Observation of turbulence profiles with lidar synergy

Abstract

<p>The energy reaching the earth surface in form of solar radiation during the daytime is partly reflected as outgoing radiation, partly conducted into the ground and partly trans- ported into the atmosphere by turbulent eddies of various scales forming the convective boundary layer (CBL) during the daytime. The latter energy flux partitions into sensible heat flux H and latent heat flux L. The understanding of H and L profiles is decisive for correct atmospheric simulations with models since these profiles rule the heat and water budgets, the distribution of humidity and temperature, and thus the atmospheric stability and furthermore the formation of clouds and precipitation (Behrendt et al. 2020).</p><p>In recent years, it has been demonstrated that lidar, is capable of not only determining mean profiles and gradients in the daytime CBL, the interfacial layer, and the lower free troposphere above but also higher-order-moment profiles of turbulent fluctuations for more and more variables, like vertical wind, moisture, temperature, aerosol backscatter, horizontal wind and dissipation rate, taking advantage of the synergy between a Raman lidar (temperature, moisture and aerosol backscatter) and Doppler lidars (vertical and horizontal wind) (Wulfmeyer, et al. 2016).</p><p>In this regard, the Institute of Physics and Meteorology of the University of Hohenheim has developed a thermodynamic profiler based on the Raman lidar technique, namely the Atmospheric Raman Temperature and Humidity Sounder (ARTHUS) (Lange et al. 2019). ARTHUS can be operated on ground-based, ship-borne and airborne platforms.</p><p>Stable 24/7 operations over long periods were achieved during several field campaigns and at the Land Atmosphere Feedback Observatory (LAFO) at the University of Hohenheim accumulating almost a year of data until now and covering a huge variety of weather conditions. Two collocated Doppler lidars (one in vertically staring mode and a second one in a 6-beam scanning mode) give the horizontal and vertical wind components, needed for H and L calculations, as well as dissipation rate.</p><p>ARTHUS has been also deployed during the EUREC4A field campaign (Stevens et al, 2020), on board RV Maria S Merian, to study ocean-atmosphere interaction, (18 Jan to 18 Feb 2020), along with two Doppler lidars.</p><p>Between 15th July and 20th September 2021, ARTHUS was deployed at Lindenberg Observatory from the German Weather Service (DWD).</p><p>At the conference, L, H and dissipation rate case examples from these campaigns will be presented.</p><p><strong>References</strong></p><p>Behrendt et al. 2020, https://doi.org/10.5194/amt-13-3221-2020</p><p>Lange et al. 2019, https://doi.org/10.1029/2019GL085774</p><p>Stevens et al. 2021, https://doi.org/10.5194/essd-2021-18</p><p>Wulfmeyer et al. 2016, https://doi.org/10.1175/JAS-D-14-0392.1</p>