Meaning Construction Of Multimodal Discourse In Global Warming Public Service Posters

Since American linguist Harris proposed Discourse Analysis in the 1950s, the discourse analysts had used different kinds of methods to analyze the texts. However, the previous studies mainly regarded the language as the research subject, which ignored other things,such as image, sound, color and action, etc.. Until Barthes started to analyze the meaning of image, music and text, multimodal discourse was born at the right moment. This thesis conducts a research on 50 Global Warming public service posters, which in the following parts, will the author put it "Global Warming posters" for short, selected online and analyzes their multimodal discourse meanings from the perspectives of representational meaning,interactive meaning, and compositional meaning within the framework of Visual Grammar.The research shows that the representational meaning is constructed through narrative process and conceptual process, with the former playing more roles than the latter. Secondly, the interactive meaning is constructed through contact, social distance and attitude, reflecting the relations between represented participants and interactive participants. To be specific,offer is more than demand; medium shot constructs more meaning than long shot and close shot;there are more frontal angle than oblique angle and more eye-eye angle than high angle, low angle. Thirdly, the compositional meaning is constructed by means of information value,salience and framing, among which information value constructs more meaning than salience,with framing being the least. As a result, this research is conducive to the poster designers to produce posters with better quality and to help the poster viewers to better understand the meaning of posters as well.