THE VARIATION OF SEA LEVEL COSMIC RAY INTENSITY BETWEEN 1954 AND 1957

1958 ◽  
Vol 36 (7) ◽  
pp. 824-839 ◽  
Author(s):  
A. G. Fenton ◽  
D. C. Rose ◽  
K. B. Fenton
Keyword(s):  
Solar Activity ◽  
Sea Level ◽  
Geomagnetic Latitude ◽  
Cosmic Ray ◽  
High Solar Activity ◽  
General Level ◽  
Intensity Level ◽  
Cosmic Ray Intensity ◽  
Primary Cosmic Radiation ◽  
The One

Results from neutron monitors and meson telescopes at Ottawa (geomagnetic latitude 57° N.) and Resolute (geomagnetic latitude 83° N.) are presented for the years 1954–57, a period of increasing solar activity. The results indicate that the sea level meson intensity at these latitudes decreased by 5–6% between April 1954 and December 1957. During the same period the intensity of the nucleonic component at these stations decreased by over 22%. Investigation of the relative response of the two types of recorder to transient decreases during this period indicates that the long term change in the intensity level cannot be explained completely as an accumulation of shorter transient decreases, which become more frequent at times of high solar activity. It is concluded that the transient decreases are superimposed upon the longer term changes, each being produced by a separate modulation process but ultimately controlled by the general level of solar activity. Significant differences are found in the shape of transient decreases observed at the Canadian stations, both between different components at the one station and the same component at different stations. These may be interpreted as due to a varying energy dependence from one transient decrease to another, and to anisotropy in the primary cosmic radiation at these times.

Rigidity spectra of primary cosmic radiation

1968 ◽  
Vol 46 (10) ◽  
pp. S923-S926
Author(s):  
K. Kasturirangan ◽  
N. W. Nerurkar
Keyword(s):  
Solar Activity ◽  
North America ◽  
Cosmic Radiation ◽  
Cosmic Ray ◽  
Cosmic Ray Intensity ◽  
Slow Change ◽  
Primary Cosmic Radiation ◽  
Ion Chambers

The comparison of the cosmic-ray intensity measured with balloon-borne ion chambers at different atmospheric depths at stations in North America and in the U.S.S.R. for the period 1937–67 is presented. It is found that there is no difference in variations of cosmic-ray spectra in periods of increasing and decreasing solar activity in 1954–64. In 1937–40 the cosmic-ray spectra are found to be distinctly different, suggesting a slow change in the spectrum over periods greater than the 11-year cycle of solar activity.

HIGH-ALTITUDE COSMIC RAY MEASUREMENTS AT FORT CHURCHILL

1960 ◽  
Vol 38 (5) ◽  
pp. 638-641 ◽  
Author(s):  
I. B. McDiarmid ◽  
D. C. Rose
Keyword(s):  
Solar Activity ◽  
High Altitude ◽  
Solar Minimum ◽  
Solar Maximum ◽  
Cosmic Ray ◽  
Geiger Counter ◽  
Low Energy ◽  
High Solar Activity ◽  
Energy Radiation ◽  
Cosmic Ray Intensity

Measurements with rocket-borne Geiger counters have been carried out at altitudes up to 250 km at Fort Churchill, Manitoba. The total primary cosmic ray intensity at a time near a solar maximum has been determined and compared with other measurements taken at times of high solar activity and also with other Geiger counter measurements obtained near a solar minimum. A low-energy radiation was observed whose intensity increased with altitude up to about 25% of the primary intensity at 250 km.

The cosmic-ray intensity variations with periods of 19-24 days

1968 ◽  
Vol 46 (10) ◽  
pp. S831-S834
Author(s):  
G. A. Bazilevskaya
Keyword(s):  
Solar Activity ◽  
Sunspot Number ◽  
Neutron Monitor ◽  
Cosmic Ray ◽  
High Solar Activity ◽  
Radio Emissions ◽  
Cosmic Ray Intensity ◽  
Cyclic Variations

Sporadic cyclic variations of the cosmic-ray intensity with periods of 19 to 24 days have been found from the results of balloon and neutron monitor observations. These variations were observed mainly in the years of high solar activity, 1958–62. They appeared to be caused by the general solar activity which, as our treatment has shown, undergoes similar cyclic variations (according to sunspot number or 10.7-cm radio-emissions). The variations under investigation appear with a lag of about 1.5 months compared with the solar-activity variations.

