GNSS反演资料在GRAPES_Meso三维变分中的应用   总被引：3，自引：1，他引：2       下载免费PDF全文

王金成  龚建东  邓莲堂 《应用气象学报》2014,25(6):654-668

为了进一步提高GRAPES_Meso的分析和预报效果,该文在GRAPES_Meso三维变分同化系统中建立了同化GNSS/RO反演的大气资料的观测算子,实现了对GNSS/RO反演的大气资料的同化应用,并通过2013年7月1个月的同化和预报试验分析了GNSS/RO反演大气资料对GRAPES_Meso模式系统分析和预报的影响。结果表明:增加了GNSS/RO反演大气资料的同化后,GRAPES_Meso位势高度场的分析误差明显减小,平均分析误差减小约8%,预报误差略有减小,平均预报误差减小约1%;湿度场的分析误差和预报误差变化不明显,常规观测资料稀少的青藏高原地区的降水预报技巧有所提高,小雨到大雨的ETS (equitable threat score) 评分提高约0.01,对全国及其他分区的降水预报技巧总体上有正效果。  相似文献   

The REMO Ocean Data Assimilation System into HYCOM （RODAS_H）： General Description and Preliminary Results          下载免费PDF全文

Clemente Augusto Souza TANAJURA  ;Alex Novaes SANTANA  ;Davi MIGNAC  ;Leonardo Nascimento LIMA  ;Konstantin BELYAEV  ;XIE Ji-Ping 《大气和海洋科学快报》2014,(5):464-470

The first version of the Brazilian Oceano- graphic Modeling and Observation Network （REMO） ocean data assimilation system into the Hybrid Coordi- nate Ocean Model （HYCOM） （RODAS H） has recently been constructed for research and operational purposes. The system is based on a multivariate Ensemble Optimal Interpolation （EnOI） scheme and considers the high fre- quency variability of the model error co-variance matrix. The EnOl can assimilate sea surface temperature （SST）, satellite along-track and gridded sea level anomalies （SLA）, and vertical profiles of temperature （T） and salinity （S） from Argo. The first observing system experiment was carried out over the Atlantic Ocean （78°S-50°N, 100°W-20°E） with HYCOM forced with atmospheric reanalysis from 1 January to 30 June 2010. Five integra- tions were performed, including the control run without assimilation. In the other four, different observations were assimilated： SST only （A SST）; Argo T-S profiles only （AArgo）; along-track SLA only （A_SLA）; and all data employed in the previous runs （A_All）. The A_SST, A_Argo, and A_SLA runs were very effective in improv- ing the representation of the assimilated variables, but they had relatively little impact on the variables that were not assimilated. In particular, only the assimilation of S was able to reduce the deviation of S with respect to ob- servations. Overall, the A_All run produced a good analy- sis by reducing the deviation of SST, T, and S with respect to the control run by 39%, 18%, and 30%, respectively, and by increasing the correlation of SLA by 81%.  相似文献   

Comparisons of Two Cloud-Detection Schemes for Infrared Radiance Observations          下载免费PDF全文

XU Dong-Mei  HUANG Xiang-Yu  LIU Zhi-Quan  MIN Jin-Zhong 《大气和海洋科学快报》2014,(4):358-363

The cloud-detection procedure developed by McNally and Watts （MW03） was added to the Weather Research and Forecasting Data Assimilation System. To provide some guidelines for setting up cloud-detection schemes, this study compares the MW03 scheme to the Multivariate and Minimum Residual （MMR） scheme for both simulated and real Advanced Infrared Sounder （AIRS） radiances. Results show that there is a high level of consistency between the results from simulated and real AIRS data. As expected, both cloud-detection schemes perform well in finding the cloud-contaminated channels based on the channels＇ peak levels. The cloud- detection results from MW03 are sensitive to the prescribed brightness temperature innovation threshold and brightness temperature gradient threshold. When increasing the brightness temperature innovation threshold for MW03 to roughly eight times the default threshold, the two cloud-detection schemes produce consistent data rejection distributions overall for high channels. MMR generally retains more data for long-wave channels. For both cloud-detection schemes, there is a high level of consistency between the cloud-free pixels and the visible/near-IR （Vis/NIR） cloud mask.  相似文献   

长江口海域悬浮颗粒有机物的稳定氮同位素季节分布与关键生物地球化学过程   总被引：2，自引：2，他引：0  

于海燕  俞志明  宋秀贤  刘丽丽  曹西华  袁涌铨 《海洋学报》2014,36(2):16-22

对2010年2、5、8、11月份长江口海域水体中的悬浮颗粒物进行稳定氮同位素分析。根据不同季节、不同区域内悬浮颗粒有机物的稳定氮同位素组成(δ15 Np)值的变化研究水体中氮的迁移、转化等生物地球化学过程,揭示其环境行为,从而对该海域的氮循环机制进行探索。研究发现:长江口海域悬浮颗粒物的稳定氮同位素组成具有较宽的分布范围,δ15 Np值分布范围为-1.1‰~8.6‰,具有明显的时空分布特点,反映了不同程度的陆源输入和氮的生物地球化学过程的影响。其中,2月份生物反应较弱,δ15 Np分布体现了陆源和海源的混合特征;5月和11月份上层水体δ15 Np随叶绿素a升高而降低,指示了生物的同化吸收作用;8月和11月δ15 Np和总溶解无机氮呈现极显著正相关关系,说明该海域发生了氮的矿化再生。  相似文献   

