Modeling of Surface UV Radiation Using Satellite Data

Solar UV radiation is harmful for life on planet Earth, but fortunately the atmospheric oxygen and ozone absorb almost entirely the most energetic UVC radiation photons. However, part of the UVB radiation and much of the UVA radiation reaches the surface of the Earth, and affect human health, environment, materials and drive atmospheric and aquatic photochemical processes. In order to quantify these effects and processes there is a need for ground-based UV measurements and radiative transfer modeling to estimate the amounts of UV radiation reaching the biosphere. Satellite measurements with their near-global spatial coverage and long-term data conti-nuity offer an attractive option for estimation of the surface UV radiation. This work focuses on radiative transfer theory based methods used for estimation of the UV radiation reaching the surface of the Earth. The objectives of the thesis were to implement the surface UV algorithm originally developed at NASA Goddard Space Flight Center for estimation of the surface UV irradiance from the meas-urements of the Dutch-Finnish built Ozone Monitoring Instrument (OMI), to improve the original surface UV algorithm especially in relation with snow cover, to validate the OMI-derived daily surface UV doses against ground-based measurements, and to demonstrate how the satellite-derived surface UV data can be used to study the effects of the UV radiation. The thesis consists of seven original papers and a summary. The summary includes an introduction of the OMI instrument, a review of the methods used for modeling of the surface UV using satellite data as well as the con-clusions of the main results of the original papers. The first two papers describe the algorithm used for estimation of the surface UV amounts from the OMI measurements as well as the unique Very Fast Delivery processing system developed for processing of the OMI data received at the Sodankylä satellite data centre. The third and the fourth papers present algorithm improvements related to the surface UV albedo of the snow-covered land. Fifth paper presents the results of the comparison of the OMI-derived daily erythemal doses with those calculated from the ground-based measurement data. It gives an estimate of the expected accuracy of the OMI-derived sur-face UV doses for various atmospheric and other conditions, and discusses the causes of the differences between the satellite-derived and ground-based data. The last two papers demonstrate the use of the satellite-derived sur-face UV data. Sixth paper presents an assessment of the photochemical decomposition rates in aquatic environment. Seventh paper presents use of satellite-derived daily surface UV doses for planning of the outdoor material weathering tests.

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Earlier school text book studies (eg Tainio and Teräs 2010, Blumberg 2007; Ohlander 2010) have shown that women are underrepresented in school books, both in illustrations and texts, and the genders are represented stereotyped. The study will examine how gender in seen on pre-school education materials. The aim of this study is to determine what kind of representations, discourses and the subject positions of the gender are presented in pre-school materials. This study utilizes a feminist research method. The theoretical starting points are the social constructivist, poststructuralist theory and gender studies. The concept of gender as a social construct. The research used content analysis as well as discource analysis and deconstructive reading. The material was used four different publishers, WSOY, Tammi, Otava and Lasten Keskus preschool integrated material packages, which contain the child's exercise book or booklet, and teacher's guide. The analysis examined the quantity of gender-specific images and gendered words and phrases, and representations of gender, subject position, and discourses, and what linguistic means had been used for representation of masculinity and femininity. Based on the results there were on average more masculine characters and words as feminine in the illustrations and stories of pre-school materials. Feminine and masculine characters representations emphasized traditional gender stereotypes, especially in external characteristics and clothing. Genders had the highest available, with the subject position of stereotypes with reduced mobility, but also other kinds of subject position was observed. The data found in the following gender discources: difference discource, diversity discource and similarity discource. The highest number occurred in the difference and diversity discources. However, there were differences between the different materials. In some materials there were more diverse gender representations and other materials highlighted the differences between genders. Overall, the genders were represented stereotypically in the pre-school materials.