Reassessing the variability in atmospheric H2 using the two-way nested TM5 model
Pieterse, G. ; Krol, M.C. ; Batenburg, A.M. ; Brenninkmeijer, C.A. ; Popa, M.E. ; O'Doherty, S. ; Grant, A. ; Steele, L.P. ; Krummel, P.B. ; Langenfelds, R.L. ; Wang, H.J. ; Vermeulen, A.T. ; Schmidt, M. ; Yver, C. ; Jordan, A. ; Engel, A. ; Fisher, R.E. ; Lowry, D. ; Nisbet, E.G. ; Reimann, S. ; Vollmer, M.K. ; Steinbacher, M. ; Hammer, S. ; Forster, G. ; Sturges, W.T. ; Rockmann, T. - \ 2013
Journal of Geophysical Research: Atmospheres 118 (2013)9. - ISSN 2169-897X - p. 3764 - 3780.
dry deposition parameterization - stable isotopic composition - general-circulation model - global hydrogen economy - molecular-hydrogen - trace gases - environmental-impact - dissolved hydrogen - seasonal-variation - data assimilation
This work reassesses the global atmospheric budget of H2 with the TM5 model. The recent adjustment of the calibration scale for H2 translates into a change in the tropospheric burden. Furthermore, the ECMWF Reanalysis-Interim (ERA-Interim) data from the European Centre for Medium-Range Weather Forecasts (ECMWF) used in this study show slower vertical transport than the operational data used before. Consequently, more H2 is removed by deposition. The deposition parametrization is updated because significant deposition fluxes for snow, water, and vegetation surfaces were calculated in our previous study. Timescales of 1-2h are asserted for the transport of H2 through the canopies of densely vegetated regions. The global scale variability of H2 and [DH2] is well represented by the updated model. H2 is slightly overestimated in the Southern Hemisphere because too little H2 is removed by dry deposition to rainforests and savannahs. The variability in H2 over Europe is further investigated using a high-resolution model subdomain. It is shown that discrepancies between the model and the observations are mainly caused by the finite model resolution. The tropospheric burden is estimated at 165 +/- 8TgH2. The removal rates of H2 by deposition and photochemical oxidation are estimated at 53 +/- 4 and 23 +/- 2TgH2/yr, resulting in a tropospheric lifetime of 2.2 +/- 0.2year.
Emission ratio and isotopic signatures of molecular hydrogen emissions from tropical biomass burning
Haumann, F.A. ; Batenburg, A.M. ; Pieterse, G. ; Gerbig, C. ; Krol, M.C. ; Rockmann, T. - \ 2013
Atmospheric Chemistry and Physics 13 (2013)18. - ISSN 1680-7316 - p. 9401 - 9413.
atmospheric hydrogen - assimilation system - land-surface - amazon basin - trace gases - tall tower - model tm5 - h-2 - chemistry - plants
In this study, we identify a biomass-burning signal in molecular hydrogen (H-2) over the Amazonian tropical rainforest. To quantify this signal, we measure the mixing ratios of H-2 and several other species as well as the H-2 isotopic composition in air samples that were collected in the BARCA (Balanco Atmosferico Regional de Carbono na Amazonia) aircraft campaign during the dry season. We derive a relative H-2 emission ratio with respect to carbon monoxide (CO) of 0.31 +/- 0.04 ppb ppb(-1) and an isotopic source signature of -280 +/- 41 parts per thousand in the air masses influenced by tropical biomass burning. In order to retrieve a clear source signal that is not influenced by the soil uptake of H-2, we exclude samples from the atmospheric boundary layer. This procedure is supported by data from a global chemistry transport model. The Delta H-2/Delta CO emission ratio is significantly lower than some earlier estimates for the tropical rainforest. In addition, our results confirm the lower values of the previously conflicting estimates of the H-2 isotopic source signature from biomass burning. These values for the emission ratio and isotopic source signatures of H-2 from tropical biomass burning can be used in future bottom-up and top-down approaches aiming to constrain the strength of the biomass-burning source for H-2. Hitherto, these two quantities relied only on combustion experiments or on statistical relations, since no direct signal had been obtained from in-situ observations.
