scholarly journals Global NO and HONO emissions of biological soil crusts estimated by a process-based non-vascular vegetation model

2019 ◽  
Vol 16 (9) ◽  
pp. 2003-2031 ◽  
Author(s):  
Philipp Porada ◽  
Alexandra Tamm ◽  
Jose Raggio ◽  
Yafang Cheng ◽  
Axel Kleidon ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Empirical Studies ◽  
Trace Gases ◽  
Biological Soil Crusts ◽  
Oh Radicals ◽  
Strong Impact ◽  
Natural Ecosystems ◽  
Dynamic Activity ◽  
Soil Crusts ◽  
Reactive Trace Gases

Abstract. The reactive trace gases nitric oxide (NO) and nitrous acid (HONO) are crucial for chemical processes in the atmosphere, including the formation of ozone and OH radicals, oxidation of pollutants, and atmospheric self-cleaning. Recently, empirical studies have shown that biological soil crusts are able to emit large amounts of NO and HONO, and they may therefore play an important role in the global budget of these trace gases. However, the upscaling of local estimates to the global scale is subject to large uncertainties, due to unknown spatial distribution of crust types and their dynamic metabolic activity. Here, we perform an alternative estimate of global NO and HONO emissions by biological soil crusts, using a process-based modelling approach to these organisms, combined with global data sets of climate and land cover. We thereby consider that NO and HONO are emitted in strongly different proportions, depending on the type of crust and their dynamic activity, and we provide a first estimate of the global distribution of four different crust types. Based on this, we estimate global total values of 1.04 Tg yr−1 NO–N and 0.69 Tg yr−1 HONO–N released by biological soil crusts. This corresponds to around 20 % of global emissions of these trace gases from natural ecosystems. Due to the low number of observations on NO and HONO emissions suitable to validate the model, our estimates are still relatively uncertain. However, they are consistent with the amount estimated by the empirical approach, which confirms that biological soil crusts are likely to have a strong impact on global atmospheric chemistry via emissions of NO and HONO.

scholarly journals Global NO and HONO emissions of biological soil crusts estimated by a process-based non-vascular vegetation model

2018 ◽  
Author(s):  
Philipp Porada ◽  
Alexandra Tamm ◽  
Axel Kleidon ◽  
Ulrich Pöschl ◽  
Bettina Weber
Keyword(s):  
Atmospheric Chemistry ◽  
Empirical Studies ◽  
Trace Gases ◽  
Global Scale ◽  
Biological Soil Crusts ◽  
Oh Radicals ◽  
Strong Impact ◽  
Dynamic Activity ◽  
Soil Crusts ◽  
Reactive Trace Gases

Abstract. The reactive trace gases nitric oxide (NO) and nitrous acid (HONO) are crucial for chemical processes in the atmosphere, including the formation of ozone and OH radicals, oxidation of pollutants and atmospheric self-cleaning. Recently, empirical studies showed that biological soil crusts are able to emit large amounts of NO and HONO and they may therefore play an important role in the global budget of these trace gases. However, the upscaling of local estimates to the global scale is subject to large uncertainties, due to unknown spatial distribution of crust types and their dynamic metabolic activity. Here, we perform an alternative estimate of global NO and HONO emissions by biological soil crusts, using a process-based modelling approach to these organisms, combined with global datasets of climate and land cover. We thereby consider that NO and HONO are emitted in strongly different proportions, depending on the type of crust and their dynamic activity, and we provide a first estimate of the global distribution of four different crust types. Based on this, we estimate global total values of 1.04 Tg yr−1 NO-N and 0.69 Tg yr−1 HONO-N released by biological soil crusts. This is consistent with the amount estimated by the empirical approach and confirms that biological soil crusts are likely to have a strong impact on global atmospheric chemistry via emissions of NO and HONO.

scholarly journals Biological soil crusts accelerate the nitrogen cycle through large NO and HONO emissions in drylands

