Bülent O. Akkoyunlu

Composition of wet deposition in Kaynarca, Turkey.

In this work, composition of wet deposition in Kaynarca, Turkey is studied by collecting precipitation samples during more than a 2-year period. August 1993-November 1995. Concentrations of the main cations Na+, Mg2+, Ca2+, K+, NH4+ and the main anions Cl-, NO3- and SO4(2-) together with pH were studied. The average pH value at Kaynarca was near neutral, 5.59. Results indicated that SO4(2-) concentration in precipitation was very high, as was Ca2+, neutralizing the acidity. Acidic wet deposition samples were generally obtained in winter. Enrichment factors for sea and soil indicate the strong effects of sea and soil, specifically limestone on the composition of precipitation. Non-sea salt fractions of SO4(2-) were found to range from 0.955 to 0.980, showing the effect of non-sea sources, especially emissions from fossil-fuel combustion, on the pH of samples. Trajectory analysis showed that cyclones originating from northwestern, central and eastern parts of Europe have generally high sulfate and nitrate concentrations and low pH.

Analyses of wet and bulk deposition in four different regions of Istanbul, Turkey

This study presents the chemical composition of wet deposition that was collected at four different regions of Istanbul, Topkapi, Bagcilar, Maltepe and Goztepe, during the period January 2001–May 2001. Bulk deposition was collected together with the wet deposition at only one station, Goztepe, during the period of January 2001–December 2001. Fifty four wet deposition samples and 21 bulk samples were collected during the study period. The mean value of pH of wet deposition samples for all regions was found to be 5.26. Results indicate that Ca2+ concentration in precipitation was high, as was SO42−, neutralizing the acidity. The mean value of the non-sea-salt fraction in the wet deposition for Ca2+ and SO42− were 98%, 91% indicating that Ca2+ and SO42− were mainly coming from sources other than sea. Difference between bulk and wet deposition of Ca2+ and SO42− was found to be highest. Those differences between bulk and wet samples with respect to the overall concentration (wet+bulk) were lower than 30% for ammonium and nitrate, while the differences of SO42−, Ca2+, Mg2+, Cl−, Na+ vary between 62% and 36%. Higher enrichment factors were found for most ions and higher correlation coefficients were obtained among most of the ions in dry and bulk deposition, in comparison with wet deposition.

Four storms with sub-events : Sampling and analysis

Analysis of ion concentration of samples taken sequentially during a storm event is important in order to reveal the relation between the atmospheric conditions and ion concentrations in each sub-event. This study presents the interrelationship among the chemical composition parameters and atmospheric variables for four storm events that were sampled in Istanbul during a) January 21-23, 2004 b) November 9-11, 2003 c) February 12-13, 2004 and d) October 27-28, 2003. These events lasted 53.3, 47.9, 27.5 and 13.2 h and the number of collected samples for each event was 22, 14, 7 and 4, in order. Generally values of pH and concentrations of ions in the first sub-events for all four cases were found higher than those of the other sub-event samples taken in sequence owing to the strong initial washout of the atmosphere by raindrops. Precipitation events a and c include rain and snow together where precipitation started as rain and continued as snow after 16th and 3rd sub-events. Higher concentration of ions in the snow in comparison with that of rain sub-events samples can be explained by more efficient below cloud scavenging of atmospheric constituents, especially aerosol particles, by snowflakes. In general, all of the ions sampled in the sub-events for four storms have variability similar to each other, with high correlation coefficient among themselves. Cl(-) and SO(4)(2-) were found to be the dominant ions in average overall sub-events. Calculated NSS concentration values of ions indicated that the main source of SO(4)(2-) was industrial and domestic emissions, most of the Ca(2+) and K(+) came from soil, nearly half of the Mg(2+) and all of the Cl(-) originated from sea.

