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1.
贵阳机场跑道灯强度与RVR的关系 总被引：1，自引：0，他引：1
目前全国大多数省会级机场都安装了自动气象观测设备，该设备的一个重要功能就是测定跑道的跑道视程（RVR），众所周知，跑道灯强度的大小对RVR的测定是有影响的，总的认为是：跑道灯强度的大与RVR的数值是成正比的。本文：根据贵阳机场设备的实际情况，找出这种比例关系，供气象人员，管制指挥员根据这种关系来控制灯光强度，从而达到提高航班起降正常率的目的。 相似文献
2.
何驰 《高原山地气象研究》2001,21(4)
目前全国大多数省会级机场都安装了自动气象观测设备,该设备的一个重要功能就是测定跑道的跑道视程(RVR),众所周知,跑道灯强度的大小对RVR的测定是有影响的,总的认为是:跑道灯强度的大小与RVR的数值是成正比的.本文:根据贵阳机场设备的实际情况,找出这种比例关系,供气象人员,管制指挥员根据这种关系来控制灯光强度,从而达到提高航班起降正常率的目的. 相似文献
3.
利用微波辐射计资料、自动观测资料,分析了成都双流机场2019～2020年初的辐射雾中跑道视程(RVR)的变化特征。结果表明:(1)雾中各跑道RVR差别大,02R最差,20R最好。(2)微波辐射计反演温度在近地层有偏差,午后偏低,凌晨偏高,分析时需修订。(3)RVR变化特征与近地面逆温层特征及虚位温特征有较好对应,可据此更好地预计RVR变化,特别是RVR上升至550m临界值的时间。 相似文献
4.
《干旱气象》2017,(5)
利用济南机场2010—2016年逐时地面观测资料和跑道视程资料,应用数理统计方法对低能见度(VIS≤800 m)、低跑道视程(RVR≤550 m)和≤400 m RVR出现的月、日特征及其之间的关系进行对比分析。结果表明11月至次年2月为三者频发期;一天中22:00—23:00(世界时)是三者频发期,其中低RVR现象在17:00—02:00尤为突出。低能见度和低RVR持续时间和出现次数成反比。雾和冻雾是造成低能见度和低RVR的主要视程障碍现象,降水对低能见度的影响大于对低RVR的影响。11月至次年2月,两者呈显著正相关,差值较小,3—10月没有明显的相关性,差值较大。一天之中两者23:00—15:00相关性较好,差值较小,16:00—22:00没有明显的相关性,差值较大。"冲突样本"多出现在3—10月雨后有轻雾或部分雾的16:00—22:00。低能见度和低RVR与22:00的相对湿度、温度露点差、风向、前一日能见度及6 h、12 h温差呈显著性相关;用最优子集回归方法分季节建立低能见度和低RVR的预报方程,经检验,两者TS评分达到一定水平。 相似文献
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利用2017年10月26日—2018年3月14日期间,乌鲁木齐机场跑道视程≤600 m时跑道25方向大气透射仪和前向散射仪的跑道视程数据,以及跑道25方向大气透射仪和中间段大气透射仪跑道视程数据进行对比分析,得到以下结论:(1)大气透射仪的跑道视程数据大于等于前向散射仪的跑道视程数据的比例为96%,跑道视程≤400 m时,两种设备相互替代性较好;(2)相比于黑夜,白天情况下前向散射仪的跑道视程数据更接近25方向大气透射仪的跑道视程数据;(3)相比于跑道中间段大气透射仪,跑道25方向前向散射仪跑道视程数据更接近25方向的大气透射仪跑道视程数据。 相似文献
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杨晶轶 《高原山地气象研究》2018,38(2):90-95
本文利用成都双流机场2004~2015年逐时观测资料,分析了双流机场低跑道视程(RVR<550m)特征。双流机场低RVR主要出现在11~3月,05~10时出现最多,当出现低RVR时,维持在II类运行标准内的比率仅为25.9%,可实施II类运行的时间有限,低于起飞最低标准的比率为49.8%。通过对出现低RVR时,能见度、风速、温度、相对湿度和修正海平面气压逐月分布的特征分析,提取预报依据,构建了双流机场低RVR预报思路。 相似文献
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《浙江气象》2016,(2)
利用温州机场2005—2014年的自动气象观测数据,对低于机场运行最低标准的跑道视程(RVR)进行了全面地统计与分析,重点分析了跑道视程的年、月、日变化特征,及其与风向、相对湿度和温度露点差等要素的相关性,得出:温州机场R03低于着陆标准的总日数明显高于R21,但低于起飞标准的总日数两者相当;全年峰值出现在3月份,谷值出现在9月份,2—5月份为高发期;全天峰值区出现在01—08时,谷值区出现在09—21时;RVR日数与偏南风向、相对湿度和温度露点差显著相关;综合RVR分钟次数及其对应的风向考虑,R21比R03更适合飞机起降;大雾的形成具有突发性、波动性和局地性等特点。另探讨了建立大雾监测预警流程的必要性,以更好地为用户提供及时、准确的大雾信息。 相似文献
