LAFE and LAFO: New experimental and observational investigations of land-atmosphere feedback processes

Florian Späth,Thilo Streck,Tobias Weber,Andreas Behrendt,Alan Brewer,Diego Lange,Syed Saqlain Abbas,Christoph Senff,Volker Wulfmeyer

doi:10.5194/egusphere-egu22-7498

Abstract

&lt;p&gt;The exchange of energy, moisture and momentum between the atmosphere and the land-surface as well as the associated feedback processes are decisive for the development of the planetary boundary layer. Inaccurate representation and parameterization of these processes are a weakness of current weather and climate models. Improvements in these areas will contribute significantly to better simulations of cloud formation on all temporal and spatial scales. This requires simultaneous measurements of the land-atmosphere system in all compartments. Both the LAFE and the new LAFO design with their instrument synergies have already made important contributions to this. With comparisons between model parameterizations and observations, e.g. the applicability of the Monin-Obukhov similarity theory (MOST) in the case of natural heterogeneous land surface can be investigated or new parameterizations can be developed.&lt;/p&gt;&lt;p&gt;The Land-Atmosphere Feedback Experiment (LAFE, Wulfmeyer et al., 2018) was performed in August 2017 as a measurement campaign at the Atmospheric Radiation Measurements (ARM) Program Southern Great Plains site in Oklahoma, USA. For boundary layer observations, scanning Doppler lidar systems for wind measurements, rotational Raman lidar for temperature and humidity measurements, and differential absorption lidar for water vapor measurements were setup. At the land-surface, meteorological and plant dynamics variables, energy balance, and soil moisture and temperature were recorded at eddy covariance stations. These measurements are also executed at the Land-Atmosphere Feedback Observatory (LAFO, lafo.uni-hohenheim.de) at the University of Hohenheim in Stuttgart (Germany) to collect long-term time series in addition to field experiments. Here, lidar measurements are operationally operated and complemented by measurements from a Doppler cloud radar. At the land surface we measure with eddy covariance stations and a network of soil moisture and temperature sensors and the vegetation status is recorded in the study area. This sensor synergy in LAFO is prototype for GLAFOs (Gewex LAFOs, Wulfmeyer et al. 2020) to establish these measurements in different climate regions in the world.&lt;/p&gt;&lt;p&gt;In this contribution, we present the measurement concept and how observations can be used to study and improve boundary layer and turbulence parameterizations. We demonstrate this with measurement results from LAFE and LAFO with estimates of fluxes determined by combining the moisture, temperature, and wind profiles near the ground, allowing the derivation of appropriate similarity relationships for both entrainment fluxes and MOST.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;Wulfmeyer et al., 2018, doi: 10.1175/BAMS-D-17-0009.1&lt;/p&gt;&lt;p&gt;Wulfmeyer et al. 2020, GEWEX Quarterly Vol. 30, No. 1.&lt;/p&gt;

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