Detecting Anthropogenic CO2 Emissions from Mega-City Regions from Spaceby “IBUKI” (GOSAT)

September 1st, 2016
Ministry of the Environment, Japan
National Institute for Environmental Studies
Japan Aerospace Exploration Agency

The Greenhouse gases Observing SATellite (GOSAT) “IBUKI”, developed jointly by theMinistry of the Environment (MOE), the National Institute for Environmental Studies (NIES), andthe Japan Aerospace Exploration Agency (JAXA) is the world’s first satellite designed specificallyto monitor greenhouse gases from space. The satellite has continued to fulfill its main mission tomonitor atmospheric carbon dioxide (CO2) and methane (CH4) concentrations from space since its
launch in January 2009.
Anthropogenic CO2 concentrations in mega-cities including the metropolitan area inTokyo were analyzed for the five and half years from June 2009 to December 2014, based on theobservational data acquired by “IBUKI”.
It was found that the anthropogenic CO2 concentrations estimated from "IBUKI" data
generally agree with those estimated using data on fossil fuel emissions (inventory) in Japan. Theseresults indicate that satellite observations from space can become useful to monitor and verify CO2emission rates that were aggregated and published by all nations of the world based on theframework of “The Paris Agreement”.
With the progress in satellite data collection and further improvement in data analysis
methods, these observational data by “IBUKI” and its successor (GOSAT-2) accumulated overmultiple years will be compared with emission inventories.

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Global mean atmospheric CO2 levels have increased from about 280 ppm in pre-industrial
times to 400 ppm at the present time. The increase of CO2 concentrations is caused mainly byanthropogenic activities associated with fossil fuel combustion which is strongly localized at fossil
fuel power plants and mega-city regions. Moreover, the twenty-first session of the Conference of theParties to the United Nations Framework Convention on Climate Change (COP21) reached ahistorical agreement, “The Paris Agreement”, in December 2015, which requires all nations toaccelerate and intensify the actions and investments needed for a sustainable low-carbon future. To
achieve these goals, it is essential to monitor and precisely evaluate greenhouse gas emission rates
resulting from human activities.
Our previous press release in December 2014 showed the potential of satellite observations
to detect greenhouse gas emissions from fossil fuel combustion from space. This time, “IBUKI”
observations for five and half years (June 2009 – December 2014) were analyzed with improved
analysis methods.
The spatiotemporal distribution of anthropogenic CO2 concentrations derived from theobservational data acquired by “IBUKI” is shown in Figures 1 and 2. Regions with highanthropogenic CO2 concentrations can be identified as those with dense populations or industrial
zones with fossil fuel power plants and developments of oil and gas fields in North America, Europe,
Middle East, India, and China. Additionally, the observational data collected during these five andhalf years enable us to detect areas with high anthropogenic CO2 concentrations in the Kanto area,Japan.
Figure 3 shows the relationships between anthropogenic CO2 concentrations derived fromemission inventories and those derived from “IBUKI” data in four regions: the globe, North America,
South to East Asia, and Japan. Table 2 shows the differences of the regression lines between
previous and present results. Key aspects are as follows:
1. Anthropogenic CO2 concentrations derived from emission inventories and the observational dataacquired by “IBUKI” show higher correlations and lower differences compared with those ofprevious results.
2. High correlations are found in the concentrations around the globe, North America, and South toEast Asia, and the differences in concentrations decrease within the range of observational error
for “IBUKI”.
3. Whereas no correlation was found for Japan in previous analyses with fewer observational data,
we found correlations for Japan in the present analysis, thanks to the observational datacollected during these five and half years. However, further improvements are necessary in themethodology of data analysis, the volume of observational data, and the accuracy of satellite
observations to analyze anthropogenic CO2 emissions at national levels.