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《干旱气象》2016,(5)
运用数理统计方法分析浦东机场2000—2014年低跑道视程(RVR,RVR1 000 m)变化特征及其影响机制,并建立低RVR预报试验的逻辑回归(Logit)模型。结果表明,上海浦东机场近15 a低RVR日数呈明显下降趋势;低RVR日多出现在冷季,主要集中在11月—次年2月,2月出现频率最多;06:00—08:00出现最多,开始时刻主要集中在06:00—08:00;结束时刻主要在09:00—10:00;持续时间大部分在3 h以内,其中1 h频率最高;低RVR伴随的天气现象绝大部分与视程障碍有关,冷季时视程障碍比重更高,暖季强降水贡献更多;气温在0~10℃频率最高,相对湿度主要集中在90%以上,风速大多在5 m·s-1以下,风向冷季多发生在260°~360°,暖季多发生在120°~170°;低RVR的发生与08:00相对湿度呈正相关,与气温、风速呈负相关,其中与相对湿度的相关系数最高。在预报模型试验中较好地建立了Logit预报方程,历史回报的TS评分达到一定水平。 相似文献
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利用成都双流机场2012—2016年机场主导能见度和跑道视程资料,分析两者的特征和关系,旨在为机场低能见度天气时预测跑道视程提供辅助判断依据。结果表明:双流机场夏(6—8月)秋(9—11月)两季主导能见度较高,春(3—5月)冬(12—2月)两季较低;主导能见度在午后至夜间较高,日出前后较低。02L(西跑道南端)的跑道视程与主导能见度一致性较好,02R(东跑道南端)的跑道视程与主导能见度一致性较差;主导能见度观测点与大气透射仪器或前向散射仪器(用于测量跑道视程)所在位置的气象环境条件越接近,两者的一致性越好。 相似文献
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《Climate Policy》2013,13(3):191-205
Abstract In response to Article 2.2 of the Kyoto Protocol, the International Maritime Organisation (IMO) and the International Civil Aviation Organisation (ICAO) have begun to consider greenhouse gas (GHG) emissions from international aviation and shipping. However, neither ICAO nor IMO have taken any effective action on the issue yet and progress can be characterised as slow. The lack of action has so far not been made up for by measures within the climate change regime or by individual countries. An important motivation for the efforts of ICAO and IMO so far has been the potential regulatory competition with the climate change regime. However, given the lack of political will to act on the issue within the latter, this motivation has not been very forceful. Against this backdrop, I argue that there are in particular three options for furthering progress within ICAO and IMO, namely (1) enhancing the threat of regulation of GHG emissions from international transport under the climate change regime; (2) undertaking unilateral domestic action by various countries (in particular the EU); and (3) furthering a learning process within ICAO and IMO. Furthermore, a closer coordination of efforts under ICAO, IMO and the climate change regime could facilitate and accelerate progress. 相似文献
12.
