Winds and waves in the middle atmosphere at Saskatoon (52°N, 107°W), Collm (52°N, 15°E) and Badary (52°N, 105°E)

Winds data from three radar systems in the U.S.S.R. G.D.R. and Canada, which are well-spaced along the 52°N latitude circle, are used to illustrate longitudinal/regional variations in the dynamics of the upper middle atmosphere 80–97 km. Responses to the stratospheric warming of 1982/3 are noted at all three locations, but the zonal wind does not reverse at Badary, consistent with the flow there being eastward during all months of the year. Planetary wave period oscillations (2–30 days) are observed at all locations, and highly significant cross-spectral coherences exist between the three stations.     

Semidiurnal tidal winds at Collm (52°N, 15°E) and Saskatoon (52°N, 107°W) over the decade 1978–1988

Mean winds and tides have been measured by the LF and MF radar systems at Collm and Saskatoon respectively. Semidiurnal tide amplitudes and phases near 90 km evidence very similar monthly variations. A detailed comparison of mean wind and tidal profiles (85–110 km) in the Septembers of 4 years shows some differences however, which are consistent with regional (Europe-Canada) differences in the mean background winds.     

Upper atmosphere semidiurnal tides at Christchurch (44°S) and Scott Base (78°S)

Lunar and solar semidiurnal tides have been determined from winds measurements in the 82 to 100 km height range at Christchurch and Scott Base made during 1983–1984. At Christchurch, the solar tide has maximum amplitudes in April and December, while at Scott Base, only the December maximum is present at all heights. Phases at Scott base mostly agree with those measured earlier at Mawson, but vertical wavelengths are always long. The lunar tide was difficult to isolate at Christchurch, but the winter to summer phase reversal was clear. This was also seen at Scott Base.     

Quasi-biennial oscillation in ionospheric parameters measured at Juliusruh (55°N, 13°E)

When seasonal variations were eliminated by evaluating 12-month running means, the ionospheric parameters foE, foF2 and hmF2 at Juliusruh (54.6°N, 13.4°E) showed large solar cycle variations. However, when further 3-yr running averages were evaluated and subtracted, QBO (Quasi-biennial oscillations) were noticed in all these parameters. Sunspot series did not reveal a QBO, but geomagnetic Ap did show a QBO. The peaks of the ionospheric QBO and QBO of Ap could be roughly compared, with lags or leads of a few months. Also, these compared roughly with the well-known QBO peaks of tropical stratospheric (50 mb) zonal winds. Similar analyses at other locations are warranted.     

Tidal winds in the radio-meteor region over Trivandrum (8.5°N, 77°E)

Wind measurements using a meteor trail radar which performed during two June solstice and three December solstice months were analysed to study the tidal winds over Trivandrum (8.5°N). The ter-diurnal (8 h) component of wind was found to be as significant as the diurnal and semi-diurnal components. The modulations in the altitude profiles of amplitude and phase of the tidal wind components are interpreted to be due to higher order tidal modes. The amplitudes and vertical wavelengths of the tidal modes observed in the meteor zone are discussed.     

Optical interferometer measurements of thermospheric temperature at Kavalur (12.5°N, 78.5°E), India

First results on the behaviour of thermospheric temperature over Kavalur (12.5°N, 78.5°E geographic; 2.8°N geomagnetic latitude) located close to the geomagnetic equator in the Indian zone are presented. The results are based on measurements of the Doppler width of O(¹D) night airglow emission at 630 nm made with a pressure-scanned Fabry-Perot interferometer (FPI) on 16 nights during March April 1992. The average nighttime (2130-0430 IST) thermospheric temperature is found to be consistently higher than the MSIS-86 predictions on all but one of the nights. The mean difference between the observed nightly temperatures and model values is 269 K with a standard error of 91 K. On one of the nights (9/10 April 1992, Ap = 6) the temperature is found to increase by ~250 K around 2330 IST and is accompanied by a ‘midnight collapse’ of the F-region over Ahmedabad (23°N, 72°E, dip 26.3°N). This relationship between the temperature increase at Kavalur and F-region height decrease at Ahmedabad is also seen in the average behaviour of the two parameters. The temperature enhancement at Kavalur is interpreted as the signature of the equatorial midnight temperature maximum (MTM) and the descent of the F-region over Ahmedabad as the effect of the poleward neutral winds associated with the MTM.     

Long period wind oscillations in the meteor region over Trivandrum (8°N, 77°E)

The spectra of long period wind oscillations in the meteor zone over Trivandrum are presented. The spectral amplitudes were found to be much larger during June 1984 when the QBO in the stratospheric zonal wind was in a strong easterly phase compared with June 1987 when the zonal winds at the altitude of maximum QBO were weak westerlies. Zonal wind amplitudes for periods of 15 and 5 days were found to be most significant during these two June months. The amplitudes of these two oscillations in meridional wind were found to be as large as the amplitudes in the zonal wind. The vertical wavelength in both zonal wind and meridional winds of the 15-day oscillation is very large whereas for the 5-day oscillation the vertical wavelengths were 80 and 65 km during June 1984 and June 1987, respectively. The results are discussed.     