同化技术在渤海溢油应急预报系统中的应用   总被引：3，自引：1，他引：2  

李燕  朱江  王辉  林彩燕 《海洋学报》2014,36(3):113-120

溢油应急预报对溢油事故现场处理具有重要指导意义。国内外已开展大量溢油数值预报技术研究,但由于各类误差的引入(尤其风和流数值预报误差的引入)以及模型本身的不完善等各种原因导致溢油数值预报无法满足日益提高的溢油预报精度需求。随着现场观测技术和监测水平的提高,如何充分利用实时观测数据提高业务化溢油应急预报精度,并满足应急预报迅速快捷的要求,成为目前业务化溢油应急预报的首要问题。国家海洋环境预报中心于2008年实现了渤海溢油业务化预报系统的建立和业务化应用,本文针对当前渤海溢油业务化应急预报中存在的现实问题,利用已有渤海海上5个石油平台从2010年1月至2011年2月的风场观测数据,初步开展最优插值方法(optimal interpolation assimilation method,OI)同化技术在国家海洋环境预报中心渤海溢油应急预报系统风场订正的应用研究。本文采用交错订正方法,确定了OI同化技术中相关尺度因子的选取,从而实现在这5个观测站地理分布情况下,OI同化技术应用中参数的最优化,之后在理想实验和实际案例的应用中,该同化方法明显提高渤海溢油预报精度。本文为如何进一步利用同化方法迅速快捷地实现溢油应急预报精度的提高提供了一定研究基础。  相似文献   

影响浙江海域的温带气旋研究     

朱业  翟国庆  严俊  刘瑞  苏涛 《海洋预报》2014,31(5)

统计了44年来影响浙江海域的温带气旋及特征,并采用WRF中尺度数值模式对一次影响浙江海域的温带气旋的发生发展过程进行云迹风同化试验。通过分析时空变化特征和一次温带气旋发展过程中高低空的物理场变化,寻找温带气旋预报的着眼点。  相似文献   

FY-3双星MWHS资料对江西暴雨的循环同化试验     

米洁  朱克云  张杰 《成都信息工程学院学报》2014,(1):77-83

为了提高卫星资料在同化系统中使用率及验证同化卫星资料的预报效果,采用循环同化方案并通过江西2012年5月11~14日的暴雨个例进行验证。试验设计了风三卫星MWHS资料的循环同化双星资料方案和单时次同化单星资料方案,并对方案的运行结果进行了分析。结果表明,使用MWHS资料可以改进湿度场和涡度场。相比单时次同化单星MWHS资料,循环同化双星MWHS资料方案能更好地改善湿度场和动力场,模拟的降水落区和强度更接近实况,其TS评分最优。单时次同化单星MWHS资料,选用降水期间探测的卫星资料同化效果更优。  相似文献   

集合—变分数据同化方法的发展与应用   总被引：3，自引：0，他引：3  

熊春晖  张立凤  关吉平  陶恒锐  苏佳佳 《地球科学进展》2013,28(6):648-656

近年来,集合—变分数据同化方法已成为大气数据同化领域研究的热点问题.该方法能够综合利用集合卡尔曼滤波和变分同化的优势,是实现“集合预报和数据同化一体化”的有效途径.在分析变分同化和集合卡尔曼滤波优缺点的基础上引出集合—变分数据同化的概念;按照不同实现方式,将集合—变分同化分为协方差线性组合和增加控制变量2类,介绍了相应的研究进展,并将集合—变分同化概念拓展;然后介绍了集合—变分同化在英美两国的应用;最后回顾了集合—变分同化研究的主要问题,展望了未来的发展趋势.  相似文献   

FY-3A SATELLITE MICROWAVE DATA ASSIMILATION EXPERIMENTS IN TROPICAL CYCLONE FORECAST     

杨引明  杜明斌  张洁 《热带气象学报(英文版)》2013,19(3):297-304

China’s new generation of polar-orbiting meteorological satellite FY-3A was successfully launched on May 26,2008,carrying microwave sounding devices which had similar performance to ATOVS of NOAA series.In order to study the application of microwave sounding data in numerical prediction of typhoons and to improve typhoon forecasting,we assimilated data directly for numerical forecasting of the track and intensity of the 2009 typhoon Morakot(0908)based on the WRF-3DVar system.Results showed that the initial fields of the numerical model due to direct assimilation of FY-3A microwave sounding data was improved much more than that due to assimilation of conventional observations alone,and the improvement was especially significant over the ocean,which is always without conventional observations.The model initial fields were more reasonable in reflecting the initial situation of typhoon circulation as well as temperature and humidity conditions,and typhoon central position at sea was also adjusted.Through direct 3DVar assimilation of FY-3A microwave data,the regional mesoscale model improves the forecasting of typhoon track.Therefore,the FY-3A microwave data could efficiently improve the numerical prediction of typhoons.  相似文献   

加密探空资料在华南暴雨数值预报的应用试验   总被引：4，自引：2，他引：4  

黄燕燕  万齐林  陈子通  张诚忠  丁伟钰 《热带气象学报》2011,27(2):179-188

应用逐时同化预报系统CHAF进行加密探空资料同化试验,比较了同化加密探空资料与仅同化常规探空资料所得同化分析场和模式预报结果的差异.同化加密探空资料所得分析场水汽的均方根误差减小,水汽条件和大气环流形势与实况更接近.以加密同化探空资料所得分析场为模式初始场进行预报,雨区的分布和降水量级都较控制试验有改善.分析模式预报改...  相似文献