共查询到20条相似文献，搜索用时 46 毫秒
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本文利用计算流体动力学(Computational Fluid Dynamics, CFD)方法对基于076B型强制通风防辐射罩的温度传感器进行流固耦合传热分析,计算不同太阳辐射强度、下垫面反射率、强制通风速度、气象站海拔高度和下垫面长波辐射强度等影响因子条件下温度传感器的辐射误差。为实现影响因子连续变化时能提供准确修正数据的目标,采用神经网络算法仿真值计算结果进行拟合,获得辐射误差订正方程。结果表明,辐射误差订正方程的修正误差在0.005℃以内。订正后的气温观测数据有望用于气候变化研究和高精度天气预报。 相似文献
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一、概述:通风干湿表的检定分两次进行。一、按JJG207—80号“气象用内标式玻璃液体温度表检定规程”对温度表进行检定。检定记录整理程序“陕西气象”八三年第九期有过介绍,此文不再叙述。二、按JJG204—80号“气象用通风干湿表检定规程”对温度表球部管道通风速度进行检定。方法是给通风器上满弦、测定第四分钟末风速(技术要求大於2.5米/秒)和第六分钟末风速(技术要求大於2.2米/秒)。因为风速在2.5米/秒以上时,△值(干湿球温度表测湿系数)几乎不随风速大小的改变而变化。所以在此风速条件下用通风干湿表测定的相对湿度是比较准确的。大家知道用干湿球温度表测湿的基本原 相似文献
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阿斯曼通风干湿表一直以来被用作气温在0℃以上时测量湿度的仪器，外壳有防辐射镀层，球都有固定速度的气流流过，其结构轻便，精确度高，稳定可靠。[第一段] 相似文献
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目前供气象台站和野外科学考察中测定空气温湿度的通风干湿表,主要有下述两种:即机动通风干湿表和电动通风干湿表。机动通风干湿表的感温元件是两只性能规格完全一致的棒状玻璃温度表,观测时由人工上紧发条使风扇转动而实现通风。电动遥测通风干湿表的感温元件是两只形状、大小、特性完全一致的铜电阻温度表,观测时靠仪器上的马达和风扇自动通风。 相似文献
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在放球前后读取瞬间要素 ,因时间紧、观测项目多 ,易误读通风干湿表读数。如单独从基测或瞬间数据检查 ,即使出现误读也很难发现。如根据基测数据和瞬间数据 ,并结合当时天气实况及探空仪信号进行比较分析 ,可正确判断通风干湿表读数是否准确。例如 :某日 1 9时 ,基测的干湿球温度分别为 0 .4和 0 .2℃ ,仪器符号为 91 ,1 5 ,2 3 ;瞬时读取的干湿球温度分别为 0 .6和 0 .3℃ ,仪器符号为 93 ,1 5 ,2 1。根据基测时仪器所发信号 ,当时天气实况应是温度降低、湿度增大 ,恰恰和读数相反 ,显然读数不正确。通风干湿表读数技巧@崔智慧$郑州市气象… 相似文献
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On Shear-Driven Ventilation of Snow 总被引：1，自引：1，他引：0
Andrew Clifton Costantino Manes Jean-Daniel Rüedi Michele Guala Michael Lehning 《Boundary-Layer Meteorology》2008,126(2):249-261
A series of experiments have been made in a wind tunnel to investigate the ventilation of snow by shear. We argue that the
zero-plane displacement can be used as a convenient indicator of ventilation, and that this can be obtained from measurements
of mean velocity profiles in conditions of zero pressure gradient. Measurements made over a natural snow surface show a zero-plane
displacement depth of less than 5 mm, but practical considerations preclude extensive use of snow for these measurements.
