NASA's PREFIRE mission, which consists of two CubeSats launched from New Zealand, aims to resolve uncertainties in far-infrared radiation from Earth's poles and its impact on global climate. By studying how clouds and water vapor affect thermal radiation into space, PREFIRE seeks to refine climate models and improve predictions of climate dynamics and the effects of global warming.
Two small NASA satellites, each about the size of a shoebox, are on a mission to solve a long-standing atmospheric puzzle: how clouds and water vapor at Earth's poles affect the planet's climate.
The first satellite of NASA's Polar Radiant Energy Experiment in the Far Infrared (PREFIRE) mission launched from New Zealand on May 25 and began transmitting scientific data in July. The second satellite was launched on June 5 and data collection began in August.
PREFIRE's goal is to measure the amount of heat the Earth emits into space from its coldest and most remote regions - the Arctic and Antarctic. By providing detailed data on polar heat emissions, the mission aims to improve climate models used to predict the effects of global warming on Earth's ice, oceans and weather systems.
The Earth absorbs a lot of the sun's energy in the tropics, and weather and ocean currents transport this heat to the poles (which receive much less sunlight). Ice, snow and clouds in the polar environment dissipate some of the heat into space, most of which is in the form of far-infrared radiation. The difference between the heat the Earth absorbs in the tropics and the heat radiated away from the Arctic and Antarctic is a key factor in Earth's temperature, helping to drive the dynamic system of climate and weather.
However, systematic measurements of polar far-infrared radiation have never been carried out. This is where PREFIRE comes in. The mission will help researchers gain a clearer understanding of when and where Earth's polar regions emit far-infrared radiation into space, and how water vapor and clouds in the atmosphere affect the amount of radiation.
Clouds and water vapor trap far-infrared radiation from Earth, increasing global temperatures -- part of the greenhouse effect.
"Getting the influence of clouds right is critical if we want to accurately model Earth's climate," said Tristan L'Ecuyer, a professor at the University of Wisconsin-Madison and principal investigator of PREFIRE.
Clouds and water vapor at Earth's poles are like summer windows: The clear, relatively dry weather in the Arctic is like opening a window, letting heat out of a stuffy room. Cloudy, relatively humid weather acts like a closed window, trapping heat inside.
The type of cloud and the height at which it forms affects how much heat is trapped in the polar atmosphere. Low-altitude clouds, composed mostly of water droplets, act like a tinted window and have a cooling effect. High-altitude clouds are mainly composed of ice particles, which are more likely to absorb heat and produce a warming effect. Because mid-elevation clouds contain varying amounts of water droplets and ice particles, they can have a warming or cooling effect.
But clouds are notoriously difficult to study: They are made up of microscopic particles that can move and change in seconds to hours. When it rains or snows, there is a huge recombination of water and energy that completely changes the properties of the cloud. These changing factors complicate realistically capturing cloud behavior in climate models that attempt to predict global climate scenarios.
Inconsistencies in how various climate models represent cloud cover can mean the difference between forecasts of 5 or 10 degrees Fahrenheit (3 or 6 degrees Celsius) of warming. The PREFIRE mission aims to reduce this uncertainty.
Thermal infrared spectrometers on each spacecraft will make important measurements of light wavelengths in the far-infrared range. These instruments will be able to detect clouds that are largely undetectable by other types of optical instruments. PREFIRE's instrument will be sensitive enough to detect the approximate size of the particles, allowing them to differentiate between droplets and ice particles.
"PREFIRE will give us a new pair of eyes to look at clouds," said Brian Kahn, atmospheric scientist at NASA's Jet Propulsion Laboratory and a member of the PREFIRE science team. "We're not quite sure what we'll see yet, and that's really exciting." "
The PREFIRE mission is a collaboration between NASA and the University of Wisconsin-Madison. NASA's Jet Propulsion Laboratory (JPL), a division of the California Institute of Technology in Pasadena, California, manages the mission for NASA's Science Mission Directorate and provides the spectrometer. Blue Canyon Technologies designed and built the CubeSats, and the University of Wisconsin-Madison processed and analyzed the data collected.
The spacecraft were launched by Rocket Lab under a Dedicated and Rideshare-at-Risk Acquisition (VADR) contract administered by NASA's Launch Services program. CubeSats like PREFIRE are valuable tools for advancing science and technology and are cost-effective platforms for innovation in mission architecture and scientific research.
Compiled from /scitechdaily