2015 ◽  
Vol 112 (50) ◽  
pp. 15384-15389 ◽  
Author(s):  
Bettina Weber ◽  
Dianming Wu ◽  
Alexandra Tamm ◽  
Nina Ruckteschler ◽  
Emilio Rodríguez-Caballero ◽  
...  
Keyword(s):  
Nitrogen Cycle ◽  
Atmospheric Chemistry ◽  
Measurement Data ◽  
Biological Soil Crusts ◽  
Climate Feedback ◽  
Reactive Nitrogen ◽  
Satellite Measurement ◽  
Strong Impact ◽  
Nitrogen Emissions ◽  
Soil Crusts

Reactive nitrogen species have a strong influence on atmospheric chemistry and climate, tightly coupling the Earth’s nitrogen cycle with microbial activity in the biosphere. Their sources, however, are not well constrained, especially in dryland regions accounting for a major fraction of the global land surface. Here, we show that biological soil crusts (biocrusts) are emitters of nitric oxide (NO) and nitrous acid (HONO). Largest fluxes are obtained by dark cyanobacteria-dominated biocrusts, being ∼20 times higher than those of neighboring uncrusted soils. Based on laboratory, field, and satellite measurement data, we obtain a best estimate of ∼1.7 Tg per year for the global emission of reactive nitrogen from biocrusts (1.1 Tg a−1of NO-N and 0.6 Tg a−1of HONO-N), corresponding to ∼20% of global nitrogen oxide emissions from soils under natural vegetation. On continental scales, emissions are highest in Africa and South America and lowest in Europe. Our results suggest that dryland emissions of reactive nitrogen are largely driven by biocrusts rather than the underlying soil. They help to explain enigmatic discrepancies between measurement and modeling approaches of global reactive nitrogen emissions. As the emissions of biocrusts strongly depend on precipitation events, climate change affecting the distribution and frequency of precipitation may have a strong impact on terrestrial emissions of reactive nitrogen and related climate feedback effects. Because biocrusts also account for a large fraction of global terrestrial biological nitrogen fixation, their impacts should be further quantified and included in regional and global models of air chemistry, biogeochemistry, and climate.

Development of an incoherent broadband cavity-enhanced absorption spectroscopy (IBBCEAS) instrument for autonomous field measurements of HONO and NO2 in a rural area

2021 ◽  
Author(s):  
Lingshuo Meng ◽  
Gaoxuan Wang ◽  
Cécile Coeur ◽  
Alexandre Tomas ◽  
Tao Wu ◽  
...  
Keyword(s):  
Rural Area ◽  
Absorption Spectroscopy ◽  
Atmospheric Chemistry ◽  
Nitrous Acid ◽  
Trace Gases ◽  
Ambient Air ◽  
Rural Site ◽  
Oh Radicals ◽  
Enhanced Absorption ◽  
Cavity Enhanced Absorption Spectroscopy

<p>Nitrous acid (HONO) is one of the important atmospheric trace gases due to its contribution to the cycles of nitrogen oxides (NOx) and hydrogen oxides (HOx). In particular it acts as a precursor of tropospheric OH radicals, which is responsible for the self-cleansing capacity of the atmosphere [1,2]. We developed an instrument based on incoherent broadband cavity enhanced absorption spectroscopy (IBBCEAS) for automatic measurement of HONO in a rural area in a summer period during a field "Campagne d’OBservation Intensive des Aérosols et précurseurs à Caillouël-Crépigny (COBIACC)" in France. IBBCEAS technique is now extensively used in field applications for the measurements of both trace gases and aerosols [3,4].</p><p>Real-time in situ measurements of HONO and NO<sub>2</sub> have been simultaneously carried out. The IBBCEAS instrument performance has been demonstrated and validated through lab-based tests, and in particular through field intercomparison via side-by-side measurements of temporal concentration profiles of HONO and NO<sub>2</sub> in the rural area. The intercomparison of the concentration measurements between IBBCEAS and an instrument called MARGA (Monitor for AeRosols and Gases in Ambient air) for HONO, and IBBCEAS vs. a reference NOx analyzer for NO<sub>2</sub>. Good agreements have been observed which demonstrated the performance of the developed IBBCEAS instrument for the measurement of atmospheric HONO concentration (<5 ppb) in a rural area.</p><p>The preliminary experimental results will be presented and discussed.</p><p><strong>Acknowledgments</strong> This work was supported by the CPER CLIMIBIO program and the Labex CaPPA project (ANR-10-LABX005). The authors highly appreciate the offers of Mr. Eric Wetzels from Polyfluor Plastics bv for the help in our instrumental conception involving Teflon pipe.</p><p><strong>References</strong></p><p>[1] X. Li, T. Brauers, R. Häseler, R. Bohn, H. Fuchs, A. Hofzumahaus, F. Holland, S. Lou, et al., Exploring the atmospheric chemistry of nitrous acid (HONO) at a rural site in Southern China, Atmos. Chem. Phys. <strong>12</strong> (2012) 1497-1513.</p><p>[2] H. Su, Y. Cheng, M. Shao, D. Gao, Z. Yu, L. Zeng, J. Slanina, et al., Nitrous acid (HONO) and its daytime sources at a rural site during the 2004 PRIDE‐PRD experiment in China, J. Geophys. Res. <strong>113</strong> (2008) D14312.</p><p>[3] T. Wu, Q. Zha, W. Chen, Z. Xu, T. Wang, X. He, Development and deployment of a cavity enhanced UV-LED spectrometer for measurements of atmospheric HONO and NO<sub>2</sub> in Hong Kong, Atmos. Environ. <strong>95</strong> (2014) 544-551.</p><p>[4] L. Meng, G. Wang, P. Augustin, M. Fourmentin, Q. Gou, E. Fertein, T. N. Ba, C. Coeur, A. Tomas, W. Chen, Incoherent broadband cavity enhanced absorption spectroscopy-based strategy for direct measurement of aerosol extinction in lidar blind zone, Opt. Lett. <strong>45 </strong>(2020) 1611-1614.</p>

