%0 Journal Article
%T The Total Solar Irradiance, UV Emission and Magnetic Flux during the Last Solar Cycle Minimum
%A E. E. Benevolenskaya
%A I. G. Kostuchenko
%J Journal of Astrophysics
%D 2013
%R 10.1155/2013/368380
%X We have analyzed the total solar irradiance (TSI) and the spectral solar irradiance as ultraviolet emission (UV) in the wavelength range 115¨C180£¿nm, observed with the instruments TIM and SOLSTICE within the framework of SORCE (the solar radiation and climate experiment) during the long solar minimum between the 23rd and 24th cycles. The wavelet analysis reveals an increase in the magnetic flux in the latitudinal zone of the sunspot activity, accompanied with an increase in the TSI and UV on the surface rotation timescales of solar activity complexes. In-phase coherent structures between the midlatitude magnetic flux and TSI/UV appear when the long-lived complexes of the solar activity are present. These complexes, which are related to long-lived sources of magnetic fields under the photosphere, are maintained by magnetic fluxes reappearing in the same longitudinal regions. During the deep solar minimum (the period of the absence of sunspots), a coherent structure has been found, in which the phase between the integrated midlatitude magnetic flux is ahead of the total solar irradiance on the timescales of the surface rotation. 1. Introduction The minimum of the solar activity separating the activity cycles 23 and 24 is often called ¡°an unusual minimum.¡± For comparison, during the previous minimum, the lowest annual sunspot number was 8.6 in 1996. During the latest minimum, the annual sunspot number reached lower values: 7.5, 2.5, and 3.1 in 2007, 2008, and 2009, respectively. A typical minimum lasts for about 486 spotless days (http://spaceweather.com/), but since 2004, as many as 821 spotless days were observed. Woods [1] studied the irradiance during the latest solar cycle minimum and compared it with the previous minimum in 1996. He found that the solar irradiance was lower during the latest minimum. Thus, the total solar irradiance (TSI) was smaller in 2008 than that in 1996 by about 200£¿ppm. The irradiance measured with the SOHO Solar EUV Monitor (SEM) at 26 to 34£¿nm was by about 15% lower in 2008 than that in 1996. This EUV decrease could be explained by the abundance of low-latitude coronal holes during the latest cycle minimum. It is known that variations of the sunspot activity during a solar cycle occur because of the generation of the magnetic flux in the convective zone. The magnetic flux is produced by dynamo processes and moves to the solar surface on account of magnetic buoyancy. The emerged magnetic flux impacts the solar luminosity, causing its cyclic behavior. However, the relationship between the magnetic flux and solar irradiance is
%U http://www.hindawi.com/journals/jas/2013/368380/