ON THE SPATIAL LOCALIZATION OF ATMOSPHERIC JET STREAM CORES

Tropopause-level jet streams are an integral part of the atmospheric general circulation and play a role in the formation of the Earth's weather and climate, and are also an object of continuous monitoring for aviation weather services of all countries. The initial and important stage of exploration jet streams includes reliable determination of their characteristics, the main ones being the latitudinal position and intensity. A simple and universal method for identifying the jet stream core in three-dimensional space containing wind data at nodes with a regular grid is proposed. The searching algorithm of wind speed maxima related to the core of the jet stream takes into account areas with a jet deviation from the west-east direction through the ratio of the zonal component of the wind speed to its absolute value. Using reanalysis fields, the position of the Northern Hemisphere jet stream cores is given at one of the synoptic hour with estimates of the intensity of individual sections of the jet. To analyze and identify differences in jet stream regimes, latitude-longitude and latitude-altitude frequency distributions were constructed for December 2010 and 2020. It is shown that three-dimensional analysis, in particular, identifying cores in highly curved sections of jet streams, allows for a more detailed determination of characteristics such as branching, merging, degree of meandering, and intensity.