scholarly journals Understanding the influence of combustion on atmospheric CO<sub>2</sub> over Europe by using satellite observations of CO<sub>2</sub> and reactive trace gases

2021 ◽  
Author(s):  
Mehliyar Sadiq ◽  
Paul I. Palmer ◽  
Mark F. Lunt ◽  
Liang Feng ◽  
Ingrid Super ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Atmospheric Carbon Dioxide ◽  
Transport Model ◽  
Trace Gases ◽  
Satellite Observations ◽  
Secondary Source ◽  
Combustion Emissions ◽  
Full Complement ◽  
Reactive Trace Gases ◽  
Carbon Dioxide Co2

Abstract. We assess how nitrogen oxides (NOx = NO + NO2), carbon monoxide (CO) and formaldehyde (HCHO) can be used as proxies to determine the combustion contribution to atmospheric carbon dioxide (CO2) using satellite observations. We focus our analysis on 2018 when there is a full complement of column data from the TROPOspheric Monitoring Instrument (NO2, CO, and HCHO) and the Orbiting Carbon Observatory-2 (CO2). We use the nested GEOS-Chem atmospheric chemistry model to relate high-resolution emission inventories over Europe to these atmospheric data, taking into account scene-dependent averaging kernels. We find that that NO2 and CO are the better candidates to identify incomplete combustion and fingerprints of different combustion sectors, but both have their own challenges associated with properly describing their atmospheric chemistry. The secondary source of HCHO from oxidation of biogenic volatile organic compounds, particularly over southern European countries, compromises its use as a proxy for combustion emissions. We find a weak positive correlation between the CO : CO2 inventory ratio and observed column enhancements of ΔCO : ΔCO2 (R < 0.2), suggesting some consistency and linearity in CO chemistry and transport. However, we find a stronger negative correlation between the NOx : CO2 inventory ratio and observed column enhancements of ΔNO2 :ΔCO2 (R < 0.50), driven by non-linear photochemistry. Both of these observed ratios are described well by the GEOS-Chem atmospheric chemistry transport model, providing confidence of the quality of the emission inventory and that the model is a useful tool for interpreting these tracer-tracer ratios. Our results also provide some confidence in our ability to develop a robust method to infer combustion CO2 emission estimates using satellite observations of reactive trace gases that have up until now mostly been used to study surface air quality.

scholarly journals Characterization of a chemical modulation reactor (CMR) for the measurement of atmospheric concentrations of hydroxyl radicals with a laser-induced fluorescence instrument

