Global Hawk Pacific (GloPac) Mission Science Instruments
During an airborne campaign in spring 2010, NASA’s Global Hawk autonomous plane will carry 11 instruments to sample the chemical composition of air in Earth’s two lowest atmospheric layers — the stratosphere and troposphere — profile the dynamics and meteorology of both, and observe the distribution of clouds and aerosol particles. The instruments are operated by scientists and technicians from seven science institutions and are funded by NASA and the National Oceanic and Atmospheric Administration (NOAA).
ACAM — Airborne Compact Atmospheric Mapper
About the size of a microwave oven, ACAM has two miniature spectrometers and a high-definition video camera. The spectrometers measure the way sunlight is scattered and absorbed by Earth's atmosphere at hundreds of wavelengths (both visible and invisible). The high-definition video camera is used for visual identification of clouds and features on Earth's surface.
The spectrometer allows scientists to detect the presence of trace gases such as nitrogen dioxide (NO2) and ozone (O3), as well as how ultraviolet (UV) light is absorbed or scattered by aerosol particles. ACAM can also see changes in ocean color due to chlorophyll and dissolved organic matter.
Scott Janz of NASA's Goddard Space Flight Center, Greenbelt, Md., leads the ACAM team. The instrument has flown previously on missions to observe air quality over cities such as Houston, and is being used to help refine science requirements for future air quality observation satellites. For more information, visit http://dx.doi.org/10.1117/12.827035
CPL — Cloud Physics LIDAR
The CPL instrument pulses laser light into the atmosphere and observes the reflections — a process known as light detection and ranging, or LIDAR — to reveal the structure and brightness of clouds and aerosols. Clouds and aerosols have significant impacts on Earth's "radiative balance," the amount of light and heat coming into the atmosphere (mostly from the sun) and radiating back out into space. Those measurements are useful in their own right, but also help adjust the "eyesight" of NASA's Earth-observing satellites like Aura.
Matthew McGill of NASA's Goddard Space Flight Center, Greenbelt, Md., leads the CPL team, which has deployed its instruments for 10 years on NASA's ER-2 high-altitude planes. For more information, visit http://cpl.gsfc.nasa.gov
FCAS — Focused Cavity Aerosol Spectrometer
NMASS — Nuclei-mode Aerosol Size Spectrometer
FCAS and NMASS measure the size and abundance of particles (between 4 and 1000 nanometers) in the atmosphere. The measurements will improve our understanding of the properties, origin, fate, and impacts of these particles. Aerosols play an important but incompletely understood role in climate and atmospheric dynamics: reactions that occur on the surface of these particles in the stratosphere can affect ozone loss and recovery; some aerosols reflect sunlight back to space and cool the planet; and high-altitude particles can serve as nuclei for the formation of high-altitude ice clouds that play a role in the Earth's radiation budget.
FCAS and NMASS are managed by James "Chuck" Wilson, J. Michael Reeves, and colleagues at the University of Denver Aerosol Group. The instruments have flown on NASA's DC-8, ER-2, and WB-57F aircraft from 72 degrees South latitude to 90 degrees North.
HDVis — High-Definition Video System
The HDVis camera provides forward-looking time-lapse video imagery from the plane to identify cloud types and provide "situational awareness" for the plane. It has a wide-angle lens and is pointed forward at 45 degrees, so the camera shows everything from the horizon forward to the ground directly below. The view allows the science and operations teams to change course or altitude based on the interesting atmospheric phenomena ahead, and to adjust instrument measurements.
The HDVis team is led by Pat Grant of the University of California, Santa Cruz, and NASA's Ames Research Center, Moffett Field, Calif. Earlier versions of the video system have flown on missions with NASA's ER-2 and DC-8 aircraft to identify smoke plumes over the Amazon and convective cloud systems in the tropics. This is the first use of high-definition video. For more information, visit http://airbornescience.nasa.gov
MMS — Meteorological Measurement System
MMS measures atmospheric pressure, temperature, air turbulence, and the direction and speed of winds (both horizontal and vertical) immediately around the plane. These fundamental meteorological measurements give a picture of the environment through which the plane is flying and collecting samples. These variables are intertwined with other measurements, such as relative humidity.
Thaopaul "Paul" Bui of NASA's Ames Research Center, Moffet Field, Calif., leads the MMS team. Their system has flown on many different NASA and NOAA manned and unmanned aircraft since it was first deployed in 1986. The instrument package has been from Texas to Australia, from Norway to Chile, and many other locations, for studies of ozone depletion, exchanges between layers of the atmosphere, cloud formation, hurricanes, and aerosols.
