MPLNET The NASA Micro-Pulse Lidar Network National Aeronautics and
Space Administration
Goddard Space
Flight Center

Instruments Overview:

All sites in MPLNET currently use the Micro Pulse Lidar (MPL), which was developed at NASA Goddard Space Flight Center (GSFC) in the early 1990s. The MPL was patented and subsequently licensed to industry for commercial sales beginning in the mid 1990s.

The MPL (Spinhirne et al. 1995) is a compact and eye-safe lidar system capable of determining the range of aerosols and clouds by firing a short pulse of laser light (at 523, 527, or 532 nm) and measuring the time-of-flight from pulse transmission to reception of a returned signal. The returned signal is a function of time, converted into range using the speed of light, and is proportional to the amount of light backscattered by atmospheric molecules (Rayleigh scattering), aerosols, and clouds. The evolution of the MPL from the initial Spinhirne et al. (1995) optical design to the standard design now used in MPLNET is described in detail by Campbell et al. (2002) and Welton and Campbell (2002), including on-site maintenance, and calibration techniques.

Post 2002 enhancements include a new data system, telescope, fiber-coupled detectors, and a new laser. These changes do not significantly alter the basic MPL optical design but increase system reliability and allow for more in-field repair options.

Post 2014 changes: MPLNET began supporting a polarized version of the MPL. A paper is in preparation describing the newer version of the instrument and calibration/performance studies.

Commercial Off The Shelf (COTS) MPL Systems:

COTS MPL systems may not meet MPLNET specifications. In order to meet MPLNET specifications, COTS MPLs must be inspected at our GSFC facility. This process is performed for all COTS MPLs in MPLNET. Any required modifications to the COTS MPL are performed prior to operation in MPLNET. The NASA MPLNET project does not inspect COTS MPLs sold to non-MPLNET partners, nor does it support data processing for non-MPLNET partners. It is the responsibility of the commercial manufacturer to ensure high quality of COTS MPLs sold to customers outside MPLNET. It is also the responsibility of the non-MPLNET customer to operate the COTS MPL correctly and apply proper data processing and analysis techniques. As a result, the performance and data quality of COTS MPL systems are not the same as our MPLNET systems and data products.

In recent years, other small aerosol and cloud lidars have become commercially available. Some are designed for possible network use. We are currently evaluating some of those for possible support in MPLNET.

* full citations for references available on our publications page

National Aeronautics and
Space Administration
Goddard Space
Flight Center
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