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60. Simulation of atmospheric N[subscript 2]O with GEOS-Chem and its adjoint: evaluation of observational constraints

Author

Massachusetts Institute of Technology. Center for Global Change Science, Prinn, Ronald G., Wells, K. C., Millet, D. B., Bousserez, N., Henze, D. K., Chaliyakunnel, S., Griffis, T. J., Luan, Y., Dlugokencky, E. J., O'Doherty, Simon, Weiss, R. F., Dutton, G. S., Elkins, J. W., Krummel, P. B., Langenfelds, R. L., Steele, L. P., Kort, E. A., Wofsy, S. C., Umezawa, T., Massachusetts Institute of Technology. Center for Global Change Science, Prinn, Ronald G., Wells, K. C., Millet, D. B., Bousserez, N., Henze, D. K., Chaliyakunnel, S., Griffis, T. J., Luan, Y., Dlugokencky, E. J., O'Doherty, Simon, Weiss, R. F., Dutton, G. S., Elkins, J. W., Krummel, P. B., Langenfelds, R. L., Steele, L. P., Kort, E. A., Wofsy, S. C., and Umezawa, T.

Abstract

We describe a new 4D-Var inversion framework for nitrous oxide (N[subscript 2]O) based on the GEOS-Chem chemical transport model and its adjoint, and apply it in a series of observing system simulation experiments to assess how well N[subscript 2]O sources and sinks can be constrained by the current global observing network. The employed measurement ensemble includes approximately weekly and quasi-continuous N[subscript 2]O measurements (hourly averages used) from several long-term monitoring networks, N[subscript 2]O measurements collected from discrete air samples onboard a commercial aircraft (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container; CARIBIC), and quasi-continuous measurements from the airborne HIAPER Pole-to-Pole Observations (HIPPO) campaigns. For a 2-year inversion, we find that the surface and HIPPO observations can accurately resolve a uniform bias in emissions during the first year; CARIBIC data provide a somewhat weaker constraint. Variable emission errors are much more difficult to resolve given the long lifetime of N[subscript 2]O, and major parts of the world lack significant constraints on the seasonal cycle of fluxes. Current observations can largely correct a global bias in the stratospheric sink of N[subscript 2]O if emissions are known, but do not provide information on the temporal and spatial distribution of the sink. However, for the more realistic scenario where source and sink are both uncertain, we find that simultaneously optimizing both would require unrealistically small errors in model transport. Regardless, a bias in the magnitude of the N[subscript 2]O sink would not affect the a posteriori N[subscript 2]O emissions for the 2-year timescale used here, given realistic initial conditions, due to the timescale required for stratosphere–troposphere exchange (STE). The same does not apply to model errors in the rate of STE itself, which we show exerts a larger influence on the troposphe, United States. National Oceanic and Atmospheric Administration (Grant NA13OAR4310086), Minnesota Supercomputing Institute

Published
2015

63. Simulation of atmospheric N<sub>2</sub>O with GEOS-Chem and its adjoint: evaluation of observational constraints

Author

Wells, K. C., primary, Millet, D. B., additional, Bousserez, N., additional, Henze, D. K., additional, Chaliyakunnel, S., additional, Griffis, T. J., additional, Luan, Y., additional, Dlugokencky, E. J., additional, Prinn, R. G., additional, O'Doherty, S., additional, Weiss, R. F., additional, Dutton, G. S., additional, Elkins, J. W., additional, Krummel, P. B., additional, Langenfelds, R., additional, Steele, L. P., additional, Kort, E. A., additional, Wofsy, S. C., additional, and Umezawa, T., additional

Published
2015
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68. Supplementary material to "Simulation of atmospheric N2O with GEOS-Chem and its adjoint: evaluation of observational constraints"

Author

Wells, K. C., primary, Millet, D. B., additional, Bousserez, N., additional, Henze, D. K., additional, Chaliyakunnel, S., additional, Griffis, T. J., additional, Luan, Y., additional, Dlugokencky, E. J., additional, Prinn, R. G., additional, O'Doherty, S., additional, Weiss, R. F., additional, Dutton, G. S., additional, Elkins, J. W., additional, Krummel, P. B., additional, Langenfelds, R., additional, Steele, L. P., additional, Kort, E. A., additional, Wofsy, S. C., additional, and Umezawa, T., additional

Published
2015
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71. Variations in global methane sources and sinks during 1910–2010

