Om Upadhyay - Academia.edu (original) (raw)
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The Interdisciplinary Center, Herzliya
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Papers by Om Upadhyay
Journal of Earth System Science, 1991
Materials Today: Proceedings, 2021
Solar Physics, 1998
The Pioneer Venus Orbiter (PVO) had on board the electron temperature probe experiment which meas... more The Pioneer Venus Orbiter (PVO) had on board the electron temperature probe experiment which measured temperature and concentration of electrons in the ionosphere of Venus. When the probe was outside the Venus ionosphere and was in the solar wind, the probe current was entirely due to solar photons striking the probe surface. This probe thus measured integrated solar EUV flux (Ipe) over a 13-year period from January 1979 to December 1991, thereby covering the declining phase of solar cycle 21 and the rising phase of solar cycle 22. In this paper, we examine the behavior of Ipe translated to the solar longitude of Earth (to be called EIpe) during the two solar cycles. We find that total EUV flux changed by about 60% during solar cycle 21 and by about 100% in solar cycle 22. We also compare this flux with other solar activity indicators such as F10:7, Lae, and the solar magnetic field. We find that while the daily values of EIpe are highly correlated with F10:7 (correlation coefficient 0.87), there is a large scatter in EIpe for any value of this Earth-based index. A comparison of EIpe with SME and UARS SOLSTICE Lae measurements taken during the same period shows that EIpe tracks Lae quite faithfully with a correlation coefficient of 0.94. Similar comparison with the solar magnetic field (B s) shows that EIpe correlates better with Bsthan with F10:7. We also compare EIpe with total solar irradiance measured during the same period.
Journal of Earth System Science, 1991
Materials Today: Proceedings, 2021
Solar Physics, 1998
The Pioneer Venus Orbiter (PVO) had on board the electron temperature probe experiment which meas... more The Pioneer Venus Orbiter (PVO) had on board the electron temperature probe experiment which measured temperature and concentration of electrons in the ionosphere of Venus. When the probe was outside the Venus ionosphere and was in the solar wind, the probe current was entirely due to solar photons striking the probe surface. This probe thus measured integrated solar EUV flux (Ipe) over a 13-year period from January 1979 to December 1991, thereby covering the declining phase of solar cycle 21 and the rising phase of solar cycle 22. In this paper, we examine the behavior of Ipe translated to the solar longitude of Earth (to be called EIpe) during the two solar cycles. We find that total EUV flux changed by about 60% during solar cycle 21 and by about 100% in solar cycle 22. We also compare this flux with other solar activity indicators such as F10:7, Lae, and the solar magnetic field. We find that while the daily values of EIpe are highly correlated with F10:7 (correlation coefficient 0.87), there is a large scatter in EIpe for any value of this Earth-based index. A comparison of EIpe with SME and UARS SOLSTICE Lae measurements taken during the same period shows that EIpe tracks Lae quite faithfully with a correlation coefficient of 0.94. Similar comparison with the solar magnetic field (B s) shows that EIpe correlates better with Bsthan with F10:7. We also compare EIpe with total solar irradiance measured during the same period.