The Multi-Purpose Airborne Sensor Carrier MASC-3 for Wind and Turbulence Measurements in the Atmospheric Boundary Layer.

Alexander Rautenberg,Bram Van Kesteren,Andreas Platis,Kjell Zum Berge,Patrick Manz,Martin Schön,Stephan T Kral,Irene Suomi,Jens Bange,Moritz Mauz

doi:10.3390/s19102292

Abstract

For atmospheric boundary-layer (ABL) studies, unmanned aircraft systems (UAS) can provide new information in addition to traditional in-situ measurements, or by ground- or satellite-based remote sensing techniques. The ability of fixed-wing UAS to transect the ABL in short time supplement ground-based measurements and the ability to extent the data horizontally and vertically allows manifold investigations. Thus, the measurements can provide many new possibilities for investigating the ABL. This study presents the new mark of the Multi-Purpose Airborne Sensor Carrier (MASC-3) for wind and turbulence measurements and describes the subsystems designed to improve the wind measurement, to gain endurance and to allow operations under an enlarged range of environmental conditions. The airframe, the capabilities of the autopilot Pixhawk 2.1, the sensor system and the data acquisition software, as well as the post-processing software, provide the basis for flight experiments and are described in detail. Two flights in a stable boundary-layer and a close comparison to a measurement tower and a Sodar system depict the accuracy of the wind speed and direction measurements, as well as the turbulence measurements. Mean values, variances, covariance, turbulent kinetic energy and the integral length scale agree well with measurements from a meteorological measurement tower. MASC-3 performs valuable measurements of stable boundary layers with high temporal resolution and supplements the measurements of meteorological towers and sodar systems.

Highlights

For atmospheric boundary-layer (ABL) studies, unmanned aircraft systems (UAS) can provide new information in addition to traditional in-situ measurements or ground- and satellite-based remote sensing techniques
This study aims to validate the measurements of the new mark of the Multi-Purpose Airborne Sensor Carrier (MASC-3) by closely comparing them with measurements from a meteorological tower and subsequently being able to fuse both systems for investigations of stable boundary layers (SBL)
The autopilot system and the durable airframe can be deployed in polar conditions and provides manifold maneuverability including a multitude of flight patterns for different missions, as well as automatic landing

Summary

Introduction

For atmospheric boundary-layer (ABL) studies, unmanned aircraft systems (UAS) can provide new information in addition to traditional in-situ measurements or ground- and satellite-based remote sensing techniques. Recent developments of UAS and high-performance high-resolution in-situ sensors allow the observation of processes at different levels within the ABL, which so far can only be accomplished by tall meteorological towers or to some extent, with limited spatial and temporal resolution, by ground based remote sensing systems. Sensors 2019, 19, 2292 sample data of the ABL along the flight path supplements ground based measurements and the ability to extend the data horizontally and vertically allows manifold investigations. Turbulence along a straight horizontal flight path is not precisely a spatial snapshot, nor a temporally averaged snapshot, but a mixture of both, which can be labeled as quasi-spatial snapshot. The use of such data presumes the following assumptions, pros and cons. The most important compendium is Taylor’s hypothesis of frozen turbulence [1,2]

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