Person: Ries, Ludwig
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Veröffentlichung Aerosole(2013) Ries, LudwigVeröffentlichung Multivariate statistical air mass discrimination for the high-alpine observatory at the Zugspitze mountain, Germany(2019) Sigmund, Armin; Freier, Korbinian; Rehm, Till; Ries, LudwigTo assist atmospheric monitoring at high-alpine sites, a statistical approach for distinguishing between the dominant air masses was developed. This approach was based on a principal component analysis using five gas-phase and two meteorological variables. The analysis focused on the site Schneefernerhaus at Mt. Zugspitze, Germany. The investigated year was divided into 2-month periods, for which the analysis was repeated. Using the 33.3 % and 66.6 % percentiles of the first two 5 principal components, nine air mass regimes were defined. These regimes were interpreted with respect to vertical transport and assigned to the air mass classes ML (recent contact with the mixing layer), UFT/SIN (undisturbed free troposphere or stratospheric intrusion), and HYBRID (influences of both the mixing layer and the free troposphere or ambiguous). 78 % of the investigated year were classifiable. ML accounted for 31 % of the cases with similar frequencies in all seasons. UFT/SIN comprised 14 % of the cases but were not found from April to July. HYBRID (55 %) mostly exhibited intermediate charac10 teristics, whereby 17 % of HYBRID suggested an influence of the marine boundary layer or the lower free troposphere. The statistical approach was compared to a mechanistic approach using the ceilometer-based mixing layer height from a nearby valley site and a detection scheme for thermally induced mountain winds. Only 25 % of the cases were classifiable with the mechanistic approach. Both approaches agreed well, except in the rare cases of thermally induced uplift. The statistical approach is a promising step towards a real-time discrimination of air masses. Future work is necessary to assess the uncertainty 15 arising from the standardization of real-time data.Copyright: Author(s) 2019. CC BY 4.0 LicenseVeröffentlichung Pollution Events at the High-Altitude Mountain Site Zugspitze-Schneefernerhaus (2670 m a.s.l.), Germany(2019) Ghasemifard, Homa; Vogel, Felix R.; Ries, Ludwig; Yuan, YeWithin the CO2 time series measured at the Environmental Research Station Schneefernerhaus (UFS), Germany, as part of the Global Atmospheric Watch (GAW) program, pollution episodes are traced back to local and regional emissions, identified by 13C(CO2) as well as ratios of CO and CH4 to CO2 mixing ratios. Seven episodes of sudden enhancements in the tropospheric CO2 mixing ratio are identified in the measurements of mixing/isotopic ratios during five winter months from October 2012 to February 2013. The short-term CO2 variations are closely correlated with changes in CO and CH4 mixing ratios, achieving mean values of 6.0 0.2 ppb/ppm for CO/CO2 and 6.0 0.1 ppb/ppm for CH4/CO2. The estimated isotopic signature of CO2 sources (s) ranges between -35%0 and -24%0, with higher values indicating contributions from coal combustion or wood burning, and lower values being the result of natural gas or gasoline. Moving Keeling plots with site-specific data selection criteria are applied to detect these pollution events. Furthermore, the HYSPLIT trajectory model is utilized to identify the trajectories during periods with CO2 peak events. Short trajectories are found covering Western and Central Europe, while clean air masses flow from the Atlantic Ocean and the Arctic Ocean. Quelle: https://www.mdpi.comVeröffentlichung Green Economy in the Alps(2018) Bünger, Björn; Burger, Andreas; Glante, Frank; Hedden-Dunkhorst, Bettina; Landgraf, Richard; Lange, Andrej; Reppe, Silvia; Ries, Ludwig; Wachotsch, Ulrike; Deutschland. Umweltbundesamt. Fachgebiet I.1.2 - Internationale Umweltschutz- und Nachhaltigkeitsstrategien, Politik- und WissenstransferThe Alpine area wants to turn into a green economy model region. The background paper describes important aspects for a development of a green economy in the Alps in four topic areas: Low-carbon economy and adaptation to climate change, resource-efficient economy, ecosystem services and natural capital, quality of life and well-being. To complement this, current information from relevant projects of the German Environment Agency is added.Veröffentlichung Regional and intercontinental pollution signatures on modeled and measured PAN at northern mid-latitude mountain sites(2018) Fiore, Arlene M.; Fischer, Emily V.; Deola, Shubha Pandey; Fischer, Bernd; Ries, LudwigPeroxy acetyl nitrate (PAN) is the most important reservoir species for nitrogen oxides (NOx) in the remote troposphere. Upon decomposition in remote regions, PAN promotes efficient ozone production. We evaluate monthly mean PAN abundances from global chemical transport model 48 simulations (HTAP1) for 2001 with measurements from five northern mid-latitude mountain sites (four European and one North American). The multi-model mean generally captures the observed monthly mean PAN but individual models simulate a factor of ~4-8 range in monthly abundances. We quantify PAN source-receptor relationships at the measurement sites with sensitivity simulations that decrease regional anthropogenic emissions of PAN (and ozone) precursors by 20% from North America (NA), Europe (EU), and East Asia (EA). The HTAP1 models attribute more of the observed PAN at Jungfraujoch (Switzerland) to emissions in NA and EA, and less to EU, than a prior trajectory-based estimate. The trajectory-based and modeling approaches agree that EU emissions play a role in the observed springtime PAN maximum at Jungfraujoch. The signal from anthropogenic emissions on PAN is strongest at