A5074649638- Solar and Space Plasma Dynamics
- Geomagnetism and Paleomagnetism Studies
- Ionosphere and magnetosphere dynamics
- Geophysics and Gravity Measurements
- Historical Astronomy and Related Studies
- History and Developments in Astronomy
- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Earthquake Detection and Analysis
- Climate variability and models
- Archaeology and ancient environmental studies
- Atmospheric chemistry and aerosols
- Colonialism, slavery, and trade
- Meteorological Phenomena and Simulations
- Impact of Light on Environment and Health
- Solar Radiation and Photovoltaics
- Historical and Architectural Studies
- Architecture and Art History Studies
- Tree-ring climate responses
- earthquake and tectonic studies
University of Oulu
2021-2025
St Petersburg University
2012-2022
Astronomy and Space
2022
University Centre in Svalbard
2021
Abstract The polar stratosphere in the Northern Hemisphere influences wintertime surface weather across Eurasia, Eastern Canada, Middle East, and United States. This influence is pronounced following sudden stratospheric warmings (SSWs), during which vortex displaced from pole or collapses. impacts vary considerably are challenging to predict. Here, we study extratropical temperature anomalies winters with without SSW. Our analysis reveals a statistically significant impact of SSWs observed...
<title>Abstract</title> Sunspot engravings made in the Maunder minimum are used to evaluate fine structure of sunspots. Based on 78 images full solar disk and 77 individual sunspots, we have evaluated ratio penumbral-to-umbral area (P/U) be 4.16 ± 2.5 3.84 2.3, respectively. These estimates consistent with previous studies sunspots during after P/U largest sunspot groups cycle 24.
Energetic Electron Precipitation (EEP) has been shown to influence wintertime stratospheric dynamics through the production of NOy species, which subsequently deplete ozone in lower mesosphere and upper stratosphere. It previously that EEP can occurrence probability sudden warmings (SSWs) where polar vortex breaks. Here we show also influences evolution during after SSWs.These results indicate incorporating into climate forecast models potentially enhance predictability their on surface...
In Arctic countries, a large fraction of wintertime electricity consumption is used for heating spaces and, thus, the highly sensitive to outside temperature variations. Also, production by wind turbines depends directly on surface speed. Wintertime weather in Northern Europe significantly influenced state stratospheric polar vortex, westerly pattern circulating region during winter. When vortex strong (weak), winter temperatures are more likely mild (cold) and speeds higher (lower)...
Abstract The OMNI database is formed by propagating the solar wind measured at around Lagrange point L1, whose result may differ from actual in vicinity of bow shock nose. To test quality database, we cross‐correlate 2‐hr intervals 1‐min interplanetary magnetic field (IMF) data provided mostly ACE and WIND spacecraft with Geotail measurements front (10,409 cases 1997–2016). We used two metrics: Pearson correlation coefficient ( CC ) prediction efficiency PE ). Confirming previous studies,...
We review observations of solar activity, geomagnetic variation, and auroral visibility for the extreme storm on 1872 February 4. The (referred to here as Chapman-Silverman storm) apparently originated from a complex active region moderate area (\approx 500 {\mu}sh) that was favorably situated near disk center (S19{\deg} E05{\deg}). There is circumstantial evidence an eruption this at 9--10 UT 3, based location, complexity, evolution region, reports prominence activations, which yields...
Abstract. Svalgaard (2014) has recently pointed out that the calibration of Helsinki magnetic observatory's H component variometer was probably in error published data for years 1866–1874.5 and this makes interdiurnal variation index based on daily means, IDV(1d), (Lockwood et al., 2013a), interplanetary field strength derived from it 2013b), too low around peak solar cycle 11. We use modern Nurmijarvi station, relatively close to site original Observatory, confirm a 30% underestimation...
Abstract The polar vortex is a strong jet of westerly wind which forms each winter around the stratosphere. Sometimes, roughly every other winter, in Northern Hemisphere experiences dramatic breakdown and associated warming Such events are called sudden stratospheric warmings (SSWs) they known to have significant influence on ground weather Eurasia large parts North America. Typically, these thought occur due planetary waves propagating stratosphere where may disrupt vortex. Here, we show...
Abstract Using the list of omega structures based on Magnetometers‐Ionospheric Radars‐All‐sky Cameras Large Experiment network (Partamies et al., 2017, https://doi.org/10.5194/angeo-35-1069-2017 ), we obtained a number important statistical characteristics describing surface magnetic field. Based 438 events, typical variations associated with passage single were obtained. The variation, using superposed epoch analysis, is local bending westward electrojet and statistically confirms...
Abstract Digital images of sunspot drawings the archives Georg Christoph Eimmart stored at National Library Russia, St. Petersburg, are analyzed to obtain sunspot-group numbers and areas as well heliographic positions. Overall, more than a hundred were processed. The impact drawing reproduction uncertainties aims historical observations considered. positions compared those reported by contemporary observers Maunder minimum. restored latitudes extracted Hoyt Schatten ( Solar Phys . 179 , 189,...
The interplanetary magnetic field (IMF) is the of Sun stretched out by solar wind. polarity IMF either positive or negative according to original field. equivalent ionospheric Disturbance Polar current powered azimuthal Y component system located at polar latitudes and provides specific geomagnetic variations. It known that configuration this depends on IMF. Thus, in absence direct data presatellite era, sector structure could only be inferred from ground‐based observations (Svalgaard,1968;...
In this paper, we propose a modified procedure to infer the interplanetary magnetic field (IMF) polarities from geomagnetic observations. It allows identify polarity back 1905. As previous techniques it is based on well‐known Svalgaard‐Mansurov effect. We have improved quality and accuracy of inference compared with results Svalgaard (1975) Vennerstroem et al. (2001) by adding new stations extracting carefully diurnal curve. The data demonstrates an excess one two IMF sectors within...
Abstract The interplanetary magnetic field (IMF) B y component affects the configuration of field‐aligned currents (FAC) whose geomagnetic response is observed from high to low latitudes. ground perturbations induced by FACs are opposite on dawnside and duskside depend upon IMF polarity. Based multilinear regression analysis, we show that this effect presented at midlatitude observatories, Niemegk Arti, in X Y components field. This allows us infer sector structure old records made...
Abstract Historical sunspot records provide piece by more information on solar variability a centennial scale. In this work, we analyze observations from the archives of Georg Christoph Eimmart, which is second-richest data set Maunder minimum after Paris observatory. Comparing dates blank disk database Hoyt & Schatten (1998) with at Eimmart observatory, find that spotless days reports originate astrometric observations. A comparison La Hire and Müller 1719 suggests were for purposes as...
Abstract In 1612, Galileo Galilei made very accurate drawings of the solar disk. Currently, 47 them are in open access: 9 May 3 – 11, 35 June and July, late August. Unfortunately, reports have not provided clock time, which results uncertainty sunspots heliographic coordinates. present study, we determine exact time by comparing positions same spots from day to day. The observations, varies 12 16 UT, gives us direction rotation axis position helioequator. Unlike drawn Christopher Scheiner...
Abstract This paper discussed whether 17 th Century observers left historical records of the plasma tails comets that would be adequate to enable us extract physical parameters solar wind. The size aberration angle between a comet’s tail and its radius-vector defines type tail: or dust. We considered Bredikhin’s calculations for 10 comet observed during Maunder minimum (1645 – 1715). For those tail’s axis on average exceeded value 10° is typical dust tails. It was noted visual observations...