Conceitos e métodos da transferência de gases na interface água-ar (Concepts and methods of gas transfer in air-water interface)

Estudos relacionados com fluxo de gases na interface agua-ar tem recebido a atencao da comunidade cientifica nas ultimas decadas. Os primeiros estudos foram iniciados em tuneis de vento e logo depois levados para o campo. Os oceanos foram o primeiro alvo de estudo, devido seu papel fundamental no ciclo global do carbono. No entanto, estudos realizados em aguas interiores revelaram que estes ambientes desempenham, tambem, um papel importante no ciclo regional e global do carbono. O avanco nos estudos levou a um melhor entendimento dos processos que controlam a transferencia de gas e das estimativas de fluxo na interface agua-ar. Este trabalho reune, dentro de um contexto historico, os principais e mais relevantes estudos relacionados a transferencia de gases na interface agua-ar. Esta revisao aborda principios fundamentais de transferencia gasosa na interface agua-ar e avancos na teoria de transferencia de gases, modelos e tecnicas de medicao. Com base nesses estudos, apresentamos os conceitos e processos envolvidos no calculo da velocidade de transferencia gasosa e dos fluxos de gases. Palavras-chave: fluxo de gases, velocidade de transferencia e interface agua-ar. A B S T R A C T Studies related to gas fluxes at the water-air interface have been examined by the scientific community during the last decades. Firstly, studies were initiated in wind tunnels and, then, were carried out in the field. The oceans were the first place of study, due to its fundamental role on the global carbon cycle. However, investigations carried out in the continental waters have shown that these environments also have an important role on regional and global carbon cycles. Advances in this topic of research led to a better understanding of the processes that control the gas transfer, which improved the estimates of fluxes at the interface water-air. In a historic context, this study brings together the main and the most important studies related to gas transfer in the interface water-air. Based on these studies, we attempt to show, clearly, the concepts and processes involved in the calculation of the transfer velocity and gas fluxes. This review discusses the fundamental principles of gas transfer at the interface water-air and the advances in the theory of gas transfer, models and techniques of measurements. Keywords : gas fluxes, transfer velocity and air-water interface.