农业气象测报工作基数统计系统开发与应用     

成兆金  庄立伟  李轩  吴门新 《气象科技》2019,47(2):367-372

本文介绍了农业气象测报工作基数统计系统(AgMOBase)的框架、数据库、功能模块设计与业务应用情况。AgMOBase系统是农业气象测报业务系统(AgMODOS)配套的业务软件,采用面向对象技术与模块化结构技术开发,由数据层、技术层、应用层和用户层组成4层架构结构。系统已在全国农业气象观测站业务应用,实现气象部门开展的农业气象观测质量考核和软件应用质量考核所规定的日常工作基数统计工作,提供个人和台站的月份/年度详细的基数统计报告。  相似文献   

机场主导能见度仪器自动观测方法研究     

台宏达  庄子波  刘海文  孙东松 《气象科技》2019,47(2):222-228

主导能见度是航空活动能否正常进行的重要标准之一。伴随我国通用机场建设,主导能见度的自动观测具有重要的实际意义。本文使用中值法、图形比例法和均值法3种方法,利用机场现有多套能见度传感器进行主导能见度自动观测,并使用3种方法研究分析了天津、大连、海拉尔、成都和重庆5个机场2014年12月10日起连续100天的07:00和19:00 2个时间点的多能见度传感器测量值。结果表明:相比于中值法和图形比例法,均值法具有更小的观测偏差;观测原理和方法、能见度传感器数量、地区气候差异和观测位置差异是影响主导能见度自动观测数据质量的主要影响因素。  相似文献   

The Tibetan Plateau Surface–Atmosphere Coupling System and Its Weather and Climate Effects: The Third Tibetan Plateau Atmospheric Science Experiment     

Ping ZHAO  Yueqing LI  Xueliang GUO  Xiangde XU  Yimin LIU  Shihao TANG  Wenming XIAO  Chunxiang SHI  Yaoming MA  Xing YU  Huizhi LIU  La JIA  Yun CHEN  Yanju LIU  Jian LI  Dabiao LUO  Yunchang CAO  Xiangdong ZHENG  Junming CHEN  An XIAO  Fang YUAN  Donghui CHEN  Yang PANG  Zhiqun HU  Shengjun ZHANG  Lixin DONG  Juyang HU  Shuai HAN  Xiuji ZHOU 《Journal of Meteorological Research》2019,(3):375-399

The Tibetan Plateau(TP) is a key area affecting forecasts of weather and climate in China and occurrences of extreme weather and climate events over the world. The China Meteorological Administration, the National Natural Science Foundation of China, and the Chinese Academy of Sciences jointly initiated the Third Tibetan Plateau Atmospheric Science Experiment(TIPEX-Ⅲ) in 2013, with an 8–10-yr implementation plan. Since its preliminary field measurements conducted in 2013, routine automatic sounding systems have been deployed at Shiquanhe, Gaize, and Shenzha stations in western TP, where no routine sounding observations were available previously. The observational networks for soil temperature and soil moisture in the central and western TP have also been established. Meanwhile, the plateau-scale and regional-scale boundary layer observations, cloud–precipitation microphysical observations with multiple radars and aircraft campaigns, and tropospheric–stratospheric air composition observations at multiple sites, were performed. The results so far show that the turbulent heat exchange coefficient and sensible heat flux are remarkably lower than the earlier estimations at grassland, meadow, and bare soil surfaces of the central and western TP. Climatologically, cumulus clouds over the main body of the TP might develop locally instead of originating from the cumulus clouds that propagate northward from South Asia. The TIPEX-Ⅲ observations up to now also reveal diurnal variations, macro-and microphysical characteristics, and water-phase transition mechanisms, of cumulus clouds at Naqu station. Moreover, TIPEX-Ⅲ related studies have proposed a maintenance mechanism responsible for the Asian "atmospheric water tower" and demonstrated the effects of the TP heating anomalies on African, Asian, and North American climates. Additionally, numerical modeling studies show that the Γ distribution of raindrop size is more suitable for depicting the TP raindrop characteristics compared to the M–P distribution, the overestimation of sensible heat flux can be reduced via modifying the heat transfer parameterization over the TP, and considering climatic signals in some key areas of the TP can improve the skill for rainfall forecast in the central and eastern parts of China. Furthermore, the TIPEX-Ⅲ has been promoting the technology in processing surface observations, soundings, and radar observations, improving the quality of satellite retrieved soil moisture and atmospheric water vapor content products as well as high-resolution gauge–radar–satellite merged rainfall products, and facilitating the meteorological monitoring, forecasting, and data sharing operations.  相似文献   

