共查询到20条相似文献，搜索用时 453 毫秒
1.
R. P. Kane 《Annales Geophysicae》1997,15(12):1581-1594
Data for geomagnetic activity index aa for 1868–1994 were subjected to spectral analysis for 12 intervals each of 11 consecutive years. In each interval, QBO and QTO (quasi-biennial and quasi-triennial oscillations) were observed at ∼ 2.00, 2.15, 2.40, 2.70 y and ∼ 3.20, 3.40 y, but not all in all intervals. These fluctuations are absent near (2–3 y before and after) the sunspot minima and are present only as 2 or 3 peaks in aa indices, one near or before the sunspot maximum and the other (one or two, generally the larger ones) in the declining phase of the sunspot cycle. Comparison with the solar wind (1965 onwards) showed a fairly good match, indicating that the aa variations were mostly due to similar variations in the solar wind, which must have their origin in solar physical processes. A few aa variations did not match with solar wind. When compared with terrestrial phenomena, no match was found with stratospheric low-latitude zonal wind QBO; but some QTO in aa matched QTO in ENSO (El Nino/ Southern Oscillation). This may or may not be a chance coincidence and needs further exploration. 相似文献
2.
R. P. Kane 《Pure and Applied Geophysics》1996,147(3):567-583
A spectral analysis of the 12-month running averages of several atmospheric parameters for 40 years (1951–1990) indicated prominent QBO (Quasi-Biennial Oscillations) and QTO (Quasi-Triennial Oscillations). The 50 mb tropical wind has a very prominent QBO peak atT=2.33 years, which was well reflected in N. Pole 30 mb temperature but not in average surface air temperatures of Northern and Southern Hemispheres. The 50 mb wind had no prominent QTO; but sea-surface temperatures showed prominent QTO at 3.6 years as well as peaks at 4.8 years (also shown by N. Pole 30 mb temperature) which matched very well with similar peaks in the Pacific SST and SO (Southern Oscillation) index. Specific humidity in the lower troposphere (1000 and 700 mb) and temperature at 300 mb obtained by radiosondes in the western Pacific for 15 years (1974–1988) showed mainly a biennial oscillation. 相似文献
3.
The minimum winter temperature series for the United States Gulf Coast for 1799–1988 (190 values) was subjected to Maximum Entropy Spectral Analysis. Significant periodicities in the QBO region (T-2–3 years) and atT=3.7, 4.5, 5.5, 6.5, 7.5, 12.9, 15.5 and 22 years were detected. Some of these were present in the first half only (1799–1893) while others in the latter half only (1894–1988), indicating a transient nature. Also, more than 50% of the variance was random. Many of the significant periodicities are seen in other geophysical parameters. Some may be harmonics of the 11-year sunspot cycle and the 22-year Hale magnetic sunspot cycle. 相似文献
4.
B. Soukharev 《Annales Geophysicae》1997,15(12):1595-1603
The interaction between the factors of the quasi-biennial oscillation (QBO) and the 11-year solar cycle is considered as an separate factor influencing the interannual January–March variations of total ozone over Northeastern Europe. Linear correlation analysis and the running correlation method are used to examine possible connections between ozone and solar activity at simultaneous moment the QBO phase. Statistically significant correlations between the variations of total ozone in February and, partially, in March, and the sunspot numbers during the different phases of QBO are found. The running correlation method between the ozone and the equatorial zonal wind demonstrates a clear modulation of 11-y solar signal for February and March. Modulation is clearer if the QBO phases are defined at the level of 50 hPa rather than at 30 hPa. The same statistical analyses are conducted also for possible connections between the index of stratospheric circulation C1 and sunspot numbers considering the QBO phase. Statistically significant connections are found for February. The running correlations between the index C1 and the equatorial zonal wind show the clear modulation of 11-y solar signal for February and March. Based on the obtained correlations between the interannual variations of ozone and index C1, it may be concluded that a connection between solar cycle – QBO – ozone occurs through the dynamics of stratospheric circulation. 相似文献
5.
