52 citations · 104 across the 8 of their papers we have counts for
8 papers
The ratio between the number of sunspot and the number of sunspot groups
K. Georgieva, A. Kilcik, Yu. Nagovitsyn +1
Data from three solar observatories, Learmonth, Holloman, and San Vito, are used to study the variations in the average number of sunspots per sunspot group. It is found that the d…
About the recalibration of the sunspot record
Katya Georgieva, Ali Kilcik, Yury Nagovitsyn +1
In 2015 the calculation of the International (Zurich) sunspot number was cancelled, and it was replaced by a new "recalibrated" series. A new data series was proposed also for the…
What causes geomagnetic activity during sunspot minimum
Boian Kirov, Simeon Asenovski, Katya Georgieva +1
The average geomagnetic activity during sunspot minimum has been continuously decreasing in the last four cycles. The geomagnetic activity is caused by both interplanetary disturba…
Solar magnetic fields and terrestrial climate
Katya Georgieva, Yury Nagovitsyn, Boian Kirov
Solar irradiance is considered one of the main natural factors affecting terrestrial climate, and its variations are included in most numerical models estimating the effects of nat…
Solar dynamo and geomagnetic activity
Katya Georgieva, Boian Kirov
The correlation between geomagnetic activity and the sunspot number in the 11-year solar cycle exhibits long-term variations due to the varying time lag between the sunspot-related…
Does human activity widen the tropics?
Katya Georgieva, Boian Kirov
The progress article - Widening of the tropical belt in a changing climate - by Seidel et al. (2008) published in the first issue of Nature Geosciences, summarizes the results of s…