Study of Bulk and Sub-Event Wet Deposition in Gebze, Turkey

This study presents the chemical composition of bulk deposition during the period of February 1996–May 1997 and the chemical composition of sub-event wet deposition on 13 August 1997 in Gebze. Samples were analyzed for SO42-, NO3-, Cl-,Ca2+, Mg2+, K+, Na+, and NH4+ in addition to pH. The source of some ionic components in the bulk deposition such as K+ and Ca2+ were found to be the terrestrial regions, as expected. The (non-sea Cl-)/Cl- ratio of 0.05 suggests that the very large portion of Cl- in the bulkdeposition was of marine origin. The ratio of (non-sea SO42-)/SO42- varied between 0.86 and 0.99,indicating that the main source of sulfate was not the sea. It is found that the sulfate and calcium concentrations were highest in summer and lowest in fall. The analysis of bulk deposition also indicated that nearly 24% of the events were acidic (pH < 5.6). During sub-event wet deposition collectedon the same site pH decreased continually, and during the passageof cold front concentrations of Cl-, SO42- and NO3- increased.

Relationships between teleconnection patterns and Turkish climatic extremes

This is a study on the effects of teleconnection patterns (TPs) on the extremes of temperature and precipitation over Turkey. Relationships between five teleconnection patterns, North Atlantic Oscillation (NAO), Arctic Oscillation (AO), East Atlantic-Western Russia (EAWR), East Atlantic (EA), and Scandinavian (SCA) patterns, and 11 climate extreme indices were studied by using 94 uniformly distributed meteorological stations over Turkey for the period of 1965–2014. Analyzing strong positive and negative temperature deviations from the 50-year-winter means shows that such extremes can often be explained by using AO and EAWR patterns. During the negative AO, generally more warm days occur over Black Sea (r = −0.6) and Aegean regions (r = −0.7). This phase of AO also generates above-normal precipitation in the western parts of the Anatolian Peninsula (r around − 0.5). Winter-time negative AO is mainly associated with the presence of a deepened Genoa cyclone over Italy that can transport warm and moist air mass from Mediterranean Sea towards Turkey by strong westerly winds. In contrast, positive EAWR is mainly connected to cold nights over Black Sea (r = 0.6) and Aegean regions (r = 0.6) together with positive precipitation anomalies at the seaside stations of the eastern Black Sea region. On the other hand, when positive EAWR prevails, Azores high-pressure center expands towards continental Europe bringing cold air by strong northerly winds together with higher moisture transport from the Black Sea. These results could pave the way for new possibilities regarding the projection of extremes in downscaling techniques.

DESIGN AND CONSTRUCTION OF A COMPUTER CONTROLLED AUTOMATIC SEQUENTIAL RAIN SAMPLER

ABSTRACT The preliminary goal of this study was to design, construct and apply a new automatic sequential precipitation sampling instrument. The proposed sequential sub-event sampler was designed in two sections: mechanical and electronical sections. The mechanical part includes a series of 100 mL sampling bottles on it, and a metallic body. The electronic part is composed of digital and analog sensors, various electronic material and a computer as the main controller of the system. Commands generated by the computer control the system, and the sub-event sampling period and the volume can be adjusted. Besides the volume and time controlled sampling, intelligent control and sampling is possible by developing adequate algorithms. Since the system consists of automatic sensors that can be controlled by the computer, anthropogenic errors in sampling are expected to be kept at minimum. The proposed instrument is open to development and additions can be easily made. The application phase includes collection of sequential precipitation samples, their analysis and an attempt to determine the sources of environmental pollution. The developed equipment was used to collect samples for five rain events that took place on 7 September 2007. The samples were analyzed for Na+, Mg2+, Ca2+ and K+ to obtain the temporal variation of the chemical composition during the precipitation event.

Investigation of the Variability Of So2 and Pm in the Large Cities of Turkey

This study presents the analysis of SO2 and PM concentrations that were sampled in 14 large cities of Turkey during the period of 1990–2000. In the atmosphere of these cities higher SO2 and PM levels exist than those of the other cities in Turkey. Results indicate that heating season (october-march) average concentration of SO2 for all these cities ranges between 37–404 μg/m3 and PM ranges between 72.1–158.4 μg/m3. The main reason of high SO2 and PM concentration is the low quality lignite consumption. The other reasons can be the industrial activities and the topography of the urban areas. However in 9 cities, decreasing SO2 concentrations are detected in the late 1990s.