El Niño-Southern Oscillation influence on tropospheric mercury concentrations

The El Nino-Southern Oscillation (ENSO) affects the tropospheric concentrations of many trace gases. Here we investigate the ENSO influence on mercury concentrations measured in the upper troposphere during Civil Aircraft for the Regular Investigation of the atmosphere Based on an instrumented Container flights and at ground at Cape Point, South Africa, and Mace Head, Ireland. Mercury concentrations cross-correlate with Southern Oscillation Index (SOI) with a lag of 8 +/- 2 months. Highest mercury concentrations are always found at the most negative SOI values, i.e., 8 months after El Nino, and the amplitude of the interannual variations fluctuates between similar to 5 and 18%. The time lag is similar to that of CO whose interannual variations are driven largely by emissions from biomass burning (BB). The amplitude of the interannual variability of tropospheric mercury concentrations is consistent with the estimated variations in mercury emissions from BB. We thus conclude that BB is a major factor driving the interannual variation of tropospheric mercury concentrations

Studies on CO variation and trends over South Africa and the Indian Ocean using TES satellite data

In this study, we used measurements from the tropospheric emission spectrometer aboard the Earth Observing System’s Aura satellite over South Africa, Madagascar and Reunion Island to investigate variations and trends in tropospheric carbon monoxide (CO) over 5 years, from 2005 to 2009, and at 47 pressure levels from 1000 hPa to 10 hPa. We believe that the study is the first of its kind to address the use of space-borne data for CO distribution over southern Africa. Maximum CO was recorded during spring and minimum during summer. Positive anomalies were identified in 2005 and 2007 during the spring and negative anomalies in the beginning of the year (especially in 2006, 2008 and 2009). The estimated trends based on a linear regression method on inter-annual distribution predicted a decreasing rate of 2.1% per year over South Africa, 1.8% per year over Madagascar and 1.7% per year over Reunion Island. The surface CO measurements made at Cape Point station (34.35°S, 18.48°E) showed an average decline of 0.1 ppb per month, which corresponded to 2.4% of the average annual mean for the studied period. The observed decrease in CO was linked to the La Niña event which occurred in 2006 and 2008 and a declining rate of biomass burning activity in the southern hemisphere over the observation period. TES measurements are in agreement with ground-based measurements and can be used with confidence to complement CO measurements for future analyses over the southern tropics and middle latitude

Studies on CO variation and trends over South Africa and the Indian Ocean using TES satellite data AUTHORS

In this study, we used measurements from the tropospheric emission spectrometer aboard the Earth Observing System's Aura satellite over South Africa, Madagascar and Reunion Island to investigate variations and trends in tropospheric carbon monoxide (CO) over 5 years, from 2005 to 2009, and at 47 pressure levels from 1000 hPa to 10 hPa. We believe that the study is the first of its kind to address the use of space-borne data for CO distribution over southern Africa. Maximum CO was recorded during spring and minimum during summer. Positive anomalies were identified in 2005 and 2007 during the spring and negative anomalies in the beginning of the year (especially in 2006, 2008 and 2009). The estimated trends based on a linear regression method on inter-annual distribution predicted a decreasing rate of 2.1% per year over South Africa, 1.8% per year over Madagascar and 1.7% per year over Reunion Island. The surface CO measurements made at Cape Point station (34.35°S, 18.48°E) showed an average decline of 0.1 ppb per month, which corresponded to 2.4% of the average annual mean for the studied period. The observed decrease in CO was linked to the La Niña event which occurred in 2006 and 2008 and a declining rate of biomass burning activity in the southern hemisphere over the observation period. TES measurements are in agreement with ground-based measurements and can be used with confidence to complement CO measurements for future analyses over the southern tropics and middle latitude

Results from the International Halocarbons in Air Comparison Experiment : (IHALACE) [Discussion paper]

The International Halocarbons in Air Comparison Experiment (IHALACE) was conducted to document relationships between calibration scales among various laboratories that measure atmospheric greenhouse and ozone depleting gases. Six stainless steel cylinders containing natural and modified natural air samples were circulated among 19 laboratories. Results from this experiment reveal relatively good agreement among commonly used calibration scales for a number of trace gases present in the unpolluted atmosphere at pmol mol−1 (parts per trillion) levels, such as chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs). Some scale relationships were found to be consistent with those derived from bi-lateral experiments or from analysis of atmospheric data, while others revealed discrepancies. The transfer of calibration scales among laboratories was found to be problematic in many cases, meaning that measurements tied to a common scale may not, in fact, be compatible. These results reveal substantial improvements in calibration over previous comparisons. However there is room for improvement in communication and coordination of calibration activities with respect to the measurement of halogenated and related trace gases

Five-year records of mercury wet deposition flux at GMOS sites in the Northern and Southern hemispheres

