Andreas Pauling

Chapter 1 Mediterranean climate variability over the last centuries: A review

Publisher Summary This chapter discusses a necessary task for assessing to which degree the industrial period is unusual against the background of pre-industrial climate variability. It is the reconstruction and interpretation of temporal and spatial patterns of climate in earlier centuries. There are distinct differences in the temporal resolution among the various proxies. Some of the proxy records are annually or even higher resolved and hence record year-by-year patterns of climate in past centuries. Several of the temperature reconstructions reveal that the late twentieth century warmth is unprecedented at hemispheric scales and is explained by anthropogenic, greenhouse gas (GHG) forcing. The chapter discusses the availability and potential of long, homogenized instrumental data, documentary, and natural proxies to reconstruct aspects of past climate at local- to regional-scales within the larger Mediterranean area, which includes climate extremes and the incidence of natural disasters. The chapter describes the role of external forcing, including natural and anthropogenic influences, and natural, internal variability in the coupled ocean–atmosphere system at subcontinental scale.

Numerical simulation of birch pollen dispersion with an operational weather forecast system.

We included a parameterisation of the emissions of pollen grains into the comprehensive model system COSMO-ART. In addition, a detailed density distribution of birch trees within Switzerland was derived. Based on these new developments, we carried out numerical simulations of the dispersion of pollen grains for an episode that occurred in April 2006 over Switzerland and the adjacent regions. Since COSMO-ART is based on the operational forecast model of the German Weather Service, we are presenting a feasibility study of daily pollen forecast based on methods which have been developed during the last two decades for the treatment of anthropogenic aerosol. A comparison of the model results and very detailed pollen counts documents the current possibilities and the shortcomings of the method and gives hints for necessary improvements.

The Onset, Course and Intensity of the Pollen Season

The onset, duration and intensity of the period when pollen is present in the air varies from year to year. Amongst other things, there is an effect upon the quality of life of allergy sufferers. The production and emission of pollens are governed by interacting environmental factors. Any change in these factors may affect the phenology and intensity of the season. Readiness to flower in a plant, and the amount of pollen produced, is the result of conditions during an often long period foregoing flowering. When a plant is ready to flower, temporary ambient circumstances e.g., irradiation and humidity, determine the timing of the actual pollen release. In order to understand variation between years and to be able to safely predict future situations, not least due to the ongoing climate change, it is necessary to know the determinants of all related processes and differences between and within species, here reviewed.

Monitoring, Modelling and Forecasting of the Pollen Season

The section about monitoring covers the development of phenological networks, remote sensing of the season cycle of the vegetation, the emergence of the science of aerobiology and, more specifically, aeropalynology, pollen sampling instruments, pollen counting techniques, applications of aeropalynology in agriculture and the European Pollen Information System. Three data sources are directly related with aeropalynology: phenological observations, pollen counts and remote sensing of the vegetation activity. The main future challenge is the assimilation of these data streams into numerical pollen forecast systems. Over the last decades consistent monitoring efforts of various national networks have created a wealth of pollen concentration time series. These constitute a nearly untouched treasure, which is still to be exploited to investigate questions concerning pollen emission, transport and deposition. New monitoring methods allow measuring the allergen content in pollen. Results from research on the allergen content in pollen are expected to increase the quality of the operational pollen forecasts.

Regional differences in winter sea level variations in the Baltic Sea for the past 200 yr

Decadal sea level variations in selected stations located in the southwestern, central and eastern Baltic Sea are found to be less coherent in the 19th century than in the 20th century. The effect of the North Atlantic sea level-pressure (SLP), precipitation and air-temperature in the 19th and 20th centuries from gridded climate reconstructions, and their relationship to Baltic Sea level, are statistically analysed to explain this difference. The influence of these factors on sea level varies geographically. In the central and eastern Baltic, Sea level variations are well described by SLP alone, whereas in the southern Baltic Sea area-averaged precipitation better explains the decadal sea level variations. The evolution of precipitation in the 19th century could explain the different behaviour of the southern Baltic stations; however, the physical mechanism for this relationship remains unclear. The effect of temperature variations is either already contained in the SLP field or is less important for decadal sea level variations than the other two factors.

Quantitative DNA Analyses for Airborne Birch Pollen

Birch trees produce large amounts of highly allergenic pollen grains that are distributed by wind and impact human health by causing seasonal hay fever, pollen-related asthma, and other allergic diseases. Traditionally, pollen forecasts are based on conventional microscopic counting techniques that are labor-intensive and limited in the reliable identification of species. Molecular biological techniques provide an alternative approach that is less labor-intensive and enables identification of any species by its genetic fingerprint. A particularly promising method is quantitative Real-Time polymerase chain reaction (qPCR), which can be used to determine the number of DNA copies and thus pollen grains in air filter samples. During the birch pollination season in 2010 in Mainz, Germany, we collected air filter samples of fine (<3 μm) and coarse air particulate matter. These were analyzed by qPCR using two different primer pairs: one for a single-copy gene (BP8) and the other for a multi-copy gene (ITS). The BP8 gene was better suitable for reliable qPCR results, and the qPCR results obtained for coarse particulate matter were well correlated with the birch pollen forecasting results of the regional air quality model COSMO-ART. As expected due to the size of birch pollen grains (~23 μm), the concentration of DNA in fine particulate matter was lower than in the coarse particle fraction. For the ITS region the factor was 64, while for the single-copy gene BP8 only 51. The possible presence of so-called sub-pollen particles in the fine particle fraction is, however, interesting even in low concentrations. These particles are known to be highly allergenic, reach deep into airways and cause often severe health problems. In conclusion, the results of this exploratory study open up the possibility of predicting and quantifying the pollen concentration in the atmosphere more precisely in the future.