Assessment of middle atmosphere climatology using lidar for aerospace applications
Nicolas Gilbert Tufel, P. Keckhut, L. Dumas, Alexis Mariaccia, Mustapha Meftah, Yann Courcoux, Marie Vicomte, Alain Hauchecorne
Abstract
This study evaluates temperature and density variations in the upper stratosphere and in the mesosphere using ERA-5 and NRLMSISE-2.0 models, by comparing them with our forty-years long temperature lidar observations. NRLMSISE-2.0, while reliable in terms of seasonal trends, is less accurate daily: it shows high biases with the lidar at high altitudes (globally less than 4 K below 50 km, up to 14 K at 80km). The European Climate and Weather Forecast reanalysis model ERA-5 shows a bias to the lidar of -5 K the upper stratosphere but shows a larger difference reaching +20 K in the mesosphere. Lidar observations can reveal non-Gaussian distributions because of extreme events, such as Mesospheric Inversion Layers (MILs), minor and Major Sudden Stratospheric Warmings (m- and M-SSWs) or Double Stratopauses (DSs). These events are atmospheric particularities which should not be mixed with steady-state profiles to compute a mean climatology if the aim is to create a reference. To address this issue, a new methodology was developed to remove those events, resulting in what we called ”Steady-State” climatology. Our method based on lidar observation in four sites (Observatory of Haute-Provence, Reunion Island, Table Mountain and Mauna Loa) allowed us to give statistical information about these extreme phenomena. Furthermore, our findings show that when m-SSWs and MILs occur, the density profile deviates strongly from the NRLMISE-2.0 density, which highlights the need for refined atmospheric models for aerospace applications. Corresponding density differences between NRLMSISE and lidar can reach -15% and +25% at most for MILs and m-SSWs, respectively.