Potsdam Institute for Climate Impact Research

About: Potsdam Institute for Climate Impact Research is a facility organization based out in Potsdam, Germany. It is known for research contribution in the topics: Climate change & Global warming. The organization has 1519 authors who have published 5098 publications receiving 367023 citations.

The influence of temperature on ozone production under varying NO x conditions – a modelling study

Abstract: . Surface ozone is a secondary air pollutant produced during the atmospheric photochemical degradation of emitted volatile organic compounds (VOCs) in the presence of sunlight and nitrogen oxides (NOx). Temperature directly influences ozone production through speeding up the rates of chemical reactions and increasing the emissions of VOCs, such as isoprene, from vegetation. In this study, we used an idealised box model with different chemical mechanisms (Master Chemical Mechanism, MCMv3.2; Common Representative Intermediates, CRIv2; Model for OZone and Related Chemical Tracers, MOZART-4; Regional Acid Deposition Model, RADM2; Carbon Bond Mechanism, CB05) to examine the non-linear relationship between ozone, NOx and temperature, and we compared this to previous observational studies. Under high-NOx conditions, an increase in ozone from 20 to 40 °C of up to 20 ppbv was due to faster reaction rates, while increased isoprene emissions added up to a further 11 ppbv of ozone. The largest inter-mechanism differences were obtained at high temperatures and high-NOx emissions. CB05 and RADM2 simulated more NOx-sensitive chemistry than MCMv3.2, CRIv2 and MOZART-4, which could lead to different mitigation strategies being proposed depending on the chemical mechanism. The increased oxidation rate of emitted VOC with temperature controlled the rate of Ox production; the net influence of peroxy nitrates increased net Ox production per molecule of emitted VOC oxidised. The rate of increase in ozone mixing ratios with temperature from our box model simulations was about half the rate of increase in ozone with temperature observed over central Europe or simulated by a regional chemistry transport model. Modifying the box model set-up to approximate stagnant meteorological conditions increased the rate of increase of ozone with temperature as the accumulation of oxidants enhanced ozone production through the increased production of peroxy radicals from the secondary degradation of emitted VOCs. The box model simulations approximating stagnant conditions and the maximal ozone production chemical regime reproduced the 2 ppbv increase in ozone per degree Celsius from the observational and regional model data over central Europe. The simulated ozone–temperature relationship was more sensitive to mixing than the choice of chemical mechanism. Our analysis suggests that reductions in NOx emissions would be required to offset the additional ozone production due to an increase in temperature in the future.

Using Meta-Analysis and GIS for Value Transfer and Scaling Up: Valuing Climate Change Induced Losses of European Wetlands

Abstract: There is growing policy and academic interest in transferring ecosystem service values from existing valuation studies to other ecosystem sites at a large geographic scale. Despite the evident policy demand for this combined transfer and "scaling up" of values, an approach to value transfer that addresses the challenges inherent in assessing ecosystem changes at a national or regional level is not available. This paper proposes a methodology for scaling up ecosystem service values to estimate the welfare effects of ecosystem change at this larger geographical scale. The methodology is illustrated by applying it to value the impact of climate change on European wetlands for the period 2000-2050. The proposed methodology makes use of meta-analysis to produce a value function. The parameters of the value function include spatial variables on wetland size and abundance, GDP per capita, and population. A geographic information system is used to construct a database of wetland

Syndromes of Global Change: a qualitative modelling approach to assist global environmental management

Abstract: A novel transdisciplinary approach to investigate Global Change (GC) is presented. The approach rests on the decomposition of the intrigue dynamics of GC into patterns of civilization–nature interactions (“syndromes”) by an iterative scientific process of observations, data and system theoretical analyses, and modelling attempts. We illustrate the approach by a detailed analysis of the Sahel Syndrome, which describes the rural poverty driven overuse of natural resources. The investigation is performed by (i) identifying relevant “symptoms” and interlinkages which are characteristics for this pattern, and (ii) a qualitative model representing the internal dynamics of the essential flywheel. The geographical patchwork of the regions affected by the syndrome which is obtained by global data analysis, proves the high global relevance of this pattern. The qualitative model is employed for an evaluation of basic policy strategies debated in the context of rural poverty driven environmental degradation. It turns out that a mixed policy of combating poverty and introducing soil preserving agricultural techniques and practices is most promising to tackle the syndrome dynamics.

Validation practices for satellite-based Earth observation data across communities

Abstract: Assessing the inherent uncertainties in satellite data products is a challenging task. Different technical approaches have been developed in the Earth Observation (EO) communities to address the validation problem which results in a large variety of methods as well as terminology. This paper reviews state-of-the-art methods of satellite validation and documents their similarities and differences. First, the overall validation objectives and terminologies are specified, followed by a generic mathematical formulation of the validation problem. Metrics currently used as well as more advanced EO validation approaches are introduced thereafter. An outlook on the applicability and requirements of current EO validation approaches and targets is given.

C and N mineralisation in the decomposer food webs of a European forest transect

Abstract: Schro¨ter, D., Wolters, V. and De Ruiter, P. C. 2003. C and N mineralisation in thedecomposer food webs of a European forest transect. – Oikos 102: 294–308.Belowground processes are essential for the overall carbon and nitrogen fluxes inforests. Neither the functioning of the soil food web mediating these fluxes, nor itsmodulation by environmental factors is sufficiently understood. In this study thebelowground carbon and nitrogen mineralisation of four European coniferous forestsites (northern Sweden to north-east France) with different climate and N deposi-tional inputs was analysed by investigating the soil food webs using field observationsand modelling. The soil fauna directly contributed 7–13% to C mineralisation,among which the testate amoebae (Protozoa) made the largest contribution. Micro-bial grazing was suggested to have an important indirect effect by stimulatingbacterial turnover. Due to relatively high C:N ratios of their substrate, bacteriaimmobilized N, while the fauna i.e. testate amoebae, nematodes, microarthropodsand enchytraeids, counteracted this N immobilisation.Despite similar food web biomass, the sites differed with respect to food webstructure and C and N flows. Model calculations suggested a significant influence offood web structure on soil ecosystem processes in addition to environmental factorsand resource quality. Mineralisation rates were lowest at the low N input boreal sitewith a food web dominated by fungal pathways. Further south, as N availabilityincreased, bacterial pathways became more important and the cycling of C and Nwas faster. The bioavailability of degradable C sources is suggested to be a limitingfactor for microbial activity and overall mineralisation rates. In this respect, above-and belowground interactions e.g. transfers of labile C sources from the vegetation tothe decomposer system deserve further attention.Our study revealed the combined effects of climate and nutrient inputs to ecosys-tems and the subsequent changes in the structure and functioning of the systems. Ifdecomposition, and therefore carbon loss, is stimulated as a consequence of struc-tural and/or nutritional changes, resulting for example from continuous industrial Nemission, the storage capacity of forest ecosystems could be altered.