洞庭湖湖面风速与湖区陆地风速的对比分析

对洞庭湖区水平方向与垂直方向的湖面风速与陆地风速进行对比分析。结果表明：在水平方向上,湖面平均风速比陆地平均风速大2．3m／s,湖面瞬时风速是陆地瞬时风速的2倍左右;在垂直方向上,湖面平均风速与陆地平均风速之间也存在一定差异。     

Neptune's Wind Speeds Obtained by Tracking Clouds in Voyager Images

Images of Neptune obtained by the narrow-angle camera of the Voyager 2 spacecraft reveal large-scale cloud features that persist for several months or longer. The features' periods of rotation about the planetary axis range from 15.8 to 18.4 hours. The atmosphere equatorward of -53 degrees rotates with periods longer than the 16.05-hour period deduced from Voyager's planetary radio astronomy experiment (presumably the planet's internal rotation period). The wind speeds computed with respect to this radio period range from 20 meters per second eastward to 325 meters per second westward. Thus, the cloud-top wind speeds are roughly the same for all the planets ranging from Venus to Neptune, even though the solar energy inputs to the atmospheres vary by a factor of 1000.     

Venus winds are zonal and retrograde below the clouds

Winds in the lower atmosphere of Venus, inferred from three-dimensional radio interferometric tracking of the descents of the Pioneer day and north probes, are predominantly easterly with speeds of about 1 meter per second near the surface, 50 meters per second at the bottom of the clouds, and more than 200 meters per second within the densest, middle cloud layer. Between about 25 and 55 kilometers altitude the average flow was slanted equatorward, with superimposed wavelike motions and alternating layers of high and low shear.     

Detection of overflow events in the shag rocks passage, scotia ridge

During an almost yearlong period of observations made with a current meter in the fracture zone between the Falkland Islands (Islas Malvinas) and South Georgia, several overflow events were recorded at a depth of 3000 meters carrying cold bottom water from the Scotia Sea into the Argentine Basin. The outflow bursts of Scotia Sea bottom water, a mixing product of Weddell Sea and eastern Pacific bottom water, were associated with typical speeds of more than 28 centimeters per second toward the northwest and characteristic temperatures below 0.6 degrees C. The maximum 24-hour average speed of 65 centimeters per second, together with a temperature of 0.29 degrees C, was encountered on 14 November 1980 at a water depth of 2973 meters, 35 meters above the sea floor.     

Tidally controlled stick-slip discharge of a West Antarctic ice

A major West Antarctic ice stream discharges by sudden and brief periods of very rapid motion paced by oceanic tidal oscillations of about 1 meter. Acceleration to speeds greater than 1 meter per hour and deceleration back to a stationary state occur in minutes or less. Slip propagates at approximately 88 meters per second, suggestive of a shear wave traveling within the subglacial till. A model of an episodically slipping friction-locked fault reproduces the observed quasi-periodic event timing, demonstrating an ice stream's ability to change speed rapidly and its extreme sensitivity to subglacial conditions and variations in sea level.     

Solar wind origin in coronal funnels

The origin of the solar wind in solar coronal holes has long been unclear. We establish that the solar wind starts flowing out of the corona at heights above the photosphere between 5 megameters and 20 megameters in magnetic funnels. This result is obtained by a correlation of the Doppler-velocity and radiance maps of spectral lines emitted by various ions with the force-free magnetic field as extrapolated from photospheric magnetograms to different altitudes. Specifically, we find that Ne7+ ions mostly radiate around 20 megameters, where they have outflow speeds of about 10 kilometers per second, whereas C3+ ions with no average flow speed mainly radiate around 5 megameters. Based on these results, a model for understanding the solar wind origin is suggested.     

Seasat scanning multichannel microwave radiometer: results of the gulf of alaska workshop

The scanning multichannel microwave radiometer results for the Gulf of Alaska Seasat Experiment Workshop are quite encouraging, especially in view of the immaturity of the data-processing algorithms. For open ocean, rain-free cells of highest-quality surface truth wind determinations exhibit standard deviations of 3 meters per second about a bias of 1.5 meters per second. The sea-surface temperature shows a standard deviation of approximately 1.5 degrees C about a bias of 3 degrees to 5 degrees C under a variety of changing meteorological conditions.     

