The fourth time’s the charm for NASA’s new aircraft-powered global warming research mission. After multiple delays working in the constraints of the space agency’s notoriously hobbled Earth-based research budget, a team of atmospheric scientists is set to take advantage of new satellites, balloons and planes during a potentially groundbreaking mission this summer in Costa Rica.

Announced yesterday, the Tropical Composition Cloud Climate Coupling (TC4) field campaign will examine a somewhat mysterious layer of the atmosphere that could provide a crucial link to climate change. To better understand how ozone-depleting pollutants move from earth to the vulnerable, ozone-rich stratosphere, about 100 scientists will study the space between: the tropical tropopause transition layer (TTL), which can funnel air and its pollutants much faster than other atmospheric movements.

According to TC4 program scientist Dr. Brian Toon, air involved in a cloud convection column can take “only 10 or 20 minutes to move from the ground level to the top of the troposphere. An airplane can’t follow it up—I’ve tried.” During these violent updrafts, storm-type clouds nearer the earth’s surface containing very fine particles and pollutants transfer their cargo into tiny ice crystals—on the order of microns—that balloon into extremely long-lasting, expansive, often sub-visible clouds in the stratosphere.

To track the debris as it passes through the TTL, the high-tech research team in Costa Rica will be the first to extensively utilize and verify data collected by the so-called “A-train,” a recently completed group of five satellites launched to gather complementary data profiling the earth’s atmosphere. The newest of these satellites, launched last year, come equipped with radar and special “LIDAR” sensors, which measure laser light pulses and reflections to help draw conclusions about atmospheric chemistry.

In addition to these indirect measurements from above, several air-sampling balloons and three high-altitude planes will develop the first three-dimensional, contact-based understanding of the TTL. The airplanes, including a civilian-science version of the Air Force’s U-2 reconnaissance platform, are capable of flying at the edge of space—so high that pilots and scientists must begin breathing pure oxygen an hour before flight in order to acclimate, and must wear space-suit-style pressure suits to protect them in the otherwise fatal event of cabin depressurization. 

Program scientist Michael Kurylo stressed that “many facets of the TTL are not well understood” but finding more about its identity is “essential to understanding ozone depletion.” Direct funding from NASA may have delayed this project, but as the agency’s top official, Michael Griffin, told PM this month, “you can always use more money. But we have a $5.5-billion science program overall; 27 percent of that this year is Earth science. Nearly all of the results that people are debating come from NASA missions, NASA work, NASA researchers. I think we’re doing a pretty good job.” —Jancy Langley