We analyze simultaneous, or near‐simultaneous, coregistered, digital, photometric images of solar photospheric intensity and line‐of‐sight magnetic field. Images were made with the Lockheed tunable filter instrument at the Swedish Solar Observatory, La Palma, with the video spectra‐spectroheliograph system at the San Fernando Observatory and with the new NASA spectromagnetograph at the National Solar Observatory at Kitt Peak. We study the disk center contrasts of small magnetic elements. While active region faculae are dark at disk center quiet Sun network features are bright. The populations of magnetic field elements that make up these two kinds of features are quite different. Different contrast center‐limb functions must be used when estimating their irradiance or luminosity contributions. The disk center contrasts of active region faculae are color dependent and indicate a depth effect related to the H− opacity of the facular atmosphere. This result is important for calibration of monochromatic observations of faculae to bolometric irradiance fluctuations. We emphasize the value of cooperative observations among installations whose differing strengths are complementary.
The di †usion properties of photospheric bright points associated with magnetic elements (magnetic bright points) in the granulation network are analyzed. We Ðnd that the transport is subdi †usive for times less than 20 minutes but normal for times larger than 25 minutes. The subdi †usive transport is caused by the walkers being trapped at stagnation points in the intercellular pattern. We Ðnd that the distribution of waiting times at the trap sites obeys a truncated type (power-law) distribution. The Le vy fractal dimension of the pattern of sites available to the random walk is less than 2 for the subdi †usive range and tends to 2 in the normal di †usion range. We show how the continuous time random walk formalism can give an analytical explanation of the observations. We simulate this random walk by using a version of a phenomenological model of renewing cells introduced originally for supergranules by Simon, Title, & Weiss. We Ðnd that the traps that cause the subdi †usive transport arise when the renewed convection cell pattern is neither Ðxed nor totally uncorrelated from the old pattern, as required in LeightonÏs model, but in some intermediate state between these extremes.
A simple dynamic model, truncated from the stratospheric wave–zonal flow interaction Holton and Mass model, is introduced and studied. This model consists of three ordinary differential equations controlled by two parameters: the initial amplitude of planetary waves and the vertical gradient of the zonal wind. The changes associated with seasonal variations and with the solar variability are introduced as periodic modulations of the zonal wind gradient. The major climatic response to these changes is seen through modulation of the number of cold and warm winters.
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