基于优化样本组合的集合-变分混合同化方案研究     

陈耀登  郭闪  王元兵  臧增亮  潘晓滨 《热带气象学报》2020,36(4):464-476

为有效引入“流依赖”的背景场误差协方差,同时降低集合预报带来的计算量,尝试通过优选与同化时刻天气形势更相似的历史预报样本,并结合预报过程中的时间滞后样本,将两种样本引入集合-变分混合同化系统中,构建基于优选历史预报样本和时间滞后样本的集合-变分混合同化方案。单点观测理想试验表明,优选历史预报样本结合时间滞后样本,既能够缓解样本不足所导致的采样误差,又能够为同化系统提供“流依赖”的背景场误差协方差。连续一周的循环同化及预报试验结果显示,相较于ERA5资料和探空资料,三维变分方案整体表现稍差,样本组合混合同化方案分析场和预报场的均方根误差最小,且比仅用时间滞后样本的混合同化方案有所改进;降水评分整体也表现最优,尤其对中雨和暴雨的模拟改进较明显,较好地模拟出了强降水中心的强度和位置,且改善了降水过报的问题。   相似文献   

区域雷灾易损性分析、评估及易损度区划   总被引：27，自引：0，他引：27       下载免费PDF全文

尹娜  肖稳安 《热带气象学报》2005,21(4):441-448

根据广东省近10年来的雷电灾害统计资料和近35年来的雷暴日观测统计资料，提炼出雷击密度、雷电灾害频度、经济损失模数、生命易损模数作为雷灾易损性评价指标。在详细分析了广东省各地市的自然环境、经济状况和各地区雷灾损失情况，对广东省各地市面对雷电灾害的脆弱性和易损性进行了综合评估，初步形成了各地易损性结构和广东省雷灾易损度区划。提出雷电灾害区域易损性分析、评估的模式，为区域防御雷电灾害、减低雷电损失的规划提供科学依据。  相似文献   

近50年来全球海温异常对我国东部地区冬季温度异常影响的诊断研究   总被引：28，自引：0，他引：28  

陈佩燕  倪允琪  殷永红 《热带气象学报》2001,17(4):371-380

利用1951－1997年全球海温、风场月平均资料和我国东部地区100个测站的冬季地面气温等资料，分析了我国东部地区冬季温度异常的时空特征和变化规律，探讨了全球海温异常与我国东部地区冬季温度异常的关系。发现赤道印度洋、赤道东太平洋、黑潮区是影响我国东部地区冬季温度异常的关键海区。前期夏、秋季赤道印度泣、赤道东太平洋海温异常与我国东部地区冬季温度异常有较好的相关关系，对预测我国东部地区冬季温度异常有一定的前兆意义。且不同关键海区的海温异常在不同季节对我国东部地区冬季温度异常产生影响的区域不同。  相似文献   

胶州--莱阳盆地白垩纪莱阳群中的震积岩及构造意义讨论   总被引：16，自引：2，他引：14  

殷秀兰  杨天南 《地质论评》2005,51(5):502-506

通过对胶州-莱阳盆地沉积层的野外考察和岩心观察,系统分析了莱阳群的沉积特征及其变化规律,鉴别出一些较典型的震积岩类型;较详细描述了其中的粉砂质液化脉、震裂液化角砾岩、震褶岩和砂枕构造等地震液化特征。最后从盆地的区域地质背景出发,初步认为白垩纪早期胶州-莱阳盆地的形成与其南部苏鲁造山带的后期隆升同时,造成研究区总体处于伸展-裂解的构造环境之中。强烈的同沉积构造活动伴随频繁的地震发生,致使盆地内早期沉积的莱阳群以普遍发育震积岩为特征。  相似文献   

A Review on the Global Stratotype Section and Point of the Permian-Triassic Boundary   总被引：6，自引：0，他引：6  