Instead, the influence of permeability is investigated using reticulated foams in place of snow. We demonstrate that the foam
and snow have similar structure and flow-relevant properties. Although the surface of the foam is flat, the roughness lengths
increase by two orders of magnitude as the permeability increases from 6 × 10−9 to 160 × 10−9 m2. The zero-plane displacement for the least permeable foams is effectively zero, but more than 15 mm for the most permeable
foams. Our data compare well to the few studies available in the literature. By analogy to conditions over snow surfaces,
we suggest that shear-driven ventilation of snow is therefore limited to the upper few millimetres of snow surfaces. 相似文献
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Summary The spatial and temporal pattern of nocturnal airflow in and around two urban parks in Scandinavia were analysed. The results,
based on 724 field measurements during 21 case studies, showed that both parks generated a local airflow during clear and
calm weather conditions. The spatial pattern was characterised by calm in the middle of the park and a steady airflow towards
the surrounding built-up areas at the park borders. The airflow from the park started one to two hours after sunset and continued
during a period of four to eight hours. The wind speed was low (< 0.5 ms−1) and the local air flow reached a short distance from the park border. In the flat park in K?benhavn, Denmark, the air flow
from the park was attributed solely to the development of a thermally induced park breeze. The park breeze development was
also predominant in the park in G?teborg, Sweden, but the influence of topography could not be totally excluded. The origin
of the airflow from the park and its importance for urban air quality were discussed.
Received April 15, 1999Revised December 2, 1999 相似文献
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V. A. Sosnin P. Ya. Tishchenko A. N. Salyuk N. Biebow 《Russian Meteorology and Hydrology》2007,32(1):50-53
Data of field observations are indicative of the periodic appearance of intrusions of cold water at depths of 250–400 m near the northeastern Sakhalin continental slope in summer. Monitoring of the oceanographic conditions in the area shows that the density contrast between shelf and offshore waters persists throughout the year. The static instability of the water column in the vicinity of shelf break and the continental slope is a permanent feature of the area during the year and is the main cause of ventilation of the Sea of Okhotsk water in summer. The energy of tides can be an additional drive for the penetration of shelf waters into the sea interior and modulate the ventilation process. 相似文献
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新一代全相干多普勒天气雷达具有较高的可靠性、稳定性、可维护性及全天候的连续工作能力,具有自动数据采集、产品生成和显示、数据存储、运行监控和标校等功能. 相似文献
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通过对1994年8月4日与2004年9月16日若尔盖湿地TM影像1～5波段和7波段数据以及归一化植被指数(INDVI)、归一化水指数(INDWI)、归一化水分指数(INDMI)和改进的归一化水指数(IMNDWI)的分析,选择通道7、4、3合成假彩色图作为若尔盖湿地的目视解译图,确定了湿地的TM影像标志.分析结果表明,第7波段能较好地将沙地与其它地物区分,改进的归一化水指数与归一化植被指数之差是非常有效的水体提取因子.还制定了若尔盖湿地主要地物的自动判识流程.判识结果与目视解译结果非常吻合,1994年比1984年湖泊面积,沼泽湿地面积明显减小,而沙化地面积扩大. 相似文献
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在柳州新一代天气雷达建设过程中,发现其通风系统存在不足及缺陷,通过分析其通风系统的设计及安装原理,提出了改进的措施,并应用到实际当中,取得了很好的效果。 相似文献
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在柳州新一代天气雷达建设过程中，发现其通风系统存在不足及缺陷，通过分析其通风系统的设计及安装原理，提出了改进的措施，并应用到实际当中，取得了很好的效果。 相似文献
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城市通风廊道能增加城市空气流通能力,缓解城市热岛,为了定量评估城市通风廊道的气象效应,本文采用区域边界层化学模式(RBLM-Chem),利用杭州市高分辨率地表类型、城市建筑等资料,开展了杭州市通风廊道影响的模拟研究,模式水平分辨率为250 m。本文针对冬季和夏季两个典型个例进行数值模拟和敏感性试验,夏季个例时间为2013年8月12日,盛行南风,风向顺着通风廊道;冬季个例时间为2014年1月28日,盛行东风,风向垂直于通风廊道。主要结论如下:城市绿色通风廊道有增加风速、降低气温、提高湿度的作用,与没有通风廊道的情况相比,夏季风顺着廊道方向时,廊道区域风速平均增加可达1.4 m/s,廊道区域内60 m高度风速平均增加可达1 m/s。而冬季风垂直于廊道时,廊道区域风速增加较小,仅有0.5 m/s左右。通风廊道夏季降温幅度平均可达2.7°C,冬季降温幅度较小,仅有0.6°C左右。通风廊道对气象场的影响随风向向下游延伸,夏季在通风廊道下游250 m处,风速增加、气温下降、相对湿度增加最大值分别为1.5 m/s、2.9°C、3.1%,即使在通风廊道下游1500 m处,最大降温仍有1.2°C。 相似文献