B200 - LARC

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 Polarized Imaging Nephelometer is an in situ instrument designed and built at the Laboratory for Aerosols, Clouds and Optics (LACO) at the University of Maryland Baltimore County for the measurement of components of the aerosol phase matrix in high angular resolution between 2 to 178 deg scattering angles. The measured phase matrix provides extensive characterization of the scattering properties of the studied aerosols allowing for a very comprehensive set of aerosol scattering parameters. These measurements are essential for the validation of the new generation of aerosol remote sensors like the APS polarimeter in the Glory satellite, and for the construction of accurate models of real aerosol particles, specially the non-spherical ones.

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.

The RC-30 is an airborne film camera system, using color infrared, natural color and black and white film, to obtain high resolution earth imagery.

Estimation of surface wind speed by matching the shape of the reflected GPS signal correlation function against analytical models. Wind speed obtained from this method has agreed with that recorded from buoys with a bias of less than 0.1 m/s, and with a standard deviation of 1.3 m/s.

A modified GPS receiver is used to track the direct line of sight satellites through a zenith-oriented right hand circularly polarized (RHCP) antenna and record the cross-correlation function of the reflected signals using a nadir-oriented left hand circularly polarized (LHCP) antenna. The cross-correlation for one or two satellites is continuously recorded in 10 to 12 range bins. Accumulation is done in hardware for an integration time of 1 ms. Batches of 0.1 seconds of the sum square of the inphase and quadrature components are then averaged before being saved to disk.

The Raman Airborne Spectroscopic Lidar (RASL) consists of a 15W ultraviolet laser, a 24-inch (61-centimeter) diameter Dahl-Kirkham telescope, a custom receiver package, and a structure to mount these components inside an aircraft. Both the DC-8 at NASA Dryden and the P-3 at NASA/Wallops are aircrafts that could carry RASL. The system is unique because it requires the largest window ever put into either of these aircraft. A fused-silica window, diameter of 27 inches (68.6 centimeters) and 2.375 inches (6 centimeters) thick is needed to withstand the pressure and temperature differentials at a 50,000-foot (15.2-kilometer) altitude.

In June through August of 2007, RASL flew numerous times on board a King Air B-200 aircraft out of Bridgewater, VA, in support of the 2007 Water Vapor Validation Experiments (WAVES) campaign. The WAVES campaign was a series of field experiments to validate satellite measurements. RASL data, along with data from ground-based and balloon-borne instruments, were used to assess the CALIPSO and TES instruments and for studies of mesoscale water vapor variability. During the test flights, RASL produced the first-ever simultaneous measurements of tropospheric water vapor mixing ratio and aerosol extinction from an airborne platform.

POS AV is a hardware and software system specifically designed for direct georeferencing of airborne sensor data. By integrating precision GNSS with inertial technology, POS AV enables geospatial projects to be completed more efficiently, effectively, and economically. POS AV is engineered for aerial cameras, scanning lasers, imaging sensors, synthetic aperture radar, and LIDAR technology.

NASA’s Land, Vegetation and Ice Sensor (LVIS) is a wide-swath, high-altitude, full-waveform airborne laser altimeter and camera sensor suite designed to provide elevation and surface structure measurements over hundreds of thousands of square kilometers. LVIS is an efficient and cost-effective capability for mapping land, water, and ice surface topography, vegetation height and vertical structure, and surface dynamics. The LVIS Facility is comprised of two high-altitude scanning lidar systems plus cameras that have been integrated on numerous NASA, NSF, and commercial aircraft platforms providing a diverse and flexible capability to meet a broad range of science needs. The newest Facility lidar (LVIS-F) began operations in 2017 using a 4,000 Hz laser, and an earlier 1,000 Hz sensor built in 2010 has undergone various upgrades (LVIS-Classic). High-resolution, commercial off-the-shelf cameras are co-mounted with LVIS lidars providing geotagged image coverage across the LVIS swath. LVIS sensors have flown extensively for a wide range of science applications and have been installed on over a dozen different aircraft, most recently on NASA’s high-altitude Gulfstream-V jet based at Johnson Space Center

The LVIS lidars are full-waveform laser altimeters, meaning that the systems digitally record both the outgoing and reflected laser pulse shapes providing a true 3-dimensional record of the surface and centimeter-level range precision. Multiple science data products are available for each footprint, including the geolocated waveform vector, sub-canopy topography, canopy or structure height, surface complexity, and others. LVIS lidars map a ±6 degree wide data swath centered on nadir (e.g., at an operating altitude of 10 km, the data swath is 2 km wide). They are designed to fly at higher altitudes than what is typical for commercial lidars in order to map a wider swath with low incidence angles, avoid the need for terrain following, while operating at much higher speeds that maximize the range of the aircraft. Recent data campaigns include deployments to Antarctica, Greenland, Canada, Alaska, the conterminous US, Central America, French Guiana, and Gabon.