TRENDS IN EXTREME ANOMALIES IN METEOROLOGICAL VALUES IN THE NORTHERN HEMISPHERE AT THE BEGINNING OF THE 21st CENTURY

This study estimated the spatial and temporal distribution of non-Gaussian climate anomalies in the Northern Hemisphere for 1979–2018, and determined characteristics and trends in time series, including synoptic-scale variability.

Time series of meteorological parameters were used from the Era Interim reanalysis with a spatial resolution of 1.125°×1.125° and a 6-hour time step at the levels of 1000 hPa and 500 hPa (TS). According to [7], from the TS series, synoptic scale variability with a duration of 2–7 days (SV) was determined. From the TS and SV series anomalies of meteorological parameters were derived: air temperature (t'), specific air humidity (q'), wind speed components (zonal - u', meridional - v' and vertical - ω') and geopotential (Φ ').

Areas with the maximum number of anomalies in climatic parameters are located, as a rule, predominantly over the continents: in winter - the northern part of the Far East and North America, as well as in the Siberian region; in summer - at low latitudes. The exception is the anomalies of vertical wind speed, which are located mainly over the oceans (mid-latitudes of the Pacific and Atlantic oceans, near the Kuroshio and Gulf Stream currents, subpolar gyres).

The application of R/S analysis within the framework of our study made it possible to establish that the identified trends will be stable (persistent processes H>0.72) in the above regions and in the ocean areas of the Russian Arctic. At the same time, the number of regions with antipersistent processes (H<0.33) decreases. Synoptic-scale anomalies are more predictable in comparison with the anomalies in the initial time series.