We studied the possibility to apply the ionospheric electric potential (EP) as a parameter describing the effects of solar activity on the troposphere. EP was calculated using the semi-empirical model where the potential spatial distribution is determined by solar wind and interplanetary magnetic field parameters, and AL index of geomagnetic activity for 1975– 2019. It has been shown that EP can be used as an indicator of solar activity to study correlation of long-term EP variations and tropospheric parameters. The revealed similar trends in long-term EP and near-surface temperature variations suggest that the changes in climate system parameters are induced by slower changes in large-scale magnetic field of the Sun. The performed analysis of EP and near-surface temperature correlation maps revealed that natural tropospheric conditions impose their influence on spatial distribution of tropospheric response to solar impact.
Based on observational data, we studied the spatial structure of relation of the sea surface temperature and upper 100- meter ocean layer heat contents with variations in geomagnetic activity. It has been shown that geomagnetic activity contributes significantly to the total temperature variability on time scales greater than 12 months. The enhanced temperature response to geomagnetic activity is observed in regions of surface ocean currents for the periods of the solar poloidal field negative polarity. Variations of the solar poloidal field are the essential factor impacting climatic characteristics. This impact is underconsidered in geomagnetic indices describing activity of the Earth's magnetic field that is basically related to dynamic processes on the Sun.
Based on data from the Met Office Hadley Centre, we studied variations in heat content of the upper active layer (UAL) at middle and high latitudes of the World Ocean using the method of empirical orthogonal functions (EOF). The maximum contribution to the UAL heat contents is provided by the first harmonic that refers to seasonal variations. We analyzed features of spatial distribution of the UAL heat content seasonal variations for the first few EOF modes. Meridional structures are descriptive of the first harmonic. One can observe the first vector maxima in the Atlantics south-western part and in the zone of its eastern coast, and in the Pacific north-western part. Differences in thermal regime between the Atlantics and Pacific western and eastern parts may be due to radiation heating and systems of warm currents. The second and third harmonics have zonal structures.
It has been shown, on the basis of observational data, that under the change in the level of solar activity, well-formed changes are observed in the field of velocities in lower atmospheric layer and in the ocean. The changes depend on the season and the solar activity level. Increased solar activity is followed by amplification of circulation at 10-meter level and changing of wind stresses in most regions. In this case, oceanic surface currents change too. Specifically in September– October, the pre-equatorial current is significantly enhanced in the western part of Pacific and weakened in the eastern part of it.
Based on classification of macrosynoptic processes by Wangenheim – Girs and B.L. Dzerdzeevskii, we analyzed atmospheric circulation of the Northern hemisphere extratropical latitudes for different levels of geomagnetic activity. It has been shown that under quiet geomagnetic conditions, meridional circulation enhances, which generates northern blocking processes on the hemisphere. During geomagnetic disturbances, circulation processes grow stronger causing intense cyclonic activity that is related to the transition of southern cyclones to the middle and high latitudes. Cyclonic circulation leads to a decrease in correlation and increase in anticorrelation between the outgoing longwave radiation and near-surface temperature in winter.
Based on observational data, we analyzed seasonal variations of the outgoing longwave radiation at the outer boundary of the atmosphere and air temperature near the Earth's surface. It has been shown that under quiet geomagnetic conditions, there is positive annual average correlation between the outgoing longwave radiation and near-surface temperature at latitudes higher than 30°. In the seasonal course, this dependence remains, with the exception of the winter period. At low latitudes, the outgoing longwave radiation correlates with the near-surface temperature above land, and over the oceans these characteristics are anticorrelated throughout the year.
Based on NCEP/NCAR reanalysis, variations in the integral absorption function and outgoing long-wave flux for cloudless atmosphere during heliophysical disturbances were studied. In our calculations, we used parametrization of the long-wave outgoing radiation for a simple semi-empirical radiation model. The mechanism of solar effect on the troposphere, which is being developed in the ISTP SB RAS, was taken into account. For comparative analysis, distribution maps of radiation characteristics and tropospheric temperature were plotted. Similarity was shown between the spatial structure of temperature field, integral absorption function and the outgoing long-wave flux. Correlation between the temperature and integral absorption function, as long as anticorrelation between the temperature and outgoing long-wave flux might prove validity of the employed parametrization of the mechanism of solar effect on the troposphere.
