共查询到20条相似文献，搜索用时 15 毫秒
1.
AI Bo YU Mengchao GUO Jingtian ZHANG Wei JIANG Tao LIU Aichao WEN Lianjie LI Wenbo 《中国海洋大学学报(英文版)》2022,21(2):277-290
Numerical models and correct predictions are important for marine forecasting,but the forecasting results are often unable to satisfy the requirements of operational wave forecasting.Because bias between the predictions of numerical models and the actual sea state has been observed,predictions can only be released after correction by forecasters.This paper proposes a spati-otemporal interactive processing bias correction method to correct numerical prediction fields applied to the production and release of operational ocean wave forecasting products.The proposed method combines the advantages of numerical models and Forecast Discussion;specifically,it integrates subjective and objective information to achieve interactive spatiotemporal correc-tions for numerical prediction.The method corrects the single-time numerical prediction field in space by spatial interpolation and sub-zone numerical analyses using numerical model grid data in combination with real-time observations and the artificial judg-ment of forecasters to achieve numerical prediction accuracy.The difference between the original numerical prediction field and the spatial correction field is interpolated to an adjacent time series by successive correction analysis,thereby achieving highly efficient correction for multi-time forecasting fields.In this paper,the significant wave height forecasts from the European Centre for Medium-Range Weather Forecasts are used as background field for forecasting correction and analysis.Results indicate that the proposed method has good application potential for the bias correction of numerical predictions under different sea states.The method takes into account spatial correlations for the numerical prediction field and the time series development of the numerical model to correct numerical predictions efficiently. 相似文献
2.
Examining Forest Net Primary Productivity Dynamics and Driving Forces in Northeastern China During 1982–2010 总被引：2，自引：2，他引：0
Forest net primary productivity （NPP） is a key parameter for forest monitoring and management. In this study, monthly and annual forest NPP in the northeastern China from 1982 to 2010 were simulated by using Carnegie-Ames-Stanford Approach （CASA） model with normalized difference vegetation index （NDVI） sequences derived from Advanced Very High Resolution Radiometer （AVHRR） Global Invento y Modeling and Mapping Studies （GIMMS） and Terra Moderate Resolution Imaging Spectroradiometer （MODIS） products. To address the problem of data inconsistency between AVHRR and MODIS data, a per-pixel unary linear regres- sion model based on least ~;quares method was developed to derive the monthly NDVI sequences. Results suggest that estimated forest NPP has mean relative error of 18.97% compared to observed NPP from forest inventory. Forest NPP in the northeastern China in- creased significantly during the twenty-nine years. The results of seasonal dynamic show that more clear increasing trend of forest NPP occurred in spring and awmnn. This study also examined the relationship between forest NPP and its driving forces including the climatic and anthropogenic factors. In spring and winter, temperature played the most pivotal role in forest NPR In autumn, precipitation acted as the most importanl factor affecting forest NPP, while solar radiation played the most important role in the summer. Evaportran- spiration had a close correlation with NPP for coniferous forest, mixed coniferous broadleaved forest, and broadleaved deciduous forest. Spatially, forest NPP in the Da Hinggan Mountains was more sensitive to climatic changes than in the other ecological functional re- gions. In addition to climalie change, the degradation and improvement of forests had important effects on forest NPP. Results in this study are helpful for understanding the regional carbon sequestration and can enrich the cases for the monitoring of vegetation during long time series. 相似文献
3.
以中国典型黄土滑坡域甘肃黑方台党川6#滑坡体为例,基于滑坡体北斗和位移计时序监测数据,首先利用深度学习框架Tensorflow分别构建3种循环神经网络滑坡位移预测模型：简单循环神经网络(simple recurrent neural network,SimpleRNN)、长短期记忆网络(long short-term memory,LSTM)和门控循环单元(gated recurrent unit,GRU),并进一步针对循环神经网络在参数设置时多采用经验手动调参或采用网格搜索法,易造成人为主观影响较大和计算效率低下的突出问题,引入遗传算法（genetic algorithm,GA）优化循环神经网络参数的自动最佳化选取,分别构建3种基于遗传算法改进的循环神经网络滑坡位移高精度预测模型：GA-SimpleRNN、GA-LSTM、GA-GRU。研究结果表明,改进参数自动寻优后的3种循环神经网络预测模型具有更优的预测性能,特别是GA-GRU模型预测精度最高,更适用于滑坡体长时序位移的高精度预测。 相似文献
4.
柴华金 《广东海洋大学学报》2000,20(2):58-62
由预估校正法 ,构造了一个收敛加速的解常微分方程的方法 ,即所谓的二阶 C变换法。此法的稳定域与校正法的相同。数值检验表明此新方法很有用 相似文献
5.
X波段气象雷达回波强度的衰减订正 总被引：1，自引：0，他引：1
用KZS算法(地物回波)做标准来实现X波段气象雷达回波的微波衰减订正.首先对晴空地物回波进行多次采样,表明地物回波强度具有较好的稳定性.然后对业务性X波段气象雷达回波强度衰减订正进行观测,同时把订正后的回波与采用经验公式进行衰减订正的雷达回波强度进行比较,结果表明地物回波衰减订正法对X波段气象雷达衰减订正是可行的. 相似文献
6.