Author

Ghosh, A., primary, Patra, P. K., additional, Ishijima, K., additional, Umezawa, T., additional, Ito, A., additional, Etheridge, D. M., additional, Sugawara, S., additional, Kawamura, K., additional, Miller, J. B., additional, Dlugokencky, E. J., additional, Krummel, P. B., additional, Fraser, P. J., additional, Steele, L. P., additional, Langenfelds, R. L., additional, Trudinger, C. M., additional, White, J. W. C., additional, Vaughn, B., additional, Saeki, T., additional, Aoki, S., additional, and Nakazawa, T., additional

Published
2015
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76. Variations in global methane sources and sinks during 1910–2010

Author

Ghosh, A., primary, Patra, P. K., additional, Ishijima, K., additional, Umezawa, T., additional, Ito, A., additional, Etheridge, D. M., additional, Sugawara, S., additional, Kawamura, K., additional, Miller, J. B., additional, Dlugokencky, E. J., additional, Krummel, P. B., additional, Fraser, P. J., additional, Steele, L. P., additional, Langenfelds, R. L., additional, White, J. W. C., additional, Vaughn, B., additional, Saeki, T., additional, Aoki, S., additional, and Nakazawa, T., additional

Published
2014
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82. N2O as a tracer of mixing stratospheric and tropospheric air based on CARIBIC data with applications for CO2

Author

Assonov, S. S., Brenninkmeijer, C. A. M., Schuck, T., Umezawa, T., Assonov, S. S., Brenninkmeijer, C. A. M., Schuck, T., and Umezawa, T.

Abstract

Stratosphere-troposphere exchange (STE) affects distributions of trace gases, with ozone (O-3) and CO being commonly used to study mixing process in the UTLS (Upper Troposphere and Lower Stratosphere) region. Here we explore the application of N2O as a tracer of stratosphere to troposphere flux for CO2 and its isotopes, using N2O and CO2 mixing ratios including a set of CO2 isotope data for CARIBIC aircraft samples and NOAA-Carbon Cycle flask samples. A frequency distribution of CARIBIC N2O data (mostly UTLS at mid- and high-latitudes) reveals a narrow distribution around a tropospheric maximum at nearly the same N2O mixing ratio as the distribution peak for the station Mauna Loa (MLO) however with a skewing due to STE. We demonstrate that upper-tropospheric and STE-affected air can be distinguished using a threshold value based on the N2O distribution width at MLO. A comparison with the use of O-3 is given. N2O is discussed to be a robust and linear (season and latitude independent) tracer of STE mixing proportions. We propose that CARIBIC data coupled with CO2 isotopic data published for the stratosphere and data of NOAA stations can be used as a frame of reference for delta O-18(CO2) and Delta O-17(CO2) STE fluxes. The Delta O-17(CO2) flux is of particular interest as it is thought to constrain estimates of biosphere productivity, atmospheric oxygen cycle and global gross CO2 fluxes. CARBIC data can also help tracing STE flux by deep stratospheric intrusions and a data analysis is given for the Walliguan (WLG) observatory on the Tibetan Plateau. (C) 2013 Elsevier Ltd. All rights reserved.

Published
2013

83. Threonine at position 306 of the KAT1 potassium channel is essential for channel activity and is a target site for ABA-activated SnRK2/OST1/SnRK2.6 protein kinase

Author

Sato, A., Sato, Y., Fukao, Y., Fujiwara, M., Umezawa, T., Shinozaki, K., Hibi, T., Taniguchi, M., Miyake, H., Goto, D.B., Uozumi, N., Sato, A., Sato, Y., Fukao, Y., Fujiwara, M., Umezawa, T., Shinozaki, K., Hibi, T., Taniguchi, M., Miyake, H., Goto, D.B., and Uozumi, N.

Abstract

The Arabidopsis thaliana K+ channel KAT1 has been suggested to have a key role in mediating the aperture of stomata pores on the surface of plant leaves. Although the activity of KAT1 is thought to be regulated by phosphorylation, the endogenous pathway and the primary target site for thismodification remained unknown. In the present study, we have demonstrated that the C-terminal region of KAT1 acts as a phosphorylation target for the Arabidopsis calcium-independent ABA (abscisic acid)-activated protein kinase SnRK2.6 (Snf1-related protein kinase 2.6). This was confirmed by LC-MS/MS (liquid chromatography tandem MS) analysis, which showed that Thr306 and Thr308 of KAT1 were modified by phosphorylation. The role of these specific residues was examined by single point mutations and measurement of KAT1 channel activities in Xenopus oocyte and yeast systems. Modification of Thr308 hadminimal effect onKAT1 activity. On the other hand, modification of Thr306 reduced the K+ transport uptake activity of KAT1 in both systems, indicating that Thr306 is responsible for the functional regulation of KAT1. These results suggest that negative regulation of KAT1 activity, required for stomatal closure, probably occurs by phosphorylation of KAT1 Thr306 by the stress-activated endogenous SnRK2.6 protein kinase.