Comparative Analyses of Vertical Structure of Deep Convective Clouds Retrieved from Satellites and Ground-Based Radars at Naqu over the Tibetan Plateau     

Hui Wang  Xueliang Guo 《Journal of Meteorological Research》2019,(3):446-462

In order to improve understanding of deep convective clouds over the Tibetan Plateau, characteristics of vertical structure of a deep strong convective cloud over Naqu station and a deep weak convective cloud approximately 100 km to the west of Naqu station, which occurred over 1300-1600 Beijing Time (BT) 9 July 2014 during the Third Tibetan Plateau Atmospheric Science Experiment (TIPEX-Ⅲ), are analyzed, based on multi-source satellite data from TRMM, CloudSat, and Aqua, and radar data from ground-based vertically pointing radars (C-band frequency-modulated continuous-wave radar and KA-band millimeter wave cloud radar). The results are as follows.(1) The horizontal scales of both the deep strong and deep weak convective clouds were small (10-20 km), and their tops were high[15-16 km above sea level (ASL)]. Across the level of 0℃ isotherm in the deep strong convective cloud, the reflectivity increased rapidly, suggesting that the melting process of solid precipitation particles through the 0℃ level played an important role. A bright band located at 5.5 km ASL (i.e., 1 km above ground level) appeared during the period of convection weakening.(2) The reflectivity values from TRMM precipitation radar below 11 km were found to be overestimated compared to those derived from the C-band frequency-modulated continuous-wave radar.(3) Deep convective clouds were mainly ice clouds, and there were rich small ice particles above 10 km, while few large ice particles were found below 10 km. The microphysical processes of deep strong and deep weak convective clouds mainly included mixed-phase process and glaciated process, and the mixed-phase process can be divided into two types:one was the rimming process below the level of -25℃(deep strong convective cloud) or -29℃(deep weak convective cloud) and the other was aggregation and deposition process above that level. The latter process was accompanied with fast increase in ice particle effective radius. The above evidence from space-based and ground-based observational data further clarify the characteristics of vertical structure of deep convective clouds over the Tibetan Plateau, and provide a basis for the evaluation of simulation results of deep convective clouds by cloud models.  相似文献   

风云四号静止轨道气象卫星成像仪典型观测区域设计     

赵磊  商建  冯小虎  张志清 《气象科学进展》2019,(1):37-40,59

风云四号气象卫星是我国新一代静止轨道气象卫星,采用三轴稳定姿态控制方式,极大地提高对地观测精度及观测频次,同时也对有效载荷观测模式的灵活设计提出了更高要求。星上装载的静止轨道辐射成像仪是我国静止轨道气象卫星携带的同类仪器中最为先进的。利用最先进的观测仪器,提高观测效率,在气象服务中发挥更大的作用是气象卫星应用的根本。深入探讨了风云四号静止轨道气象卫星成像仪的工作模式,首次针对不同的观测需求提出了灵活的成像仪观测区域设计方案,有效满足典型区域的不同观测需求,在成像仪在轨测试中发挥了重要作用,为开展业务运行奠定了坚实的基础。  相似文献   

Observational Study on the Supercooled Fog Droplet Spectrum Distribution and Icing Accumulation Mechanism in Lushan,Southeast China     

Tianshu WANG  Shengjie NIU  Jingjing Lü  Yue ZHOU 《大气科学进展》2019,36(1):29-40

A fog monitor, hotplate total precipitation sensor, weather identifier and visibility sensor, ultrasonic wind speed meter,an icing gradient observation frame, and an automated weather station were involved in the observations at the Lushan Meteorological Bureau of Jiangxi Province, China. In this study, for the icing process under a cold surge from 20–25 January2016, the duration, frequency, and spectrum distribution of agglomerate fog were analyzed. The effects of rain, snow, and supercooled fog on icing growth were studied and the icing and meteorological conditions at two heights(10 m and 1.5 m)were compared. There were 218 agglomerate fogs in this icing process, of which agglomerate fogs with durations less than and greater than 10 min accounted for 91.3% and 8.7%, respectively. The average time interval was 10.3 min. The fog droplet number concentration for sizes 2–15 μm and 30–50 μm increased during rainfall, and that for 2–27 μm decreased during snowfall. Icing grew rapidly(1.3 mm h-1) in the freezing rain phase but slowly(0.1 mm h-1) during the dry snow phase. Intensive supercooled fog, lower temperatures and increased wind speed all favored icing growth during dry snow(0.5 mm h-1). There were significant differences in the thickness, duration, density, and growth mechanism of icing at the heights of 10 m and 1.5 m. Differences in temperature and wind speed between the two heights were the main reasons for the differences in icing conditions, which indicated that icing was strongly affected by height.  相似文献   