—The 4-season (12-month) running means of temperatures at five atmospheric levels (surface, 850–300 mb, 300–100 mb, 100–50 mb, 100–30 mb) and seven climatic zones (60°N–90°N, 30°N–60°N, 10°N–30°N, 10°N–10°S, 10°S–30°S, 30°S–60°S, 60°S–90°S) showed QBO (Quasi-biennial Oscillation), QTO (Quasi-triennial Oscillation) and larger periodicities. For stratosphere and tropopause, the temperature variations near the equator and North Pole somewhat resembled the 50mb low latitude zonal winds, mainly due to prominent QBO. For troposphere and surface, the temperature variations, especially those near the equator, resemble those of eastern equatorial Pacific sea-surface temperatures, mainly due to prominent QTO. In general, the temperature trends in the last 35 years show stratospheric cooling and tropospheric warming. But the trends are not monotonic. For example, the surface trends were downward during 1960–70, upward during 1970–82, downward during 1982–85 and upward thereafter. Models of green-house warming should take these non-uniformities into account. 相似文献
6.
G.A. Mansilla P. Fernandez de Campra M. Zossi de Artigas 《Journal of Atmospheric and Solar》2009,71(14-15):1610-1612
The aim of this paper is to report some periodicities observed in the ionospheric parameter foF2 measured at Tucuman (26.9°S; 65.4°W), station placed near the southern crest of the equatorial anomaly. For that, monthly medians of foF2 at several hours of LT for the period 1958–1987 are used. The data are run with Fast Fourier Transform (FFT). Data gaps (4–5 months) are filled by means of linear interpolation. Several periodicities are present. Besides the solar cycle dominant dependence (11 years), semi-annual, annual, five years and quasi-biennial periodicities are also observed. A marked quasi-biennial periodicity is observed at daytime and nighttime hours being their greater amplitude at local noon and midnight. Different mechanisms or combined effects possibly cause them. It is suggested that the solar activity by means of extreme ultraviolet radiation (EUV), which present a quasi-biennial oscillation (QBO) and it is responsible for the ionization, could be the dominant mechanism for the diurnal quasi-biennial periodicity of foF2. At night, since the photoionization by extreme ultraviolet radiation is not significant and the F2 layer is lower than during daytime (100 km) other mechanism may be operative for the quasi-biennial periodicity observed. Possibly the stratospheric QBO contributes to the modulation of the observed behaviour in foF2 at night. This result is preliminary because it needs to be extended to other stations so as to extract definite conclusions. Moreover, we cannot dismiss the possibility of a combined effect of both these mechanisms mainly at daytime and/or QBO influence of geomagnetic parameters. 相似文献
7.
The north-south asymmetry of the Fe XIV 530.3 nm coronal emission line (the green corona) over cycle 22 was investigated. The green corona line brightness was dominant in the southern hemisphere during cycle 22 (A = –0.07), except for short periods of the ascending phase of the activity cycle. The asymmetry of the semi-annual mean over the period 1940 – 1996 was also studied. The asymmetry, during these years, reached its maximum in 1962 – 1966, and then decreased. Important periodicities of the asymmetry in cycle 22, e.g., 158 and 350 days, 2.39 years were found. Similar periodicities were also detected in the years 1940 – 1996. An FFT analysis was used to detect these periodicities. 相似文献
8.