Sebastian Oberthür 《Climate Policy》2003,3(3):191-205
In response to Article 2.2 of the Kyoto Protocol, the International Maritime Organisation (IMO) and the International Civil Aviation Organisation (ICAO) have begun to consider greenhouse gas (GHG) emissions from international aviation and shipping. However, neither ICAO nor IMO have taken any effective action on the issue yet and progress can be characterised as slow. The lack of action has so far not been made up for by measures within the climate change regime or by individual countries. An important motivation for the efforts of ICAO and IMO so far has been the potential regulatory competition with the climate change regime. However, given the lack of political will to act on the issue within the latter, this motivation has not been very forceful. Against this backdrop, I argue that there are in particular three options for furthering progress within ICAO and IMO, namely (1) enhancing the threat of regulation of GHG emissions from international transport under the climate change regime; (2) undertaking unilateral domestic action by various countries (in particular the EU); and (3) furthering a learning process within ICAO and IMO. Furthermore, a closer coordination of efforts under ICAO, IMO and the climate change regime could facilitate and accelerate progress. 相似文献
13.
可见光通信作为一种结合了照明与通信的新型无线通信技术,近几年成为一个研究的热点.光学天线是可见光通信系统中的重要组成部分,在优化光能分布、提高接收功率、提升系统信噪比和通信质量方面起重要作用.目前国内外对于光学天线的研究可以分为发射天线和接收天线两个部分.发射天线一般与LED光学设计相结合,按照配光方式可以分为准直型、均匀照明型和聚焦型等类型.接收天线采用复合抛物面聚光器、菲涅尔透镜等光学元件作为光学接收前端,主要目的是提高接收信号的功率.本文介绍了近年来国内外光学天线的研究进展,评价并比较了各种类型光学天线的光学性能,并对光学天线的发展趋势做出了展望. 相似文献
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Lanzhou Zhongchuan International Airport [International Civil Aviation Organization(ICAO) code ZLLL] is located in a wind shear prone area in China, where most low-level wind shear events occur in dry weather conditions.We analyzed temporal distribution and synoptic circulation background for 18 dry wind shear events reported by pilots at ZLLL by using the NCEP final(FNL) operational global analysis data, and then proposed a lidar-based regional divergence algorithm(RDA) to determine wind shear intensity and location. Low-level wind shear at ZLLL usually occurs in the afternoon and evening in dry conditions. Most wind shear events occur in an unstable atmosphere over ZLLL, with changes in wind speed or direction generally found at 700 hPa and 10-m height. Based on synoptic circulations at 700 hPa, wind shear events could be classified as strong northerly, convergence, southerly, and weak wind types. The proposed RDA successfully identified low-level wind shear except one southerly case, achieving94% alerting rate compared with 82% for the operational system at ZLLL and 88% for the ramp detection algorithm(widely used in some operational alert systems) based on the same dataset. The RDA-unidentified southerly case occurred in a near neutral atmosphere, and wind speed change could not be captured by the Doppler lidar. 相似文献
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通过2010年7月12日—8月1日第8届世界气象组织阳江国际探空比对,采取同球比对施放方式,选择芬兰Vaisala探空仪作为比对标准,对中国参加国际比对的长峰探空仪与华云探空仪,使用共29次同球比对数据,从典型个例分析与统计分析两方面开展系统性评估。初步评估结果表明:对于温度探测,中国长峰探空仪整体系统偏差在0.4℃之内,标准偏差在0.7℃之内,中国华云探空仪在30 km高度以下性能与长峰探空仪相当,但是30 km高度以上偏差明显增大;对于气压与风的探测,两者系统偏差与标准偏差均较小,表明GPS定位以及气压与风的算法准确;对于湿度探测,与芬兰Vaisala探空仪相比,还存在一定差距,特别是低温性能需要提高。 相似文献
