Observations of Near-Zero Ozone Concentrations Over the Convective Pacific: Effects on Air Chemistry

Kley, D.; Crutzen, Paul J.; Smit, H. G. J.; Vömel, H.; Oltmans, S. J.; Graßl, Hartmut; Ramanathan, V.

doi:10.1126/science.274.5285.230

Cited by 224 publications

(224 citation statements)

References 9 publications

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“…Here, GOME-2 measures minimum tropospheric ozone columns of ∼ 10 DU. These low ozone values are consistent with ozonesonde measurements in the West Pacific, showing ozone concentrations of ∼ 15 ppbv and lower in the tropical troposphere (Kley et al, 1996;Rex et al, 2014). Lidar measurements carried out during the PEM-Tropics B campaign also show very low ozone in the marine boundary layer and upper troposphere in the Pacific (Browell et al, 2001).…”

Section: Tropical Tropospheric Ozone and No 2 Distributionssupporting

confidence: 85%

Tropical tropospheric ozone column retrieval for GOME-2

et al. 2014

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Abstract. This paper presents the operational retrieval of tropical tropospheric ozone columns (TOCs) from the Second Global Ozone Monitoring Experiment (GOME-2) instruments using the convective-cloud-differential (CCD) method. The retrieval is based on total ozone and cloud property data provided by the GOME Data Processor (GDP) 4.7, and uses above-cloud and clear-sky ozone column measurements to derive a monthly mean TOC between 20 • N and 20 • S. Validation of the GOME-2 TOC with several tropical ozonesonde sites shows good agreement, with a high correlation between the GOME-2 and sonde measurements, and small biases within ∼ 3 DU. The TOC data have been used in combination with tropospheric NO 2 measurements from GOME-2 to analyse the effect of the 2009-2010 El Niño-Southern Oscillation (ENSO) on the tropospheric ozone distribution in the tropics. El Niño induced dry conditions in September-October 2009 resulted in relatively high tropospheric ozone columns over the southern Indian Ocean and northern Australia, while La Niña conditions in September-October 2010 resulted in a strong increase in tropospheric NO 2 in South America, and enhanced ozone in the eastern Pacific and South America. Comparisons of the GOME-2 tropospheric ozone data with simulations of the ECHAM/MESSy Atmospheric Chemistry (EMAC) model for 2009 El Niño conditions illustrate the usefulness of the GOME-2 TOC measurements in evaluating chemistry climate models (CCMs). Evaluation of CCMs with appropriate satellite observations helps to identify strengths and weaknesses of the model systems, providing a better understanding of driving mechanisms and adequate relations and feedbacks in the Earth atmosphere, and finally leading to improved models.

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Section: Tropical Tropospheric Ozone and No 2 Distributionssupporting

confidence: 85%

Tropical tropospheric ozone column retrieval for GOME-2

et al. 2014

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“…Measurements from the southeast edge of the warm pool in 1993 carried out on the Research Vessel (RV) Vickers and on Christmas Island during the CEPEX campaign (Kley et al, 1996;Lawrence et al, 1999) and lidar measurements carried out during the PEM-Tropics B campaign onboard the NASA DC-8 aircraft (Browell et al, 2001, Plate 5) show extremely low ozone in the marine boundary layer and in the upper troposphere, the main outflow region of convection. Individual profiles from the stations Samoa, Fiji, Tahiti and Christmas Island further southeast (Solomon et al, 2005;Takashima et al, 2008) and from Indonesian stations Pontianak and Kototabang slightly to the west (Fujiwara et al, 2003) also show very low ozone values, typically occuring in some ten percent of the measurements.…”

Section: Ozone Profile Measurementsmentioning

confidence: 99%

“…This favors ozone loss over the westernmost tropical Pacific, where marine boundary layer air temperature is highest globally and overhead ozone lowest (e.g., Kley et al, 1996). Odd oxygen (O 3 +O) lifetime (which determines the effective lifetime of ozone) drops to less than a week under these conditions near the surface (e.g., Kley et al, 1996). The odd oxygen lifetime increases steeply with altitude due to decreasing temperature which leads to lower water vapor.…”

Section: Introductionmentioning

confidence: 99%

“…The efficiency is a function of actinic fluxes at λ < 340 nm (in clear sky conditions mostly determined by overhead ozone and solar zenith angle) and concentration of water vapor, with higher air temperatures corresponding to higher water concentrations and faster ozone loss. This favors ozone loss over the westernmost tropical Pacific, where marine boundary layer air temperature is highest globally and overhead ozone lowest (e.g., Kley et al, 1996). Odd oxygen (O 3 +O) lifetime (which determines the effective lifetime of ozone) drops to less than a week under these conditions near the surface (e.g., Kley et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

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A tropical West Pacific OH minimum and implications for stratospheric composition

et al. 2014

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Abstract. Most of the short-lived biogenic and anthropogenic chemical species that are emitted into the atmosphere break down efficiently by reaction with OH and do not reach the stratosphere. Here we show the existence of a pronounced minimum in the tropospheric column of ozone over the West Pacific, the main source region for stratospheric air, and suggest a corresponding minimum of the tropospheric column of OH. This has the potential to amplify the impact of surface emissions on the stratospheric composition compared to the impact when assuming globally uniform OH conditions. Specifically, the role of emissions of biogenic halogenated species for the stratospheric halogen budget and the role of increasing emissions of SO 2 in Southeast Asia or from minor volcanic eruptions for the increasing stratospheric aerosol loading need to be reassessed in light of these findings. This is also important since climate change will further modify OH abundances and emissions of halogenated species. Our study is based on ozone sonde measurements carried out during the TransBrom cruise with the RV Sonne roughly along 140-150 • E in October 2009 and corroborating ozone and OH measurements from satellites, aircraft campaigns and FTIR instruments. Model calculations with the GEOS-Chem Chemistry and Transport Model (CTM) and the ATLAS CTM are used to simulate the tropospheric OH distribution over the West Pacific and the transport pathways to the stratosphere. The potential effect of the OH minimum on species transported into the stratosphere is shown via modeling the transport and chemistry of CH 2 Br 2 and SO 2 .

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“…Recently, lhe significance of tropospheric ozone in the tropics has been recognized in terms of the oxidizing efficiency and greenhouse effect, and various efforts have been made to investigate its spatial distribution and temporal variation [Kley et al, 1996; Thompson et al, 1997; Crutzen and Lawrence, 19971. However, especially in the upper troposphere, the ozone budget in the tropics has not been fully understood yet because of the sparsity of the ground-based and long-term observations.…”

mentioning

confidence: 99%