Aktuelle Aerosoltrends an der GAW Globalstation Hohenpeißenberg und ihre Relevanz für Luftreinhaltung und Klima

Aim and Scope

This study was aimed at representing current aerosol trends measured at the GAW global station and their relevance for the present fine dust discussion and a possible impact on climate.

Results and Discussion

1) The intensive GAW measuring program at Hohenpeissenberg covers numerous parameters for the characterization of the physical, optical and chemical characteristics of the atmospheric aerosol. The time series of the number concentration of ultra fine particles with diameters of about 0.004 to 3 μm shows an increase of about 50% since 1995. 2) The introduction of soot particle filters would lower the dust mass only slightly since soot particles from diesel cars only about 8–10% contribute to the dust mass, but about 90% to the number concentration of particles. 3) The single scattering albedo (SSA) is a key parameter determining whether the existing aerosol mixture causes a cooling (negative radiative forcing) or a warming (positive radiative forcing) in the atmosphere. At Hohenpeißenberg the SSA changed from 0.85 to 0.91 in the time period 1999 to 2005, i.e. the regional aerosol as a whole is dominated by scattering rather than absorbing particles.

Conclusion and Perspective

From current aerosol trends at the GAW global station Hohenpeißenberg it was possible to analyze their relevance for air pollution control and possible influences on climate. Dust mass is not a suitable parameter for accessing the contribution of diesel engined vehicles. Measuring the number concentration of particles much more reflects the influence of diesel engined vehicles and also shows, as expected, an upward trend due to a strong increase of the fraction of diesel vehicles in comparison to the total number of cars. Aerosol particles scatter and absorb solar radiation and thus cause a cooling or warming in the atmosphere. Calculated values of the single scattering albedo at Hohenpeissenberg show, that in the initial years the aerosol did not diminish the temperature rise, but rather caused it to increase. Only a data comparison from a global network like GAW can demonstrate, if the results are even representative for the large scale situation.     

Spatial and temporal variability of water repellency in a sandy soil contaminated with tar oil and heavy metals

Water repellency can induce preferential flow and thus affect water flow and contaminant transport at hazardous waste sites. Since the spatial patterns of water repellency are mostly unknown, it is problematic to use numerical transport models to predict leachate composition. In this study, the spatial variability of soil water repellency was studied at an industrial site contaminated with tar oil, chromium, copper and arsenic. The persistence of water repellency was assessed by the water drop penetration time (WDPT), and the degree of water repellency was quantified by the ethanol percentage (EP) test. Measurements were made at the soil surface along 3.5-12.1 m long transects at different times between March and October 2002. The spatial variability of WDPT, EP, water content, and organic matter content was quantified by variogram analyses. Both the persistence and the degree of water repellency varied seasonally, with the highest water repellency during the summer months. The correlation lengths of WDPT values ranged between 16 and 406 cm, whereas EP values showed no spatial correlation. For field-moist samples, a critical soil water threshold, below which water repellency prevails, was estimated to be 2.5-4%. For oven dry samples, the WDPT values were dependent on the water content prior to drying. The wide range of correlation lengths and the temporal dynamics of spatial repellency patterns suggest that simulations of solute leaching must consider the spatial and temporal variability of soil hydrophobic properties.     

Konzentrationen von Schwermetallen in Bodenlösungen aus bayerischen Wäldern

Goal and Methods

During two years, soil solution samples were collected at 18 forest sites with low anthropogenic heavy metal loads in Bavaria using ceramic suction cups. The collected samples were analysed for pH, conductivity, dissolved organic compounds, and the trace elements Al, Cr, Fe, Mn, Ni, Cu, Zn, Cd, Ba, and Pb.

Results

In addition to initial interference effects caused by the installation of suctions cups, time series were characterised by seasonal variations. The results obtained for the replicated suction cups were comparable for every individual area with standard deviations of 20 to 25 percent. With increasing soil depth, the pH of the soil solution increases specifically at those sites (up to 2.5 pH units) where the topsoils have been acidified. On the other hand, concentrations of all trace elements investigated — excepted of Al and Mn — are not influenced by the soil depth. The forest stand has no significant additional effect on trace element concentrations. Contents of Al, Mn, and Zn are correlated with low pH-values in the soil solution, whereas the mobilisation of Ba is mainly caused by ion exchange. Complexes of trace elements and dissolved organic matter were only detected for Cu at one site. Element concentrations in the soil solution are not significantly influenced by the contents of aqua regia soluble portions in the soil matter. Only very high qua soluble portions increase the concentrations in the soil solution. The overall heavy metal concentrations determined in soil solutions are low compared with different limiting and threshold values, respectively.