The characteristics of the mesospheric two-day wave as observed at Grahamstown (33.3°S, 26.5°E)

The characteristics of the quasi two-day wave, as observed in meteor wind data recorded at Grahamstown (33°19′S, 26°30′E) between April 1986 and April 1989, are described and discussed in the context of existing knowledge. As is typical, the wave amplitude has been largest during the summer months December–February with a maximum in late January, but this amplitude has differed markedly from year-to-year. The period and phase are found to be variable and, where possible, have been obtained as functions of date. January 1987 and 1989 were both characterised by clear drifts toward longer periods, with corresponding drifts in phase. At each of the summer maxima observed the period was found to be close to 48 h, with the phase of the meridional component within 3 h of local midnight. Direct comparison of local data for January 1987 with published data obtained simultaneously in Australia and Antarctica confirms the well-established westward propagation of the wave, but with an apparent zonal wavenumber somewhat smaller than the expected value of 3. It is shown that the discrepancy could arise from a combination of observational effects and a northward tilt to the wave velocity. The best result of an attempt to detect a horizontal phase gradient from local data alone is, however, more consistent with a southward tilt. There is theoretical support for both conclusions, but the matter cannot be resolved with the data presently available. It is also concluded that the background circulation at meteor heights has little influence on the wave parameters, and that indications of wave activity outside the summer season are of doubtful significance.     

Winds oscillations (∼ 6h–6days) in the upper middle atmosphere at Monpazier (France, 45°N, 1°E) and Saskatoon (Canada, 52°N, 107°W) in 1979–1980

The medium frequency radar (∼ 2.2 MHz) at Saskatoon has been run continuously since 1978 and the Meteor Radar at Monpazier ran continuously for ∼ 10 day intervals in most months of 1979/1980. The radars are separated by ∼ 8000 km. Because of the excellent quality of the data, spectral and harmonic analyses have been completed from ∼ 70 to 100km and oscillations with periods of ∼ 6h–6days studied.There are substantial similarities in the mean zonal winds, both with regard to magnitudes and times of seasonal reversals; also in annual and semi-annual oscillations. In general, the semi-diurnal tide has similar amplitudes, phases and vertical wavelengths : there are consistent summer (long λ) and winter (short λ) characteristics, with rapid transitions between them. Differences between the timing of these transitions and in some of the mid-season tides are discussed. The diurnal tide is less regular and of smaller amplitude at both locations, often being too small to reliably characterize at Monpazier. However, seasonal variations between summer and winter months may be discerned.In addition to the 24 and 12 h tidal oscillations, which traditionally are studied in most detail, there is clear evidence for additional osculations near 6,8, ∼ 10 and ∼ 16 h and longer periods of ∼ 2 and ∼ 5 days. The amplitudes of these are often comparable or larger than the ‘dominant’ 24 and 12 h tides. The monthly and seasonal variations of these additional oscillations are studied, as a function of height, at the two locations. There is evidence for large scale (global) and small scale (local) disturbances in the wind field.     

神秘北纬30°

在地球北纬30度附近,有许多神秘而有趣的自然现象,该区域自然谜团频频发生。在中国,神秘的北纬30度横贯整个大陆腹地,各类自然现象和奇绝景观比比皆是。同样,位于北纬30度附近的浙东新昌,各类自然现象和奇绝景观也层出不穷,让人啧喷称奇……     

360°瑞士美景

<正>MySwitzerland.com在中国,提起瑞士,有人说那儿有美丽的阿尔卑斯雪山:有人想起经历了几个世纪的传奇——瑞士手表:也有人提及带些神秘色彩的瑞士银行……的确.这个西欧中不大的袖珍小国承载了太多的传奇。来瑞士.领略自然本色和人类文明发展到极致的完美与和谐:来瑞士.在依然纯净如初的保鲜空气里为自己洗去旅居大都市的尘嚣;来瑞士.敞开心肺.深呼吸!瑞士,一个你不能擦肩而过的地方……     

挪威北纬58°以北

飞机穿过云雾。带着我向斯堪的纳维亚前进,北极囤一点点在靠近,纬度不断地爬升。北纬58度,挪威最南端,比中国最北点还要北：北纬71度10分21秒,还是挪威,欧洲大陆到此结束。     

Mesopause temperatures and integrated band brightnesses calculated from airglow OH emissions recorded at Maynooth (53.2°N, 6.4°W) during 1993