R. P. Kane 《Pure and Applied Geophysics》1991,136(2-3):201-210
During solar cycle 21 (1976–86), the primary solar irradiance at 300 nm was steady during 1980–82 and thereafter decreased until 1986 by only 2–3%. The stratospheric ozone in middle latitudes had a QBO of 3–4% in this interval but the long-term ozone trend was less than 3% per decade, which could result in a UVB increase of only 5–6% per decade. Thus, the combined effect of changes in primary solar irradiance and ozone changes could be an increase of 5–6% in UVB, observed at ground during 1977–81 and a steady level during 1981–86. During 1976–86, the average cloudiness changed by less than 5% indicating UVB changes of 5% or less on this count. The aerosol level was almost constant during 1976–82 and increased abruptly in 1982 due to the E1 Chichon eruption and decayed slowly unitl 1986. Thus, due to aerosols only, the UVB was expected to be constant during 1976–82, to decrease sharply in 1982 and to recoup slowly thereafter.Measurements of clear-sky solar UVB at ground made at Jungfraujoch (Swiss Alps, 47°N, 8°E) during 1981–89 and at Rockville, USA (39°N, 77°W) were not comparable between themselves and did not follow the above expected patterns. Neither did the all-day R-B meter UVB measurements at Philadelphia, USA (40°N, 75°W) and Minneapolis, USA (45°N, 93°W). We suspect that some of these measurements are erroneous. This needs further detailed scrutiny. 相似文献
9.
R. P. Kane 《Annales Geophysicae》1995,13(2):211-216
Stratospheric temperatures show distinct trends, not necessarily monotonically upward or downward. At the North Pole, trends were large only during winter and spring and were different for different months; downward for November, December, mixed for January and upward for February, March and April. For the 10°-90°N belt, the trends were variable, viz., downward during 1971-1975, upward during 1975–1978 and downward again from 1978 onwards up to date, opposite to the upward trend of ground temperature in the Northern hemisphere in recent years. Twelve-monthly running averages revealed strong QBO (quasi-biennial oscillation). For the North Pole, the QBO showed colder (lower) temperatures during 50-mb wind QBO westerly phase maxima. For the 10°-90°N belt, the QBO was similar for 30 mb and 50 mb but the QBO phases did not match well with 50-mb wind QBO phases. 相似文献
10.
Kp and Ap indices covering the period 1932 to 1995 are analysed in a fashion similar to that attempted by Bartels for the 1932–1961 epoch to examine the time variations in their characteristics. Modern analysis techniques on the extended data base are used for further insight. The relative frequencies of occurrence of Kp with different magnitudes and the seasonal and solar cycle dependences are seen to be remarkably consistent despite the addition of 35 years of observations. Many of the earlier features seen in the indices and special intervals are shown to be replicated in the present analysis. Time variations in the occurrence of prolonged periods of geomagnetic calm or of enhanced activity are presented and their relation to solar activity highlighted. It is shown that in the declining phase the occurrence frequencies of Kp = 4–5 (consecutively over 4 intervals) can be used as a precursor for the maximum sunspot number to be expected in the next cycle. The semiannual variation in geomagnetic activity is reexamined utilising not only the Ap index but also the occurrence frequencies of Kp index with different magnitudes. Lack of dependence of the amplitude of semiannual variation on sunspot number is emphasised. Singular spectrum analysis of the mean monthly Ap index shows some distinct periodic components. The temporal evolution of 44 month, 21 month and 16 month oscillations are examined and it is postulated that while QBO and the 16 month oscillations could be attributed to solar wind and IMF oscillations with analogous periodicity, the 44 month variation is associated with a similar periodicity in recurrent high speed stream caused by sector boundary passage. It is reconfirmed that there could have been only one epoch around 1940 when solar wind speed could have exhibited a 1.3-year periodicity comparable to that seen during the post-1986 period. 相似文献
11.
