南京长江第二大桥桥位风速观测及设计风速的计算   总被引：6，自引：0，他引：6  

张忠义  刘聪 《气象科学》2000,20(2):200-205

本文给出适用于大桥设计风速计算的方法,并利用南京长江第二大桥桥位风速观测资料、南京小教场40年的实测风资料及两处的同步风速观测资料,经统计学分析计算得到南京长江第二桥设计风速的计算值.  相似文献   

鲅鱼圈地区污染气象特征分析   总被引：10，自引：6，他引：4       下载免费PDF全文

刘翠玲  常艳君 《气象与环境学报》2006,22(1):29-33

利用近3a的鲅鱼圈地区地面常规气象资料和2005年3～4月鲅鱼圈地区低空污染气象探测资料,分析了鲅鱼圈地区低空污染气象特征。结果表明:鲅鱼圈地区各类型风速廓线出现频率比较均匀,而且由于地面粗糙度较大,因此风速廓线指数比平原地区稍大。  相似文献   

石家庄大气污染与沙尘天气的关系分析   总被引：3，自引：1，他引：2       下载免费PDF全文

李国翠  王建国  连志鸾 《气象与环境学报》2007,23(2):1-5

利用2002—2006年石家庄市逐时气象资料和环境监测资料,分析了8次典型沙尘天气对空气污染的影响。结果表明:沙尘天气的首要污染物均是可吸入颗粒物,春季中度以上污染日平均出现在沙尘日当日或次日;造成石家庄沙尘天气污染源分外来型、本地型以及二者共同影响型3种;其中,本地型沙尘污染多受冷锋影响,PM10浓度与风速呈正相关。而外来型污染多处于弱气压场控制,PM10浓度与南风呈反相关,而当风向转偏北时则利于污染物积累。  相似文献   

江苏南部两次暴雨-大暴雨过程分析     

雷正翠  夏文梅  徐芬  黄文彦  刘梅  刘银峰 《气象科技》2021,49(1):95-106

2011年6月10日(简称"11·06")和2017年6月10日(简称"17·06")在江苏南部出现了两次暴雨-大暴雨过程,本文利用常规观测资料、FNL再分析资料和雷达资料等,对两次过程进行了分析,结果表明:异常的高低纬度环流形势配合,为强降水的发生提供了有利的环流背景.两次过程代表站的物理量场差异较大:"17·06"...  相似文献   

The Falkland Islands’ palaeoecological response to millennial‐scale climate perturbations during the Pleistocene–Holocene transition: Implications for future vegetation stability in the southern ocean islands     

Robert G. Scaife  Antony J. Long  Alistair J. Monteath  Paul D. M. Hughes  Michael J. Bentley  Philip Stone 《第四纪科学杂志》2019,34(8):609-620

Oceanic island flora is vulnerable to future climate warming, which is likely to promote changes in vegetation composition, and invasion of non‐native species. Sub‐Antarctic islands are predicted to experience rapid warming during the next century; therefore, establishing trajectories of change in vegetation communities is essential for developing conservation strategies to preserve biological diversity. We present a Late‐glacial‐early Holocene (16 500–6450 cal a bp ) palaeoecological record from Hooker's Point, Falkland Islands (Islas Malvinas), South Atlantic. This period spans the Pleistocene‐Holocene transition, providing insight into biological responses to abrupt climate change. Pollen and plant macrofossil records appear insensitive to climatic cooling during the Late‐glacial, but undergo rapid turnover in response to regional warming. The absence of trees throughout the Late‐glacial‐early Holocene enables the recognition of far‐travelled pollen from southern South America. The first occurrence of Nothofagus (southern beech) may reflect changes in the strength and/or position of the Southern Westerly Wind Belt during the Late‐glacial period. Peat inception and accumulation at Hooker's Point is likely to be promoted by the recalcitrant litter of wind‐adapted flora. This recalcitrant litter helps to explain widespread peatland development in a comparatively dry environment, and suggests that wind‐adapted peatlands can remain carbon sinks even under low precipitation regimes. © 2019 The Authors. Journal of Quaternary Science Published by John Wiley & Sons Ltd.  相似文献   

The Ultraviolet Coronagraph Spectrometer for the solar and heliospheric observatory     

