CINRAD/CC雷达速调管工作状态控制及维护

雷达速调管的性能直接影响到雷达探测的回波质量及操作成本,因此速调管的使用维护也日益受到人们的重视。以德宏雷达速调管使用维护为个例,分析归纳出一些速调管使用维护技巧。结合工作经验,从业务实际出发,对速调管的使用维护及工作状态提出一些新指标和建议。对其他型号CINRAD雷达也有较好的借鉴,以提高速调管使用技术和新一代天气雷达业务运行质量。     

CINRAD／CC雷达速调管维护及思考

本文根据本地CINRAD／CC雷达多年运行经验,结合最新一次速调管更换后出现的问题,提出速调管更换和维护中应该注意的一些问题。速调管是发射机的核心部件,价格昂贵,维护应当是慎之又慎。细心的维护能够保证速调管工作稳定可靠,且达到较长的使用寿命。     

雷达发射机灯丝电源故障维修

灯丝电源是一个交流稳压电源,通过灯丝中间变压器和位于油箱中的脉冲变压器及灯丝变压器,为速调管灯丝供电.2011年7月18日,内蒙古气象局通辽天气雷达站的CINRAD/CB雷达发射机反复出现灯丝电源故障,且无法加高压导致雷达停机,经分析和排查故障原因,最终排除了雷达故障.就此次故障的出现,分析其原因,举一反三,对雷达台站在今后的工作中加强备件的管理和测试数据的管理有一定的启示.     

CINRAD／CD型天气雷达发射机速调管故障诊断分析

该文介绍了CINRAD／CD型天气雷达速调管的工作原理和速调管的外围工作电路特点,当发生故障时,根据雷达返回的探测信息的变化,外围电路结构特点等,认真分析,判断故障所在,最终解决故障。此类经验对各台站机务人员有一定借鉴作用,达到提高雷达发射机稳定运行能力的目的。     

基于SYSCAL方法的天气雷达反射率因子在线标定技术

CINRAD天气雷达采用了一种基于SYSCAL的反射率因子在线标定技术,能够在雷达运行中动态检测和校正发射和接收通道的性能变化导致的反射率因子测量偏差,且标定具有良好的性能和时效。通过理论推演详细解析了CINRAD天气雷达反射率因子在线标定的原理,介绍了其在CINRAD/SA天气雷达中的技术实现方式和相应的标定方法及由来。以武汉CINRAD/SA天气雷达的一次在线标定为例对标定实效进行检验和分析,指出了CINRAD天气雷达反射率因子在线标定技术中存在的一些问题。掌握天气雷达反射率因子在线标定原理和技术,对于正确实施标定,保证回波质量和提高雷达故障诊断分析能力,十分必要。     

新一代天气雷达回波异常情况分析

针对新一代天气雷达CINRAD/SA,在运行过程中出现的雷达回波异常情况,从新一代天气雷达受到外界电磁波的干扰、计算机系统、接收机系统、天伺系统等方面,来分析造成雷达回波异常的故障成因,在此基础上,归纳出该型号雷达在使用过程中出现回波异常时,雷达操作、维护人员应掌握的故障排查方法及技巧.     

浅谈CINRAD/CD雷达IGBT故障控制及维护

新一代天气雷达的脉冲调制器性能直接影响到雷达的正常业务运行,因此其维护也日益受到重视。以毕节新一代天气雷达脉冲调制器维护为个例,分析调制开关故障原因。结合工作经验,从业务实际出发,对脉冲调制器的使用维护及工作状态提出一些建议。希望对我省其他CINRAD/CD雷达有一定的借鉴,以提高新一代天气雷达业务运行质量。     

CINRAD/SA天气雷达RDA适配参数的组成与应用

通过例证的方法,系统介绍了CINRAD/SA天气雷达RDA适配参数的组成、特点和作用,以及适配参数在雷达维护、标定中的重要应用,以便雷达保障人员在CINRAD/SA天气雷达的运行维护工作中能很好使用适配参数。CINRAD/SA天气雷达保障工作的实际经验表明,RDA适配参数在CINRAD/SA天气雷达的智能管理、运行控制、运行维护、系统标定、故障报警、信号处理和数据生成等方面具有重要作用,系统了解和充分运用RDA适配参数对保障CINRAD/SA天气雷达系统的高效、可靠运行具有十分重要的现实意义。     

X波段相控阵雷达与S波段雷达的对比分析

为检验X波段双极化相控阵雷达(XPAR-D)的探测性能,以广州XPAR-D观测的层云降水过程为例,与附近直线距离3.8 km的S波段双偏振天气雷达(CINRAD/SA-D)的观测数据进行对比分析。结果表明:XPAR-D与CINRAD/SA-D探测的反射率、径向速度的回波结构、位置基本一致,回波强度偏弱5 dBz左右;XPAR-D的灵敏度明显比CINRAD/SA-D低,难以探测到远处的弱回波,造成弱回波面积偏小;XPAR-D观测的层云降水的差分反射率接近于0,相关系数接近于1。     

CINRAD/SA雷达灯丝电源调试与故障判定

详细叙述了CINRAD/SA雷达灯丝电源控制电路的工作状态,分析了控制电路中脉宽调制器SG1525A的特性,调试了控制斩波器的脉宽调制电路和振荡器控制电路的关键测试波形,并对灯丝电源输出电压、灯丝电压保护和灯丝电流保护进行了分步调试.根据实际经验总结了在灯丝电源调试过程中出现的故障判定流程和故障排查、排除方法,旨在为雷达灯丝电源的故障处理提供参考和借鉴.     

