Maximal growth rate of the ascending phase of a sunspot cycle for predicting its amplitude

Forecasting the solar cycle amplitude is important for a better understanding of the solar dynamo as well as for many space weather applications. We demonstrated a steady relationship between the maximal growth rate of sunspot activity in the ascending phase of a cycle and the subsequent cycle amplitude on the basis of four data sets of solar activity indices: total sunspot numbers, hemispheric sunspot numbers from the new catalogue from 1874 onwards, total sunspot areas, and hemispheric sunspot areas. For all the data sets, a linear regression based on the maximal growth rate precursor shows a significant correlation. Validation of predictions for cycles 1-24 shows high correlations between the true and predicted cycle amplitudes reaching r = 0.93 for the total sunspot numbers. The lead time of the predictions varies from 2 to 49 months, with a mean value of 21 months. Furthermore, we demonstrated that the sum of maximal growth rate indicators determined separately for the north and the south hemispheric sunspot numbers provides more accurate predictions than that using total sunspot numbers. The advantages reach 27% and 11% on average in terms of rms and correlation coefficient, respectively. The superior performance is also confirmed with hemispheric sunspot areas with respect to total sunspot areas. The maximal growth rate of sunspot activity in the ascending phase of a solar cycle serves as a reliable precursor of the subsequent cycle amplitude. Furthermore, our findings provide a strong foundation for supporting regular monitoring, recording, and predictions of solar activity with hemispheric sunspot data, which capture the asymmetric behaviour of the solar activity and solar magnetic field and enhance solar cycle prediction methods.Comment: 11 pages, 11 figures, accepted for publication in the Astronomy & Astrophysic

Sustainable independent tourism: the role of the information and communication technologies

This paper focuses on the role of information and communication technologies (ICT) in the sustainable independent tourism and hospitality. Moreover, it attempts to identify emerging trends in tourism of the 21st century. Nowadays, tourism has become more independent on large travel agencies and package tours and this transition has been caused by the development of Internet and information technologies. Most recently, the rise of the sharing economy had an array of important implications for the tourism sector with such digital platforms as Uber, Airbnb, Gett, Lyft, TripAdvisor, Expedia or Booking.com replacing the traditional ways to travel. Surely, independent tourism is not for everyone and might be restricted to small groups of people. However, it is crucial for sustainable development in tourism and hospitality sector due to the fact that it can replace massive tourism and limit the extent of overtourism in many popular destinations