Based on NCEP/NCAR reanalysis data, we investigated changes in temperature spatial distribution during geomagnetic disturbance considering moisture content in the atmosphere. As a characteristic representing the external impact effectiveness, we suggested the impact index that accounts for both strength of geomagnetic disturbance and water vapor content in the atmospheric column. Similarity between changes in spatial structure of the external impact index and temperature is shown.
We analyzed variations of the vertical humidity profile in warm and cold sectors of extratropical cyclones of both hemispheres in their evolution during geomagnetic disturbances in minimum solar activity. Position and movement of cyclones was detected using temperature and baric charts at the 500 hPa level. The cyclones for analysis were selected provided that the moment of geomagnetic disturbance onset and time of cyclone emergence coincided. We revealed that during geomagnetic disturbances, conditions are created that lead to increased temperature in cyclone warm sector, cold sector warming slower. Consequently, the temperature gradient persists at the heights below 300 hPa between the sectors, which can result in cyclone growth. It is shown that, in the process of emergence and development of extratropical cyclones during geomagnetic disturbances, humidity changes reflect physical mechanisms of relationship between temperature and humidity in both sectors of the cyclones.
We study variations in the vertical temperature profile in central parts of warm and cold sectors of extratropical cyclones which emerge and evolve in the Northern Hemisphere during solar minimum. Dynamics of the vertical temperature profile during cyclogenesis over the land and ocean under quiet and disturbed geomagnetic conditions is analyzed. The classic cyclolysis occur under quiet geomagnetic conditions; the temperature decreases in the warm sector and increases in the cold one at a level up to 300 hPa. Under disturbed geomagnetic conditions, there is a slow increase in temperature in the cold sector. The warm sector of the cyclone is characterized by a small increase and stabilization of temperature, which perhaps results in slow cyclolysis and in increased lifetime of cyclones.
A water vapor is the most important greenhouse gas in the atmosphere. Therefore, variations of the water vapor content
can be one of the important factors determining observable changes of a climate. Based on NCEP/NCAR Reanalysis data
(http://www.cdc.noaa.gov/), a complex analysis of humidity and air temperature is carried out at standard isobaric levels
at middle and high latitudes in the Northern hemisphere. It is shown that atmospheric water vapor variations are
produced, for the most part, by air temperature variations caused by radiation balance variations.
Long-time variations of the minimal (night), maximal (daytime) surface air temperatures and the daily amplitude of the
air temperature are researched in middle and high latitudes of the northern hemisphere in the second half of the 20th
century. Rise of extreme air temperatures and the decrease of daily variation are determined starting from 1970-s of the
last century. The largest changes both of extreme values and the daily variation value are registered in continental
regions at middle latitudes of the northern hemisphere and, in particular, in Siberia and at high latitudes during the winter
season. It is determined that the increase of average daily temperature of the air takes place generally because of the
increase of minimal temperature of the air. Comparison of extreme temperatures changes of the air and the daily
variation amplitude with geomagnetic activity variations at high latitudes has been carried out. It is shown that the
major part of observed changes is caused by the solar activity influence, which is not considered by the contemporary
climate models.
In the last decade a special attention has been paid to study of variability of atmospheric electricity parameters. The
reason is that the atmospheric electricity can be considered as a connecting link between solar activity variations and
climatic characteristics of the troposphere. On the one hand, the atmospheric electricity parameters are affected by
heliophysical and meteorological parameters such as intensity of galactic cosmic rays, atmospheric circulation, pressure
and temperature, as well as underlying surface conditions. On the other hand, they can influence the atmosphere
distribution of charged aerosols and condensation nuclei that act upon water phase state, cloudiness, and thereby, the
atmosphere radiation balance. The data of measurement of atmospheric electricity parameters at high-mountain stations
are of special interest and significance because these stations are situated above the mixing layer, so this make it
possible to obtain a reliable information about the global electric circuit. The results are presented of the measurements
and study of the atmospheric electricity parameters such as electric field intensity E and conductivity λ at high-mountain
stations (Khulugaisha, 3000 m above S.L., Chasovye Sopki, 2000 m above S.L.), as well as the global and
local components of the diurnal variation and their seasonal variations.
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