Time Series and Trends at GAW Global Site Hohenpeissenberg Christian Plass-Duelmer, Stefan Gilge, Harald Flentje, Anja Werner, Stéphane Sauvage And the GAW Team at Hohenpeissenberg TFMM Meeting, Krakow, May 2015

TFMM Meeting, Krakow, May 2015 Long-term observations at Hohenpeissenberg TFMM Meeting, Krakow, May 2015

TFMM Meeting, Krakow, May 2015 Time series by monthly means (anthropog. VOC) Fit of an exponential decay and sine-curve Zeitreihen ausgewählter anthropogener Kohlenwasserstoffe Yields: exponential decay seasonal amplitude phase shift Comparison of different time series TFMM Meeting, Krakow, May 2015

TFMM Meeting, Krakow, May 2015 Exponential decay compared for different stations Different Central European Stations show similar trends - gives confidence in observed trends TFMM Meeting, Krakow, May 2015

TFMM Meeting, Krakow, May 2015 Hohenpeissenberg NOxy: Monthly means, linear trends, 12 months running mean 12 months running means enable visualization of long-term changes TFMM Meeting, Krakow, May 2015

TFMM Meeting, Krakow, May 2015 Linear trends of 12-months-running-means: before and after 2000 trends need long-term observation TFMM Meeting, Krakow, May 2015

TFMM Meeting, Krakow, May 2015 Non-organic trace gases 1995-2014 12-M-running-means, normalized to year 2000 Max. Min. TFMM Meeting, Krakow, May 2015

TFMM Meeting, Krakow, May 2015 Organic gases (alkanes) Max. Min. Again, similar general max/min = „chemical weather“ Similar sources(fossil)/sinks(OH)/transport(meteo) fluctuations Interesting tool for long-term trends: use of ratios TFMM Meeting, Krakow, May 2015

Hohenpeissenberg aerosol time series Linear trends of monthly means -37 ± 9 cm-3yr-1 Declining aerosol concentrations whereas increasing scattering ? Neph data need to be checked w.r.t. humidity and sampling changes TFMM Meeting, Krakow, May 2015

TFMM Meeting, Krakow, May 2015 PMF yields factors representing different sources and different ageing Factor contributions to total NMHC Factor contributions to individual NMHC NMHC annual/weekly patterns represent various source impacts – powerful tool for model evaluation Leuchner et al., 2015 TFMM Meeting, Krakow, May 2015

TFMM Meeting, Krakow, May 2015 Evaluation of CAMS Model (Copernicus) Expand NRT delivery from ACTRIS/GAW/ EMEP stations for CO, O3, NO, NO2, SO2 TFMM Meeting, Krakow, May 2015

ACTRIS Aerosols, Clouds, and Trace gases Research Infrastructure Network FP7-INFRASTRUCTURES-2010-1 ACTRIS – 2 H2020-INFRAIA-2014-2015 “Integrating the key ground-based facilities for long-term observation of aerosols, cloud-aerosol interactions, and trace gases in Europe” GAW+ EMEP-Aerosol EMEP-VOC EMEP-NOx IGACO GALION Longitude [°] Latitude [°] Example: European VOC network TFMM Meeting, Krakow, May 2015

Round Robin and Side-by-side intercomparison OVOC NOx in guest-lab ACTRIS Quality Assessment Round Robin and Side-by-side intercomparison OVOC NOx in guest-lab Hohenpeissenberg 10x CLD LIF CEAS CAPS CRDS 5 on-line GC 1 off-line GC DNPH/HPLC 3 PTR-MS Good results can be achieved by suitable techniques, but challenging Need for enhanced quality management – ACTRIS-2 TFMM Meeting, Krakow, May 2015

TFMM Meeting, Krakow, May 2015 Questions in trend assessment / verification of emissions Which measurements do we need? Those regulated (EC) and those relevant for atmospheric processes (GAW and EMEP) important: NO2 not by MO-converters, VOC not just NMHC but also OVOC/BVOC What quality of measurements do we need? Such that we can evaluate regulations and understand processes e.g. GAW/ACTRIS DQO‘s of 5-10%, standardized quality management (ACTRIS) Which density of measurements do we need? Model related question How can we verify emissions? Models, inverse modelling, source apportionment (e.g. PMF), trend analyses How can we separate emission changes from transport/meteorology changes? Models, variability in weekly and seasonal cycles, Models and long-term observations must go hand in hand TFMM Meeting, Krakow, May 2015

TFMM Meeting, Krakow, May 2015 Thanks! We acknowledge the contribution by the ACTRIS Research Infrastructure Project supported by the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement n. 262254 TFMM Meeting, Krakow, May 2015