Conclusions

Trace element concentrations in soil solutions are mainly influenced by the soil properties themselves. The contribution of the forest stand is negligible. Therefore, from the ecotoxicologic point of view, the risk of leaching heavy metals contaminating the groundwater is not significant for the investigated forest sites and without any respect to silviculture practices.     

Entsorgung von Pflanzenschutzmittel-Restmengen

Currently, in the Federal Republic of Germany residual amounts of pesticide residues are not separately collected but usually disposed in sanitary landfills with household waste. A concept is presented to prevent this way of waste disposal. It recommends specific incineration methods or, in special cases, the underground disposal. Strategies for collecting systems are also discussed.     

Anwendungen von Pflanzenschutzmitteln in der Landwirtschaft

A political dispute has broken out over a research project by the Federal Environmental Agency (UBA) concerning the use of plant protection agents in agriculture. Under Article 15 para. 1 No. 3 d and e of the Plant Protection Act, plant protection agents can only be authorised if their proper and appropriate use, or the consequences of such use, have no negative impacts on human or animal health or on other biological communities, especially water bodies. In specific cases the Federal Environmental Agency as the approving authority fulfils the legislative requirements with a conditional authorisation. Thus, for example, specified minimum distances to the water body must be observed according to the toxicity and exposure of the plant protection agent. The many continuing negative impacts on water bodies from the use of plant protection agents raise questions as to whether certain plant protection agents ought not to have been authorised, and whether environmental requirements were strict enough in the past or whether farmers did not comply with them to a sufficient degree. The research project described here will clarify and document possible improper practices and practical problems. Investigations will be undertaken without prior notice, as only this will enable the actual practices to be recorded. Data will be anonymous, since the project does ’not aim to ‘convict’ individual farmers. The task of the project is to collect representative data for the whole of Germany. Initial interim results will be available in 2006. This report will then be continued in a ‘Part 2’.     

Klima?nderungen: M?gliche Ursachen in Vergangenheit und Zukunft

In this overview two definitions of climate are presented, from the meteorological point of view and from the climate system’s point of view. The origin of climate change is discussed, i.e., externally forced variability and free, or internal variability that is caused without external trigger by internal instabilities of the system. Both, forced and free variability can appear as periodic, randomly quasi-periodic, and abrupt climate change. Finally, various possibilities of climate forecast are considered.

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Klima?nderungen: M?gliche Ursachen in Vergangenheit und Zukunft

Zusammenfassung  In diesem übersichtsartikel werden zwei Klimadefinitionen, die meteorologische und die systemanalytische, vorgestellt. Verschiedene Ursachen für Klima?nderungen werden vergleichend diskutiert: die extern angetriebene Klimavariabilit?t und die ohne ?u?eren Ansto?, aufgrund von internen Instabilit?ten im System ausgel?ste, freie oder interne Klimavariabilit?t. Sowohl die angetriebene als auch die freie Klimavariabilit?t kann sich durch periodische, zuf?llig periodische und abrupte Klima?nderungen bemerkbar machen. Abschlie?end werden die verschiedenen M?glichkeiten der Klimavorhersage betrachtet.

Professor Dr. Martin Claussen ist amtierender Direktor des Potsdam-Instituts für Klimafolgenforschung und Vorsitzender der Deutschen Meteorologischen Gesellschaft (Amtsperiode 2003–2005). Sein aktuelles Forschungsgebiet umfasst die Klimasystemmodellierung einschlie?lich der Pal?oklimamodellierung, wobei die Wechselwirkung zwischen dem physikalischen Klimasystem und der Biosph?re im Vordergrund der Forschung steht. Professor Claussen ist ausgebildeter Meteorologe und lehrt zurzeit Klimaphysik an der Universit?t Potsdam.