Balloon-borne and airborne measurements

The relationship between global temperature and greenhouse gases (GHGs) content of the atmosphere has been documented in prehistorical records. Due to human activity, the actual concentration of GHGs is higher than in the past 800,000 years, and today's rate of increase is worrying. In a near future, the increase of GHGs in the atmosphere will have serious consequences on the radiative and chemical balance of our atmosphere, leading to serious damages on the biodiversity and human health. Then, climate change has become a fundamental issue. To understand the processes driving our atmosphere, scientists have been probing our atmosphere since 1783 when first temperature and pressure measurements were performed onboard hydrogen-filled balloon. Stratospheric balloons are unique platforms to probe the atmosphere, particularly at the interface between the troposphere and the stratosphere, where major processes occur. Numerous open questions remain about our climate future. The atmosphere is a complex environment where various interaction processes occur which are not well understood to date. Further observations are required to improve climate models and therefore predictions to help taking action to limit anthropogenic contribution to climate change. To probe the atmosphere, scientists have been developing more and more precise and accurate instruments. In this chapter, we focused on in situ diode laser spectrometers which are high-resolution sensors allowing for continuous measurements of GHGs in the atmosphere. This chapter describes also some important atmospheric processes driving our climate and actual capabilities offered by stratospheric balloons to probe our atmosphere. Examples of results obtained from past balloon campaigns are also shown, demonstrating the actual state of the art in atmospheric sciences and particularly on open questions related to climate change.