LONG-TERM VARIATIONS IN ULTRAVIOLET SUNLIGHT REACHING THE BIOSPHERE: . CALCULATIONS FOR THE PAST THREE DECADES

1991 ◽  
Vol 54 (5) ◽  
pp. 781-788 ◽  
Author(s):  
J. E. Frederick ◽  
E. C. Weatherhead ◽  
E. K. Haywood
Keyword(s):  
The Past ◽  
Long Term Variations

Long-term variations in the geomagnetic activity level Part II: Ascending phases of sunspot cycles

1994 ◽  
Vol 12 (10/11) ◽  
pp. 1065-1070 ◽  
Author(s):  
V. Mussino ◽  
O. Borello Filisetti ◽  
M. Storini ◽  
H. Nevanlinna
Keyword(s):  
Correlation Coefficient ◽  
Geomagnetic Activity ◽  
Activity Level ◽  
Activity Levels ◽  
Data Set ◽  
The Past ◽  
Long Term Trends ◽  
A Minor ◽  
Long Term Variations

Abstract. Monthly averages of the Helsinki Ak-values have been reduced to the equivalent aa-indices to extend the aa-data set back to 1844. A periodicity of about five cycles was found for the correlation coefficient (r) between geomagnetic indices and sunspot numbers for the ascending phases of sunspot cycles 9 to 22, confirming previous findings based on a minor number of sunspot cycles. The result is useful to researchers in topics related to solar-terrestrial physics, particularly for the interpretation of long-term trends in geomagnetic activity during the past, and to forecast geomagnetic activity levels in the future.

scholarly journals Flare Stars in the ETA Tauri Fields Significant Long-Term Variations of their Flaring Activity

1989 ◽  
Vol 104 (2) ◽  
pp. 143-146
Author(s):  
G. Szécsényi-Nagy
Keyword(s):  
New Method ◽  
The Past ◽  
Flare Stars ◽  
Frequency Variations ◽  
Flare Frequency ◽  
Long Term Variations

Photographic surveys completed during the past 30 years yielded data of about 600 flare stars in these fields. Although their average flare number is very low 17 of the stars produced 10… 120 flare ups. In order to investigate the possible long-term activity changes of these objects a new method - which is described below -was developed. Making use of it significant flare frequency variations were found at two out of three ‘active’ flare stars.

scholarly journals Errors of Observation in Double-Star Work

1971 ◽  
Vol 5 ◽  
pp. 133-135
Author(s):  
W. D. Heintz
Keyword(s):  
Noise Level ◽  
Double Star ◽  
Astronomical Observation ◽  
Time Interval ◽  
The Past ◽  
Visual Binary ◽  
Long Time ◽  
Observational Errors ◽  
Long Term Variations

Astronomical observation frequently is focused on minute quantities, and on digging information even from below the 'noise level'. In all cases of long-term variations, such as visual binary motions, measurements over a long time interval have to be combined. All of this requires a knowledge of the observational errors in the past and present. We usually are not at liberty to discard old observations since we cannot repeat them at any later time desired. Visual observations leave no re-measurable records, so we have to take the word of the observer, and make the best of it.

scholarly journals A Transient Shock-Wave in the Shell of the Be Star HD 184279

1987 ◽  
Vol 92 ◽  
pp. 95-98
Author(s):  
D. Ballereau ◽  
J. Chauville
Keyword(s):  
Shock Wave ◽  
Radial Velocity ◽  
Emission Spectrum ◽  
Short Term ◽  
Balmer Series ◽  
Spectroscopic Observations ◽  
The Past ◽  
Be Star ◽  
Long Term Variations

HD 184279 (V1294 Aql) has presented in the past an emission spectrum on the first terms of the Balmer series, and shell absorptions on the hydrogen and neutral helium lines. Their variations have been reported by Merrill (1952), Merrill and Lowen (1953) and Svolopoulos (1975). Ballereau and Hubert-Delplace (1982) evidenced long-term V/R variations with an amplitude of ∼100 km s-1. Short-term photometric variations are irregular (Tempesti and Patriarca, 1976), while long-term variations are correlated with radial velocity (RV) of shell lines (Horn et al., 1982). Ballereau and Chauville (in preparation) extended the spectroscopic observations until 1984 and confirmed the pseudo-periodic variations, the last half-period ranging over 3.4 years (April 1, 1980-August 1, 1983).