Correction to "Interannual variability of carbon monoxide emission estimates over South America from 2006 to 2010"
Krol, M.C. ; Hooghiemstra, P.B. ; Leeuwen, T.T. van; Werf, G.R. van der; Novelli, P.C. ; Deeter, M.N. ; Aben, I. ; Rockmann, T. - \ 2013
Journal of Geophysical Research: Atmospheres 118 (2013)10. - ISSN 2169-897X - p. 5061 - 5064.
Analysis of global methane changes after the 1991 Pinatubo volcanic eruption
Banda, N. ; Krol, M.C. ; Weele, M. van; Noije, T. van; Rockmann, T. - \ 2013
Atmospheric Chemistry and Physics 13 (2013)4. - ISSN 1680-7316 - p. 2267 - 2281.
chemistry transport model - atmospheric methane - mount-pinatubo - growth-rate - tropospheric chemistry - isotopic composition - isoprene emissions - mt-pinatubo - variability - ch4
The global methane (CH4) growth rate showed large variations after the eruption of Mount Pinatubo in June 1991. Both sources and sinks of tropospheric CH4 were altered following the eruption, by feedback processes between climate and tropospheric photochemistry. Such processes include Ultra Violet (UV) radiative changes due to the presence of volcanic sulfur dioxide (SO2) and sulphate aerosols in the stratosphere, and due to stratospheric ozone depletion. Changes in temperature and water vapour in the following years caused changes in tropospheric chemistry, as well as in natural emissions. We present a sensitivity study that investigates the relative effects that these processes had on tropospheric CH4 concentrations, using a simple one-dimensional chemistry model representative for the global tropospheric column. To infer the changes in UV radiative fluxes, the chemistry model is coupled to a radiative transfer model. We find that the overall effect of natural processes after the eruption on the CH4 growth rate is dominated by the reduction in CH4 lifetime due to stratospheric ozone depletion. However, all the other processes are found to have non-negligible effects, and should therefore be taken into account in order to obtain a good estimate of CH4 concentrations after Pinatubo. We find that the overall effect was a small initial increase in the CH4 growth rate after the eruption, followed by a decrease of about 7 ppb yr(-1) by mid-1993. When changes in anthropogenic emissions are employed according to emission inventories, an additional decrease of about 5 ppb yr(-1) in the CH4 growth rate is obtained between the years 1991 and 1993. The results using the simplified single column model are in good qualitative agreement with observed changes in the CH4 growth rate. Further analysis, taking into account changes in the dynamics of the atmosphere, variations in emissions from biomass burning, and in biogenic emissions of non-methane volatile organic compounds (NMVOC), requires the use of a full three-dimensional model.
The stable isotopic signature of biologically produced molecular hydrogen (H-2)
Walter, S. ; Laukenmann, S. ; Stams, A.J.M. ; Vollmer, M.K. ; Gleixner, G. ; Rockmann, T. - \ 2012
Biogeosciences 9 (2012)10. - ISSN 1726-4170 - p. 4115 - 4123.
