CMIP6与CMIP5对历史大气层顶和地表辐射收支模拟的时空对比     

万梓文  王伟  吕恒  仇培宇  李雨竹  卢阳 《气候变化研究进展》2022,18(4):468-481

基于云和地球辐射能量系统观测数据集（CERES),对比分析了耦合模式比较计划第五（CMIP5）和第六阶段（CMIP6）模拟的历史大气层顶和地表辐射收支的年际变化和空间分布,明确了多模式间不确定性大的关键区域。结果表明：在年际尺度上,除地表向上长波辐射外,CMIP6的辐射分量的集合均值较CMIP5更接近于CERES观测值,全球地表向下短波辐射的高估和大气逆辐射的低估在CMIP6中分别降低了1.9 W/m²和3.3 W/m²。除大气逆辐射外,CMIP6的辐射分量在多模式间的一致性较CMIP5提高。在北极,CMIP6对大气层顶反射短波、大气层顶出射长波和地表向下短波辐射的模拟偏差较CMIP5大。在南北纬60°,CMIP6对大气逆辐射的模拟偏差较CMIP5大。其他区域CMIP6的辐射分量更接近CERES观测值。CMIP6模拟的地表向下短波辐射和大气逆辐射的不确定性较大区域面积较CMIP5减小,但不确定性极大区域面积无变化。地表净辐射的不确定性空间分布在两代CMIP间变化甚小。青藏高原、赤道太平洋、热带雨林、阿拉伯半岛和南极洲沿海依然是地球系统模式模拟辐射收支不确定性极大的关键区域。  相似文献   

Surface Elevation Distribution of Sea Waves Based on the Maximum Entropy Principle     

DAI Dejun 《中国海洋工程》2001,(2):217-228

A probability density function of surface elevation is obtained through improvement of the method introduced by Cieslikiewicz who employed the maximum entropy principle to investigate the surface elevation distribution. The density function can be easily extended to higher order according to demand and is non-negative everywhere, satisfying the basic behavior of the probability. Moreover because the distribution is derived without any assumption about sea waves, it is found from comparison with several accepted distributions that the new form of distribution can be applied in a wider range of wave conditions. In addition, the density function can be used to fit some observed distributions of surface vertical acceleration although something remains unsolved.  相似文献   

双涡互旋的数值模拟试验     

吴德辉  连东英 《台湾海峡》2005,24(3):377-382

本文应用准地转正压无辐散模式对双涡的相互作用进行了数值模拟试验。试验结果表明：（1）只考虑相对涡度平流的情况下双涡以互旋为主，而且随着初始间距的缩小，互旋越来越明显。双涡的相互作用与它们的初始间距以及它们的强度和结构有密切的关系。（2）双涡的移动加速和减速都是出现在它们移动方向改变的时刻，当移动方向向逆时针方向变化时移速减慢，否则加快。  相似文献   

太平洋海域海平面变化的灰色系统分析   总被引：3，自引：1，他引：3  

左军成  陈宗镛  戚建华 《中国海洋大学学报(自然科学版)》1997,(2)

应用灰色系统理论，对太平洋海域４８个长期验潮站的月均海平面分别建立了ＧＭ（１，１）模型。ＧＭ（１，１）模型能较好地反映太平洋海域的海平面变化的趋势，它除了能给出连续的海平面变化速率外，同时能方便地给出海平面变化的加速率。模拟结果表明，在太平洋地壳均衡假设下，太平洋海域的月均海平面以平均速率０．１７ｃｍ／ａ上升。在太平洋海域所取的４８个长期验潮站中，有４０个站在加速上升，全部站的平均加速度为０．０００２９ｃｍ／ａ２。且加速率逐渐增大。当然这些加速率都很小，但作为一种普遍性的趋势，这已足以说明：太平洋海域的海平面在加速上升  相似文献   

广东三水盆地晚自垩世—始新世古地磁研究及构造意义     

侯红明  袁友仁  张毅祥  汤贤赞  王保贵 《热带海洋学报》1994,(4)

对广东三水盆地上白垩统三水组、大　山组、古新统莘庄组及始新统　心组、宝月组的系统的古地磁研究结果表明：（１）旋转运动是该区构造运动的主要形式，顺时针旋转盆地拉张发育，这时针旋转盆地挤压衰亡，发育的程度与旋转角度有关；（２）始新世该区旋转方向由顺时针旋转变为道时针旋转，对应于太平洋－库拉板块对欧亚板块作用方向的改变，说明三水盆地的形成发育与太平洋－库拉板块对欧亚板块的作用密切相关；（３）三水盆地所在的华南地块从晚白垩世至始新世在纬向上不存在明显的运动，一直停留在略低于现今纬度的位置上。  相似文献   