YIN Hongfu  TONG Jinnan  ZHANG Kexin Lab of Biological  Environmental Geology  China University of Geosciences  Wuhan  Hubei  State Key Lab of Geological Process  Mineral Resources  China University of Geosciences  Wuhan  Hubei 《《地质学报》英文版》2005,79(6):715-728

1 Introduction The Global Stratotype Section and Point (GSSP) of the Permian-Triassic Boundary (PTB) has been ratified by IUGS in 2001 (Yin et al., 2001). It is defined at the base of the Hindeodus parvus horizon, i.e. the base of Bed 27c of Meishan Section D, Changxing County, Zhejiang Province, South China. The PTB is important because it is not only an erathem boundary but also a great turning point of geological history symbolized by profound global changes and the strongest …  相似文献   

地球系统多圈层构造观     

任纪舜  牛宝贵  徐芹芹  赵磊  刘建辉  李舢  朱俊宾  刘仁燕 《地质学报》2022,96(1):50-64

地球系统多圈层构造观的基本理论框架是:①把大地构造学从研究地球表层的地壳构造、岩石圈构造推进到研究地球整体多圈层构造的新阶段.②地球系统和宇宙天体系统共同作用下形成的全球动力学,太阳能、地球系统多圈层相互作用以及宇宙天体运行的联合作用是各种地质作用的动力来源.③洋陆转化论:陆与洋是对立统一、相互转化的.陆与洋都不会永存...  相似文献   

Transition of Zonal Asymmetry of the Arctic Oscillation and the Antarctic Oscillation at the End of 1970s     

LIU Shan  WANG Huijun 《大气科学进展》2013,30(1):41-47

In this study,the interdecadal changes in the zonal symmetry of both Arctic Oscillation(AO) and Antarctic Oscillation(AAO) were analyzed.To describe the zonal asymmetry,a local index of AO and AAO was defined using the normalized sea level pressure(SLP) differences between 40° and 65°(latitudes) in both hemispheres.The zonal covariability of local AO and AAO can well represent the zonal symmetry of AO and AAO.Results show that the zonal asymmetry of both AO and AAO significantly changed in the late 1970s.AO was less asymmetric in the zonal direction in the boreal winter season during the latter period,while in the boreal summer it became more asymmetric after 1979.The zonal symmetry of AAO in both austral summer and winter has also significantly decreased since the late 1970s.These changes may imply interdecadal transition in the atmospheric circulation at middle and high latitudes,which is of vital importance to understanding climate variability and predictability across the globe,including the African-Asian-Australian monsoon regions.  相似文献   

Relationship between cloud characteristics and radar reflectivity based on aircraft and cloud radar co-observations     

宗蓉  刘黎平  银燕 《大气科学进展》2013,30(5):1275-1286

Cloud properties were investigated based on aircraft and cloud radar co-observation conducted at Yitong, Jilin, Northeast China. The aircraft provided in situ measurements of cloud droplet size distribution, while the millimeter-wavelength cloud radar vertically scanned the same cloud that the aircraft penetrated. The reflectivity factor calculated from aircraft measurements was compared in detail with simultaneous radar observations. The results showed that the two reflectivities were comparable in warm clouds, but in ice cloud there were more differences, which were probably associated with the occurrence of liquid water. The acceptable agreement between reflectivities obtained in water cloud confirmed that it is feasible to derive cloud properties by using aircraft data, and hence for cloud radar to remotely sense cloud properties. Based on the dataset collected in warm clouds, the threshold of reflectivity to diagnose drizzle and cloud particles was studied by analyses of the probability distribution function of reflectivity from cloud particles and drizzle drops. The relationship between reflectivity factor (Z) and cloud liquid water content (LWC) was also derived from data on both cloud particles and drizzle. In comparison with cloud droplets, the relationship for drizzle was blurred by many scatter points and thus was less evident. However, these scatters could be partly removed by filtering out the drop size distribution with a large ratio of reflectivity and large extinction coefficient but small effective radius. Empirical relationships of Z-LWC for both cloud particles and drizzle could then be derived.  相似文献   

