I. I. Ippolitov

Relation of anomalous atmospheric conditions to electric field variation

Aerosol influence on strength value of atmospheric electric field in near-ground layer, based on in-situ measurements data, has been analyzed. The peculiarities of electrooptical relations in haze and smoke haze, cased by forest fires in summer, and through aerosol accumulation in near-ground layer at temperature inversion occurrence in winter, have been studied. The reasons of the revealed differences in the influence of smoke haze of various origin on atmospheric electric field value have been discussed.

Climate variability over the Asian territory of Russia during 1975–2012

Observational data for 1975–2012 have been used in analyzing the formation of air temperature and atmospheric pressure fields over the Asian territory of Russia (ATR). The climatic trends at the end of the 20th — beginning of the 21st centuries for the ATR as a whole as well as for its separate regions were assessed through comparison of temperature and pressure variability indices for two time intervals: 1975–2005, and 1982–2012. It was established that climatic changes during 1982–2012 continued to manifest themselves in a rise of mean annual surface air temperature; however, the warming process was less intense than during 1975–2005. A large role in the decrease of the temperature growth rates is played by the winter months when the warming process is replaced by the cooling process. Furthermore, the latter time interval showed a tendency for an increase in pressure.

Connections between climatic characteristics and cyclonic activity in winter over Siberia in 1976–2011

The temperature, surface pressure, and cloud cover for Siberia (50°–70° N; 60°–110° E) in the winter period (December–February) are estimated over 1976–2011 based on data from 163 meteorological stations. Using surface synoptic maps, time series of winter cyclone characteristics, such as the total number and central pressure, are derived for the same period. Two time intervals are found in variations of climatic characteristics and cyclone activity characteristics: 1976–1990 and 1991–2011. In the first period, the temperature and cloud cover increased and the surface pressure fell, which reduced the number of cyclones and intensified (deepened) them. In the second period, opposite trends took place. The correlation analysis between the climate variables and cyclonic activity characteristics allowed us to consistently describe the impact of cyclones on the surface pressure and cloudiness.

Influence of radiation and circulation factors on climate change in Western Siberia at the end of the 20th century and beginning of the 21st century

An analysis of the air-temperature and atmospheric-pressure fields in Western Siberia is performed based on observations in 1976–2014; a comparison of temperature and pressure variability in two temporal intervals, 1976–2005 and 1985–2014, is carried out. The estimation of contributions from such climate-forming factors as radiation and circulation is performed for the same intervals. It is revealed that an increase in the annual mean ground–air temperature in the investigated region of Western Siberia was still taking place in the period of 1985–2014; however, the warming process was less active than in the 1976–2005 period. Winter months play the largest role in decreasing the temperature growth rate; during these months, the warming process was replaced by a cooling one in the second time interval. It is shown that the circulation factors, that is, the mechanisms described by indices of global circulation, played the dominant role in the period from 1985 to 2014.

Forecasting estimates of surface air temperature changes by the wavelet transformation method

Analysis of a series of average annual surface air temperature (SAT) shows that they consist of three major components: a long-term trend, a set of harmonic components, and anomalies whose characters are close to a random process. We propose to use wavelet transformation of the source series to set aside quasi-periodic fluctuations. In this case, the distribution of the transformation coefficients enables one to set aside fluctuations of various scales, both the ones that are almost harmonic and those characterized as nonstationary fluctuation process. Then, forward extrapolation is performed by wavelet transformation coefficients for the set-aside scales in view of their temporal dynamics. The series’ fluctuation component is restored by inverse wavelet transformation. The proposed approach is demonstrated by the example of average annual SAT series registered by stations in the towns of Syktyvkar and Tomsk with an instrumental observation period of more than 100 years.

Analysis of interannual oscillations of the surface air temperature in the cities of Tomsk and Irkutsk and their relation to some geophysical processes

Time series of the surface air temperature for Tomsk and Irkutsk over a period of 1881-1995 were investigated using wavelet transformations. In both time series the oscillation structures of the scales of 3 - 7; 8 - 12; 13 - 24; 28 - 40; 50 - 64 years were found out. Simultaneously, we analyzed the series of the South Oscillation Index (SOI), the geomagnetic planetary index Ap, the Wolf numbers W, the critical frequencies of the F2 layer of the ionosphere foF2. We also performed a correlation analysis both of the series of the considered values and the periodicities of various scales. The significant correlation for the series taking on the value of 0.69 is observed only between the surface temperature series. A significant anticorrelation was found between the temperature oscillations and the SOI in the scales of the order of 22 years. A positive correlation occurred for the temperature and Ap in the scale of 30 years, and for the temperature and W over a period of 22 years.

Influence of total ozone content and cloudiness on scattered UV radiation fluxes on the Earth's surface

Correlation between total ozone content and scattered UV fluxes (A and B portions) measured in Tomsk (56.6N, 85E) during 1994 - 1998 has been investigated. It was shown that for the data corresponding to cloudless days the regression curve may be satisfactorily described both by exponential and linear dependence. With the cloudy days included the correlation decreases. There is no correlation between UV-A and UV-B fluxes when taking into account the observations at any cloudiness.