MENG Fanqi LI Guangjie College of Construction Engineering Jilin University Changchun China 《东北亚地学研究》2009,12(2):105-108
The Chedaren ravine belongs to high-prone areas of debris flow in Jilin Province, which threaten the local people＇ s life and security seriously. The authors used the residual correction theory to amend the GM （ 1, 1 ） model and forecast annual precipitation in disaster year of the Chedaren ravine ; it provides scientific foundation for early warning of debris flow disaster in the rainy season based on weather forecast. The prediction resuits show that annual precipitation is 724.7 mm in 2009 ; the region will probably occur large-scale debris flow during the rainy season. 相似文献
7.
The Chedaren ravine belongs to high-prone areas of debris flow in Jilin Province,which threaten the local people's life and security seriously. The authors used the residual correction theory to amend the GM (1, 1) model and forecast annual precipitation in disaster year of the Chedaren ravine; it provides scientific foundation for early warning of debris flow disaster in the rainy season based on weather forecast. The prediction results show that annual precipitation is 724.7 mm in 2009; the region will probably occur large-scale debris flow during the rainy season. 相似文献
8.
基于航空重力测量的独特优越性,研究了陀螺稳定平台在航空测量系统中的作用。运用Matlab simulink仿真模块建立单轴陀螺稳定平台稳定回路系统;建立修正回路数学模型,给定仿真条件下进行系统仿真并得出仿真结果;给出航空重力测量水平误差改正模型,并得出水平误差改正值。 相似文献
9.
对国家气候中心１９９６年１～１２月用Ｔ６３模式所作的５００ｈＰａ３４次月延伸预报进行了检验评估,并对模式的系统性误差进行了分析和订正。在假定订正后的Ｔ６３延伸预报完全准确的条件下,用ＥＣＭＷＦ旬平均高度场和西南区域月平均气温和月雨量资料,建立了用Ｔ６３预报产品预测西南区域月要素场的一种完全预报（ＰＰ）的动力统计关系。并对西南区域１９９６年２月至１９９７年１月逐月平均气温和降水进行了预报试验。 相似文献
10.
针对现有专业气象服务效益不高,集约化程度低的问题,结合现有专业气象服务模式和业务流程,提出以实现专业气象服务的集约化、规模化和标准化为目标,集数据采集、产品加工、产品显示发布、业务管理于一体的专业气象服务集成系统。系统采用数据解析技术将不同的专业气象服务所需的数据解析为统一的格式,利用网络地理信息系统等技术生成动态服务产品,实现产品自动化制作。自2011年4月汛期投入贵州省气象服务中心使用以来,取得了明显的经济效益和社会效益,满足了业务的需要,有效地提高了专业气象服务的水平。 相似文献
11.
This paper studies the relationship between net primary productivity (NPP) and annual average air temperature (GT) at 0cm above ground in permafrost regions by using revised Chikugo NPP model,cubic spline interpolating functions,and non-linear regression methods.The source regions of the Yangtze and Yellow Rivers were selected as the research areas.Results illustrate that:(1) There is significant non-linear relationship between NPP and GT in various typical years;(2) The maximum value of NPP is 6.17,5.87,7.... 相似文献
12.
????GAMIT???????????????ο???????????????????????????????????????????????????????????????????????TRACK??顣?????飬TRACK????в?????????????Saastamoinen???????GPS???????????????????? 相似文献
13.
各级自动气象站的建立极大地改善了气象分析预报现状。如何最大化地利用现有自动气象站资料并使之为经济发展服务是一个亟待解决的问题。提出了一个基于WINDOWS2000SERVER、WINDOWS 2003SERVER或更高服务版本的操作系统环境下,进行自动气象站实时多任务数据采集和发布应急响应信息的气象资料综合利用方案,以SQL2000和ACCESS数据模型为基础,相关硬件系统集成以及软件开发已经完成。系统目前已经在广西部分地区气象局投入实际应用,并得到了众多专业人员的肯定。 相似文献
14.
针对4类持续性、灾害性天气,利用集合平均、离散度、概率以及盒须图等方法对T213集合预报的数据进行再加工,得到其中期概率预报,包括全国范围的持续性降水、南方春季持续低温（重度低温）、南方春季低温（重度低温）连阴雨、江淮梅雨。其结果表明：（1）对于全国范围内的持续性降水过程,各类图都能很好的反映集合预报中不同量级的降水预报在10天之内的落区变化以及持续情况,并与实况对应较好。（2）对于南方低温和低温连阴雨,集合平均、离散度和概率图都能明显的反映出实际天气过程和范围的变化。（3）对于江淮梅雨这5个指标站的盒须图,能明显看出各集合成员在15个集合成员中的相对位置,以及数据的分布情况。同时还能看出集合成员与集合平均数之间的关系。梅雨日概率图则能直观的反映出10天之内每天达到梅雨日标准的概率,更有利于判断梅雨天气． 相似文献
15.