R. P. Kane 《Pure and Applied Geophysics》1991,135(4):611-624
A comparison of monthly mean values of total ozone at South Pole, Buenos Aires (Argentina), Cachoeira Paulista and Natal (Brazil), and Huancayo (Peru) revealed that whereas South Pole showed an ozone depletion of 45% in October 1987 (as compared to October, 1977), Buenos Aires showed a small decrease (10%) while the other locations showed very small decreases (1–2%). When daily values are considered, the Antarctic ozone hole of October 1987 seems to have caused 10% depletion at Buenos Aires and 5% at Natal and Huancayo in December 1987. However, a large part of this is normal seasonal variation, except at Huancayo, where a residual effect of 5% depletion in December 1987 remains. The QBO effects (5–8% changes in the ozone level in 2–3 years) could cause 10–15% fluctuations in solar UVB on the ground on clear-sky days and could be a possible health hazard unless factors like cloudiness reduce the UVB intensities. 相似文献
12.
利用EMD和小波对试验信号进行分解比较,结果表明EMD方法能够更加真实的再现数据本身的频谱分量和对应幅度．利用EMD方法对1932年~2006年地磁Ap指数月均值进行了分解,分别得到一系列模式和一个趋势项．其中可能包含了6个月周期分量,准1年周期分量,QBO（准两年震荡）分量,准5年周期分量,准11年周期分量和22年Hale周分量等．地磁活动Ap指数与太阳黑子数都有着11年周期变化,我们比较发现Ap指数11年周期分量极值出现要比太阳黑子数11年周期分量极值出现平均滞后1~2年． 相似文献
13.
Tropospheric temperature and pressure fields on the Northern Hemisphere in the winter periods 1952–1996 were investigated. Composite maps of those fields, created for the high and low geomagnetic activity and individual quasi-biennial oscillation (QBO), phases show clear differences not only between different levels of geomagnetic activity, but also between the two phases of QBO. Special attention was given to the behaviour of the lower troposphere in January and February 1982. 相似文献
14.
N.R. Rigozo M.P. Souza Echer H. Evangelista D.J.R. Nordemann E. Echer 《Journal of Atmospheric and Solar》2011,73(11-12):1294-1299
The prediction of solar activity strength for solar cycles 24 and 25 is made on the basis of extrapolation of sunspot number spectral components. Monthly sunspot number data during the 1850–2007 interval (solar cycles 9–23) are decomposed into several levels and searched for periodicities by iterative regression in each level. For solar cycle 24, the peak is predicted in November 2013 with a sunspot number of 113.3. The cycle is expected to be weak, with a length of 133 mo (months) or 11.1 yr. The sunspot number maximum in cycle 25 is predicted to occur in April 2023 with a sunspot number 132.1 and a solar cycle length of 118 mo or 9.8 yr. Thus, solar cycle 24 is predicted to have an intensity 23% lower than cycle 23, and cycle 25 will be 5% lower than cycle 23. 相似文献
15.
利用气象场的再分析资料和太阳辐射活动资料,对太阳11年周期活动影响北半球冬季(11月~3月)大气环流的过程进行了统计分析和动力学诊断.根据赤道平流层纬向风准两年振荡(QBO)的东、西风状态对太阳活动效应进行了分类讨论,结果表明：东风态QBO时,太阳活动效应主要集中在赤道平流层中、高层和南半球平流层,强太阳活动时增强的紫外辐射加热了赤道地区的臭氧层,造成平流层低纬明显增温,同时加强了南半球的Brewer-Dobson(B-D)环流,引起南极高纬平流层温度增加;而北半球中高纬的环流主要受行星波的影响,太阳活动影响很小.西风态QBO时,太阳活动效应在北半球更为重要,初冬时强太阳活动除了加热赤道地区臭氧层外,还抑制了北半球的B-D环流,造成赤道平流层温度增加和纬向风梯度在垂直方向的变化,从而改变了对流层两支行星波波导的强度;冬末时在太阳活动调制下,行星波向极波导增强,B-D环流逐渐恢复,造成北半球极地平流层明显增温,同时伴随着赤道区域温度的下降. 相似文献
16.
