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Integrated enstrophy (IE) is the square of vorticity integrated over an entire hemisphere at a particular level in the atmosphere. Previous work has shown this quantity is correlated to the positive Lyapunov Exponent for hemispheric flow, and as such is a measure of flow stability or predictability. In this study, IE is calculated at 500 hPa over an area that encompasses 0° to 70° in the Northern Hemisphere. The data sets used were the 500 hPa initial and forecast fields for the Global Ensemble Forecasting System (GEFS) (on a 1 × 1 latitude-longitude grid) provided by the National Oceanic and Atmospheric Administration (NOAA) Weather Prediction Center (WPC) and the National Centers for Environmental Prediction/NOAA reanalyses (on a 2.5 × 2.5 latitude-longitude grid) archived in Boulder, CO. The GEFS forecast fields were provided every 24 h out to 240 h. By examining these forecasts over a year, it was found here that significant changes in the calculated IE values, as quantitatively determined, are a good predictor of flow regime transition, and 34 cases were found. We also found that the model IE forecasts identified these regime transitions reliably out to about seven days, however, the probability of detection and the skill decreased after this time. Additionally, a threshold for changes in IE was found for the cases studied here.

A number of examples for the reaction of chernozems in the center of the East European Plain and their relation to different periodical climatic changes are examined. According to unequal-age chernozems properties, the transition from the Middle Holocene arid conditions to the Late Holocene wet conditions occurred at 4000 yr BP. Using data on changes of soil properties, the position of boundary between steppe and forest-steppe and the annual amount of precipitation at approximately 4000 yr BP were reconstructed. The change from warm-dry to cool-moist climatic phases, which occurred at the end of the XX century as a reflection of intra-age-long climatic cyclic recurrence, led to the strengthening of dehumification over the profile of automorphic chernozems and to the reduction of its content in the upper meter of the soils. The leaching of carbonates and of readily soluble salts contributed to the decrease in soil areas occupied by typical and solonetzic chernozems, and to the increase in areas occupied by leached chernozems.