Browsing by Author "Kleissl, J."
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- Impacts of anthropogenic and boreal fire emissions in the central North Atlantic lower free troposphere: summertime observations at the PICO-NARE observatory.Publication . Val Martin, Maria; Honrath, Richard; Kleissl, J.; Owen, Robert; Lapina, K.; Fialho, Paulo; Helmig, Detlev; Tanner, D. M.We present measurements of CO, O3, aerosol Black Carbon (BC) made over the central North Atlantic lower Free Troposphere (FT) during the summers of 2001-2004 along with measurements of nitrogen oxides (NOx and NOy) made during the summer of 2004 (ICARTT period) and non-methane hydrocarbons (NMHCs) made during the winter 2004-spring 2005.
- Large-scale impacts of anthropogenic and boreal fire emissions apparent in multi-year free tropospheric observations in the Azores.Publication . Honrath, Richard; Val Martin, Maria; Kleissl, J.; Owen, Robert; Lapina, K.; Fialho, Paulo; Helmig, Detlev; Tanner, D. M.Pico Mountain in the Azores Islands provides an ideal location for studies of the central N. Atlantic lower free troposphere. The PICO-NARE station has operated there since summer 2001. Here, we present key findings from summertime measurements, during 2001-2004. Main Findings: Anthropogenic and boreal wildfire emissions dominate variations in CO and have major impacts on O3, nitrogen oxides, non-methane hydrocarbons (NMHCs) and black carbon.
- A permanent free tropospheric observatory at Pico summit in the Azores Islands? Past measurements (2001–2005) and future plans.Publication . Honrath, Richard; Fialho, Paulo; Helmig, Detlev; Val Martin, Maria; Owen, Robert; Kleissl, J.; Strane, J. M.; Dziobak, Michael P.; Tanner, D. M.; Barata, Filipe; Lapina, K.Pico mountain in the Azores Islands provides a base for continuous, free tropospheric measurements that is unique in the central North Atlantic region. The PICO-NARE station was installed there in 2001 as a temporary observatory. However, the location proved ideal for studies of aged emissions from anthropogenic (N. American) and boreal fire (N. American and Russian) emissions, as well as for less frequent interception of European and African plumes. As a result, station operation was continued through summer 2005, and we are planning for continuing operation and conversion into a permanent Portuguese GAW station in the future. This poster will provide an overview of the station, the measurements made there, typical transport pathways to the station and interannual variability in transport, and an overview of the full suite of multi-season observations and key findings from measurements to date. In addition, data availability and near-term and long-term plans for the station's future will be discussed.
- Regional and hemispheric impacts of anthropogenic and biomass burning emissions on summertime CO and O3 in the North Atlantic lower free tropospherePublication . Honrath, Richard; Owen, R. Chris; Val Martin, Maria; Reid, J. S.; Lapina, K.; Fialho, Paulo; Dziobak, Michael P.; Kleissl, J.; Westphal, D. L.We report summertime measurements of CO and O3 obtained during 2001–2003 at the PICO-NARE mountaintop station in the Azores. Frequent events of elevated CO mixing ratios were observed. On the basis of backward trajectories arriving in the free troposphere and global simulations of biomass burning plumes, we attribute nearly all these events to North American pollution outflow and long-range transport of biomass burning emissions. There was a high degree of interannual variability in CO levels: median [CO] ranged from 65 ppbv in 2001 to 104 ppbv in 2003. The highest concentrations were associated with transport of Siberian fire emissions during summer 2003, when Siberian fire activity was unusually high. Ozone mixing ratios also increased (by up to ∼30 ppbv) during the fire events. These findings demonstrate the significant hemispheric scale impact that biomass burning events have on background CO and O3 levels. O3 enhancements of similar magnitude were also observed in North American pollution outflow. O3 and CO were correlated during North American outflow events, with a slope averaging 1.0 (d[O3]/d[CO], ppbv/ppbv) when no fire impact was present. This slope is more than 80% larger than early 1990s observations made in the eastern United States and nearshore outflow region, even after accounting for declining U.S. CO emissions and for CO loss during transport to the Azores, and is not consistent with simple dilution of U.S. outflow with marine background air. We conclude that a significantly larger amount of O3 production occurred in the air sampled during this study, and we suggest several potential reasons for this, each of which could imply potentially significant shortcomings in current estimates of the hemispheric impact of North American emissions on tropospheric ozone and should be evaluated in future studies.