《Solar physics》1995,162(1-2):313-356

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Eolian controlled modification of the martian south polar layered deposits     

Michelle R. Koutnik  Shane Byrne  Anthony D. Toigo 《Icarus》2005,174(2):490-501

Data from the Mars Orbiter Laser Altimeter (MOLA) and Mars Orbiter Camera (MOC) aboard the Mars Global Surveyor (MGS) mission and the Thermal Emission Imaging System (THEMIS) aboard the Mars Odyssey mission have revealed unique surface features in a particular region of the South Polar Layered Deposits (SPLD). The dominant morphology is large-scale quasi-parallel grooves that extend for hundreds of kilometers with only tens of meters of vertical relief, that we have termed here the “Wire Brush” terrain. The grooves are also transected by disjointed, yet roughly continuous, low-relief sinuous ridges that cross roughly perpendicular to the trend-direction of the large-scale grooves and show only tens of meters of relief. We interpret these ridges to be eroded remnants of folded layers. At the northern end of the large-scale grooves there are non-symmetric mounds. They are frequently preceded by a significant depression and/or trailing grooves that are parallel to the Wire Brush trend. We find that a two-stage process involving winds that intermittently remove a low-density crust exposing the underlying ice to ablation is the interpretation that best explains the multitude of features observed here. These features appear to be currently inactive indicating higher winds in previous epochs.  相似文献   

近20年来风电场（群）对气候的影响研究进展     

陈正洪  何飞  崔杨  张雪婷 《气候变化研究进展》2018,14(4):381-391

随着风电场的大规模开发,其对气候的影响受到关注,自2000年以来美国和欧洲等国陆续开展了一定的研究,中国也开展了一些观测和模拟研究,对已有研究进行综述可指导这项工作的进一步开展。通过对文献的梳理,总结了风电场对气候影响的研究进程、研究方法、影响机理和研究成果。大量观测和数值模拟结果显示风电场会导致地表气温上升,风电场下游一定距离范围内风速衰减,并间接影响降水、蒸发等其他气象要素,风电场对局地气候变化产生影响的结论具有较高信度;部分模式模拟结果显示未来大规模风电场（群）开发对全球气候也有可能产生一定影响,但仍需进一步的探索。  相似文献   

Wind speed prediction using statistical regression and neural network   总被引：1，自引：0，他引：1  

Makarand A. Kulkarni  Sunil Patil  G. V. Rama  P. N. Sen 《Journal of Earth System Science》2008,117(4):457-463

Prediction of wind speed in the atmospheric boundary layer is important for wind energy assessment, satellite launching and aviation, etc. There are a few techniques available for wind speed prediction, which require a minimum number of input parameters. Four different statistical techniques, viz., curve fitting, Auto Regressive Integrated Moving Average Model (ARIMA), extrapolation with periodic function and Artificial Neural Networks (ANN) are employed to predict wind speed. These methods require wind speeds of previous hours as input. It has been found that wind speed can be predicted with a reasonable degree of accuracy using two methods, viz., extrapolation using periodic curve fitting and ANN and the other two methods are not very useful.  相似文献   

FIELD STUDY ON WIND EROSION IN THE NORTHWESTSHANXI PROVINCE     

LI Jianhua 《国际泥沙研究》1992,(1)

Field study on wind erosion in the hilly regions with gentle slope in the Northwest Shanxi Province has been carried out from 1983 through 1988. Based on the data observed in the field, quantitative analyses of the wind erosion and the effects of the wind-break forest are presented in this paper in detail. Most of the strong windy days occur in the period of March to May. The coincidence of drought and strong wind in the Spring days with no vegetative cover at all on the loose top soil lead to severe wind erosion in this region. The rate of soil erosion is as high as 12800 t / km2. Major characteristics of wind and other meteorological factors are given in graphs and tables. Wind-break forest reduces the wind velocity by 51. 1 %. Consequently, the amount of wind erosion is reduced by 90% and the dust content in the atmosphere is reduced by 97. 1 % in comparison with those measured in the farmland. This paper provides a preliminary summary on the result of data analyses of wind erosion on the Loess Plateau. It can serve as scientific basis for control of the wind erosion in regions of similar conditions.  相似文献