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The University of Illinois

New Frontiers Initiative Webinar Series

Tuesday, December 15

The 50 cm Quest for the Land Carbon Sink

by Compton Tucker, NASA/GSFC; Martin Brandt, University of Copenhagen; Ankit Kariryaa, University of Bremen; and 21 other coauthors

8 AM Pacific / 9 AM Mountain / 10 AM Central / 11 AM Eastern


Only 50% of total CO2 emissions and emissions from deforestation accumulate in our atmosphere: of the other half, 20% is absorbed into the oceans and 30% goes somewhere on land. We haven't a clue where on land this CO2 from the atmosphere is stored in vegetation via photosynthesis in plant tissues such as wood. Understanding carbon storage on land is critical for dealing with global warming--where this occurs and what are the mechanisms that control this carbon storage. Currently, our understanding of the Land Carbon Sink is based on numerical simulation models that run at grid cells sizes of 50 x 50 km or larger. These simulation studies indicate a large proportion of the land carbon sink occurs in semi-arid regions.

Our team has undertaken to quantitatively determine the carbon in trees in a large semi-arid area, stretching from the Sahara Desert to the humid sub-tropics in West Africa, over an area of 1.3 million km2. The first step is to map individual trees. Trees are important because of carbon residence time in wood. Furthermore, no one has successfully mapped discrete trees with satellite data in semi-arid areas. We used 50,000 individual commercial satellite images with a 50 cm x-y spatial resolution to map tree crowns, using high performance computing on Blue Waters with artificial intelligence and machine learning. We distinguished trees from non-trees, mapped 1.8 billion trees, determined the area of leaves within the tree crown, and know their location to ± 5 m. We are presently determining tree elevation, when that is combined with tree crown area, this will be an accurate predictor of carbon in the wood of trees over vast semi-arid regions. Whether this will be important with respect to climate is unknown. We should have the answer soon.


Compton J. Tucker
NASA/Goddard Space Flight Center
Earth Science Division, Code 610.9
Greenbelt, Maryland 20771

Compton Tucker, a native of Carlsbad New Mexico, received his B.S. degree in biological science in 1969 from Colorado State University in Ft. Collins. After working for Colorado National Bank in Denver and the First National Bank in Albuquerque, he returned to Colorado State University for graduate school in Earth science. He received his M.S in 1973 and his Ph.D. in 1975, both from the College of Forestry. In 1975, he came to NASA/Goddard as a National Academy of Sciences post-doctoral fellow, and in 1977 became an employee of NASA. At NASA/Goddard, Tucker has used satellite data to study the Earth, in research areas that include famine early warning, deforestation, desert boundary determination, ecologically-coupled diseases, terrestrial primary production, food security, and identifying degraded lands. Since 2015, he has devoted most of his time complimenting NASA satellite observations with commercial satellite data. He took part from 2002 to 2012 in NASAs Space Archaeology Program, leading a group that assisted archaeologists mapping ancient sites with ground-penetrating radar and magnetometry in Turkey, at the sites of Troy of Trojan War fame, in the Granicus River Valley, and at Gordion, the home of King Midas.

He has authored or coauthored more than 190 journal articles that have been cited more than 20,000 times according to the Web of Science and more than 70,000 time according to Google Scholar. He has a Google Scholar "H" index of 122 and a Google Scholar "H" index since 2015 of 71. He is an adjunct professor at the University of Maryland and is a consulting scholar at the University of Pennsylvanias Museum of Archaeology and Anthropology. He taught "Introduction to Remote Sensing" seven times at the University of Maryland, which forced him to learn the subject better. He has appeared on more than forty radio and TV programs. He is a Fellow of the American Geophysical Union & the American Association for the Advancement of Science. He has been awarded several medals and honors, including NASAs Exceptional Scientific Achievement Medal, the Pecora Award from the U.S. Geological Survey, the National Air and Space Museum Trophy for Current Achievement, the Henry Shaw Medal from the Missouri Botanical Garden, the Galathea Medal from the Royal Danish Geographical Society, the Vega Medal from the Swedish Society of Anthropology and Geography, and the Mongolian Friendship Medal.

Please register for the webinar.