A STATISTICAL ANALYSIS OF THE BAROMETER COEFFICIENTS FOR COSMIC-RAY INTENSITIES

1962 ◽  
Vol 40 (6) ◽  
pp. 687-697 ◽  
Author(s):  
S. M. Lapointe ◽  
D. C. Rose
Keyword(s):  
Statistical Analysis ◽  
Sea Level ◽  
Neutron Monitor ◽  
Seasonal Variations ◽  
Geomagnetic Latitude ◽  
Cosmic Ray ◽  
Seasonal Fluctuations ◽  
Latitude Effect ◽  
Standard Neutron ◽  
The One

The data from all four Canadian cosmic-ray stations, Ottawa, Resolute, Churchill, and Sulphur Mountain, have been analyzed statistically with the help of an I.B.M. 650 computer over a period of three and a half years extending from the beginning of the I.G.Y. in July 1957 to the end of 1960. The barometer coefficients for triple and double coincidences in the international cubical telescope and for the nucleon intensity in the standard neutron monitor have been derived. A single correlation between intensity and pressure was used; two different ways of effecting this correlation were tried over a 6-month period. The results were compared and the best method was applied to the remaining three years. Monthly values were calculated, as were yearly values and also values for the 3-year period. The results reveal no significant seasonal variations in the barometer coefficients and no significant year-to-year variation. However, the seasonal fluctuations of the nucleon coefficient unsuspectedly follow those of the meson. A small latitude effect seems to be present. The nucleon coefficient at Sulphur Mountain, a high altitude station, is larger than the one at Ottawa (same geomagnetic latitude, sea level station).

scholarly journals A Neural Network-Based TEC Model Capable of Reproducing Nighttime Winter Anomaly

2021 ◽  
Vol 13 (22) ◽  
pp. 4559
Author(s):  
Marjolijn Adolfs ◽  
Mohammed Mainul Hoque
Keyword(s):  
Neural Network ◽  
Solar Activity ◽  
Geomagnetic Latitude ◽  
Machine Learning Techniques ◽  
High Solar Activity ◽  
Electron Content ◽  
Solar Cycles ◽  
Total Electron ◽  
The Neural Network ◽  
Winter Anomaly

With the availability of fast computing machines, as well as the advancement of machine learning techniques and Big Data algorithms, the development of a more sophisticated total electron content (TEC) model featuring the Nighttime Winter Anomaly (NWA) and other effects is possible and is presented here. The NWA is visible in the Northern Hemisphere for the American sector and in the Southern Hemisphere for the Asian longitude sector under solar minimum conditions. During the NWA, the mean ionization level is found to be higher in the winter nights compared to the summer nights. The approach proposed here is a fully connected neural network (NN) model trained with Global Ionosphere Maps (GIMs) data from the last two solar cycles. The day of year, universal time, geographic longitude, geomagnetic latitude, solar zenith angle, and solar activity proxy, F10.7, were used as the input parameters for the model. The model was tested with independent TEC datasets from the years 2015 and 2020, representing high solar activity (HSA) and low solar activity (LSA) conditions. Our investigation shows that the root mean squared (RMS) deviations are in the order of 6 and 2.5 TEC units during HSA and LSA period, respectively. Additionally, NN model results were compared with another model, the Neustrelitz TEC Model (NTCM). We found that the neural network model outperformed the NTCM by approximately 1 TEC unit. More importantly, the NN model can reproduce the evolution of the NWA effect during low solar activity, whereas the NTCM model cannot reproduce such effect in the TEC variation.

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