Low frequency variations in currents on the southern continental shelf of the Caspian Sea     

《Dynamics of Atmospheres and Oceans》2019

The Caspian Sea (CS) is the largest enclosed basin in the world, located inside the Eurasian continent in the Northern Hemisphere. Although there have been few studies of the dynamics of the coastal zone in the CS, observations show that oscillations with periods from 2–3 days to 1–3 weeks dominate. These oscillations are presumed to be related to the synoptic variability of direct wind impact and to coastally-trapped waves (CTW). Here, we describe and interpret current meter observations on the continental margins of the southern CS from 2012 to 2014 to identify and characterize CTW there. Time series analysis provides evidence for both remote and locally wind-forced eastward traveling signals with time lags consistent with CTW theory. A wind-forced model with two CTW modes is able to reproduce the structure, amplitudes, and phases of observed alongshore current fluctuations, explaining half of the variance at frequencies less than 1 cpd. Remote forcing effects are present at all times, but are most striking when the local winds are weak, as in summer. The CTW calculations also suggest that the source region for the remote forcing may extend farther north along the west coast of the CS.  相似文献   

国产海洋气象漂流观测仪在台风观测中的应用分析     

曹晓钟  李肖霞  雷勇  温华洋  王榭 《气象》2019,45(10):1457-1463

介绍了由我国自主研制的、基于北斗导航通信卫星的、集海洋水文要素和气象要素一体观测的、在恶劣海况条件下能进行连续、可靠观测的海洋气象漂流观测仪,及其在多个海域开展实际的外海观测试验情况。2017年8月20日至9月5日,三台漂流观测仪在广东博贺海洋气象综合试验基地,经历了2017年第13号台风天鸽和第14号台风帕卡两次台风天气过程。对试验期间获取的台风天气过程中气温、气压、海温等观测数据的分析表明,漂流观测仪所获得的观测数据与相关国家级业务观测站点的观测数据具有较好的相关性,揭示了台风天气过程的明显特征,并表现出合理、清晰的日变化特征。上述试验表明,国产海洋气象漂流观测仪已具备在恶劣海况下进行实际观测的能力。  相似文献   

卫星资料揭示的青藏高原对流层上层温度气候演变趋势特征     

明绍慧  秦正坤  黄瑜 《高原气象》2019,(2):264-277

利用1982—2016年MSU/AMSU-A亮温资料,分析了青藏高原地区对流层上层温度的气候趋势及其演变特征,并利用ERA-Interim和NCEP-R2再分析资料的相应高度大气温度资料进行了对比分析。结果表明,青藏高原地区对流层高层卫星亮温资料总体表现为逐渐增暖现象,这与再分析资料的对应层次大气温度变化有很好的相似性。基于集合经验模式分解方法 EEMD的非线性趋势分析表明,青藏高原地区对流层上层亮温的增温首先出现在青藏高原中部,随着时间演变,增温现象逐渐向青藏高原四周扩散,最后在整个青藏高原地区都出现了一致增温现象。相比于NCEP-R2再分析资料而言,ERA-Interim再分析资料300 h Pa大气温度的演变趋势与观测亮温有很好的相似性,只是增温现象是首先在青藏高原附近,随着时间推移,增温现象逐步向周边地区扩张,最终整个青藏高原地区出现了整体升温现象。但是NCEP-R2再分析资料则是与上述两种资料的温度演变特征有很大的差异,其300 h Pa高度大气温度在前20年表现为明显的降温特征,在最近10年才出现了增温,并逐步向周边地区扩张的现象。  相似文献   

中国大陆速度场在CGCS2000坐标转换中的应用研究     

王建红  李涌涛  马洪磊 《大地测量与地球动力学》2022,42(4):398-402

基于中国大陆区域2 074个具有实测速度的已知测站,进行中国大陆速度场在CGCS2000坐标转换中的应用研究。采用不同内插组合方法,充分考虑未知点与已知速度测站的距离因素,使已知速度测站的数据得到充分利用。相比于单纯利用速度场格网模型,该方法得到的未知点速度精度具有较大幅度提高,其在点位X、Y、Z三个方向上的历元归算精度最高可提高24.00 cm、10.89 cm和17.82 cm,对利用已知速度的测站提高历元归算精度具有一定指导意义。  相似文献