Jungfraujoch and Mount Bachelor (Oregon, U.S.A.) during April. In this month, PAN source-receptor relationships correlate both with model differences in regional anthropogenic volatile organic compound (AVOC) emissions and with ozone source-receptor relationships. PAN observations at mountaintop sites can thus provide key information for evaluating models, including links between PAN and ozone production and source-receptor relationships. Establishing routine, long-term, mountaintop measurements is essential given the large observed interannual variability in PAN. © 2018 Author(s).Veröffentlichung 1987 - 2017: 30th Anniversary of the Montreal Protocol(2018) Baumann, Sven; Elsner, Cornelia; Graaf, Daniel de; Graaf, Daniel de ; Hoffmann, Gabriele; Martens, Kerstin; Noack, Constance; Plehn, Wolfgang; Ries, Ludwig; Thalheim, Diana; Deutschland. Umweltbundesamt. Fachgebiet III.1.4 - Stoffbezogene ProduktfragenVeröffentlichung Weitere Treibhausgase(2013) Ries, LudwigVeröffentlichung Variability of black carbon mass concentrations, sub-micrometer particle number concentrations and size distributions: results of the German Ultrafine Aerosol Network ranging from city street to high alpine locations(2019) Sun, Junying; Birmili, Wolfram; Gerwig, Holger; Hermann, Markus; Ries, Ludwig; Schwerin, Andreas; Sohmer, Ralf; Meinhardt, Frank; Wirtz, KlausThis work reports the first statistical analysis of multi-annual data on tropospheric aerosols from the German Ultrafine Aerosol Network (GUAN). Compared to other networks worldwide, GUAN with 17 measurement locations has the most sites equipped with particle number size distribution (PNSD) and equivalent black carbon (eBC) instruments and the most site categories in Germany ranging from city street/roadside to High Alpine. As we know, the variations of eBC and particle number concentration (PNC) are influenced by several factors such as source, transformation, transport and deposition. The dominant controlling factor for different pollutant parameters might be varied, leading to the different spatio-temporal variations among the measured parameters. Currently, a study of spatio-temporal variations of PNSD and eBC considering the influences of both site categories and spatial scale is still missing. Based on the multi-site dataset of GUAN, the goal of this study is to investigate how pollutant parameters may interfere with spatial characteristics and site categories. © 2019 The AuthorsVeröffentlichung The underestimated role of stratosphere-to-troposphere transport on tropospheric ozone(2018) Trickl, Thomas; Ries, Ludwig; Vogelmann, HannesThe atmospheric composition is strongly influenced by changing atmospheric dynamics, in potential relation to climate change. A prominent example is the doubling of the stratospheric ozone component at the summit station Zugspitze (2962 m a.s.l., Garmisch-Partenkirchen, Germany) between the mid-seventies and 2005, roughly from 11 ppb to 23 ppb (43 %). Systematic efforts for identifying and quantifying this influence have been made since the late 1990s. Meanwhile, routine lidar measurements of ozone and water vapour carried out since 2007, combined with in-situ and radiosonde data and trajectory calculations, have revealed the presence of stratospheric intrusion layers on 84 % of the yearly measurement days. The seasonal cycle for deep intrusions with a pronounced summer minimum seen at Alpine summit stations disappears if one looks at the entire free troposphere. The seasonal cycle previously obtained for the Zugspitze summit is rather well reproduced by the lidar data. The mid- and upper-tropospheric intrusion layers seem to be dominated by very long downward transport up to a full tour around the northern hemisphere in an altitude range starting at about 4.5 km a.s.l. Unless there is a strong perturbation, these layers remain considerably dry, typically with RHVeröffentlichung Peroxy acetyl nitrate (PAN) measurements at northern midlatitude mountain sites in April: a constraint on continental source-receptor relationships(2018) Fiore, Arlene M.; Fischer, Emily V.; Milly, George P.; Fischer, Bernd; Ries, LudwigAbundance-based model evaluations with observations provide critical tests for the simulated mean state in models of intercontinental pollution transport, and under certain conditions may also offer constraints on model responses to emission changes. We compile multiyear measurements of peroxy acetyl nitrate (PAN) available from five mountaintop sites and apply them in a proof-of-concept approach that exploits an ensemble of global chemical transport models (HTAP1) to identify an observational emergent constraint. In April, when the signal from anthropogenic emissions on PAN is strongest, simulated PAN at northern midlatitude mountaintops correlates strongly with PAN source-receptor relationships (the response to 20% reductions in precursor emissions within northern midlatitude continents; hereafter, SRRs). This finding implies that PAN measurements can provide constraints on PAN SRRs by limiting the SRR range to that spanned by the subset of models simulating PAN within the observed range. In some cases, regional anthropogenic volatile organic compound (AVOC) emissions, tracers of transport from different source regions, and SRRs for ozone also correlate with PAN SRRs. Given the large observed interannual variability in the limited available datasets, establishing strong constraints will require matching meteorology in the models to the PAN measurements. Application of this evaluation approach to the chemistry-climate models used to project changes in atmospheric composition will require routine, long-term mountaintop PAN measurements to discern both the climatological SRR signal and its interannual variability. © 2018 Author(s).