Influence of Changes in Solar Radiation on Changes of Surface Temperature in China          下载免费PDF全文

ZHANG Hu  YIN Qing  Teruyuki NAKAJIMA  Nakata Mukai MAKIKO  LU Peng  HE Jinhai 《Acta Meteorologica Sinica》2013,27(1):87-97

The long-term trends of total surface solar radiation(SSR),surface diffuse radiation,and surface air temperature were analyzed in this study based on updated 48-yr data from 55 observational stations in China,and then the correlation between SSR and the diurnal temperature range(DTR) was studied.The effect of total solar radiation on surface air temperature in China was investigated on the basis of the above analyses.A strong correlation between SSR and DTR was found for the period 1961-2008 in China.The highest correlation and steepest regression line slope occurred in winter,indicating that the solar radiation effect on DTR was the largest in this season.Clouds and water vapor have strong influences on both SSR and DTR,and hence on their relationship.The largest correlations between SSR and DTR occurred in wintertime in northern China,regardless of all-day(including clear days and cloudy days) or clear-day cases.Our results also showed that radiation arriving at the surface in China decreased significantly during 1961-1989(dimming period),but began to increase during 1990-2008(brightening period),in agreement with previous global studies.The reduction of total SSR offset partially the greenhouse warming during 1961-1989.However,with the increase of SSR after 1990,this offsetting effect vanished;on the contrary,it even made a contribution to the accelerated warming.Nonetheless,the greenhouse warming still played a controlling role because of the increasing of minimum and mean surface temperatures in the whole study period of 1961-2008.We estimated that the greenhouse gases alone may have caused surface temperatures to rise by 0.31-0.46℃(10 yr) 1 during 1961-2008,which is higher than previously estimated.Analysis of the corresponding changes in total solar radiation,diffuse radiation,and total cloud cover indicated that the dimming and brightening phenomena in China were likely attributable to increases in absorptive and scattering aerosols in the atmosphere,respectively.  相似文献   

Microphysical Responses to Catalysis During a Stratocumulus Aircraft Seeding Experiment over the Sanjiangyuan Region of China     

WANG Lijun  YIN Yan  YAO Zhanyu  SUN Anping 《Acta Meteorologica Sinica》2013,27(6):849-867

This study explores the microphysical responses to a cloud seeding operation in the Sanjiangyuan region, China. The cloud seeding was performed using a zigzag flight pattern, while the detection phase was accomplished using a back-and-forth flight pattern through the top of a stratocumulus layer. Global Position System（GPS） and Particle Measuring System（PMS） data obtained during the operation are used to determine the efective cloud area before and after the operation, diferentiate the phase states of cloud particles, and analyze changes in the concentrations of liquid cloud particles and ice crystals, the evolution of the cloud particle spectrum, and the content of supercooled water. The median diameter of liquid cloud particles in the area of the cloud-seeding operation was 3.5–18.5 μm, most cloud particles observed in the 21.5–45.5-μm size regime were ice crystals, while all particles of size 50 μm and above were in the ice phase. Changes in the concentration and typical diameter of cloud particles within 36 km downwind of the cloudseeding operation did not exceed natural fluctuations in the cloud area before the operation; however, the concentration of liquid cloud particles decreased substantially in areas with high concentrations of supercooled water（concentrations of supercooled water exceeding 0.01 g m 3）. The concentration of ice crystals within the measuring range of the Forward Scattering Spectrometer Probe（FSSP） increased substantially, the water content of ice-phase particles increased, and the average supercooled water content in the cloud decreased from（68.3± 23.1）% before the operation to（34.2± 12.4）%. The efects of cloud seeding were more pronounced in parts of the cloud where the content of supercooled water was higher. Little to no efects were observed in parts of the cloud with low concentrations of supercooled water.  相似文献