LEANDRE 2 is a water vapor differential absorption lidar (DIAL) developed at Service d'Aeronomie (Paris) in cooperation with the Technical Division of the Institut National des Sciences de l'Univers (INSU) and was funded by the Centre National de Recherches Spatiales (CNES). This system was developed mainly to measure water vapor contents in the lower troposphere. Its broad tunability in the spectral region between 720 and 770 nm enables to reach a variety of water vapor lines with different line-strengths.