双线偏振多普勒天气雷达遥测降水强度和液态含水量的方法和精度研究   总被引：13，自引：1，他引：12  

刘黎平  葛润生  张沛源 《大气科学》2002,26(5):709-719

利用雨滴谱的Г分布和散射计算模式,研究了C波段双线偏振多普勒天气雷达遥测降水强度、液态含水量和识别降水粒子相态的方法,给出了利用反射率因子ZH、差分反射率因子ZDR、差传播相移KDP反演降水强度和液态含水量的三种公式以及这三个物理量的关系公式,并从雨滴谱的变化和雷达测量误差两方面比较了几种方法的测雨精度.结果表明:雨滴谱在很大范围变化时,利用ZDR和KDP可以很好地反演出降水强度和液态含水量,它受滴谱分布的影响不大,它的探测精度优于(ZH,ZDR)方法.单参数KDP方法优于传统的Z-R关系方法.同时给出的ZH与ZDR和KDP关系公式也基本不受雨滴谱变化的影响,它可以用于降水粒子相态的识别.双参数方法的测量误差主要来源于雷达测量ZDR和KDP的误差,特别是KDP的误差,改善KDP的测量误差是发挥双线偏振多普勒雷达探测降水强度或液态含水量潜力的关键.  相似文献   

新一代天气雷达灾害性天气警报和短时预报系统     

杨洪平胡绍萍  周海光张沛源 《中国气象科学研究院年报》2006,(1):17-19

由中国气象科学研究院主持，北京、湖北、广东、安徽和厦门等省市气象局科研人员参与的以多普勒天气雷达实时观测资料为基础的新一代天气雷达灾害性天气警报和短时预报系统于2006年底完成，建立了一整套回波特征参数定量提取技术、风场反演技术、灾害性天气自动识别技术以及自动和人机交互的0～2h暴雨、大风、冰雹的预报和0～2h降水预报技术。  相似文献   

静海地震台地磁加卸载响应比与邻区地震关系研究     

庞群英  徐学恭  胡培元  宋金钟  田山 《地震地磁观测与研究》2007,28(1):52-56

研究分析了静海地磁台2002～2006年观测资料的加卸载响应比异常与邻区ML 4.0以上地震之间的关系,提出了适用于静海地磁台的地震分析预报异常形态特征和阈值判据.  相似文献   

Late Cambrian to Early Silurian Granitic Rocks of the Gemuri Area, Central Qiangtang, North Tibet: New Constraints on the Tectonic Evolution of the Northern Margin of Gondwana     

WANG Haitao  ZHAI Qingguo  HU Peiyuan  ZENG Lingsen  TANG Yue  ZHU Zhicai 《《地质学报》英文版》2020,94(4):1007-1019

The Paleozoic tectonic framework and paleo–plate configuration of the northern margin of Gondwana remain controversial. The South Qiangtang terrane is located along the northern margin of Gondwana and records key processes in the formation and evolution of this supercontinent. Here, we present new field, petrological, zircon U-Pb geochronological, and Lu-Hf isotopic data for granitic rocks of the Gemuri pluton, all of which provide new insights into the evolution of the northern margin of Gondwana. Zircon U-Pb dating of the Gemuri pluton yielded three concordant ages of 488.5 ± 2.1, 479.9 ± 8.9, and 438.5 ± 3.5 Ma. Combining these ages with the results of previous research indicates that the South Qiangtang terrane records two magmatic episodes at 502–471 and 453–439 Ma. These two episodes are associated with enriched zircon Hf isotopic compositions(εHf(t) =-10.1 to-3.9 and-16.6 to-6.5, respectively), suggesting the granites were formed by the partial melting of Paleoproterozoic–Mesoproterozoic metasedimentary rocks(Two–stage Hf model ages(TCDM) = 2094–1704 and 2466–1827 Ma, respectively). Combining these data with the presence of linearly distributed, contemporaneous Paleozoic igneous rocks along the northern margin of Gondwana, we suggest that all of these rocks were formed in an active continental margin setting. This manifests that the two magmatic episodes within the Gemuri area were associated with southward subduction in the Proto-(Paleo-) Tethys Ocean.  相似文献   

利用SLR计算地心运动方法研究     

李欣  郭唐永  张念  骆天天  王培源  邹彤 《大地测量与地球动力学》2007,27(Z1):47-48

Three methods for calculation of geocenter motion are intruduced.  相似文献   

北京地区细菌性痢疾医疗气象预报模式及流行风险水平评估     

张姝丽  孙培源  张德山  蒲永兰  韦懿云  赵娜  宛公展 《气候与环境研究》2009,14(6):673-677

研究了北京市海淀区2004～2006年全年逐日细菌性痢疾发病率与地面气象要素的相关关系.结果发现,细菌性痢疾发病与水汽压(空气绝对湿度)高度相关,单相关系数平均可达0.85以上.在所有候选预报因子中,它的方差贡献可占80%.采用多元回归概率分级技术,建立了细菌性痢疾医疗气象预报及风险水平评估模式.该模式预报结果可为各级疾病预防控制中心指导广大城乡居民卫生防疫提供科学依据.  相似文献   

