high vertical resolution limits the performance of the TRAMS model in typhoon forecasting to a certain extent. In order to study the potential improvement of typhoon forecasting by increasing the vertical resolution, this paper increases the vertical resolution of the TRAMS model from 65 to 125 layers for the first time for a comparative simulation test. The results of the case study with Typhoon Hato (2017) show that the model with high vertical resolution can significantly enhance the warm structure caused by water vapor flux convergence and vertical transport, thus accurately simulating the rapid strengthening process of the typhoon. Meanwhile, the model with 125-layer vertical resolution can simulate the asymmetric structural characteristics of the wind field, which are closer to the observations and can help to reduce the bias in typhoon track forecasting. The improvement of vertical resolution is also trialed by using the batch test results of several landfalling typhoons in 2016-2017. The experimental results show that the typhoon forecast of the model becomes consistent with the observations only when the number of vertical layers of the model increases to about 125 layers, which in turn causes a large computational burden. In the next step, we will try to solve the computational burden problem caused by ultra-high vertical resolution with the top boundary nesting technique, and realize the application of high vertical resolution in the actual operation of the TRAMS model.