The Orbiting Carbon Observatory-2: first 18 months of science data products

Eldering, A.; O’Dell, Chris; Wennberg, P. O.; Crisp, David; Gunson, M. R.; Viatte, Camille; Avis, Charles; Braverman, Amy; Castaño, Rebecca; Chang, Albert Y.; Chapsky, Lars; Cheng, Cecilia; Connor, B. J.; Dang, Lan; Doran, Gary; Fisher, B.; Frankenberg, Christian; Fu, Dejian; Granat, Robert; Hobbs, Jonathan; Lee, Richard A.; Mandrake, Lukas; McDuffie, James; Miller, Charles E.; Myers, Vicky; Natraj, Vijay; O’Brien, D. M.; Osterman, G. B.; Oyafuso, Fabiano; Payne, Vivienne H.; Pollock, H. R.; Polonsky, I. N.; Roehl, Coleen M.; Rosenberg, Robert; Schwandner, F. M.; Smyth, Mike; Tang, Vivian; Taylor, Thomas E.; To, Cathy; Wunch, Debra; Yoshimizu, Jan

doi:10.5194/amt-10-549-2017

Cited by 209 publications

(196 citation statements)

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“…Satellite measurements would be very helpful for understanding the global CO 2 flux distribution if the CO 2 column-averaged dry-air mole fraction (XCO 2 ) could be measured with a precision of 1-2 ppm (Baker et al, 2010). The Greenhouse Gases Observing Satellite (GOSAT) (Yokota et al, 2009;Yoshida et al, 2013;Kuze et al, 2014) was launched in 2009, followed by the Orbiting Carbon Observatory 2 (OCO-2) (Eldering et al, 2016;Crisp et al, 2017;Bösch et al, 2011) in 2014. Tansat, a Chinese Earth observation satellite dedicated to monitoring CO 2 , was launched in December 2016 and is the third satellite capable of monitoring greenhouse gases by hyper-spectral nearinfrared/shortwave infrared (NIR/ SWIR) measurement.…”

Section: The Need For Global Carbon Monitoring From Space and The Tanmentioning

confidence: 99%

First Global Carbon Dioxide Maps Produced from TanSat Measurements

et al. 2018

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Section: The Need For Global Carbon Monitoring From Space and The Tanmentioning

confidence: 99%

First Global Carbon Dioxide Maps Produced from TanSat Measurements

et al. 2018

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“…We then characterized the fit for each spectrum using the reduced χ 2 measure (Eldering et al, 2017), a statistical summary of the residual relative to the expected measurement errors. Specifically, it was the chi-squared score per degree of freedom, with χ 2 = 1 equivalent to estimated measurement noise.…”

Section: Methodsmentioning

confidence: 99%

Global spectroscopic survey of cloud thermodynamic phase at high spatial resolution, 2005–2015

et al. 2018

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Abstract. The distribution of ice, liquid, and mixed phase clouds is important for Earth's planetary radiation budget, impacting cloud optical properties, evolution, and solar reflectivity. Most remote orbital thermodynamic phase measurements observe kilometer scales and are insensitive to mixed phases. This under-constrains important processes with outsize radiative forcing impact, such as spatial partitioning in mixed phase clouds. To date, the fine spatial structure of cloud phase has not been measured at global scales. Imaging spectroscopy of reflected solar energy from 1.4 to 1.8 µm can address this gap: it directly measures ice and water absorption, a robust indicator of cloud top thermodynamic phase, with spatial resolution of tens to hundreds of meters. We report the first such global high spatial resolution survey based on data from 2005 to 2015 acquired by the Hyperion imaging spectrometer onboard NASA's Earth Observer 1 (EO-1) spacecraft. Seasonal and latitudinal distributions corroborate observations by the Atmospheric Infrared Sounder (AIRS). For extratropical cloud systems, just 25 % of variance observed at GCM grid scales of 100 km was related to irreducible measurement error, while 75 % was explained by spatial correlations possible at finer resolutions.

