It has recently been suggested that the solar irradiance has varied in phase with the 80- to 90-year period represented by the envelope of the 11-year sunspot cycle and that this variation is causing a significant part of the changes in the global temperature. This interpretation has been criticized for statistical reasons and because there are no observations that indicate significant changes in the solar irradiance. A set of data that supports the suggestion of a direct influence of solar activity on global climate is the variation of the solar cycle length. This record closely matches the long-term variations of the Northern Hemisphere land air temperature during the past 130 years.

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The large‐scale patterns of ionospheric convection and particle precipitation are described during two intervals of steady magnetospheric convection (SMC) on November 24, 1981. The unique data set used in the analysis includes recordings from the worldwide network of magnetometers and all‐sky cameras, global auroral images from the DE 1 spacecraft, and particle precipitation data from low‐altitude NOAA 6 and NOAA 7 spacecraft. The data show that intense magnetospheric convection continued during more than 10 hours under the steady southward interplanetary magnetic field without any distinct substorm signatures. All data sets available confirmed the stable character of the large‐scale magnetospheric configuration during this period. In particular, the magnetic flux threading the polar cap was stable (within 10%) during 3.5 hours of continued DE 1 observations. The dayside cusp was located at an unusually low latitude (70° CGL). The nightside auroral pattern consisted of two distinct regions. The diffuse aurora in the equatorward half of the expanded (10° wide) auroral oval was well‐separated from the bright, active auroral forms found in the vicinity of the poleward boundary of the oval. The twin‐vortex convection pattern had no signature of the Harang discontinuity; its nightside “convection throat” was spatially coincident with the poleward active auroras. This region of the auroral oval was identified as the primary site of the short‐lived transient activations during the SMC intervals. The energetic particle observations show that the auroral precipitation up to its high‐latitude limit is on closed field lines and that particle acceleration up to > 30‐keV energy starts close to this limit. The isotropic boundaries of the > 30‐keV protons and electrons were found close to each other, separating regions of discrete and diffuse precipitation. This suggests that these precipitation types originate on the very taillike and very dipolelike field lines, respectively.

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