Small Interannual Variability of Global Atmospheric Hydroxyl

  title={Small Interannual Variability of Global Atmospheric Hydroxyl},
  author={Stephen A. Montzka and Maarten C. Krol and Edward J. Dlugokencky and Bradley D. Hall and Patrick J{\"o}ckel and Jos Lelieveld},
  pages={67 - 69}
The abundance of the highly reactive hydroxyl radical is well buffered against perturbations. The oxidizing capacity of the global atmosphere is largely determined by hydroxyl (OH) radicals and is diagnosed by analyzing methyl chloroform (CH3CCl3) measurements. Previously, large year-to-year changes in global mean OH concentrations have been inferred from such measurements, suggesting that the atmospheric oxidizing capacity is sensitive to perturbations by widespread air pollution and natural… 

Modulation of hydroxyl variability by ENSO in the absence of external forcing

It is found that natural OH variability can produce (unforced) methane trends as large as the observed changes in methane over the last few decades and that ENSO is the dominant mode of OH variability, with the modulation of OH occurring primarily through lightning NOx.

Large uncertainties in global hydroxyl projections tied to fate of reactive nitrogen and carbon

It is demonstrated that intermodel differences in OH are best explained by disparate implementations of chemical and physical processes that affect reactive oxides of nitrogen and organic chemical species, and implies a need for additional observational constraints on NOy partitioning and lifetime, especially in the remote free troposphere.

Global tropospheric hydroxyl distribution, budget and reactivity

Abstract. The self-cleaning or oxidation capacity of the atmosphere is principally controlled by hydroxyl (OH) radicals in the troposphere. Hydroxyl has primary (P) and secondary (S) sources, the

Mapping hydroxyl variability throughout the global remote troposphere via synthesis of airborne and satellite formaldehyde observations

This work combines the robust chemical relationship between OH and formaldehyde (HCHO) with satellite-based HCHO observations to infer total-column OH throughout the remote troposphere, and offers unique insights on near-global oxidizing capacity.

Changes in Global Tropospheric OH Expected as a Result of Climate Change Over the Last Several Decades

The oxidizing capacity of the troposphere is controlled primarily by the abundance of hydroxyl radical (OH). The global mean concentration of tropospheric OH, [OH]TROP (the burden of OH in the global

Observational evidence for interhemispheric hydroxyl-radical parity

The findings suggest that top-down emission estimates of reactive species such as nitrogen oxides in key emitting countries in the NH that are based on a NH/SH OH ratio larger than 1 may be overestimated.

Methyl Chloroform Continues to Constrain the Hydroxyl (OH) Variability in the Troposphere

Trends and variability in tropospheric hydroxyl (OH) radicals influence budgets of many greenhouse gases, air pollutant species, and ozone depleting substances. Estimations of tropospheric OH trends

Paleo-Perspectives on Potential Future Changes in the Oxidative Capacity of the Atmosphere Due to Climate Change and Anthropogenic Emissions

The oxidizing capacity of the atmosphere, defined as the global mean tropospheric abundance of the hydroxyl radical (OH·), strongly influences air pollution by controlling the lifetimes of gaseous

An observationally constrained evaluation of the oxidative capacity in the tropical western Pacific troposphere

Hydroxyl radical (OH) is the main daytime oxidant in the troposphere and determines the atmospheric lifetimes of many compounds. We use aircraft measurements of O3, H2O, NO, and other species from

Methane Feedback on Atmospheric Chemistry: Methods, Models, and Mechanisms

The atmospheric methane (CH4) chemical feedback is a key process for understanding the behavior of atmospheric CH4 and its environmental impact. This work reviews how the feedback is defined and



Evidence for variability of atmospheric hydroxyl radicals over the past quarter century

The hydroxyl free radical (OH) is the major oxidizing chemical in the atmosphere, destroying about 3.7 petagrams (Pg) of trace gases each year, including many gases involved in ozone depletion, the

Interhemispheric asymmetry in OH abundance inferred from measurements of atmospheric 14CO

THE hydroxyl radical, OH, is the chief oxidizing agent in the atmosphere, and is responsible for removing many natural and anthropogenic trace gases1. At present, OH cannot be measured directly with

Short-term variations in the oxidizing power of the atmosphere

Records of carbon monoxide containing radiocarbon (14CO), which is oxidized by hydroxyl radicals, from clean-air sites at Baring Head, New Zealand, and Scott Base, Antarctica, spanning 13 years are shown.

New observational constraints for atmospheric hydroxyl on global and hemispheric scales

These results set firm upper limits on the global and Southern Hemispheric lifetimes of methyl chloroform and confirm the predominance of hydroxyl in the tropics.

Two decades of OH variability as inferred by an inversion of atmospheric transport and chemistry of methyl chloroform

Abstract. We developed an iterative inverse method to infer inter-annual sources and sinks of methyl chloroform (MCF) from atmospheric measurements, on a monthly basis. The methodology is presented

Renewed growth of atmospheric methane

Following almost a decade with little change in global atmospheric methane mole fraction, we present measurements from the Advanced Global Atmospheric Gases Experiment (AGAGE) and the Australian

CTM study of changes in tropospheric hydroxyl distribution 1990–2001 and its impact on methane

Impacts of emission changes on hydroxyl (OH) and methane lifetime in the troposphere are studied using an emission inventory for the period 1990–2001 as input to a global Chemical Transport Model

Interannual variability and trend of CH4 lifetime as a measure for OH changes in the 1979–1993 time period

[1] The interannual variability and trend in the CH4 lifetime, as a measure for global mean OH concentration, have been analyzed systematically with three-dimensional (3-D) chemistry-transport model

Can the variability in tropospheric OH be deduced from measurements of 1,1,1‐trichloroethane (methyl chloroform)?

[1] Global three-dimensional (3-D) model calculations have been used to inversely determine OH concentrations from 1,1,1-trichloroethane (methyl chloroform or CH3CCl3) measurements at the Atmospheric