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Statistical characterizations of rainfall structure over two tropical stations in southern India are reported in this paper based on the 2-year rainfall data. The statistical characterizations has been based on cumulative distribution function, exceedance of threshold values, dependence of the intensity of rainfall on the event duration, seasonal variability, and worst months concept as well as diurnal variability. These results are needed to give the detailed insights to the system designers for the development of communication gadgets needed for better service, serve as a vital tool to estimate signal outages in a year over the region and for proper planning of radio communication in the region. Finally, the study shows that the recent International Telecommunications Union Recommendations (ITU-R) value underestimated rain rate for 0.01% exceedance for the two locations. 相似文献
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The 20-year (1976-1995) daily radiosonde data at 17 stations in the tropical western Pacific was ana lyzed. The analysis shows that the atmosphere is more humid in a warmer climate on seasonal, inter-annual and long-term (20-year) time scales, implying a positive water vapor feedback. The vertical structure of the long-term trends in relative humidity (RH) is distinct from that on short-term (seasonal and inter-annual) time scales, suggesting that observed water vapor changes on short time scales could not be considered as a surrogate of long-term climate change. The increasing trend of RH (3%-5%/decade) in the upper troposphere is stronger than that in the lower troposphere (1%-2% / decade). Such vertical structure would amplify positive water vapor feedback in comparison to the common assumption of constant RH changes vertically. The empirical orthogonal function (EOF) analysis of vertical structure of RH variations shows distinct features of the vertical structure of the first three EOFs. The first three EOFs are optimal for repre sentation of water vapor profiles and provide some hints on physical mechanisms responsible for observed humidity variability. Vaisala radiosondes were used at nine stations, and VIZ radiosondes used at other eight stations. The Vaisala data are corrected for temperature-dependence error using the correction scheme developed by NCAR / ATD and Vaisala. The comparison of Vaisala and VIZ data shows that the VIZ-measured RHs after October 1993 have a moist bias of ～ 10% at RHs ＜ 20%. During 1976-1995, several changes in cluding both instruments and reporting practice have been made at Vaisala stations and introduce errors to long-term RH variations. 相似文献
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为综合评价上海市两套闪电定位系统(Vaisala和Earth Network Total Lightning System)对上海及周边地区地闪的探测能力,利用2015 2016年两套闪电定位系统数据,从地闪数据量、雷电强度、时空分布、空间匹配度和定位精度等多个方面展开对比。结果表明,在上海市范围内相同时间段内Vaisala探测到的地闪频次稳定大于Entls的,但在上海市区域外则相反。两套系统探测到地闪雷电流强度呈单峰分布,以10~20 k A区间内的雷电居多。从数据空间匹配度来看,上海北部地区及杭州湾南岸,Entls相对Vaisala地闪探测的匹配度达70%以上,在上海市范围内该匹配度降至20%左右。两套系统探测到的地闪定位误差大部分集中在5 km以内,且以0~2 km为主。雷暴过程中两套系统探测的地闪随时间变化趋势较为一致,且与雷达回波有一定的匹配度。因此,两套系统都能实现对上海及周边地区地闪的探测,但由于设备型号、探测技术和自身误差等方面的差异,数据量上有差异,需要长时间积累数据进行对比分析,才能更好地利用数据,为防雷减灾服务。 相似文献
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国内民航机场主要使用的雨量观测设备为芬兰维萨拉公司生产的RG13型雨量传感器,为保证雨量测量数据的真实可靠,对其测量结果的不确定度分析很有必要。根据自动气象站现场校准方法,分别进行大雨强和小雨强的重复测试,并依据JJF1059.1-2012测量不确定度的评定与表示要求,进行A类不确定度评定。分析测量过程中的B类不确定度来源,进行B类评定,最终给出扩展不确定度。结果表明：在小雨强下,测量不确定度为U95=0.17mm,包含因子k=2。在大雨强下,测量不确定度为U95=0.16mm,包含因子k=2。该研究完善了雨量传感器的现场校准工作流程,对雨量传感器测量结果的可信度评定具有参考价值。 相似文献