atmospheric hydrogen - stratosphere - economy - budget - model - cycle - air - fractionation - troposphere - photolysis
Biologically produced molecular hydrogen (H-2) is characterised by a very strong depletion in deuterium. Although the biological source to the atmosphere is small compared to photochemical or combustion sources, it makes an important contribution to the global isotope budget of H-2. Large uncertainties exist in the quantification of the individual production and degradation processes that contribute to the atmospheric budget, and isotope measurements are a tool to distinguish the contributions from the different sources. Measurements of delta D from the various H-2 sources are scarce and for biologically produced H-2 only very few measurements exist. Here the first systematic study of the isotopic composition of biologically produced H-2 is presented. In a first set of experiments, we investigated delta D of H-2 produced in a biogas plant, covering different treatments of biogas production. In a second set of experiments, we investigated pure cultures of several H-2 producing microorganisms such as bacteria or green algae. A Keeling plot analysis provides a robust overall source signature of delta D = -712 parts per thousand (+/-13 parts per thousand) for the samples from the biogas reactor (at 38 degrees C, delta D-H2O = +73.4 parts per thousand), with a fractionation constant epsilon H-2-H2O of -689 parts per thousand (+/-20 parts per thousand) between H-2 and the water. The five experiments using pure culture samples from different microorganisms give a mean source signature of delta D = -728 parts per thousand (+/-28 parts per thousand), and a fractionation constant epsilon H-2-H2O of -711 parts per thousand (+/-34 parts per thousand) between H-2 and the water. The results confirm the massive deuterium depletion of biologically produced H-2 as was predicted by the calculation of the thermodynamic fractionation factors for hydrogen exchange between H-2 and water vapour. Systematic errors in the isotope scale are difficult to assess in the absence of international standards for delta D of H-2. As expected for a thermodynamic equilibrium, the fractionation factor is temperature dependent, but largely independent of the substrates used and the H-2 production conditions. The equilibrium fractionation coefficient is positively correlated with temperature and we measured a rate of change of 2.3 parts per thousand/degrees C between 45 degrees C and 60 degrees C, which is in general agreement with the theoretical prediction of 1.4%/degrees C. Our best experimental estimate for epsilon H-2-H2O at a temperature of 20 degrees C is -731 parts per thousand (+/-20 parts per thousand) for biologically produced H-2. This value is close to the predicted value of -722 parts per thousand, and we suggest using these values in future global H-2 isotope budget calculations and models with adjusting to regional temperatures for calculating delta D values.
Interannual variability of carbon monoxide emission estimates over South America from 2006 to 2010
Hooghiemstra, P.B. ; Krol, M.C. ; Leeuwen, T.T. van; Werf, G.R. van der; Novelli, P.C. ; Deeter, M.N. ; Aben, I. ; Rockmann, T. - \ 2012
Journal of Geophysical Research: Atmospheres 117 (2012). - ISSN 2169-897X
variational data assimilation - land-use change - climate-change - co emissions - amazon deforestation - brazilian amazon - fire emissions - model tm5 - mopitt - inversion
We present the first inverse modeling study to estimate CO emissions constrained by both surface and satellite observations. Our 4D-Var system assimilates National Oceanic and Atmospheric Administration Earth System Research Laboratory (NOAA/ESRL) Global Monitoring Division (GMD) surface and Measurements Of Pollution In The Troposphere (MOPITT) satellite observations jointly by fitting a bias correction scheme. This approach leads to the identification of a positive bias of maximum 5 ppb in MOPITT column-averaged CO mixing ratios in the remote Southern Hemisphere (SH). The 4D-Var system is used to estimate CO emissions over South America in the period 2006-2010 and to analyze the interannual variability (IAV) of these emissions. We infer robust, high spatial resolution CO emission estimates that show slightly smaller IAV due to fires compared to the Global Fire Emissions Database (GFED3) prior emissions. South American dry season (August and September) biomass burning emission estimates amount to 60, 92, 42, 16 and 93 Tg CO/yr for 2006 to 2010, respectively. Moreover, CO emissions probably associated with pre-harvest burning of sugar cane plantations in Sao Paulo state are underestimated in current inventories by 50-100%. We conclude that climatic conditions (such as the widespread drought in 2010) seem the most likely cause for the IAV in biomass burning CO emissions. However, socio-economic factors (such as the growing global demand for soy, beef and sugar cane ethanol) and associated deforestation fires, are also likely as drivers for the IAV of CO emissions, but are difficult to link directly to CO emissions.