Evaporation from seasonally frozen bare and vegetated ground at various groundwater table depths in the Ordos Basin,Northwest China     

Zaiyong Zhang  Wenke Wang  Chengcheng Gong  Zhoufeng Wang  Lei Duan  Tian‐chyi Jim Yeh  Peiyuan Yu 《水文研究》2019,33(9):1338-1348

In cold climates, the process of freezing–thawing significantly affects the ground surface heat balance and water balance. To better understand the mechanism of evaporation from seasonally frozen soils, we performed field experiments at different water table depths on vegetated and bare ground in a semiarid region in China. Soil moisture and temperature, air temperature, precipitation, and water table depths were measured over a 5‐month period (November 1, 2016, to March 14, 2017). The evaporation, which was calculated by a mass balance method, was high in the periods of thawing and low in the periods of freezing. Increased water table depth in the freezing period led to high soil moisture in the upper soil layer, whereas lower initial groundwater levels during freezing–thawing decreased the cumulative evaporation. The extent of evaporation from the bare ground was the same in summer as in winter. These results indicate that a noteworthy amount of evaporation from the bare ground is present during freezing–thawing. Finally, the roots of Salix psammophila could increase the soil temperature. This study presents an insight into the joint effects of soil moisture, temperature, ground vegetation, and water table depths on the evaporation from seasonally frozen soils. Furthermore, it also has important implications for water management in seasonally frozen areas.  相似文献   

无旋转倾角的NAV/CNAV型GEO广播星历拟合   总被引：1，自引：1，他引：0  

杜兰  刘泽军  周佩元  方善传  刘利  马高峰 《测绘学报》2017,46(3):297-306

目前北斗GEO的星历拟合算法和用户卫星位置算法均引进了人为设置的5°倾角旋转,此外,少数星历参数还有超限现象。取消GEO的旋转倾角和抑制参数超限能够统一北斗混合星座的用户算法。基于第一类无奇点根数,分析了无旋转倾角的GEO两步法星历参数拟合算法。讨论了GEO的参数超限原因,提出采用固定1至2个超限参数取值的缩减参数拟合法。北斗GEO卫星在非地影期和地影期的拟合试验表明,拟合成功率和拟合精度能够保证,拟合用户距离误差(URE)的平均值优于3mm;缩减参数拟合法能够抑制特定时段下的参数超限问题,但是拟合URE放大到2cm。  相似文献   

神农架地区第四纪冰川遗迹与冰期划分     

赵志中  何培元 《地质力学学报》1997,3(2):18-23

神农架是中国第四纪地质环境演变的热点地区之一。本文通过对第四纪冰川地貌、冰碛残迹及二者关系研究,提供了本区第四纪古冰川发育的多方面证据。神农架地区在第四纪时期曾发生三期冰期和两期冰缘期,即松柏冰期、木鱼坪冰期、龙潭冰期、松香坪冰缘期、神农架冰缘期。本文首次系统地建立了本区第四纪气候地层系列.   相似文献   

“9·5”泸定震后落井沟泥石流灾变过程预测分析          下载免费PDF全文

李林泽  常鸣  李宏杰  胡锦凤  徐恒志  刘沛源 《地震工程学报》2023,(5):1116-1124

落井沟位于四川省泸定县得妥镇东南部,从沟口至其东南部约11 km处有正在运营的大岗山水电站。为有效防止落井沟泥石流对得妥人民的生命财产及大岗山水电站的运维造成的威胁与损毁,开展对泸定震后落井沟内物源分布特征与不同降雨周期下泥石流运动演化过程分析。“9·5”泸定地震后,耦合现场调查与地震前后遥感影像解译,得出强震致使落井沟流域内产生滑坡37处,总面积约0.125 km²,并采用LiDAR航拍技术优化解译结果,得到实际松散堆积物方量为15.52万m³。随后结合精准物源、精细化地形及5%、2%、1%降雨频率,开展基于OpenLISEM数值计算的落井沟泥石流运动演化特征研究。结果表明：5%、2%、1%降雨重现周期下落井沟泥石流运动过程的最大泥深分别为6、8、11 m,最大流速分别为5、7、10 m/s; 5%、2%降雨频率下泥石流对大渡河的堵江程度较小,1%频率下可造成半堵江状态。  相似文献