Regional Peculiarities of Circulation Factors and Their Influence on the Amount of Summer Precipitation in the South of the Western Siberia

Abstract

The purpose of the work is to study the characteristics of pressure fields in Siberia, which determine the variability of summer precipitation depending on the phase of the North-East Pacifi c index (EPNP). Materials and methods. The study area is a fl at territory of the Altai Territory, limited by the coordinate area (52-54º N, 81-85º E). For the selected coordinate region, a statistical analysis of time series of average monthly values of summer precipitation obtained at weather stations, as well as those constructed from grid arrays and reanalysis data on time intervals of 1966-2023, was performed. and 1979-2023. Composite maps (schemes) of the spatial distribution of the meridionality index, geopotential and streamlines of the velocity fi eld at the level of 850 hPa were constructed. Results and discussion. A statistically signifi cant relationship has been established between the amount of precipitation in the summer season on the study plain territory of the Altai Territory and the phase of the North-East Pacifi c Index (EPNP). It is shown that during the positive phase of the Northeast Pacifi c Index (EPNP) in the fl at part of the Altai Territory in the summer season, meridional processes become more active. Conclusion. It has been established that for the study area there are diff erences in the confi guration of pressure fi elds for cases of strong positive and negative phases of the Northeast Pacifi c EPNP index. Based on statistical analysis of data from weather stations, grid arrays and reanalysis, it is shown that for the study area, under the conditions of the positive phase of the EPNP circulation index, the amount of summer precipitation is greater than under the conditions of the negative phase of this index.