Áron József Deák

Climate sensitivity of allergenic taxa in Central Europe associated with new climate change related forces

The aim of the study was to analyse trends of the pollen season with its duration, start and end dates, as well as trends of the annual total pollen count and annual peak pollen concentration for the Szeged agglomeration in Southern Hungary. The data set covered an 11-year period (1997-2007) that included eight taxa and seven daily climate variables. Trend analysis was performed on both annual and daily bases. Trend analysis on a daily basis is a new approach that provides information on the annual cycles of the trends. To quantify the strength of the relationship between the annual cycle of the slope of a pollen concentration trend and the annual cycles of the slopes of the climate variable trends, an association measure and a multiple association measure are introduced. Individual taxa were sorted into three categories according to their climate sensitivities. These were compared with two novel climate change-related forces, namely risk potential and expansion potential due to the climate change. The total annual pollen counts indicated significant trends for 4 taxa and 3 of these 4 trends increased on a daily basis. At the same time, significant changes were detected for the pollen season characteristics of three taxa. The association measures performed well when compared to the climate change-related forces. Significant changes in pollen season characteristics were also in accordance with the risk potential and expansion potential due to the climate change. A novel procedure was applied to separate the effects of the past and current weather conditions that influence the current Ambrosia pollen concentrations. The potential effect of land use changes on pollen release of the given taxa was also discussed using the CORINE Land Cover Database.

The influence of extreme high and low temperatures and precipitation totals on pollen seasons of Ambrosia, Poaceae and Populus in Szeged, southern Hungary

Abstract Extreme high and low temperatures and precipitation totals may have important effect on daily and annual pollen concentrations. The aim of this study is to analyse the associations between pollen characteristics and meteorological variables, furthermore between the rank of pollen characteristics and the rank of annual values of meteorological variables for Szeged, southern Hungary. Pollen characteristics include pollen count parameters (TPA, total annual pollen amount; APC, annual peak pollen concentration) and pollen season parameters (start, end and duration of the pollen season). Meteorological variables are temperature and precipitation. The data set used covers a 14-year period (1997–2010) and contains daily values of Ambrosia (ragweed), Poaceae (grasses) and Populus (poplar) pollen concentrations, as well as those of temperature and precipitation. Both Pearson and Spearman rank correlations were calculated, because the rank correlation is less sensitive than the correlation to outliers that are in the tails of the sample. Our results suggest that Ambrosia and Populus are reversely related to temperature (negative correlations), while Poaceae exhibit a parallel relationship with precipitation (positive correlations). On the whole, pollen count characteristics (TPA and APC) indicate a decrease for Ambrosia and Poaceae, while for Populus an increase is expected.

Plants remember past weather: a study for atmospheric pollen concentrations of Ambrosia, Poaceae and Populus

After extreme dry (wet) summers or years, pollen production of different taxa may decrease (increase) substantially. Accordingly, studying effects of current and past meteorological conditions on current pollen concentrations for different taxa have of major importance. The purpose of this study is separating the weight of current and past weather conditions influencing current pollen productions of three taxa. Two procedures, namely multiple correlations and factor analysis with special transformation are used. The 11-year (1997–2007) data sets include daily pollen counts of Ambrosia (ragweed), Poaceae (grasses) and Populus (poplar), as well as daily values of four climate variables (temperature, relative humidity, global solar flux and precipitation). Multiple correlations of daily pollen counts with simultaneous values of daily meteorological variables do not show annual course for Ambrosia, but do show definite trends for Populus and Poaceae. Results received using the two methods revealed characteristic similarities. For all the three taxa, the continental rainfall peak and additional local showers in the growing season can strengthen the weight of the current meteorological elements. However, due to the precipitation, big amount of water can be stored in the soil contributing to the effect of the past climate elements during dry periods. Higher climate sensitivity (especially water sensitivity) of the herbaceous taxa (Ambrosia and Poaceae) can be definitely established compared to the arboreal Populus. Separation of the weight of the current and past weather conditions for different taxa involves practical importance both for health care and agricultural production.

