Lidar experiments

ABLE (AirBome Lidar Experiment) is a Nd-Yag high energy lidar for the measurement of aerosols and PSC. It will operate in either a dual wavelength configuration 532 nm or 355 nm emissions or at 532 nm with dual polarisation detection capacity. It will detect aerosols, PSC and tropospheric clouds. 

Several systems based on LIDAR (Section 2.3.) have been developed for explosives and explosive device detection. While not fitting the conventional LIDAR experiment definition, these systems apply LIDAR principles to the detection of explosive sources. 

Fig. 16. Na and Na+ density profiles calculated using the one-dimensional model developed by McNeil et The calculations are conducted for different rate coefficients for sodium charge transfer with atmospheric ions, NO" " and O2. The dashed line is a typical neutral profile as observed in a lidar experiment.

There are many more hazards in an experiment such as this one. However, it is worthwhile to focus on what is unique about the LIDAR experiment. In studying this experiment, it was important for NASA to go back and study in detail certain aspects of the design. Other safety analyses in this book will demonstrate how to conduct a detailed safety analysis of other systems, such as pressure or hazardous fluids and processes. 

FIGURE 5.8 Function/concern organization chart. (From National Aeronantics and Space Administration, Goddard Space Flight Center, Methane LIDAR Experiment, Preliminary Hazard Analysis, Prepared by Hernandez Engineering, Inc., nnder NASA Contract NAS5-31825, Task S-11-94, no date. With permission.)... 

A safety checklist (which will be further described in Chapter 6) was also used in tandem with the operation of the LIDAR experiment. This is a good example of combining various safety methods for maximum safety coverage. 

An example of practical importance in atmospheric physics is the inference of effective optical constants for atmospheric aerosols composed of various kinds of particles and the subsequent use of these optical constants in other ways. One might infer effective n and k from measurements—made either in the laboratory or remotely by, for example, using bistatic lidar—of angular scattering fitting the experimental data with Mie theory would give effective optical constants. But how effectual would they be Would they have more than a limited applicability Would they be more than merely consistent with an experiment of limited scope It is by no means certain that they would lead to correct calculations of extinction or backscattering or absorption. We shall return to these questions in Section 14.2. 

The advent of new intense laser sources allowed probing of additional metals, such as Fe, Ca and Ca+, and K, using the lidar techniques. All of the investigated layers exhibit sporadic events. Von Zahn and coworkers have improved the time resolution of their experiments to 1 s, allowing them to observe individual meteor trails and the associated local metal atom density increases. ... 

Winker D. M., (1998). EITE—a view from space. Lidar In-space Technology Experiment, http //www-lite.larc.nasa. gov/index.html... 

IronEx Iron Enrichment Experiment LIDAR Light detection and ranging LNHC Low-nitrate high-chlorophyll... 

Van den Eeckhaut et al. (2007) conducted an experiment by providing lidar images of a forested area 125 km in extent to seven experienced geomorphologists and asking each of them to... 

It was planned a field experiment series in which the sensitivity of the two s stems was measured. A 2 m polyethylene foil chamber was used as a gas cell and some free disseminations w re used in the experiments. Sensitivity of the differential absorption lidar systems are charaterized by the minimum detectable path integrated concentration of materials to be detected, their response time and their range. During the field test integration times were 1 sec for all measurements with both VTB-2 and LRS-3 systems. With post processing moving averages were calculated for 10 sec and 30 sec in 1 sec steps. 

Various equipment supports the system. Instrumentation racks include computers, laser synchronization units, sensors, and other equipment used to control the experiment. The entire LIDAR setup is mounted on high-grade aluminum beams. 

D. M. Winker, M.P. McCormick Aerosol and cloud sensing with the Lidar in Space Technology experiment (LITE). SPIE 2310, 98 (1994)... 

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