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The present estimates demonstrated the potential utility of observations by “IBUKI” and its
successor (GOSAT-2) to monitor anthropogenic CO2 emission rates that all nations are required to
publish based on “The Paris Agreement”. The methodology to improve both the frequency and net
volume of observational data will be further investigated to improve the accuracy of estimates ofanthropogenic CO2 concentrations. Additionally, further studies and evaluations, for example,
ground-based observations in the surrounding of large emission sources, will be implemented torefine estimates of anthropogenic emission rates from CO2 concentration measurements acquired bysatellites.
[Contact Information]
About GOSAT data and analysis results:
GOSAT Project, Satellite Observation Center,
National Institute for Environmental Studies (NIES)
Phone: +81-29-850-2035 (English)
About GOSAT, onboard sensors, and observation status: Masakatsu Nakajima
JAXA Space Technology Directorate I
GOSAT-2 Project Team
Phone: +81-50-3362-6130

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Table 1. List of regions indicating high anthropogenic CO2 concentrations derived from “IBUKI” inFigures 1 and 2.
No.

Rough range of the region
for high concentrations ofanthropogenic CO2emissions derived from
IBUKI”

Countries, regions or
major cities in the region

1Latitude: 33 – 46 N
Longitude: 114 – 127 E
Latitude: 20 – 23 N
Longitude: 84 – 89 E
Latitude: 40 – 41 N
Longitude: 67 – 73 E

China: Zhangjiakou, Anshan,Harbin, and Tianjin
India: Kolkata (Calcutta)

234

Latitude: 30 – 32 N
Longitude: 37 – 38 E

5Latitude: 38 – 41 N
Longitude: 79 – 83 W
Latitude: 33 – 35 N
Longitude: 114 – 119 W
Latitude: 17 – 19 N
Longitude: 99 – 102 W
Latitude: 35 – 37 N
Longitude: 139 – 141 E

67
8*Maximum value of theconcentrations ofanthropogenic CO2
emissions for the region(1 deg. × 1 deg., in 5.5years)
6.2 ppm
2.1 ppm

Eastern part of Uzbekistan,Southern edge of Kazakhstan,
Eastern area of Kyrgyzstan,
Northern edge of Tajikistan
Northern part of Saudi
Arabia,JordanThe United States: Pittsburgh

2.8 ppm

The United States:
Los Angeles
Mexico: Acapulco

3.5 ppm

Japan : Tokyo and Its Vicinity

0.5 ppm

2.1 ppm

2.1 ppm

2.7 ppm*As for Japan, a different method was used to derive the maximum value due to its small number (5- 14) of data per 1 degree x 1 degree grid.
Table 2. Comparisons of the number of observational data and the slopes of regression lines inFigure 3 for four regions: the globe, North America, Southeast Asia, and Japan.

The Globe
North America
South - East Asia
Japan

Previous Result:
Period : 2009 - 2012
Number of data
Slope
8315
1.21 ± 0.213011
1.05 ± 0.383243
1.22 ± 0.32
262
0.81 ± 1.42

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Present Result:
Period : 2009 - 2014
Number of data
Slope
13616
1.08 ± 0.134684
0.99 ± 0.28
5589
0.99 ± 0.17396
0.95 ± 0.79

Figure 1. Distribution of anthropogenic CO2 concentrations estimated from observational dataacquired by “IBUKI” (1° grid; only grids with more than 24 observational data points are plotted).
Anthropogenic CO2 concentrations are shown in colors.

Figure 2. Enlarged views of North America (left) and South to East Asia (right) in Figure 1.

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Figure 3. Relationships between anthropogenic CO2 concentrations derived fromemission inventories and those acquired by “IBUKI” for the globe (top-left), North
America (top-right), South to East Asia (bottom-left), and Japan (bottom-right).
Anthropogenic CO2 concentrations were classified for each 0.2 ppm of concentrations
from the inventories and then averages and standard deviations were calculated in eachclass. Broken lines show the relationship of 1:1 between the concentrations frominventories and those from “IBUKI”. This study excluded data with concentrations frominventories greater than 1.4 ppm (1.0 ppm for Japan).

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