CHARACTERISTICS AND TRENDS OF CLIMATIC EXTREMES IN CHINA DURING 1959–2014

The spatial and temporal variations of daily maximum temperature(Tmax), daily minimum temperature(Tmin), daily maximum precipitation(Pmax) and daily maximum wind speed(WSmax) were examined in China using Mann-Kendall test and linear regression method. The results indicated that for China as a whole, Tmax, Tmin and Pmax had significant increasing trends at rates of 0.15℃ per decade, 0.45℃ per decade and 0.58 mm per decade,respectively, while WSmax had decreased significantly at 1.18 m·s~(-1) per decade during 1959—2014. In all regions of China, Tmin increased and WSmax decreased significantly. Spatially, Tmax increased significantly at most of the stations in South China(SC), northwestern North China(NC), northeastern Northeast China(NEC), eastern Northwest China(NWC) and eastern Southwest China(SWC), and the increasing trends were significant in NC, SC, NWC and SWC on the regional average. Tmin increased significantly at most of the stations in China, with notable increase in NEC, northern and southeastern NC and northwestern and eastern NWC. Pmax showed no significant trend at most of the stations in China, and on the regional average it decreased significantly in NC but increased in SC, NWC and the mid-lower Yangtze River valley(YR). WSmax decreased significantly at the vast majority of stations in China, with remarkable decrease in northern NC, northern and central YR, central and southern SC and in parts of central NEC and western NWC. With global climate change and rapidly economic development, China has become more vulnerable to climatic extremes and meteorological disasters, so more strategies of mitigation and/or adaptation of climatic extremes,such as environmentally-friendly and low-cost energy production systems and the enhancement of engineering defense measures are necessary for government and social publics.     

ANALYSIS OF “BIMODAL PATTERN” STORM ACTIVITY CHARACTERISTICS OF THE BAY OF BENGAL

Storms that occur at the Bay of Bengal (BoB) are of a bimodal pattern, which is different from that of the other sea areas. By using the NCEP, SST and JTWC data, the causes of the bimodal pattern storm activity of the BoB are diagnosed and analyzed in this paper. The result shows that the seasonal variation of general atmosphere circulation in East Asia has a regulating and controlling impact on the BoB storm activity, and the “bimodal period” of the storm activity corresponds exactly to the seasonal conversion period of atmospheric circulation. The minor wind speed of shear spring and autumn contributed to the storm, which was a crucial factor for the generation and occurrence of the “bimodal pattern” storm activity in the BoB. The analysis on sea surface temperature (SST) shows that the SSTs of all the year around in the BoB area meet the conditions required for the generation of tropical cyclones (TCs). However, the SSTs in the central area of the bay are higher than that of the surrounding areas in spring and autumn, which facilitates the occurrence of a “two-peak” storm activity pattern. The genesis potential index (GPI) quantifies and reflects the environmental conditions for the generation of the BoB storms. For GPI, the intense low-level vortex disturbance in the troposphere and high-humidity atmosphere are the sufficient conditions for storms, while large maximum wind velocity of the ground vortex radius and small vertical wind shear are the necessary conditions of storms.     

LOW-FREQUENCY CIRCULATION AND EXTENDED-RANGE FORECAST IN CONNECTION WITH AUTUMN EXTREME HEAVY RAINFALL PROCESS IN HAINAN

Observed daily precipitation data from the National Meteorological Observatory in Hainan province and daily data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis-2 dataset from 1981 to 2014 are used to analyze the relationship between Hainan extreme heavy rainfall processes in autumn (referred to as EHRPs) and 10–30 d low-frequency circulation. Based on the key low-frequency signals and the NCEP Climate Forecast System Version 2 (CFSv2) model forecasting products, a dynamical-statistical method is established for the extended-range forecast of EHRPs. The results suggest that EHRPs have a close relationship with the 10–30 d low-frequency oscillation of 850 hPa zonal wind over Hainan Island and to its north, and that they basically occur during the trough phase of the low-frequency oscillation of zonal wind. The latitudinal propagation of the low-frequency wave train in the middle-high latitudes and the meridional propagation of the low-frequency wave train along the coast of East Asia contribute to the ‘north high (cold), south low (warm)’ pattern near Hainan Island, which results in the zonal wind over Hainan Island and to its north reaching its trough, consequently leading to EHRPs. Considering the link between low-frequency circulation and EHRPs, a low-frequency wave train index (LWTI) is defined and adopted to forecast EHRPs by using NCEP CFSv2 forecasting products. EHRPs are predicted to occur during peak phases of LWTI with value larger than 1 for three or more consecutive forecast days. Hindcast experiments for EHRPs in 2015–2016 indicate that EHRPs can be predicted 8–24 d in advance, with an average period of validity of 16.7 d.     