Evidence for Alfvén waves in solar x-ray jets

Coronal magnetic fields are dynamic, and field lines may misalign, reassemble, and release energy by means of magnetic reconnection. Giant releases may generate solar flares and coronal mass ejections and, on a smaller scale, produce x-ray jets. Hinode observations of polar coronal holes reveal that x-ray jets have two distinct velocities: one near the Alfvén speed ( approximately 800 kilometers per second) and another near the sound speed (200 kilometers per second). Many more jets were seen than have been reported previously; we detected an average of 10 events per hour up to these speeds, whereas previous observations documented only a handful per day with lower average speeds of 200 kilometers per second. The x-ray jets are about 2 x 10(3) to 2 x 10(4) kilometers wide and 1 x 10(5) kilometers long and last from 100 to 2500 seconds. The large number of events, coupled with the high velocities of the apparent outflows, indicates that the jets may contribute to the high-speed solar wind.     

Seasat scatterometer: results of the gulf of alaska workshop

The Seasat microwave scatterometer was designed to measure, globally and in nearly all weather, wind speed to an accuracy of +/- 2 meters per second and wind direction to +/- 20 degrees in two swaths 500 kilometers wide on either side of the spacecraft. For two operating modes in rain-free conditions, a limited number of comparisons to high-quality surface truth indicates that these specifications may have been met.     

Local influences on shear-flow turbulence in the equatorial ocean

A 12-day series of 1749 profiles of turbulent kinetic energy dissipation above the equatorial undercurrent at 140 degrees west showed that, in the upper 110 meters of the ocean, the dissipation radically decreased during the solar heating period each day. Daily averages were linearly related to the local wind power. When integrated over the depth range of 10 to 110 meters, the dissipation was 10.6 ergs per square centimeter per second or 0.92 +/- 0.10 percent of the wind power, a proportion not substantially different from those found in mid-latitude surface mixed layers. These results suggest that much of the energy dissipated above the equatorial undercurrent may be extracted directly from the local wind.     

High winds of neptune: a possible mechanism

Neptune receives only 1/900th of the earth's solar energy, but has wind speeds of nearly 600 meters per second. How the near-supersonic winds can be maintained has been a puzzle. A plausible mechanism, based on principles of angular momentum and energy conservation in conjunction with deep convection, leads to a regime of uniform angular momentum at low latitudes. In this model, the rapid retrograde winds observed are a manifestation of deep convection, and the high efficiency of the planet's heat engine is intrinsic from the room allowed at low latitudes for reversible processes, the high temperatures at which heat is added to the atmosphere, and the low temperatures at which heat is extracted.     

温室周围气流运动的有限元法模拟分析

以有限元法分析流体力学问题为基础,运用ANSYS 9．0软件模拟了温室周围空气流的运动情况, 并分析了利用风压进行通风换气时比较实用的开窗方式。模拟结果显示:采用天窗与侧窗组合通风的效果优于仅利用侧窗通风。最后将二维模拟温室周围气流运动的方法进一步推广到三维模拟中,模拟了温室周围气流的运动情况。结果表明,下风向风速在距离温室0-3 m处为3．260 4-2．905 5 m／s,在3-12 m处为2．888 8-2．845 7 m／s;上风向风速在距离温室0-4．2 m处为3．120 5-2．698 9 m／s,在4．2-12 m处为2．698 9-2．946 m／s。     

Eruptions of the st. Augustine volcano: airborne measurements and observations

Airborne measurements of the effluents from the St. Augustine volcano obtained during a 10-day period of activity showed that aerosol was ejected at the rate of about 10(5) kilograms per second during brief eruptions (3 to 8 minutes). Steadier emissions contained much more water vapor and gaseous sulfur but less aerosol mass. A nuée ardente (glowing avalanche) produced by one eruption reached a maximum average speed of about 50 meters per second.     

