A Dynamic Analysis of the Role of the Planetary- and Synoptic-Scale in the Summer of 2010 Blocking Episodes over the European Part of Russia

Abstract

During the summer of 2010, an unusually persistent blocking episode resulted in anomalously warm dry weather over the European part of Russia. The excessive heat resulted in forest and peat fires, impacted terrestrial ecosystems, greatly increased pollution in urban areas, and increased mortality rates in the region. Using the National Centers for Atmospheric Research (NCAR), National Centers for Environmental Prediction (NCEP) reanalysis datasets, the climatological and dynamic character of blocking events for summer 2010 and a precursor May blocking event were examined. We found that these events were stronger and longer lived than typical warm season events. Using dynamic methods, we demonstrate that the July 2010 event was a synoptic-scale dominant blocking event; unusual in the summer season. An analysis of phase diagrams demonstrated that the planetary-scale did not become stable until almost one week after block onset. For all other blocking events studied here and previously, the planetary-scale became stable around onset. Analysis using area integrated regional enstrophy (IRE) demonstrated that for the July 2010 event, synoptic-scale IRE increased at block onset. This was similar for the May 2010 event, but different from case studies examined previously that demonstrated the planetary-scale IRE was prominent at block onset.

The Predictability of Northern Hemispheric Blocking Using an Ensemble Mean Forecast System

“…his value can be used as a mesure of predictability, higher values correspond to a lesser degree of predictabilty or possibly the transitioning of atmospheric flow, while lower values correspond to a greater degree of predictability in a more stable flow configuration (e.g., Lupo et al, 2012;Jensen and Lupo, 2014). In order to calculate this quantity, the geostrphic vorticity, = ∇ was used and differentials were calculated using second order finite differencing over a 20° latitude by 20° longitude grid box encompassing the center of the blocking event.…”

“…Also, the work of [4,7], and many other studies examined the persistent and severe summer heat wave of 2010 over Eastern Europe and Russia. There were more than 50,000 deaths in Russia alone including more than 1600 people who drowned as they entered water to escape the heat.…”

“…An increase in wildfires and smog levels in major Russian cities led to severe illness as well. The heat wave was the result of three atmospheric blocking events that covered the Euro-Russian region lasting from late June to mid-August [7]. The low predictability of the models caused the under forecasting for extreme surface temperatures, and the timing for the decay and maintenance of the blocking events [4].…”

The Occurrence of Extreme Monthly Temperatures and Precipitation in Two Global Regions

“…Here two case studies of extremely warm events from the central USA are examined as researchers have long associated ridging and blocking with cold periods (e.g., Quiroz, 1984;Jensen, 2015). Also, Lupo et al (2012b) studied the summer of 2010 drought that impacted western Russia, including the Belgorod region, which was due to strong and persistent blocking. Studying warm extremes in the cUSA has not been performed recently, although anomalous summer season warmth was studied previously (Namias, 1982(Namias, , 1983Lupo and Bosart, 1999).…”

“…Studies of the interannual or interdecadal variability of the occurrence of extreme events is not new and has typically been accomplished using phenomenological events such as hurricanes (e.g., Zuki and Lupo, 2008a;Lupo, 2011), tornadoes (e.g., Marzban andSchaefer, 2001;Akyuz et al 2004), or blocking events (e.g., Hakkinen et al 2011;Lupo et al 2012b;Mokhov et al 2012;Abraham et al 2012). Many have examined the occurrence of extreme temperatures and how their occurrence might change in the 21st century (e.g., Birk et al 2010).…”