L. A. Hajkowicz 《Annales Geophysicae》1996,14(9):906-916
The equatorial ionospheric response to 228 isolated, rapid-onset auroral substorms (as defined from the auroral electrojet index AE) was found from enhancements of the virtual (minimum) height of the F-region (h′F) in the declining phase of a solar cycle (1980-85). The responses, found for three longitudinal sectors at the equator: Africa (Ouagadougou and Dakar), Asia (Manila) and America (Huancayo), were compared with the response close to the auroral source region at Yakutsk (northern Siberia). The auroral substorm onsets were centered at 17 and 15 UT at sunspot maximum (1980-82) and minimum (1983-85), preceding by 3–5 h the period of post-sunset height rise in the African sector whereas other sectors were in the early afternoon (Huancayo) and morning (Manila). The African response, particularly at Ouagadougou, was distinctly different from other sectors. In the sunspot maximum years (1980-81) the auroral surges were followed after about 3 h by a sharp depression (h′F<0) in the post-sunset height rise, with a period of little or no response (h′F=0) in 1982. A response polarity reversal (h′F>0) was noted in this sector for sunspot minimum (1983-85) when large h′F enhancements were observed at the sunset region. The responses in the Asian and American sector were positive except for a case in Huancayo when response was negative, following an auroral surge before the sunset at this station. It appears that the aurorally generated large-scale travelling ionospheric disturbances (LSTIDs), which first cause positive height enhancements in a sub-auroral location (Yakutsk), subsequently affect the unstable post-sunset ionosphere in the equatorial Africa. 相似文献
17.
Regular measurements of the atmospheric ozone in the Brazilian sector were started at Cachoeira Paulista (22.7°S, 45.0°W), and Natal (5.8°S, 35.2°W) in May 1974 and November 1978, respectively. The results of the total ozone measurements carried out at these two stations up to 1981 are presented in this communication and compared with other low-and mid-latitude stations. Although Natal is an equatorial station, it presents a prominent annual variation, and the average total ozone content is high compared to satellite measurements. During 1977–78, abnormally low values of total ozone were observed at Cachoeira Paulista. Some preliminary results about the QBO 9quasi-biennial oscillation) during 1974–81 are also presented. 相似文献
18.
19.
The biological processes have been proposed as climate variability contributors. Dimethylsulfide (DMS) is the main biogenic sulfur compound in the atmosphere; it is mainly produced by the marine biosphere and plays an important role in the atmospheric sulfur cycle. Currently it is accepted that terrestrial biota not only adapts to environmental conditions but also influences them through regulations of the chemical composition of the atmosphere. In the present study we used a wavelet method to investigate the relationship between DMS, Low cloud cover (LCC), Ultraviolet Radiation A (UVA), Total Solar Irradiance (TSI) and Sea Surface Temperature (SST) in the so called pristine zone of the Southern Hemisphere. We found that the series analyzed have different periodicities which can be associated with large scale climatic phenomena such as El Niño (ENSO) or the Quasi-Biennial Oscillation (QBO), and/or to solar activity. Our results show an intermittent but sustained DMS-SST correlation and a DMSUVA anti correlation; but DMS-TSI and DMS-LCC show nonlinear relationships. The time-span of the series allow us to study only periodicities shorter than 11 years, then we limit our analysis to the possibility that solar radiation influences the Earth climate in periods shorter than the 11-year solar cycle. Our results also suggest a positive feedback interaction between DMS and solar radiation. 相似文献
20.
J. Chattopadhyay 《Pure and Applied Geophysics》1970,83(1):111-119
Summary Atmospheric total ozone contents over three stations in north India have been studied. A power spectrum analysis has been made of daily values recoreded at these stations during the winter season. Three types of periodicities have been observed in the available records, namely, oscillations with a period of (a) 2.5–3.5 days, (b) 4.0–5.3 days and (c) 8.0–9.6 days. The first and third type of oscillations were also observed when the data were extended to cover an entire year, instead of the winter season alone. A possible mechanism for the occurrence of these periodicities is discussed. 相似文献