2020 ◽  
Author(s):  
Changmin Cho ◽  
Andreas Hofzumahaus ◽  
Hendrik Fuchs ◽  
Hans-Peter Dorn ◽  
Marvin Glowania ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Trace Gases ◽  
Ambient Air ◽  
Laser Induced Fluorescence ◽  
Optical Absorption Spectroscopy ◽  
Oh Radicals ◽  
Atmospheric Conditions ◽  
Atmospheric Measurements ◽  
Chemical Modulation ◽  
Scavenging Efficiency

Abstract. Precise and accurate hydroxyl radical (OH) measurements are essential to investigate how trace gases are oxidized and transformed in the troposphere and how secondary pollutants like ozone (O3) are formed. Laser induced fluorescence (LIF) is a widely used technique for the measurement of ambient OH radicals and was used for the majority of field campaigns and chamber experiments. Recently, most LIF instruments in use for atmospheric measurements of OH radicals introduced chemical modulation to separate the ambient OH radical concentration from possible interferences by chemically removing ambient OH radicals before they enter the detection cell. In this study, we describe the application, characterization, and validation of a chemical modulation reactor (CMR) applied to the Forschungszentrum Jülich LIF (FZJ-LIF) instrument in use at the atmospheric simulation chamber SAPHIR. Besides dedicated experiments in synthetic air, the new technique was extensively tested during the year-round Jülich Atmospheric Chemistry Project (JULIAC) campaign, in which ambient air was continuously flowed into the SAPHIR chamber. It allowed performing OH measurement comparisons with Differential Optical Absorption Spectroscopy (DOAS) and investigation of interferences in a large variety of chemical and meteorological conditions. A good agreement was obtained in the LIF DOAS intercomparison within instrumental accuracies (18 % for LIF, 6.5 % for DOAS) which confirms that the new chemical modulation system of the FZJ-LIF instrument is suitable for measurement of interference-free OH concentrations. Known interferences from O3 + H2O and the nitrate radical (NO3) were quantified with the CMR in synthetic air in the chamber and found to be 3.0 × 105 cm-3 and 0.6 × 105 cm-3, respectively, for typical ambient air condition (O3 = 50 ppbv, H2O = 1 %, NO3 = 10 pptv). The interferences measured in ambient air during the JULIAC campaign in summer season had the median diurnal variation of the interference with a maximum daytime value of 0.9 × 106 cm-3 and a minimum nighttime value of 0.4 × 106 cm-3. The highest interference of 2 × 106 cm-3 occurred in a heat wave from 22–29 August, when the air temperature and ozone increased to 40 °C and 100 ppbv, respectively. All observed interferences could be fully explained by the known O3 + H2O interference, which is routinely corrected in FZJ-LIF measurements when no chemical modulation is applied. No evidence for unexplained interference was found during the JULIAC campaign. A kinetic chemical model of the chemical modulation reactor was developed and applied to estimate the possible perturbation of the OH transmission and scavenging efficiency by reactive atmospheric trace gases. These can remove OH by gas phase reactions in the reactor, or produce OH by non-photolytical reactions, most importantly by the reaction of ambient HO2 with NO. The interfering processes become relevant at high atmospheric OH reactivities. For the conditions of the JULIAC campaign with OH reactivities below 20 s-1, the influence on the determination of ambient OH concentrations was small (on average: 2 %). However, in environments with high OH reactivities, such as in a rain forest or megacity, the expected perturbation in the currently used chemical modulation reactor could be large (more than a factor of 2) and would need careful analysis and correction. This implies that chemical modulation, which was developed to eliminate interferences in ambient OH measurements, itself can be subject to interferences that depend on ambient atmospheric conditions.

scholarly journals Atmospheric Chemistry Measurements at Whiteface Mountain, NY: Ozone and Reactive Trace Gases

2016 ◽  
Vol 16 (3) ◽  
pp. 873-884 ◽  
Author(s):  
Richard E. Brandt ◽  
James J. Schwab ◽  
Paul W. Casson ◽  
Utpal K. Roychowdhury ◽  
Douglas Wolfe ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Trace Gases ◽  
Whiteface Mountain ◽  
Reactive Trace Gases

scholarly journals Direct measurements of NO<sub>3</sub>-reactivity in and above the boundary layer of a mountain-top site: Identification of reactive trace gases and comparison with OH-reactivity