Mt. Everest is often referred to as the earth＇s ＇third＇ pole. As such it is relatively inaccessible and little is known about its meteorology. In 2005, an automatic weather station was operated at North Col （28°1′ 0.95＂ N, 86°57′ 48.4＂ E, 6523 m a.s.l.） of Mt. Everest. Based on the observational data, this paper compares the reanalysis data from NCEP/NCAR （hereafter NCEP-Ⅰ） and NCEP-DOE AMIP-Ⅱ （NCEP- Ⅱ）, in order to understand which reanalysis data are more suitable for the high Himalayas with Mr. Everest region. When comparing with those from the other levels, pressure interpolated from 500 hPa level is closer to the observation and can capture more synoptic-scale variability, which may be due to the very complex topography around Mt. Everest and the intricately complicated orographic land-atmosphereocean interactions. The interpolation from both NCEP-Ⅰ and NCEP-Ⅱ daily minimum temperature and daily mean pressure can capture most synopticscale variability （r〉0.82, n=83, p〈0.001）. However, there is difference between NCEP-Ⅰ and NCEP-Ⅱ reanalysis data because of different model parameterization. Comparing with the observation, the magnitude of variability was underestimated by 34.1%, 28.5 % and 27.1% for NCEP-Ⅰ temperature and pressure, and NCEP-Ⅱ pressure, respectively, while overestimated by 44.5 % for NCEP-Ⅱ temperature. For weather events interpolated from the reanalyzed data, NCEP-Ⅰ and NCEP-Ⅱ show the same features that weather events interpolated from pressure appear at the same day as those from the observation, and some events occur one day ahead, while most weather events and NCEP-Ⅱ temperature interpolated from NCEP-Ⅰ happen one day ahead of those from the observation, which is much important for the study on meteorology and climate changes in the region, and is very valuable from the view of improving the safety of climbers who attempt to climb Mt. Everest. 相似文献
16.
通过分析2018年2次典型降雨过程中大气可降水量(precipitable water vapor,PWV)的分布特征及其与实际降水量的关系,探讨PWV在预测降雨中的应用。结果表明,在降雨过程中,PWV的分布与实际降水量具有很好的相关性。PWV对降雨的发生具有一定的指示作用,在降雨发生前6~12 h,PWV开始增加;在降雨发生前1~2 h内PWV迅速上升;当PWV显著增加并保持高值时,预示强降雨的发生。PWV变化越快,降雨概率和降水量就越大。滑动平均处理结果进一步证明,强降雨发生前后,PWV会出现快速聚集和释放的现象,PWV可作为短期临近预报及天气分析等研究和应用的序列资料,为传统气象手段提供有力补充。 相似文献
17.
XIE Aihong REN Jiawen QIN Xiang JIANG Youyan 《山地科学学报》2006,3(3):181-190
Introduction Mt. Qomolangma (Everest) (27°54'N, 86°54'E) (Hereafter Mt. Qomolangma) lies between China and Nepal (Figure 1), and is the highest peak in the world, 8844.43 m asl (As promulgated by News Of-fice of the Chinese State Council in October 2005… 相似文献
18.
杨勃 《大地测量与地球动力学》2017,37(12):1234-1238
为提高桥梁变形预测的精度,探讨不同预测模型在桥梁变形预测中的效果,结合桥梁变形监测数据及组合预测思路,构建桥梁的MC误差修正优化组合预测模型。通过实例验证得出,组合预测较单项预测具有更高的预测精度及稳定性,其中以RBF神经网络组合的预测精度最高;同时,误差优化修正模型进一步减小了预测误差,优化后预测结果的相对误差期望值为0.86%,方差值为0.097 3 mm2,准确预测了桥梁变形,验证了该思路的有效性。 相似文献
19.
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徐君毅 《大地测量与地球动力学》2010,30(1):88-91
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20.
本研究旨在探讨1983-2008 年间印度植被净初级生产力(NPP)的时空变化格局及其与温度降水的关系。基于遥感数据和GLOPEM-CEVSA模型估算区域植被NPP,利用分段线性回归,分析了过去26年印度植被NPP的时空格局与变化特征。结果表明：（1）过去26年间印度植被年均NPP为414.29 gC·m-2·a-1,森林、农田和草地的NPP平均值分别为1002.32、485.98和631.39 gC·m-2·a-1。（2）分段线性回归结果显示,1983-2008 年间,印度植被总平均NPP呈先上升后下降的趋势,趋势转折点在1996年。占印度面积比例最大的农田植被类型的平均NPP也呈先上升后下降的趋势,趋势转折点在1996年,与总平均NPP的趋势转折点一致。（3）在空间上,印度大部分地区,发生了趋势转折,趋势转折点集中在1991-2000年间,大部分地区NPP在趋势转折点前呈上升趋势,其后呈下降趋势,与区域平均NPP的变化趋势一致。（4）印度西北部干旱地区植被NPP与温度呈负相关,与降水呈正相关。喜马拉雅山南部森林NPP则与温度呈正相关。降雨量较大的印度南部地区NPP与降水呈负相关。 相似文献