Background
The understanding of Earth’s system is necessary to project the state of our planet for building and maintaining our human kind. Carbon cycle is one of the key components in the Earth system. Carbon dioxide (CO2) is exchanged among atmosphere, land and oceans. The largest CO2 input to the global carbon cycle system over decadal time scales comes from CO2 emissions from fossil fuel combustion. These CO2 emissions are also the cause of the observed, increased level of atmospheric CO2. Accurately quantifying the amount of the emissions and its impact on the Earth System is a fundamental task in Earth System Science. One of the key questions to be sought was to understand the sizes and locations of carbon sources and sinks. Since the 1950s, the community has tackled this question using atmospheric observations, and later computer modeling. In the last decade, the community has entered a new era where we observe CO2 from space more broadly and frequently in order to increase our capability to study the carbon cycle.
Foundation
The ODIAC project was founded in 2008 in Tsukuba, Japan, by Tomohiro Oda and Shamil Maksyutov, shortly after Oda joined the Maksyutov research group at the National Institute for Environmental Studies (NIES). Maksyutov, the Deputy lead of the Greenhouse gas Observing SATellite (GOSAT) project at NIES, assigned Oda to a new fossil fuel CO2 emission (ffco2) data development project for the GOSAT Level 4 (flux inversion) data product. The following year was a mile stone year for the carbon cycle community where Japan’s GOSAT was placed in orbit, and on the contrary, NASA’s Orbiting Carbon Observatory (OCO) had a tragic crash. At the same time, Oda designed and wrote up the first computer code for a global high-resolution ffco2 model, later called the ODIAC model, from scratch and presented the first result at the International CO2 conference in Jena, Germany (ICDC8). At the ICDC8, Oda had a surprise visit by the legendary ffco2 scientists from the Carbon Dioxide Information Analysis Center (CDIAC), Drs. Marland, Blasing and Andres, while at his poster. With CDIAC’s encouragement and support, the ODIAC team started releasing their data product under the name of ODIAC – the Open-source Data Inventory for Anthropogenic CO2.
“As far as the name ODIAC is concerned, we feel that the subject matter relationship is clear and yet the distinction is also clear, but to make the intellectual connection is just kind of fun.” – Dr. Gregg Marland (CDIAC), June 6, 2010.
“As far as the name ODIAC is concerned, we feel that the subject matter relationship is clear and yet the distinction is also clear, but to make the intellectual connection is just kind of fun.” – Dr. Gregg Marland (CDIAC), June 6, 2010.
Pioneer of space-based global ffco2 modeling
ODIAC is the first operational fossil fuel CO2 model that is based on the satellite-observed nighttime lights data (NTL). The use of the NTL for mapping CO2 emissions had been explored by several studies. ODIAC pioneered the combined use of NTL and point source data to achieve its global 1x1km (30 arc sec) resolution emission field. Since then, the combined use has been adopted by other ffco2 models. Before ODIAC, most of the gridded CO2 products were provided at a 10x10 km spatial resolution or coarser. ODIAC’s global spatial resolution seemed to be excessively high. However, 10 years later, the high-resolution model is the one the community expects in the era of high-resolution CO2 modeling and monitoring. The performance of the emission model has been supported by the number of published literature. Oda and Maksyutov published ODIAC's debut paper in 2011 to set the new standard for ffco2 emission data product in the satellite CO2 era. The 2011 paper has been cited more than 400 times as of now, and the citation is still increasing. ODIAC keeps evolving over the time. Since the debut publication in 2011, the team has made numerous modifications to the ODIAC model, and produced updated, upgraded emission products on annual basis. The 2018 paper describes the details of the current ODIAC model/data product. Currently, the team has been working on new NTL from NASA (a.k.a. NASA's Black Marble) in order to further improve the emission spatial representations. The team expects to significantly improve ODIAC's performance in urban CO2 modeling applications.