Lidar

CRL can provide simultaneous water vapor, temperature, aerosol, and cloud profiles within the planetary boundary layer (PBL) from UWKA, NSF/NCAR C-130, and NOAA P-3. It uses a compact, lightweight transmitting-receiving system (12-inch telescope). Although the 50-mJ CRL laser limits water vapor measurement to short-range under high solar background conditions, past CRL measurements demonstrated that CRL measurements offer excellent measurements to characterize PBL structures from airborne platforms.   CRL enhances PBL observations at horizontal resolutions ranging from ~100 m to ~1 km and can revolutionize a range of atmospheric processes studies. These include: advancing our understanding of small-scale interactions between clouds and their environment, investigating air-sea and air-land interactions; documenting boundary layer structure over heterogeneous surfaces and under cloudy conditions; examining the mesoscale atmospheric environments and dynamics.

MARLi was an NSF-MRI funded new instrument development to provide water vapor, temperature, aerosol, and cloud profiles within the planetary boundary layer (PBL). MARLi was successfully flight-tested on the UWKA and the NSF/NCAR C-130 for over sixty-hours in the summer of 2016.  
MARLi transforms our capability to observe the atmosphere at horizontal resolutions ranging from ~100 m to ~1 km and can revolutionize a range of atmospheric processes studies. These include: advancing our understanding of small-scale interactions between clouds and their environment, investigating air-sea and air-land interactions; documenting boundary layer structure over heterogeneous surfaces and under cloudy conditions; examining the mesoscale atmospheric environments and dynamics.

Roscoe is a new, more compact version of the NASA GSFC Cloud Physics Lidar that has flown on multiple NASA high altitude aircraft over the past two decades. While utilizing the same proven measurement technique of coupling a high repetition rate laser with photon-counting detection, Roscoe differs from CPL in two significant ways.  First, it is designed to simultaneously observe both upwards and downwards from the aircraft, to enable studies of stratospheric aerosols above flight altitude as well as below.  It is, essentially, two small CPL instruments in one package, one pointing nadir and one pointing zenith.  Second, it operates at only 1064 and 355 nm (not 532 nm) to satisfy eye-safety considerations for airborne operation.  Roscoe measures depolarization at both wavelengths to characterize the phase of the cloud and aerosol particles detected.

The Modular Aerial Sensing System (MASS) is a compact airborne sensor package of optical remote sensing instrumentation that is coupled to a tactical grade inertial navigation system. The system includes a waveform scanning lidar; visible, infrared, and hyperspectral imaging systems; and an infrared pyrometer.

The NASA Langley airborne High-Spectral-Resolution Lidar – Generation 2 (HSRL-2) is used to characterize clouds and small particles in the atmosphere, called aerosols. From an airborne platform, the HSRL-2 instrument provides nadir-viewing profiles of aerosol and cloud optical and microphysical properties, which are used studies aerosol impacts on radiation, clouds, and air quality. HSRL-2 also provides measurements of the near-surface ocean, including depth-resolved subsurface backscatter and attenuation. HSRL-2 can also be configured to utilize the differential absorption (DIAL) technique for measuring profiles of ozone concentrations in addition to the above products.

The CLS is flown on the ER-2 to conduct cloud radiation and severe storm field experiments. Designed to operate at high altitudes in order to obtain measurements above the highest clouds, the instrument provides the true height of cloud boundaries and the density structure of less dense clouds. The height structure of cirrus, cloud top density and multiple cloud layers may also be profiled. The system specifications are as follows:

Laser Type: Nd:YAG I,II
Wavelength: 1064, 532 nanometer
Pulse Energy: 90, 30 mJ
Pulse repetition frequency: 10 Hz
Beam width: 1 mrad

Diameter: 0.15 m
Beam width: 1.4 mrad
Polarization: vert. and horiz.

Sample rate: Measurements at 20 m intervals at 200 m/s aircraft speed
Range Resolution: 7.5 m
Number of Channels: 4
Samples per Channel: 3310
Record Capacity: 8 hours

MACAWS is an airborne side-scanning Doppler laser radar (lidar) which measures two dimensional wind fields, vertical wind profiles, and aerosol backscatter from clear air and clouds. Range varies from 10-30 km depending on aerosol abundance and cloud attenuation. Upon exiting the aircraft, the lidar beam is completely eye-safe. MACAWS is developed and operated cooperatively by the atmospheric lidar remote sensing groups of NASA Marshall Space Flight Center, NOAA Environmental Technology Laboratory, and Jet Propulsion Laboratory.

MACAWS consists of: a frequency-stable pulsed transverse-excited atmospheric pressure carbon dioxide laser emitting 0.5-1.0 J per pulse at 10.6 micron wavelength at a nominal pulse repetition frequency (PRF) of ~20 Hz; a coherent receiver employing a cryogenically-cooled HgCdTe detector; a 0.3 m off-axis paraboloidal telescope shared by the transmitter and receiver in a monostatic configuration; a ruggedized optical table and three-point support structure; a scanner using two counter-rotating germanium wedges to refract the transmitted beam in the desired direction; an inertial navigation system (INS) for frequent measurements of aircraft attitude and speed; data processing, display, and storage devices; and an Operations Control System (OCS) to coordinate all system functions.

The NASA Langley Airborne Differential Absorption Lidar (DIAL) system uses four lasers to make DIAL O3 profile measurements in the ultraviolet (UV) simultaneously with aerosol profile measurements in the visible and IR. Recent changes incorporate an additional laser and modifications to the receiver system that will provide aerosol backscatter, extinction, and depolarization profile measurements at three wavelengths (UV, visible, and NIR). For SEAC4RS, the DIAL instrument will include for the first time aerosol and cloud measurements implementing the High Spectral Resolution Lidar (HSRL) technique [Hair, 2008]. The modifications include integrating an additional 3-wavelength (355 nm, 532 nm, 1064 nm) narrowband laser and the receiver to make the following measurements; depolarization at all three wavelengths, aerosol/cloud backscatter and extinction at 532 nm via the HSRL technique, and aerosol/cloud backscatter at the 355 and 1064 nm via the standard backscatter lidar technique. Integration of the aerosol extinction profile at 532nm above and below the aircraft also provides aerosol optical depth (AOD) along the aircraft flight track.

The NASA Langley airborne High Spectral Resolution Lidar (HSRL) is used to characterize clouds and small particles in the atmosphere, called aerosols. From an airborne platform, the HSRL science team studies aerosol size, composition, distribution and movement.

The HSRL-1 instrument is an innovative technology that is similar to radar; however, with lidar, radio waves are replaced with laser light. Lidar allows researchers to see the vertical dimension of the atmosphere, and the advanced HSRL makes measurements that can even distinguish among different aerosol types and their sources. The HSRL technique takes advantage of the spectral distribution of the lidar return signal to discriminate aerosol and molecular signals and thereby measure aerosol extinction and backscatter independently.

The HSRL-1 instrument provides measurements of aerosol extinction at 532 nm and aerosol backscatter and depolarization at 532 and 1064 nm. The HSRL measurements of aerosol extinction, backscattering, and depolarization profiles are being used to:

1) characterize the spatial and vertical distributions of aerosols
2) quantify aerosol extinction and optical thickness contributed by various aerosol types
3) investigate aerosol variability near clouds
4) evaluate model simulations of aerosol transport
5) assess aerosol optical properties derived from a combination of surface, airborne, and satellite measurements.