Letter tot the editor: Iconic CO2 Time Series at Risk
Houweling, S. ; Badawy, B. ; Baker, D.F. ; Basu, S. ; Belikov, D. ; Bergamaschi, P. ; Bousquet, P. ; Broquet, G. ; Butler, T. ; Canadell, J.G. ; Chen, J. ; Chevallier, F. ; Ciais, P. ; Collatz, G.J. ; Denning, S. ; Engelen, R. ; Enting, I.G. ; Fischer, M.L. ; Fraser, A. ; Gerbig, C. ; Gloor, M. ; Jacobson, A.R. ; Jones, D.B.A. ; Heimann, M. ; Khalil, A. ; Kaminski, T. ; Kasibhatla, P.S. ; Krakauer, N.Y. ; Krol, M. ; Maki, T. ; Maksyutov, S. ; Manning, A. ; Meesters, A. ; Miller, J.B. ; Palmer, P.I. ; Patra, P. ; Peters, W. ; Peylin, P. ; Poussi, Z. ; Prather, M.J. ; Randerson, J.T. ; Rockmann, T. ; Rodenbeck, C. ; Sarmiento, J.L. ; Schimel, D.S. ; Scholze, M. ; Schuh, A. ; Suntharalingam, P. ; Takahashi, T. ; Turnbull, J. ; Yurganov, L. ; Vermeulen, A. - \ 2012
Science 337 (2012)6098. - ISSN 0036-8075 - p. 1038 - 1040.
Comparing optimized CO emission estimates using MOPITT or NOAA surface network observations
Hooghiemstra, P.B. ; Krol, M.C. ; Bergamaschi, P. ; Laat, A.T.J. de; Werf, G.R. van der; Novelli, P.C. ; Deeter, M.N. ; Aben, I. ; Rockmann, T. - \ 2012
Journal of Geophysical Research: Atmospheres 117 (2012). - ISSN 2169-897X - 23 p.
variational data assimilation - zoom model tm5 - carbon-monoxide - tropospheric chemistry - inversion - validation - sciamachy - algorithm - pollution - aircraft
This paper compares two global inversions to estimate carbon monoxide (CO) emissions for 2004. Either surface flask observations from the National Oceanic and Atmospheric Administration Earth System Research Laboratory (NOAA/ESRL) Global Monitoring Division (GMD) or CO total columns from the Measurement of Pollution in the Troposphere (MOPITT) instrument are assimilated in a 4D-Var framework. Inferred emission estimates from the two inversions are consistent over the Northern Hemisphere (NH). For example, both inversions increase anthropogenic CO emissions over Europe (from 46 to 94 Tg CO/yr) and Asia (from 222 to 420 Tg CO/yr). In the Southern Hemisphere (SH), three important findings are reported. First, due to their different vertical sensitivity, the stations-only inversion increases SH biomass burning emissions by 108 Tg CO/yr more than the MOPITT-only inversion. Conversely, the MOPITT-only inversion results in SH natural emissions (mainly CO from oxidation of NMVOCs) that are 185 Tg CO/yr higher compared to the stations-only inversion. Second, MOPITT-only derived biomass burning emissions are reduced with respect to the prior which is in contrast to previous (inverse) modeling studies. Finally, MOPITT derived total emissions are significantly higher for South America and Africa compared to the stations-only inversion. This is likely due to a positive bias in the MOPITT V4 product. This bias is also apparent from validation with surface stations and ground-truth FTIR columns. Our results show that a combined inversion is promising in the NH. However, implementation of a satellite bias correction scheme is essential to combine both observational data sets in the SH.
Atmospheric constraints on global emissions of methane from plants
Houweling, S. ; Rockmann, T. ; Aben, I. ; Keppler, F. ; Krol, M.C. ; Meirink, J.F. ; Dlugokencky, E.J. ; Frankenberg, C. - \ 2006
Geophysical Research Letters 33 (2006). - ISSN 0094-8276 - 5 p.
natural wetlands - model - ch4
We investigate whether a recently proposed large source of CH4 from vegetation can be reconciled with atmospheric measurements. Atmospheric transport model simulations with and without vegetation emissions are compared with background CH4, d13C-CH4 and satellite measurements. For present–day CH4 we derive an upper limit to the newly discovered source of 125 Tg CH4 yr-1. Analysis of preindustrial CH4, however, points to 85 Tg CH4 yr-1 as a more plausible limit. Model calculations with and without vegetation emissions show strikingly similar results at background surface monitoring sites, indicating that these measurements are rather insensitive to CH4 from plants. Simulations with 125 Tg CH4 yr-1 vegetation emissions can explain up to 50% of the previously reported unexpectedly high CH4 column abundances over tropical forests observed by SCIAMACHY. Our results confirm the potential importance of vegetation emissions, and call for further research.