Long Term Variations in Jupiter’s 11 cm Radio Emission

1975 ◽  
Vol 2 (6) ◽  
pp. 340-342
Author(s):  
P.M. McCulloch
Keyword(s):  
Radio Emission ◽  
Orbital Period ◽  
Full Range ◽  
Rotational Axis ◽  
The Past ◽  
Range Of Values ◽  
Long Term Variations

During the past twelve years five series of observations have been made of the polarization of Jupiter’s radio emission at a wavelength of 11 cm. This data shows characteristics which have been stable over a period of years as well as some unexplained variations. The observations were made during one complete orbital period of Jupiter and hence were obtained over the full range of values of DE, the angle between Jupiter’s rotational axis and the plane of the sky. These are summarized in Table 1. The 1967 observations have been reported previously (Komesaroff and McCulloch 1967) and the 1963 data is from Roberts and Komesaroff (1965).

Errors of Observation in Double-Star Work

1965 ◽  
Vol 5 ◽  
pp. 132-135
Author(s):  
W. D. Heintz
Keyword(s):  
Noise Level ◽  
Double Star ◽  
Astronomical Observation ◽  
Time Interval ◽  
The Past ◽  
Visual Binary ◽  
Long Time ◽  
Observational Errors ◽  
Long Term Variations

Astronomical observation frequently is focused on minute quantities, and on digging information even from below the ‘noise level’. In all cases of long-term variations, such as visual binary motions, measurements over a long time interval have to be combined. All of this requires a knowledge of the observational errors in the past and present. We usually are not at liberty to discard old observations since we cannot repeat them at any later time desired. Visual observations leave no re-measurable records, so we have to take the word of the observer, and make the best of it.

Elemental concentration in the hair taken from healthy people for the past 20 years — 1. Long-term changes over 20 years

2016 ◽  
Vol 26 (01n02) ◽  
pp. 15-28 ◽  
Author(s):  
K. Sera ◽  
S. Goto ◽  
T. Hosokawa ◽  
C. Takahashi ◽  
J. Itoh ◽  
...  
Keyword(s):  
Toxic Elements ◽  
Elemental Concentration ◽  
Essential Elements ◽  
Healthy People ◽  
The Other ◽  
The Past ◽  
The People ◽  
Calcium Magnesium ◽  
Long Term Variations

We developed a standard-free method for untreated hairs and the method has been applied to quantitative analysis of more than 30,000 hairs taken from the people concerned in order to evaluate exposure to some toxic elements and intakes of essential elements. Besides these analyses, we have measured nearly 2000 hairs collected from healthy people in Japan over the past 20 years. It was found that concentrations of some elements, such as vanadium, chromium, manganese, copper and mercury, keep increasing up to the present. Such tendencies were particularly notable for female, while not clearly observed for male. Concentrations of some essential elements, such as calcium, magnesium and zinc, show no obvious long-term variations. On the other hand, iron and selenium show slightly decreasing tendencies. With regard to toxic elements, it was found that arsenic, chromium and mercury are tending to increase year by year.

A Study of Variation of the 11-yr Solar Cycle before the onset of the Spoerer Minimum based on Annually measured 14C Content in tree Rings

Radiocarbon ◽  
2019 ◽  
Vol 61 (6) ◽  
pp. 1749-1754 ◽  
Author(s):  
Toru Moriya ◽  
Hiroko Miyahara ◽  
Motonari Ohyama ◽  
Masataka Hakozaki ◽  
Mirei Takeyama ◽  
...  
Keyword(s):  
Solar Activity ◽  
Solar Cycle ◽  
Cycle Length ◽  
Detailed Mechanism ◽  
Grand Minimum ◽  
The Past ◽  
Shimokita Peninsula ◽  
Solar Cycle Length ◽  
Long Term Variations

ABSTRACTProxy-based observations of solar activity in the past have revealed long-term variations, such as the Gleissberg cycle (~88 yr), de Vries cycle (~200 yr), and the Hallstatt cycle (~2000 yr). Such long-term variations of solar activity sometimes cause the disappearance of sunspots for several decades. Currently, solar activity is becoming weaker, and there is a possibility that another long-term sunspot minimum could occur. However, the detailed mechanism of the weakening in solar activity is unknown, and the prediction of solar activity is ambiguous. In this study, we investigate the transitions of solar cycle length before the onset of the Spoerer Minimum, the longest grand minimum in the past 2000 yr. We measured the 14C content in an asunaro tree (Thujopsis dolabrata) excavated at Shimokita Peninsula from 1368–1420 CE using the compact AMS system at Yamagata University. It is found that the solar cycle lengthened to be 14–16 yr from 2 cycles before the onset of the Spoerer Minimum.

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