Showing papers on "Solar cycle 24 published in 2001"
TL;DR: In this paper, the authors investigated the characteristics of latitude migration of sunspot groups in the northern and southern hemispheres using the Royal Greenwich Observatory data set from the years 1874 through 1999.
Abstract: Characteristics of latitude migration of sunspot groups in the northern and southern hemispheres are investigated by using the Royal Greenwich Observatory data set from the years 1874 through 1999. Latitude migration of sunspot groups is found to be represented by a binomial formula, which quantitatively describes the law. Latitude migration velocity of sunspot groups is largest at the beginning of a Sporer solar cycle, and as the solar cycle progresses, it decreases with time, with an average of about 1-degrees6 yr(1) during a solar cycle. Two different methods have been employed to confirm that latitude migration in both hemispheres is statistically the same.
40 citations
TL;DR: In this article, the authors used the 10.7 cm radio flux to estimate the annual levels of the Sun's irradiance until 2018 using parameterizations of the radio flux and showed that future irradiance trends underlying the 11-year cycle, which are assumed not to exceed those in historical reconstructions during the past 350 years, are estimated to be less than ± 0.4 Wm−2 per decade for total irradiance.
Abstract: Annual levels of the Sun's irradiance are estimated until 2018 using parameterizations of the 10.7 cm radio flux. Peak irradiance during solar cycle 24 occurs in 2010, with levels comparable to or slightly lower than prior maxima in 2000, 1989 and 1981. Minima occur in 2006 and 2016. Future irradiance trends underlying the 11-year cycle, which are assumed not to exceed those in historical reconstructions during the past 350 years, are estimated to be less than ±0.4 Wm−2 per decade for total irradiance, ±0.01 Wm−2 per decade for UV radiation at 295–310 nm and ±0.04 Wm−2 per decade for UV radiation at 200–295 nm. When activity cycles and longer-term trend scenarios are combined, total solar irradiance forcing of climate between cycle minima in 1996 and 2016 is in the range ±0.1 Wm−2. For comparison, the forecast net anthropogenic climate forcing over this 22-year period is in the range 0.5 to 0.9 Wm−2.
33 citations