Spectra of the hydroxyl emissions in the wavelength range 1.0–1.6 μm, which originate at mesopause altitudes, have been obtained, using a Fourier transform spectrometer at Maynooth (53.2°N, 6.4°W), on all suitable nights during the period January–December 1993. Rotational temperatures and integrated band brightnesses have been calculated from the spectra of the OH(3, 1) and (4, 2) vibration-rotation bands. The mean annual temperatures calculated over all measurements were T(3, 1)=200±19 K and T(4, 2)=206±19 K, where the uncertainty represents the standard deviation on the measurements. Harmonic analysis of the nightly averaged temperature values revealed an amplitude of 27 ± 1 K and a phase of 95 ± 2 days in the annual variation of the (3, l) band at our latitude. The semiannual component was found to have an amplitude of 7 ± 1 K and a phase of −51 ± 9 days for this band. Results for the (4, 2) band were identical in both amplitude and phase for the annual component, while the semiannual component gave an amplitude of 8 ± 1 K and a phase of − 43 ± 7 days. These results are compared with data recorded by the SME satellite, and with the predictions of the MSISE-90 model for a station at 53° latitude. Temperatures predicted by the MSISE-90 model for Maynooth are consistently below the values obtained in this study by 15–20 K. Excellent agreement is observed between the absolute value of temperature, in the case of the SME satellite, and in the amplitude and phase of the annual variation predicted by MSISE-90. The phase of the semiannual component observed in our data deviates somewhat from the −99 ± 1 days predicted by MSISE-90.The annual mean brightness of the OH (3, 1) band was found to be 75 ± 18 kR, while that of the (4, 2) band was 106±26 kR. Diurnal variations generally showed a steady decrease from dusk to dawn, apart from a brief period in June and July. Monthly average values of band brightness have been calculated for each band and are compared with the predictions of a recent photochemical model (Le Texier et al., 1987). The model shows some elements of agreement with our observations, particularly a pair of maxima near the equinoxes, but it does not predict the broad winter maximum observed in both bands at this latitude.     

《健康美人36.7°》

正内容简介:东方女性中约有1/2的人受到体寒症的困扰,其中80%以上是20~35岁的职业女性。体温34℃、35℃的女性正在OL人群中激增,这种寒性体质正成为东方女性的美丽杀手!寒性体质对人体有很多害处,它不仅是你美丽肌肤的杀手,还是你健康身体的杀手。本书从教你如何判断自己是否寒性体质开始,通过向食物要体温,向运动要体温,向生活细节要体温……来帮助你改善寒性体质。     

外滩270°视野 究竟什么样

上海外滩东方商旅精品酒店如果想念维港的"幻彩咏香江",那么就来外滩。对于我来讲,面对眼前这流光溢彩的镭射灯光汇演,就如同欣赏一个happyending,有着同样的治愈疗效。华灯初上,黄浦江变身为一个声光交织的水面舞台,对岸矗立的地标景观和摩天     

Some regularities of the lower thermosphre wind regime in summer and autumn from meteor radar measurements in obninsk (55°N, 38°E)

Meteor wind measurements made at Obninsk during MAC/SINE and MAC/EPSILON, and in the summer and autumn of other years since 1973, are reported. The zonal wind, which is presumed to be in the 93–95 km height region, is generally westerly, and the meridional wind is mainly northerly. Quasi-two-day oscillations are studied, as are semidiurnal tides. There is some evidence for a 22-yr periodicity in the amplitude of the semidiurnal tide     

东经121°08’北纬29°13’到渔镇石浦做个渔民

<正>东海之滨,象山半岛的最南端,将海洋文化保存最原始的古镇——石浦无时不在的大洋气息三月三踏沙滩,海钓节,开渔节,海鲜节海浪声伴着浓郁的海鲜味让人痴迷,石浦的丰富,不知从何说起……伴着海浪声,让我们到这里做个彻头彻尾的渔民     

漠河 北纬53°的时间简史

位于中国最北部的漠河,有着与其他地主不同的时间节奏。“一天无尽的日夜”,冬天漫长的“黑昼”,注定会给漠河人留下不一样的生活印记。     

不来梅,北纬50°的童话

<正>不来梅是一座童话之城,除了重温格林兄弟笔下的著名篇章,1200年的历史,也让这座城市的现实生活充满童话色彩,遍布中世纪木屋的古老街道,威悉河畔连成一串的咖啡馆和餐厅,世界遗产与活泼市集共存的广场,讲述着文艺复兴与大航海时代的辉煌,也展示着一座古城历久弥新的独特魅力。"童话之路"的最北端Die Bremer Stadtmusikanten初夏的傍晚,漫步不来梅(Bremen),这座中世纪古城呈现出一派悠然的姿态,弯曲狭长的街道,纵横交错的路口,古老的德式建筑……不来梅位于威悉河