首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   8篇
  免费   0篇
  国内免费   6篇
测绘学   5篇
大气科学   7篇
海洋学   1篇
天文学   1篇
  2021年   1篇
  2020年   1篇
  2019年   2篇
  2018年   1篇
  2017年   1篇
  2016年   1篇
  2015年   2篇
  2013年   4篇
  2004年   1篇
排序方式: 共有14条查询结果,搜索用时 16 毫秒
1.
星载原子频率标准在许多空间系统中担当着重要的角色,其性能和可靠性对这些系统的功能有重要的影响。介绍了广泛使用的星载铷原子频率标准的基本工作原理,分析了影响其可靠性的各种因素,并探讨了提高其可靠性的基本途径。  相似文献   
2.
The Grid-point Atmospheric Model of IAP LASG version 2 (GAMIL2) has been developed through upgrading the deep convection parameterization, cumulus cloud fraction and two-moment cloud microphysical scheme, as well as changing some of the large uncertain parameters. In this paper, its performance is evaluated, and the results suggest that there are some significant improvements in GAMIL2 compared to the previous version GAMIL1, for example, the components of the energy budget at the top of atmosphere (TOA) and surface; the geographic distribution of shortwave cloud radiative forcing (SWCF); the ratio of stratiform versus total rainfall; the response of atmospheric circulation to the tropical ocean; and the eastward propagation and spatiotemporal structures of the Madden Julian Oscillation (MJO). Furthermore, the indirect aerosols effect (IAE) is -0.94 W m-2, within the range of 0 to -2 W m-2 given by the IPCC 4th Assessment Report (2007). The influence of uncertain parameters on the MJO and radiation fluxes is also discussed.  相似文献   
3.
机载激光雷达技术衍生于传统的工程测量中的激光测距技术,是传统雷达技术与现代激光技术结合的产物,是遥感测量领域的一门新兴技术。随着机载激光雷达数据的不断发展,其在基础测绘、城市三位建模、铁路、电力等领域有着越来越广泛的应用,然而机载激光雷达数据刚扫描完的数据全部存放到一个点云层,不利于后期数据的分析、应用。因此,本文以处理吉林省白城市激光点云数据的方式为例,介绍了机载激光雷达点云数据的处理方式及地物分类的原则。  相似文献   
4.
This study mainly introduces the development of the Flexible Global Ocean-Atmosphere-Land System Model: Grid-point Version 2 (FGOALS-g2) and the preliminary evaluations of its performances based on results from the pre-industrial control run and four members of historical runs according to the fifth phase of the Coupled Model Intercomparison Project (CMIP5) experiment design. The results suggest that many obvious improvements have been achieved by the FGOALS-g2 compared with the previous version,FGOALS-g1, including its climatological mean states, climate variability, and 20th century surface temperature evolution. For example,FGOALS-g2 better simulates the frequency of tropical land precipitation, East Asian Monsoon precipitation and its seasonal cycle, MJO and ENSO, which are closely related to the updated cumulus parameterization scheme, as well as the alleviation of uncertainties in some key parameters in shallow and deep convection schemes, cloud fraction, cloud macro/microphysical processes and the boundary layer scheme in its atmospheric model. The annual cycle of sea surface temperature along the equator in the Pacific is significantly improved in the new version. The sea ice salinity simulation is one of the unique characteristics of FGOALS-g2, although it is somehow inconsistent with empirical observations in the Antarctic.  相似文献   
5.
人为热释放:全球分布的估算及其气候效应的探索   总被引:1,自引:0,他引:1  
陈兵  陈良富  董理  石广玉 《大气科学》2016,40(2):289-295
人类生产和生活中大量消费各种形式的能源,除了向大气里排放温室气体和气溶胶外,还释放大量热量。人为热释放伴随着人类社会发展而长期存在,随着全球人口增长和经济发展,其影响效应不断加剧。人为热释放具有典型地域集中、不均匀分布的特征:虽然全球平均人为热释放通量仅约为0.03 W m-2,在人口密集的城市地区,人为热释放可高达每平方米数百瓦,足以影响局地气候。伴随全球经济的发展,人口的增长及城市化进程的加剧,人为热释放分布更集中,影响气候的范围逐步扩大,其对气候的影响能力逐步增强。全球气候模式的结果表明:人为热释放能够对全球大气环流产生影响,进而影响到全球气候变化。人为热释放可以导致全球地表温度增温约0.06 K,500 hPa温度场平均升温约0.04 K,尤其对北半球中高纬度升温效应明显。研究结果表明,人为热释放虽然没有温室气体如二氧化碳等影响因子对全球气候的影响那么显著,但是其仍然能够对全球气候产生影响,是全球气候变化不可忽视的影响因子。  相似文献   
6.
为参加第六次国际耦合模式比较计划(CMIP6)和进一步提高模式的模拟能力,大气科学和地球流体力学数值模拟国家重点实验室(LASG)模式团队发展了新一代的格点大气版本的FGOALS-g耦合模式。新版本模式在大气分辨率、海洋网格,以及各分量模式的物理过程等方面都有一定的改进,并正在参与CMIP6最核心的试验以及多个CMIP6模式比较子计划试验。给定CMIP6外强迫,模式在工业革命前参照试验(piControl)和大气模式比较计划(AMIP)试验中模拟的初步结果都比较合理。  相似文献   
7.
地理国情普查数据入库检查工作是地理国情普查中一个重要的工作环节,该环节对后期的数据入库和统计分析起到关键作用。本文从地理国情普查数据入库检查时发现的数据集坐标系、数据精度和容差、境界必须与上级境界共线,数据集字段错误等问题进行分析与探讨,研究其解决办法,确保普查数据顺利入库。希望能对国情普查数据入库有所裨益。  相似文献   
8.
Preliminary evaluations of FGOALS-g2 for decadal predictions   总被引:3,自引:0,他引:3  
The Flexible Global Ocean-Atmosphere-Land System model, Grid-point Version 2 (FGOALS-g2) for decadal predictions, is evaluated preliminarily, based on sets of ensemble 10-year hindcasts that it has produced. The results show that the hindcasts were more accurate in decadal variability of SST and surface air temperature (SAT), particularly in that of Nin o3.4 SST and China regional SAT, than the second sample of the historical runs for 20th-century climate (the control) by the same model. Both the control and the hindcasts represented the global warming well using the same external forcings, but the control overestimated the warming. The hindcasts produced the warming closer to the observations. Performance of FGOALS-g2 in hindcasts benefits from more realistic initial conditions provided by the initialization run and a smaller model bias resulting from the use of a dynamic bias correction scheme newly developed in this study. The initialization consists of a 61-year nudging-based assimilation cycle, which follows on the control run on 01 January 1945 with the incorporation of observation data of upper-ocean temperature and salinity at each integration step in the ocean component model, the LASG IAP Climate System Ocean Model, Version 2 (LICOM2). The dynamic bias correction is implemented at each step of LICOM2 during the hindcasts to reduce the systematic biases existing in upper-ocean temperature and salinity by incorporating multi-year monthly mean increments produced in the assimilation cycle. The effectiveness of the assimilation cycle and the role of the correction scheme were assessed prior to the hindcasts.  相似文献   
9.
10.
维修是军械装备保持良好技术状态的重要手段,以可靠性为中心的维修策略优化研究一直受行业内专家的广泛关注。基于维修活动参与条件下的军械装备部件性能退化规律,研究维修对装备性能状态的影响,并通过定期维护条件下的装备失效过程分析,建立了定期维护装备维修策略模型。通过典型组件的维修实例分析,验证了模型的有效性。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号