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“…In order to avoid the impact of relative biases in different observation modes on flux estimations, we only use land nadir observations in this study. We further filter the observations based on the quality control flag provided along with the OCO-2 v7br lite product (86). Figure S5 shows the 2015 annual total number of good quality land nadir observations at each 4° × 5° grid box.…”

Section: Oco-2 Xco2 Observationsmentioning

confidence: 99%

Contrasting carbon cycle responses of the tropical continents to the 2015–2016 El Niño

Liu

Bowman

Schimel

et al. 2017

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INTRODUCTION The influence of El Niño on climate is accompanied by large changes to the carbon cycle, and El Niño–induced variability in the carbon cycle has been attributed mainly to the tropical continents. However, owing to a dearth of observations in the tropics, tropical carbon fluxes are poorly quantified, and considerable debate exists over the dominant mechanisms (e.g., plant growth, respiration, fire) and regions (e.g., humid versus semiarid tropics) on the net carbon balance. RATIONALE The launch of the Orbiting Carbon Observatory-2 (OCO-2) shortly before the 2015–2016 El Niño, the second strongest since the 1950s, has provided an opportunity to understand how tropical land carbon fluxes respond to the warm and dry climate characteristics of El Niño conditions. The El Niño events may also provide a natural experiment to study the response of tropical land carbon fluxes to future climate changes, because anomalously warm and dry tropical environments typical of El Niño are expected to be more frequent under most emission scenarios. RESULTS The tropical regions of three continents (South America, Asia, and Africa) had heterogeneous responses to the 2015–2016 El Niño, in terms of both climate drivers and the carbon cycle. The annual mean precipitation over tropical South America and tropical Asia was lower by 3.0σ and 2.8σ, respectively, in 2015 relative to the 2011 La Niña year. Tropical Africa, on the other hand, had near equal precipitation and the same number of dry months between 2015 and 2011; however, surface temperatures were higher by 1.6σ, dominated by the positive anomaly over its eastern and southern regions. In response to the warmer and drier climate anomaly in 2015, the pantropical biosphere released 2.5 ± 0.34 gigatons more carbon into the atmosphere than in 2011, which accounts for 83.3% of the global total 3.0–gigatons of carbon (gigatons C) net biosphere flux differences and 92.6% of the atmospheric CO 2 growth-rate differences between 2015 and 2011. It indicates that the tropical land biosphere flux anomaly was the driver of the highest atmospheric CO 2 growth rate in 2015. The three tropical continents had an approximately even contribution to the pantropical net carbon flux anomaly in 2015, but had diverse dominant processes: gross primary production (GPP) reduced carbon uptake (0.9 ± 0.96 gigatons C) in tropical South America, fire increased carbon release (0.4 ± 0.08 gigatons C) in tropical Asia, and respiration increased carbon release (0.6 ± 1.01 gigatons C) in Africa. We found that most of the excess carbon release in 2015 was associated with either extremely low precipitation or high temperatures, or both. CONCLUSION Our results indicate that the global El Niño effect is a superposition of regionally specific effects. The heterogeneous climate forcing and carbon response over the three tropical continents to the 2015–2016 El Niño challenges previous studies that suggested that a single dominant process determines carbon cycle interannual variability, which could also be due to previous disturbance and soil and vegetation structure. The similarity between the 2015 tropical climate anomaly and the projected climate changes imply that the role of the tropical land as a buffer for fossil fuel emissions may be reduced in the future. The heterogeneous response may reflect differences in temperature and rainfall anomalies, but intrinsic differences in vegetation species, soils, and prior disturbance may contribute as well. A synergistic use of multiple satellite observations and a long time series of spatially resolved fluxes derived from sustained satellite observations will enable tests of these hypotheses, allow for a more process-based understanding, and, ultimately, aid improved carbon-climate model projections. Diverse climate driver anomalies and carbon cycle responses to the 2015–2016 El Niño over the three tropical continents. Schematic of climate anomaly patterns over the three tropical continents and the anomalies of the net carbon flux and its dominant constituent flux (i.e., GPP, respiration, and fire) relative to the 2011 La Niña during the 2015–2016 El Niño. GtC, gigatons C.

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The Orbiting Carbon Observatory-2: first 18 months of science data products

Cited by 209 publications

References 50 publications

First Global Carbon Dioxide Maps Produced from TanSat Measurements

First Global Carbon Dioxide Maps Produced from TanSat Measurements

Global spectroscopic survey of cloud thermodynamic phase at high spatial resolution, 2005–2015

Contrasting carbon cycle responses of the tropical continents to the 2015–2016 El Niño

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