基于MPI的LAGFD-WAM海浪数值模式并行算法研究   总被引：5，自引：0，他引：5  

王关锁  乔方利  杨永增 《海洋科学进展》2007,25(4):401-407

在LAGFD-WAM海浪串行数值模式基础上,利用MPI信息传递机制实现其并行化。通过对模拟区域合理划分,对数据采取分块加载,实现了各个节点的负载平衡;通过对算法的改进实现了粗粒度计算,大幅度减少了通信量,从而提高了程序的执行效率。对串行计算和并行计算的效率比较表明,本文建立的方法能够得到较高的加速比。对全球海浪模式,加速比和CPU数目大致呈线性关系。对高分辨率的区域海浪模式,在128 CPU条件下加速比可以达到91.9。  相似文献   

大型天线几何旋转中心的测定方法     

陈廷武  李敬东 《北京测绘》2006,(1):31-35

重点介绍了高精度确定大型天线几何旋转中心的观测方案和计算方法。结合具体实例,在ITRF2000框架下,论述了控制网布设、观测方案确定、数学模型的建立、数据处理的过程,结果与已知外部参考结果进行了比较,坐标分量上达到毫米级外附精度,验证了观测、计算方案的可行性和准确性。  相似文献   

用化石天长计算地球年龄的方法及意义——如何理解地球年龄          下载免费PDF全文

吴海威 《地质科学》2018,(2):774-780

天长（一天时长）是地球自转速度的直接反映。古生代-中生代化石记录的天长数据表明,古生代-中生代期间的天长随时间呈线性增加。根据角动量守恒定律,这意味着同时段地球自转速度呈线性衰减。如果把这个趋势应用于地球历史的全过程,计算结果为4.519～4.495 Ga,与目前公认的地球绝对年龄4.54 Ga一致。这意味着,从这个时间点起,地球有一种自转速度衰减的总趋势。地球自转速度衰减年龄等值于地球年龄说明：1）所测量的陨石样本生成的时间（表征地球年龄）与地球受月球吸引形成自转减速的时间几乎相同。这意味着地-月体系形成之前的地球比该陨石表征的地球年龄更为古老。2）地球、月球、自转速度衰减时长,三者的年龄呈现等值状态,因而此结果与月球起源于大碰撞的假说可以匹配。  相似文献   

The Digital Belt and Road program in support of regional sustainability     

Huadong Guo  Yubao Qiu  Massimo Menenti  Fang Chen  Paul F. Uhlir 《International Journal of Digital Earth》2018,11(7):657-669

The Belt and Road initiative has a significant focus on infrastructure, trade, and economic development across a vast region, and it also provides significant opportunities for sustainable development. The combined pressure of climate variability, intensified use of resources, and the fragility of ecosystems make it very challenging, however, to achieve future sustainability. To develop the path in a sustainable way, it is important to have a comprehensive understanding of these issues across nations and evaluate them in a scientific and well-informed approach. In this context, the Digital Belt and Road (DBAR) program was initiated as an international venture to share expertise, knowledge, technologies, and data to demonstrate the role of Earth observation science and technology and big Earth data applications to support large-scale development. In this paper, we identify pressing challenges, present the research priorities and foci of the DBAR program, and propose solutions where big Earth data can make significant contributions. This paper calls for further joint actions and collaboration to build a digital silk road in support of sustainable development at national, regional and global levels.  相似文献   

Semantic and syntactic interoperability in online processing of big Earth observation data     

Martin Sudmanns  Dirk Tiede  Stefan Lang  Andrea Baraldi 《International Journal of Digital Earth》2018,11(1):95-112

ABSTRACT

The challenge of enabling syntactic and semantic interoperability for comprehensive and reproducible online processing of big Earth observation (EO) data is still unsolved. Supporting both types of interoperability is one of the requirements to efficiently extract valuable information from the large amount of available multi-temporal gridded data sets. The proposed system wraps world models, (semantic interoperability) into OGC Web Processing Services (syntactic interoperability) for semantic online analyses. World models describe spatio-temporal entities and their relationships in a formal way. The proposed system serves as enabler for (1) technical interoperability using a standardised interface to be used by all types of clients and (2) allowing experts from different domains to develop complex analyses together as collaborative effort. Users are connecting the world models online to the data, which are maintained in a centralised storage as 3D spatio-temporal data cubes. It allows also non-experts to extract valuable information from EO data because data management, low-level interactions or specific software issues can be ignored. We discuss the concept of the proposed system, provide a technical implementation example and describe three use cases for extracting changes from EO images and demonstrate the usability also for non-EO, gridded, multi-temporal data sets (CORINE land cover).  相似文献