Abstract:
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There are several instruments and methods to retrieve the atmospheric Mixing Layer Height (MLH). However,
none of these instruments or methods can measure the development of the MLH under all atmospheric conditions.
For example, aerosol signatures measured by backscatter lidars can be used to determine the MLH but this
approach is reasonable only when the atmosphere is well-mixed. Microwave Radiometer (MWR) derived pro les
have low vertical resolution and cannot resolve ne structures in the boundary layer, especially, at higher altitudes.
Here we propose a method which combines data from a ground-based lidar and a MWR, in simulated as well as
real measurements scenarios, to overcome these limitations. The method works by tting an erf-like transition
model function to the section of range-corrected lidar backscatter signal. The section of the lidar backscatter
signal for tting the model function is obtained by incorporating the MWR estimates of MLH along with their
uncertainties. The tting is achieved by using an extended Kalman lter (EKF). The proposed approach, by
exploiting the synergy between the two instruments, enables to detect MLH with original vertical and temporal
resolutions. Test cases combining simulated data for a co-located lidar-ceilometer and a MWR are presented. The
simulated data is obtained from the Dutch Atmospheric Large Eddy Simulation (DALES) model for boundarylayer
studies. Doppler wind lidar along with radiosondes (whenever available) data is used to assess the quality of
the synergetic MLH estimates. Data from the HD(CP)2 Observational Prototype Experiment (HOPE) campaign
at J ulich, Germany is used to test the proposed method. |