scope:

Introduction

The guideline series VDI 3786 "Environmental meteorology; Meteorological measurements" is divided into several parts. A few of which present remote measurement methods that serve to determine the wind vector.

The guideline VDI 3786 Part 11 describes the determination of the vertical wind profile with the aid of Doppler SODAR systems.

The present guideline VDI 3786 Part 14 describes the determination of the three-dimensional wind vector using Doppler wind LIDAR ("LIght Detection and Ranging" or "Light Identification, Detection and Ranging"). The guideline refers to guideline VDI 3786 Part 2 with regard to the definition of wind measurements and to guideline VDI 3786 Part 1 in considering the averaging time. Use is also made of the guideline VDI 3786 Part 8. Safety problems are not treated; reference is made here to relevant standards [VBG 93, DIN EN 60 825-1].

The determination of the vertical wind profile with the aid of Doppler RADAR is described in guideline VDI 3786 Part 17.

The principle of operation and the handling of other LIDAR systems are explained in guideline VDI 4210; performance characteristics are also specified and characteristic examples of application are presented there.

LIDARs have proved to be valuable systems for remote sensing of atmospheric pollutants, of various meteorological parameters, for example wind velocity, cloud and aerosol distributions, and of optical properties of the atmosphere, such as the extinction coefficient and backscattering coefficient. A specific feature of LIDAR methods is their ability to allow spatially resolved remote sensing. The measurements can be performed without contact and in any direction since electromagnetic radiation is used for sensing. LIDAR systems therefore supplement the conventional measurement technology. They are suitable for a large number of measurement tasks that cannot be adequately performed using point measurements.

The wind is a decisive parameter for describing the atmospheric conditions and exchange processes, both its temporal and spatial mean and its short-term fluctuations, known as turbulence, are important [Banakh et al. 1997].

The following fields of application are of particular interest:

• routine measurements of the wind at meteorological stations

• meteorological briefing for aviation

• obtaining data for dispersion modelling, e.g. for licensing procedures according TA Luft

• industrial plant monitoring in normal operation and during accidents

• future use for determining the turbulent exchange in the troposphere up to the lower stratosphere

• future use for determining large-scale atmospheric transport (e.g. space LIDAR)

Examples of application illustrating these possible uses are set forth in Annex B.