The nature of the near-infrared features on the venus night side

Near-infrared images of the Venus night side show bright contrast features that move from east to west, in the direction of the cloud-top atmospheric superrotation. Recently acquired images of the Venus night side along with earlier spectroscopic observations allow identification of the mechanisms that produce these features, their level of formation, and the wind velocities at those levels. The features are detectable only at wavelengths near 1.74 and 2.3 micrometers, in narrow atmospheric windows between the CO(2) and H(2)O bands. The brightest features have brightness temperatures near 480 Kelvin, whereas the darkest features are more than 50 Kelvin cooler. Several factors suggest that this radiation is emitted by hot gases at altitudes below 35 kilometers in the Venus atmosphere. The feature contrasts are produced as this thermal radiation passes through a higher, cooler, atmospheric layer that has horizontal variations in transparency. The 6.5-day east-west rotation period of the features indicates that equatorial wind speeds are near 70 meters per second in this upper layer. Similar wind speeds have been measured by entry probes and balloons at altitudes between 50 and 55 kilometers in the middle cloud layer. The bright features indicate that there are partial clearings in this cloud deck. The presence of these clearings could decrease the efficiency of the atmospheric greenhouse that maintains the high surface temperatures on Venus.     

Bottom Velocity Observations Directly under the Gulf Stream

Speeds as high as 44 centimeters per second were observed 200 meters above the ocean bottom under the Gulf Stream at 70 degrees W longitude and were associated with time-dependent motion that had a speed range of 40 centimeters per second and a time scale of about 30 days. These deep current fluctuations appear to be coupled with fluctuations in the surface position of the Stream and with surface and bottom current fluctuations 200 kilometers to the north.     

干旱区苹果园小气候特征分析

以干旱区成龄苹果园为研究对象,分析了宁夏灵武陶林园艺场果园内不同季节不同层次气象要素的时间变化特征。结果表明:日平均光照度为春季夏季秋季冬季。果园内不同季节1.5 m和3.0 m高度气温都呈现出昼高夜低型的日变化波形;晴天气温变化出现单峰型曲线,阴天出现双峰型曲线,雨天变化振幅较小,两高度间差异也较小。果园内湿度较大,不同季节1.5 m和3.0 m高度相对湿度日变化均为夜高昼低的波形曲线。从风速看,春季和冬季日变化特征最明显,日振幅也最大,夏、秋季风速相对较小。不同季节地表0 cm地温受气温变化影响最大,5 cm、10 cm次之,20 cm地温受气温变化影响最小。     

乐都地区冬季低空风场分析

根据2007年1月6～11日在青海乐都高店焦化厂地区的大气边界层探测试验得到的资料,分析了该地区的低空风场随高度的垂直分布特征以及随时间的演变特征。结果表明:青海乐都地区冬季风向频率随高度的变化基本保持稳定,主导风向为偏西风,在地面主导风向频率为SW,在10～50 m最多风向频率和次多风向频率相同,分别为NW和WSW,50 m的最多风向频率为NW,100 m的主导风向频率是WNW,NW,150 m往上除了200 m的主导风向为W以外其他的都为WNW。从试验期间平均结果看,低空风速随高度和时间的变化规律比较复杂,平均而言,从地面到100 m风速随高度增加比较快,而100 m后随高度变化较小。     

安徽省安庆地区高空风特征分析

利用新一代L波段高空气象探测系统雷达采集安庆地区高空风观测资料,并根据这些观测资料分析该探测站点高空风速、风向频率分布、风的时次变化规律和风稳定度等。结果表明,安庆地区行星边界层上空处在明显的西风带环流中,风向稳定,风速自9000～14000gpm高度为大风区,行星边界层和平流层风向为偏东风。该统计结果可为进一步研究高空风场、气候变化、城市规划和农业生产等提供重要的参量。     

Cassini Imaging Science: initial results on Saturn's atmosphere

The Cassini Imaging Science Subsystem (ISS) began observing Saturn in early February 2004. From analysis of cloud motions through early October 2004, we report vertical wind shear in Saturn's equatorial jet and a maximum wind speed of approximately 375 meters per second, a value that differs from both Hubble Space Telescope and Voyager values. We also report a particularly active narrow southern mid-latitude region in which dark ovals are observed both to merge with each other and to arise from the eruptions of large, bright storms. Bright storm eruptions are correlated with Saturn's electrostatic discharges, which are thought to originate from lightning.