A new approach used to explore associations of current Ambrosia pollen levels with current and past meteorological elements.

The paper examines the sensitivity of daily airborne Ambrosia (ragweed) pollen levels of a current pollen season not only on daily values of meteorological variables during this season but also on the past meteorological conditions. The results obtained from a 19-year data set including daily ragweed pollen counts and ten daily meteorological variables are evaluated with special focus on the interactions between the phyto-physiological processes and the meteorological elements. Instead of a Pearson correlation measuring the strength of the linear relationship between two random variables, a generalised correlation that measures every kind of relationship between random vectors was used. These latter correlations between arrays of daily values of the ten meteorological elements and the array of daily ragweed pollen concentrations during the current pollen season were calculated. For the current pollen season, the six most important variables are two temperature variables (mean and minimum temperatures), two humidity variables (dew point depression and rainfall) and two variables characterising the mixing of the air (wind speed and the height of the planetary boundary layer). The six most important meteorological variables before the current pollen season contain four temperature variables (mean, maximum, minimum temperatures and soil temperature) and two variables that characterise large-scale weather patterns (sea level pressure and the height of the planetary boundary layer). Key periods of the past meteorological variables before the current pollen season have been identified. The importance of this kind of analysis is that a knowledge of the past meteorological conditions may contribute to a better prediction of the upcoming pollen season.

Investigation of Water Capillary Rise in Soil Columns Made from Clay Mineral Mixtures Pretreated with Cationic Surfactants

The study of the environmental pollution effect of surfactants is very important. Surfactants modify the wetting, surface tension, and capillary pore system of soil grains depending on their characteristics. During the research, the surface modification effect of a cationic surfactant (hexadecyl–pyridinium–chloride) was analyzed on mineral mixtures series assembled in various ratios with decreasing clay content (bentonite–loess–sand, kaoline–loess–sand). Cationic surfactants are adsorbed on the inner and outer surfaces of phyllosilicates, which could result in swelling. Our results were evaluated on the basis of the interfacial (surface tension of liquid phase, contact angle) and soil physical characteristics of the examined samples. The wetting properties and structural changes (eliminating the surface modification effect of humic materials) of mineral mixtures treated with surfactants were studied on the basis of capillary water rise. The results of our research could be used to interpret the water features of surfactant-polluted soils.

The effects of the current and past meteorological elements influencing the current pollen concentrations for different taxa

BackgroundIt is an important issue to separate the current and past components of the meteorological parameters influencing the current pollen concentration for different taxa. For this purpose a new statistical procedure, factor analysis with special transformation is introduced. The data set used covers an 11-year period (1997–2007) including daily pollen counts of 19 taxa and 4 climate variables (mean temperature, precipitation amount, global solar flux and relative humidity).ResultThe taxa examined can be classified into three groups, namely arboreal deciduous (AD), arboreal evergreen (AE) and herbaceous (H) taxa. It was found that a better comparison can be established if the taxa are separated within each group according to the starting month of their pollen season. Within the group of AD taxa, Alnus, Populus and Ulmus are marked by a late summer – early autumn peak of the role of past meteorological elements exceeding the role of the current ones almost all over the pollen-free period. For Juglans, Morus, Platanus and Quercus, the major weights of the current meteorological elements in the spring and early summer show the most characteristic contribution to the pollen production. For AE taxa, the picture is no clear. For H taxa, the curves of Cannabis, Plantago, Rumex and Urtica indicate the most equalized course of weights. Ambrosia, Artemisia and Chenopodiaceae comprise the highest weights of the past weather conditions of all taxa until at least three months before the start of the pollination. Interactions between the phyto-physiological processes and the meteorological elements are evaluated.ConclusionSeparation of the weight of the current and past weather conditions for different taxa involves practical importance both for health care and agricultural production.