**Blocking Systems Persist over North Hemisphere and Its Role in Extreme Hot Waves over Russia During Summer 2010**

Yehia Hafez

*Cairo University, Faculty of Science, Department of Astronomy, Space Science and Meteorology Egypt* 

#### **1. Introduction**

136 Atmospheric Model Applications

Wang, & Magnusdottir, G. (2006). The ITCZ in the central and eastern Pacific on synoptic

Atmos. Sci., 67,1247-1260.

timescales. Mon. Wea. Rev., 134,1405-1421. Wang, C.-C., Chou C., & Lee, W.-L. (2010). The breakdown and reformation of the ITCZ in a moist atmosphere. J. of

> The 2010 Northern Hemisphere summer included severe heat waves that impacted the European continent as a whole, along with parts of, Russia during June, July and August 2010. The 2010 summer heat wave over several parts of Russia was extraordinary, with the region experiencing the warmest July since at least 1880. During summer 2010 all of Europe lies under controlling of blocking systems that persist long time. The formation, persistence, and the role played by blocking systems in abnormal weather and climate in the northern hemisphere challenged in several scientific literatures (e.g; Rex,1951; Namias, 1964, 1978; Dickson & Namias,1976; Dole, 1983); Hafez, 1997; Lejenas, 1989; Cohen, et al., 2001; and recently Hafez, 2008b and 2011). For heat waves, (Stott et al., 2004), for the 2003 western European heat wave, they found that, human influences are estimated to have at least doubled the risk for such an extreme event. Other boundary forcing also contributed to the 2003 European heat wave, including anomalous sea surface temperatures (SSTs) (Feudale & Shukla, 2010). (Dole et al., 2011) studied the 2010 northern hemisphere summer to explore whether early warning could have been provided through knowledge of natural and human-caused climate forcings. They used Model simulations and observational data to determine the impact of observed sea surface temperatures (SSTs), sea ice conditions and greenhouse gas concentrations. They found that, analysis of forced model simulations indicates that neither human influences nor other slowly evolving ocean boundary conditions contributed substantially to the magnitude of this heat wave. Analysis of observations indicate that this heat wave was mainly due to internal atmospheric dynamical processes that produced and maintained a strong and long-lived blocking event, and that similar atmospheric patterns have occurred with prior heat waves in this region. They concluded that the intense 2010 Russian heat wave was mainly due to natural internal atmospheric variability. However, A heat wave is a prolonged period of excessively hot weather, which may be accompanied by high humidity. There is no universal definition of a heat wave, the term is relative to the usual weather in the area. Temperatures that people from a hotter climate consider normal can be termed a heat wave in a cooler area if they are outside the normal climate pattern for that area. The term is applied both to routine weather variations and to extraordinary spells of heat which may occur only once a century. Severe

Blocking Systems Persist over North Hemisphere and Its

Role in Extreme Hot Waves over Russia During Summer 2010 139

Fig. 1. The geographical map for location of Russia. [Source: climatezone.com]

Fig. 2. Shows temperature anomalies for July 20-27 relative to the average for the same dates

of precipitation, and forest fires have caused hundreds of deaths and multimillion dollars in property losses. Indirect losses of lives due to this weather anomaly, with the ensuing fires and related air pollution. In the present study the synoptic situation over Russia through 2010 summer season has been studied using of temperature and geopotential height at 500 hpa level data. Figures 3 and 4 illustrated that there positive surface air and upper level temperature at 500 hpa anomalies ( +6°C and + 3°C ) over Russia during months of 2010

2000-2008. [Source: http://earthobservatory.nasa.gov/IOTD/viewphp?id=45069]

heat waves have caused catastrophic crop failures, thousands of deaths from hyperthermia, and widespread power outages due to increased use of air conditioning (Meehl et al., 2004). The goal of the present work is to uncover the primary causes of long persistence of blocking systems over the north atmosphere and its teleconnection with the Russian hot wave in summer 2010.