AN ATTRIBUTION ANALYSIS OF CHANGES IN POTENTIAL EVAPOTRANSPIRATION IN THE BEIJING–TIANJIN–HEBEI REGION UNDER CLIMATE CHANGE

Based on the measurements obtained at 64 national meteorological stations in the Beijing–Tianjin–Hebei (BTH) region between 1970 and 2013, the potential evapotranspiration (ET0) in this region was estimated using the Penman–Monteith equation and its sensitivity to maximum temperature (Tmax), minimum temperature (Tmin), wind speed (Vw), net radiation (Rn) and water vapor pressure (Pwv) was analyzed, respectively. The results are shown as follows. (1) The climatic elements in the BTH region underwent significant changes in the study period. Vw and Rn decreased significantly, whereas Tmin, Tmax and Pwv increased considerably. (2) In the BTH region, ET0 also exhibited a significant decreasing trend, and the sensitivity of ET0 to the climatic elements exhibited seasonal characteristics. Of all the climatic elements, ET0 was most sensitive to Pwv in the fall and winter and Rn in the spring and summer. On the annual scale, ET0 was most sensitive to Pwv, followed by Rn, Vw, Tmax and Tmin. In addition, the sensitivity coefficient of ET0 with respect to Pwv had a negative value for all the areas, indicating that increases in Pwv can prevent ET0 from increasing. (3) The sensitivity of ET0 to Tmin and Tmax was significantly lower than its sensitivity to other climatic elements. However, increases in temperature can lead to changes in Pwv and Rn. The temperature should be considered the key intrinsic climatic element that has caused the "evaporation paradox" phenomenon in the BTH region.     

Could the Recent Taal Volcano Eruption Trigger an El Ni?o and Lead to Eurasian Warming?

正The Taal Volcano in Luzon is one of the most active and dangerous volcanoes of the Philippines. A recent eruption occurred on 12 January 2020(Fig. 1a), and this volcano is still active with the occurrence of volcanic earthquakes. The eruption has become a deep concern worldwide, not only for its damage on local society, but also for potential hazardous consequences on the Earth's climate and environment.     

Revisiting the Concentration Observations and Source Apportionment of Atmospheric Ammonia

正While China’s Air Pollution Prevention and Control Action Plan on particulate matter since 2013 has reduced sulfate significantly, aerosol ammonium nitrate remains high in East China. As the high nitrate abundances are strongly linked with ammonia, reducing ammonia emissions is becoming increasingly important to improve the air quality of China. Although satellite data provide evidence of substantial increases in atmospheric ammonia concentrations over major agricultural regions, long-term surface observation of ammonia concentrations are sparse. In addition, there is still no consensus on     

COMPARATIVE ANALYSIS OF VARIOUS DATA OF AIR–SEA TEMPERATURE DIFFERENCE AND ITS VARIATION ACROSS SOUTH CHINA SEA IN THE PAST 35 YEARS

Using the International Comprehensive Ocean-Atmosphere Data Set(ICOADS) and ERA-Interim data, spatial distributions of air-sea temperature difference(ASTD) in the South China Sea(SCS) for the past 35 years are compared,and variations of spatial and temporal distributions of ASTD in this region are addressed using empirical orthogonal function decomposition and wavelet analysis methods. The results indicate that both ICOADS and ERA-Interim data can reflect actual distribution characteristics of ASTD in the SCS, but values of ASTD from the ERA-Interim data are smaller than those of the ICOADS data in the same region. In addition, the ASTD characteristics from the ERA-Interim data are not obvious inshore. A seesaw-type, north-south distribution of ASTD is dominant in the SCS; i.e., a positive peak in the south is associated with a negative peak in the north in November, and a negative peak in the south is accompanied by a positive peak in the north during April and May. Interannual ASTD variations in summer or autumn are decreasing. There is a seesaw-type distribution of ASTD between Beibu Bay and most of the SCS in summer, and the center of large values is in the Nansha Islands area in autumn. The ASTD in the SCS has a strong quasi-3a oscillation period in all seasons, and a quasi-11 a period in winter and spring. The ASTD is positively correlated with the Nio3.4 index in summer and autumn but negatively correlated in spring and winter.     

Information for Authors

正AIMS AND SCOPE Atmospheric and Oceanic Science Letters (AOSL) publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. Contributions from all over the world are welcome.SUBMISSIONAll submitted     

Information for Authors

AIMS AND SCOPE Atmospheric and Oceanic Science Letters （AOSL） pub- lishes short research letters on all disciplines of the atmos- phere sciences and physical oceanography. Contributions from all over the world are welcome.