2018 ◽  
Author(s):  
Jonathan M. Liebmann ◽  
Jennifer B. A. Muller ◽  
Dagmar Kubistin ◽  
Anja Claude ◽  
Robert Holla ◽  
...  
Keyword(s):  
Trace Gases ◽  
Ground Level ◽  
Organic Nitrates ◽  
Oh Radicals ◽  
Measurement Site ◽  
Lower Reactivity ◽  
Direct Measurements ◽  
Reactive Trace Gases ◽  
Site Identification ◽  
Organic Trace

Abstract. We present direct measurements of the summertime, total reactivity of NO3 towards organic trace gases, kOTGNO3, at a rural mountain site (988 m a.s.l.) in southern Germany in 2017. The diel cycle of kOTGNO3 was strongly influenced by local meteorology with reactivity high during the day (values of up to 0.3 s-1) but usually close to the detection limit (0.005 s-1) at night when the measurement site was in the residual layer/free troposphere. Daytime values of kOTGNO3 were sufficiently large that the loss of NO3 due to reaction with organic trace gases competed with its photolysis and reaction with NO. Within experimental uncertainty, monoterpenes and isoprene accounted for all of the measured NO3-reactivity. Averaged over the daylight hours, more than 25 % of NO3 was removed via reaction with biogenic volatile organic compounds (BVOCs), implying a significant daytime loss of NOx and formation of organic nitrates due to NO3 chemistry. Ambient NO3 concentrations were measured on one night and were comparable to those derived from a stationary state calculation using measured values of kOTGNO3. We present and compare the first simultaneous, direct-reactivity measurements for the NO3 and OH radicals. The decoupling of the measurement site from ground level emissions resulted in lower reactivity at night for both radicals, though the correlation between OH- and NO3-reactivity was weak as would be anticipated given their divergent trends in rate constants with many organic trace gases.

scholarly journals Characterization of a chemical modulation reactor (CMR) for the measurement of atmospheric concentrations of hydroxyl radicals with a laser-induced fluorescence instrument

2021 ◽  
Vol 14 (3) ◽  
pp. 1851-1877
Author(s):  
Changmin Cho ◽  
Andreas Hofzumahaus ◽  
Hendrik Fuchs ◽  
Hans-Peter Dorn ◽  
Marvin Glowania ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Trace Gases ◽  
Ambient Air ◽  
Laser Induced Fluorescence ◽  
Optical Absorption Spectroscopy ◽  
Oh Radicals ◽  
Atmospheric Measurements ◽  
Chemical Modulation ◽  
Scavenging Efficiency

Abstract. Precise and accurate hydroxyl radical (OH) measurements are essential to investigate mechanisms for oxidation and transformation of trace gases and processes leading to the formation of secondary pollutants like ozone (O3) in the troposphere. Laser-induced fluorescence (LIF) is a widely used technique for the measurement of ambient OH radicals and was used for the majority of field campaigns and chamber experiments. Recently, most LIF instruments in use for atmospheric measurements of OH radicals introduced chemical modulation to separate the ambient OH radical concentration from possible interferences by chemically removing ambient OH radicals before they enter the detection cell (Mao et al., 2012; Novelli et al., 2014a). In this study, we describe the application and characterization of a chemical modulation reactor (CMR) applied to the Forschungszentrum Jülich LIF (FZJ-LIF) instrument in use at the atmospheric simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber). Besides dedicated experiments in synthetic air, the new technique was extensively tested during the year-round Jülich Atmospheric Chemistry Project (JULIAC) campaign, in which ambient air was continuously flowed into the SAPHIR chamber. It allowed for performing OH measurement comparisons with differential optical absorption spectroscopy (DOAS) and investigation of interferences in a large variety of chemical and meteorological conditions. Good agreement was obtained in the LIF–DOAS intercomparison within instrumental accuracies (18 % for LIF and 6.5 % for DOAS) which confirms that the new chemical modulation system of the FZJ-LIF instrument is suitable for measurement of interference-free OH concentrations under the conditions of the JULIAC campaign (rural environment). Known interferences from O3+H2O and the nitrate radical (NO3) were quantified with the CMR in synthetic air in the chamber and found to be 3.0×105 and 0.6×105 cm−3, respectively, for typical ambient-air conditions (O3=50 ppbv, H2O = 1 % and NO3=10 pptv). The interferences measured in ambient air during the JULIAC campaign in the summer season showed a median diurnal variation with a median maximum value of 0.9×106 cm−3 during daytime and a median minimum value of 0.4×106 cm−3 at night. The highest interference of 2×106 cm−3 occurred in a heat wave from 22 to 29 August, when the air temperature and ozone increased to 40 ∘C and 100 ppbv, respectively. All observed interferences could be fully explained by the known O3+H2O interference, which is routinely corrected in FZJ-LIF measurements when no chemical modulation is applied. No evidence for an unexplained interference was found during the JULIAC campaign. A chemical model of the CMR was developed and applied to estimate the possible perturbation of the OH transmission and scavenging efficiency by reactive atmospheric trace gases. These can remove OH by gas phase reactions in the CMR or produce OH by non-photolytic reactions, most importantly by the reaction of ambient HO2 with NO. The interfering processes become relevant at high atmospheric OH reactivities. For the conditions of the JULIAC campaign with OH reactivities below 20 s−1, the influence on the determination of ambient OH concentrations was small (on average: 2 %). However, in environments with high OH reactivities, such as in a rain forest or megacity, the expected perturbation in the currently used chemical modulation reactor could be large (more than a factor of 2). Such perturbations need to be carefully investigated and corrected for the proper evaluation of OH concentrations when applying chemical scavenging. This implies that chemical modulation, which was developed to eliminate interferences in ambient OH measurements, itself can be subject to interferences that depend on ambient atmospheric conditions.