Published
2009

92. Sequencing and Analysis of Approximately 40 000 Soybean cDNA Clones from a Full-Length-Enriched cDNA Library

Author

Umezawa, T., primary, Sakurai, T., additional, Totoki, Y., additional, Toyoda, A., additional, Seki, M., additional, Ishiwata, A., additional, Akiyama, K., additional, Kurotani, A., additional, Yoshida, T., additional, Mochida, K., additional, Kasuga, M., additional, Todaka, D., additional, Maruyama, K., additional, Nakashima, K., additional, Enju, A., additional, Mizukado, S., additional, Ahmed, S., additional, Yoshiwara, K., additional, Harada, K., additional, Tsubokura, Y., additional, Hayashi, M., additional, Sato, S., additional, Anai, T., additional, Ishimoto, M., additional, Funatsuki, H., additional, Teraishi, M., additional, Osaki, M., additional, Shinano, T., additional, Akashi, R., additional, Sakaki, Y., additional, Yamaguchi-Shinozaki, K., additional, and Shinozaki, K., additional

Published
2008
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94. Simulation of atmospheric N2O with GEOS-Chem and its adjoint: evaluation of observational constraints.

Author

Wells, K. C., Millet, D. B., Bousserez, N., Henze, D. K., Chaliyakunnel, S., Griffis, T. J., Luan, Y., Dlugokencky, E. J., Prinn, R. G., O'Doherty, S., Weiss, R. F., Dutton, G. S., Elkins, J. W., Krummel, P. B., Langenfelds, R., Steele, L. P., Kort, E. A., Wofsy, S. C., and Umezawa, T.

Subjects
NITROUS oxide, SIMULATION methods & models, STRATOSPHERE, TROPOSPHERE, EMISSIONS (Air pollution), GEOCHEMISTRY
Abstract

We describe a new 4D-Var inversion framework for N2O based on the GEOS-Chem chemical transport model and its adjoint, and apply this framework in a series of observing system simulation experiments to assess how well N2O sources and sinks can be constrained by the current global observing network. The employed measurement ensemble includes approximately weekly and quasi-continuous N2O measurements (hourly averages used) from several long-term monitoring networks, N2O measurements collected from discrete air samples aboard a commercial aircraft (CARIBIC), and quasi-continuous measurements from an airborne pole-to-pole sampling campaign (HIPPO). For a two-year inversion, we find that the surface and HIPPO observations can accurately resolve a uniform bias in emissions during the first year; CARIBIC data provide a somewhat weaker constraint. Variable emission errors are much more difficult to resolve given the long lifetime of N2O, and major parts of the world lack significant constraints on the seasonal cycle of fluxes. Current observations can largely correct a global bias in the stratospheric sink of N2O if emissions are known, but do not provide information on the temporal and spatial distribution of the sink. However, for the more realistic scenario where source and sink are both uncertain, we find that simultaneously optimizing both would require unrealistically small errors in model transport. Regardless, a bias in the magnitude of the N2O sink would not affect the a posteriori N2O emissions for the two-year timescale used here, given realistic initial conditions, due to the timescale required for stratosphere-troposphere exchange (STE). The same does not apply to model errors in the rate of STE itself, which we show exerts a larger influence on the tropospheric burden of N2O than does the chemical loss rate over short (< 3 year) timescales. We use a stochastic estimate of the inverse Hessian for the inversion to evaluate the spatial resolution of emission constraints provided by the observations, and find that significant, spatially explicit constraints can be achieved in locations near and immediately upwind of surface measurements and the HIPPO flight tracks; however, these are mostly confined to North America, Europe, and Australia. None of the current observing networks are able to provide significant spatial information on tropical N2O emissions. There, averaging kernels are highly smeared spatially and extend even to the midlatitudes, so that tropical emissions risk being conflated with those elsewhere. For global inversions, therefore, the current lack of constraints on the tropics also places an important limit on our ability to understand extratropical emissions. Based on the error reduction statistics from the inverse Hessian, we characterize the atmospheric distribution of unconstrained N2O, and identify regions in and downwind of South America, Central Africa, and Southeast Asia where new surface or profile measurements would have the most value for reducing present uncertainty in the global N2O budget. [ABSTRACT FROM AUTHOR]

Published
2015
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