The Relationship between Atmospheric Blocking and Precipitation Changes in Turkey between 1977 and 2016

The precipitation is analyzed from different perspectives for Turkey including the spatio – temporal analysis of precipitation, drought analysis by using precipitation and linkage between North Atlantic Oscillation and precipitation. On the other hand, the effects of atmospheric blocking on precipitation has not been studied in depth for Turkey. In this paper relationship between blocking and precipitation observations in Turkey is investigated. The 500 hPa geopotential height data of National Centers for Environmental Prediction (NCEP) and National Center for Atmospheric Research (NCAR) Reanalysis-1 dataset for 1977 – 2016 were used to detect atmospheric blocking events. The daily total precipitation data were obtained from Turkish State Meteorological Service for the same period. The blocking index used here is a one – dimensional atmospheric blocking detection method. Besides detecting the atmospheric blocking, its characteristics as blocking intenstiy, duration and longitudinal extent is calculated for the domain 20 ^oN – 90 ^oN and 340 ^oW – 90 ^oE. Our preliminary results show that the the mean daily total precipitation for winter is more than 10 mm/day in the vast majority cities that are in Black Sea coastline. In summer, the mean daily total precipitation is again highest in the coastal line of Black Sea with the values of greater than 2.8 mm/day. The coastal line of Black Sea has also greater mean daily total precipitation in spring and autumn. Rize is the most rainy station during blocked days in all seasons.