From Forests to Fires: Watching the World's Resources
Who Are NASA's Earth Explorers?
The elementary school student questioning if El Niño occurs anywhere besides the Pacific Ocean. The researcher investigating connections between Arctic ozone depletion and global climate change. The citizen scientist interested in how changing land cover and use affects animal migration patterns. And the businessperson projecting future needs for harvest, delivery and storage of crops. All of these people are Earth Explorers -- they are all connected by their curiosity about Earth system processes. This series will introduce you to NASA Earth Explorers, young and old, with a variety of backgrounds and interests.
Chris Justice has always been interested in geography, and the landscapes of the English countryside had inspired him as he was growing up. But when he went to college, Justice says his path shifted to the human-focused part of the discipline, "... I started off studying English literature, economics and geography -- on the arts side of geography."
Then one of Justice's professors encouraged him to explore the physical side of geography as well, so he immersed himself in challenging scientific courses to "catch up." As Justice studied physical geography, he was intrigued with how aerial photography could be used to understand natural resources.
Then, in 1973, the head of the geography department showed Justice satellite photos taken by the first Landsat satellite system (ERTS-1). The images were photographic and therefore still similar to aerial photographs, but the scale of the images had changed dramatically. "We started to do air photo interpretation with satellite imagery," Justice remembers. "As soon as the digital data became available, we sensed a revolution taking place and started to develop digital and quantitative methods using that data using the mainframe computers of the time."
Justice studied satellite imagery while earning his doctoral degree. He was accepted by NASA's Goddard Space Flight Center for a postdoctoral position. As satellite imagery changed, moving from photographic to digital, Justice helped develop methods that moved away from interpreting single images to using time-series and monitoring the land surface as it changed over time.
His most recent work with NASA has focused on global fire monitoring. His study of fires began with some Goddard colleagues as they investigated the occurrence of fires in the Amazon associated with deforestation and human activity. Using imagery recorded in the middle-infrared part of the electromagnetic spectrum by weather satellites, Justice and his colleagues looked at the fires around the globe, both in terms of their smoke and gas emissions, but also in terms of human interaction with natural resources and the way fires are managed and shape landscapes.
For the past decade, Justice and other NASA scientists have been using MODIS to monitor the land surface more broadly. MODIS is the Moderate Resolution Imaging Spectroradiometer, an instrument on NASA's Terra and Aqua satellites. Justice and his colleagues have been working on developing a long-term record of careful measurements of fire and vegetation, snow, and ice around the globe.
In October 2011, NASA launched its latest Earth observation satellite, the NPOESS Preparatory Project, which includes an instrument called the Visible Infrared Imager Radiometer Suite. The VIIRS will help scientists continue collecting data about Earth's surface and will allow Justice and his colleagues to see how fire regimes are changing. These data are increasingly important as the climate changes and human interaction with the environment changes accordingly.
In the last few decades, the human and physical sides of geography have merged into an interdisciplinary subject. "We're no longer looking at just physical systems; we're looking at the human-environment interactions," Justice says. "I think that’s really a critical area for research."
Justice believes science should benefit society. Although scientists do not make policy, Justice thinks they need to "inform policy by providing better and timely information about our natural resources, whether it's climate change, fire, flooding, drought, tropical deforestation or land degradation."
Justice sees a need to "understand how humans can better manage Earth's resources and live in a more sustainable way." He pursues research topics that are "relevant and meaningful, providing information that can make a difference." This has been a common thread through his career, and it is there that Justice finds the greatest satisfaction in his work.
› A Global Tour of Fire
› Earth Explorers Series
› NASA Careers Resources
Brandi Bernoskie/Institute for Global Environmental Strategies