MTP — Microwave Temperature Profiler
MTP is a radiometer that detects the naturally-occurring emission of microwaves (a longer wavelength form of light) from oxygen molecules in the atmosphere. This measurement is translated into a picture of the "temperature field" above, at, and below the flight path of the plane, giving context to what is observed by other instruments.
The temperature field helps scientists identify the height of the tropopause — the boundary between the troposphere (the atmospheric layer closest to Earth), and the stratosphere, where protective ozone is found. Knowing this boundary helps researchers specify the location of the gases and aerosols they measure, and perhaps where they are coming from or going to.
The MTP team is led by MJ Mahoney of NASA's Jet Propulsion Laboratory, Pasadena, Calif. Since the 1970s, variations of the MTP have been deployed 51 times on more than 800 flights in North, Central, and South America; Europe; Australia; the tropical Pacific Ocean; and from the North Pole to the South Pole over the Pacific Ocean. For more information, visit http://mtp.jpl.nasa.gov
UHSAS — Ultra-High Sensitivity Aerosol Spectrometer
UHSAS measures the concentration and size of atmospheric aerosol particles by collecting air samples and detecting laser light scattered from individual particles in the sample chamber. Aerosols come from natural sources — wildfires, volcanic eruptions, sand storms, etc. — and human sources — such as vehicle and industrial pollution. These particles play a role in the warming and cooling of the planet by modifying the amount of solar radiation that reaches Earth's surface and returns to space from reflection and emission.
The UHSAS team is lead by Bruce Gandrud of Droplet Measurement Technologies of Boulder, Colo. Their measurements contribute to the validation of information provided by satellites, giving a close-up view to verify that space-based measurements are correct. The instrument has flown on missions sponsored by the National Science Foundation, including work in the North Pacific between Japan and Alaska. For more information, visit: http://www.dropletmeasurement.com/products/airborne/71
UCATS — Unmanned Aircraft System Chromatograph for Atmospheric Trace Species
UCATS uses two gas chromatographs (GCs) to separate out the different molecules from air, and two absorption photometers to measure ozone (detectable in the ultraviolet) and water vapor (detectable in the infrared). The GCs detects the presence and amount of greenhouse gases such as nitrous oxide (N2O), sulfur hexafluoride (SF6), and methane (CH4). The instrument also measures ozone-depleting gases (such as CFC-11, CFC-12, and halon-1211), carbon monoxide (important for air quality), and hydrogen. All of these gases are important components for building models of climate change.
The UCATS team is led by Dr. James W. Elkins of NOAA's Earth System Research Laboratory in Boulder, Colo. Earlier versions of UCATS have flown on NOAA, NASA, and National Science Foundation missions from 2005 to the present. For more information, visit: http://www.acd.ucar.edu/start/ucats.shtml
UAS Ozone — NOAA Unmanned Aerial System Ozone Instrument
The UAS Ozone instrument directly samples ozone (O3) in the atmosphere. It takes a sample of air from outside the aircraft and passes it between a lamp that emits ultraviolet (UV) radiation and a UV detector. Because ozone strongly absorbs ultraviolet light, if there is more ozone in the air, then there is less UV at the detector. If there is less ozone in the air stream, then more ultraviolet light is detected.
Ozone is a crucial gas in the atmosphere because it shields us from harmful solar UV radiation, which can lead to skin cancer and other health problems. Ozone depletion in the stratosphere also contributes to climate change because ozone is a greenhouse gas.
The ozone team is led by Ru-Shan Gao of NOAA's Earth System Research Laboratory, Boulder, Colo. Their instruments have flown on NASA's WB-57F high-altitude research aircraft in Houston. For more information, visit http://sine.ni.com/cs/app/doc/p/id/cs-12343
ULH — Unmanned Aerial System Laser Hygrometer
ULH uses a continuous beam of laser light and two mirrors to sense the amount of water vapor present in packets of air around the plane. These measurements are important because the amount of water vapor in the upper troposphere and lower stratosphere has a disproportionate impact on climate and future climate change.
The stratosphere is very dry — just a few molecules per million are water, roughly 10,000 times less than at Earth's surface. Accurate measurements of water vapor provide "ground truth" for remote measurements made by satellite instruments such as the Microwave Limb Sounder on the NASA Aura spacecraft.
Robert Herman of NASA's Jet Propulsion Laboratory, Pasadena, Calif., leads the ULH team. ULH has flown previously on the NASA WB-57F high-altitude aircraft. It flew from Houston into the stratosphere over the continental United States and the Gulf of Mexico.