The atmospheric deposition of mercury (Hg) occurs via several mechanisms, including dry and wet scavenging by precipitation events. In an effort to understand the atmospheric cycling and seasonal depositional characteristics of Hg, wet deposition samples were collected for approximately 5 years at 17 selected GMOS monitoring sites located in the Northern and Southern hemispheres in the frameworkof the Global Mercury Observation System (GMOS) project. Total mercury (THg) exhibited annual and seasonal patterns in Hg wet deposition samples. Interannual differences in total wet deposition are mostly linked with precipitation volume, with the greatest deposition flux occurring in the wettest years. This data set provides a new insight into baseline concentrations of THg concentrations in precipitation worldwide, particularly in regions such as the Southern Hemisphere and tropical areas where wet deposition as well as atmospheric Hg species were not investigated before, opening the way for future and additional simultaneous measurements across the GMOS network as well as new findings in future modeling studies.JRC.D.2-Water and Marine Resource

Five-year records of Total Mercury Deposition flux at GMOS sites in the Northern and Southern Hemispheres

The atmospheric deposition of mercury (Hg) occurs via several mechanisms including dry and wet scavenging by precipitation events. In an effort to understand the atmospheric cycling and seasonal depositional characteristics of Hg, wet deposition samples were collected for approximately five years at 17 selected GMOS monitoring sites located in the Northern and Southern Hemispheres in the framework of the Global Mercury Observation System (GMOS) project. Total mercury (THg) exhibited annual and seasonal patterns in Hg wet deposition samples. Inter-annual differences in total wet deposition are mostly linked with precipitation volume, with the greatest deposition flux occurring in the wettest years. This data set provides a new insight into baseline concentrations of THg concentrations in precipitation worldwide, particularly in regions, such as the Southern Hemisphere and tropical areas where wet deposition as well as atmospheric Hg species were not investigated before, opening the way for future and additional simultaneous measurements across the GMOS network as well as new findings in future modeling studies.Fil: Sprovieri, Francesca. Institute of Atmospheric Pollution Research; ItaliaFil: Pirrone, Nicola. Institute of Atmospheric Pollution Research; ItaliaFil: Bencardino, Mariantonia. Institute of Atmospheric Pollution Research; ItaliaFil: D´Amore, Francesco. Institute of Atmospheric Pollution Research; ItaliaFil: Angot, Helene. Universite Joseph Fourier. Observatoire de Grenoble; FranciaFil: Barbante, Carlo. University Ca’ Foscari of Venice; Italia. Consiglio Nazionale delle Ricerche; ItaliaFil: Brunke, Ernst Günther. South African Weather Service; SudáfricaFil: Arcega Cabrera, Flor. Universidad Nacional Autónoma de México; MéxicoFil: Cairns, Warren. Institute for the Dynamics of Environmental Processes; ItaliaFil: Comero, Sara. Joint Research Centre; ItaliaFil: Dieguez, Maria del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Dommergue, Aurélien. Universite Joseph Fourier. Observatoire de Grenoble; FranciaFil: Ebinghaus, Ralf. Helmholtz Zentrum Geesthacht; AlemaniaFil: Feng, Xin Bin. Chinese Academy of Sciences; República de ChinaFil: Fu, Xuewu. Chinese Academy of Sciences; República de ChinaFil: Garcia, Patricia Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Gawlik, Bernd Manfred. Joint Research Centre; ItaliaFil: Hageström, Ulla. Swedish Environmental Research Inst. Ltd.; SueciaFil: Hansson, Katarina. Swedish Environmental Research Inst. Ltd.; SueciaFil: Horvat, Milena. Jožef Stefan Institute; EsloveniaFil: Kotnik, Jose. Jožef Stefan Institute; EsloveniaFil: Labuschagne, Casper. South African Weather Service; SudáfricaFil: Magand, Olivier. Laboratoire de Glaciologie et Géophysique de l’Environnement; FranciaFil: Martin, Lynwill. South African Weather Service; SudáfricaFil: Mashyanov, Nikolay. St. Petersburg State University; RusiaFil: Mkololo, Thumeka. South African Weather Service; SudáfricaFil: Munthe, John. Swedish Environmental Research Inst. Ltd.; SueciaFil: Obolkin, Vladimir. Siberian Branch of the Russian Academy of Sciences; RusiaFil: Islas, Martha Ramirez. Instituto Nacional de Ecología y Cambio Climático; MéxicoFil: Sena, Fabrizio. Joint Research Centre; ItaliaFil: Somerset, Vernon. South African Weather Service; SudáfricaFil: Spandow, Pia. Swedish Environmental Research Inst. Ltd.; SueciaFil: Vardè, Massimiliano. Institute of Atmospheric Pollution Research; Italia. Consiglio Nazionale delle Ricerche; ItaliaFil: Walters, Chavon. South African Weather Service; SudáfricaFil: Wängberg, Ingvar. Swedish Environmental Research Institute; SueciaFil: Weigelt, Andreas. Helmholtz Zentrum Geesthacht; AlemaniaFil: Yang, Xu. Chinese Academy of Sciences; República de ChinaFil: Zhang, Hui. Chinese Academy of Sciences; República de Chin