Let me try to say things a bit more clearly. Reconstruction of the EUV flux is on solid ground based on the range of the diurnal variation, rY, of the Geomagnetic East Component: The process is described

Consider a one step forward looking model where agents have beliefs about the law of motion of the system, and their forecast for the next period is made with knowledge of the past values of the state variable but not the current value, and is allowed to depend on the current realization of an extrinsic random process. The paper provides (and characterizes) the conditions for the existence of s...

We study the annual frequency of occurrence of intense geomagnetic storms (Dst < )100 nT) throughout the solar activity cycle for the last three cycles and ®nd that it shows di€erent structures. In cycles 20 and 22 it peaks during the ascending phase, near sunspot maximum. During cycle 21, however, there is one peak in the ascending phase and a second, higher, peak in the descending phase separ...

The infrared spectrum of hot water observed in a sunspot has been assigned. The high temperature of the sunspot (3200 K) gave rise to a highly congested pure rotational spectrum in the 10-micrometer region that involved energy levels at least halfway to dissociation. Traditional spectroscopy, based on perturbation theory, is inadequate for this problem. Instead, accurate variational solutions o...

Forward-looking monetary models with Taylor-type interest rate rules are known to generate indeterminacies, with a potential dependence on extraneous “sunspots,” for some structural and policy parameters. We investigate the stability of these solutions under adaptive learning, focusing on “common factor” or “resonant frequency” representations in which the observed sunspot has a suitable time-s...

Monthly averages of the sunspot number visible on the sun, observed from 1749, Zurich Observatory, and from 1848 other observatories, have been analyzed. This time signal presents a frequency power spectra with a clear 1/f behavior with α ≃ 0.8±0.2. The well known cycle of approximately 11 years, clearly present in the spectrum, does not produce a sensible distortion of that behavior. The event...

We examine stability under learning of sunspot equilibria in Real Business Cycle type models with indeterminacies. Our analysis emphasizes the importance of examining alternative representations of sunspot solutions. A general bivariate reduced form contains parameter regions in which sunspots are stable under learning. However, for parameters restricted to those generated by standard models of...