scholarly journals Direct measurements of NO<sub>3</sub> reactivity in and above the boundary layer of a mountaintop site: identification of reactive trace gases and comparison with OH reactivity

2018 ◽  
Vol 18 (16) ◽  
pp. 12045-12059 ◽  
Author(s):  
Jonathan M. Liebmann ◽  
Jennifer B. A. Muller ◽  
Dagmar Kubistin ◽  
Anja Claude ◽  
Robert Holla ◽  
...  
Keyword(s):  
Trace Gases ◽  
Ground Level ◽  
High Reactivity ◽  
Organic Nitrates ◽  
Oh Radicals ◽  
Measurement Site ◽  
Lower Reactivity ◽  
Direct Measurements ◽  
Reactive Trace Gases ◽  
Organic Trace

Abstract. We present direct measurements of the summertime total reactivity of NO3 towards organic trace gases, kOTGNO3, at a rural mountain site (988 m a.s.l.) in southern Germany in 2017. The diel cycle of kOTGNO3 was strongly influenced by local meteorology with high reactivity observed during the day (values of up to 0.3 s−1) and values close to the detection limit (0.005 s−1) at night when the measurement site was in the residual layer and free troposphere. Daytime values of kOTGNO3 were sufficiently large that the loss of NO3 due to reaction with organic trace gases competed with its photolysis and reaction with NO. Within experimental uncertainty, monoterpenes and isoprene accounted for all of the measured NO3 reactivity. Averaged over the daylight hours, more than 25 % of NO3 was removed via reaction with biogenic volatile organic compounds (BVOCs), implying a significant daytime loss of NOx and the formation of organic nitrates due to NO3 chemistry. Ambient NO3 concentrations were measured on one night and were comparable to those derived from a stationary-state calculation using measured values of kOTGNO3. We present and compare the first simultaneous, direct reactivity measurements for the NO3 and OH radicals. The decoupling of the measurement site from ground-level emissions resulted in lower reactivity at night for both radicals, though the correlation between OH and NO3 reactivity was weak as would be anticipated given their divergent trends in rate constants with many organic trace gases.

Revisiting classic water erosion models in drylands: The strong impact of biological soil crusts

2008 ◽  
Vol 40 (9) ◽  
pp. 2309-2316 ◽  
Author(s):  
Matthew A. Bowker ◽  
Jayne Belnap ◽  
V. Bala Chaudhary ◽  
Nancy C. Johnson
Keyword(s):  
Water Erosion ◽  
Biological Soil Crusts ◽  
Strong Impact ◽  
Soil Crusts ◽  
Erosion Models
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