Abstract. The knowledge of the lightning-induced nitrogen oxides (LNO x ) source is important for understanding and predicting the nitrogen oxides and ozone distributions in the troposphere and their trends, the oxidising capacity of the atmosphere, and the lifetime of trace gases destroyed by reactions with OH. This knowledge is further required for the assessment of other important NO x sources, in particular from aviation emissions, the stratosphere, and from surface sources, and for understanding the possible feedback between climate changes and lightning. This paper reviews more than 3 decades of research. The review includes laboratory studies as well as surface, airborne and satellite-based observations of lightning and of NO x and related species in the atmosphere. Relevant data available from measurements in regions with strong LNO x influence are identified, including recent observations at midlatitudes and over tropical continents where most lightning occurs. Various methods to model LNO x at cloud scales or globally are described. Previous estimates are re-evaluated using the global annual mean flash frequency of 44±5 s −1 reported from OTD satellite data. From the review, mainly of airborne measurements near thunderstorms and cloud-resolving models, we conclude that a "typical" thunderstorm flash produces 15 (2-40)×10 25 NO molecules per flash, equivalent to 250 mol NO x or 3.5 kg of N mass per flash with uncertainty factor from 0.13 to 2.7. Mainly as a result of global model studies for various LNO x parameterisations tested with related observations, the best estimate of the annual global LNO x nitrogen mass source and its uncertainty range is (5±3) Tg a −1 in this study. In spite of a smaller global flash rate, the best estimate is essentially the same as in some earlier reviews, implying larger flash-specific NO x emissions. The paper estimates the LNO x accuracy required for various applications and lays out strategies for improving estimates in the future. An accuracy of Correspondence to: U. Schumann (ulrich.schumann@dlr.de) about 1 Tg a −1 or 20%, as necessary in particular for understanding tropical tropospheric chemistry, is still a challenging goal.

Abstract. The knowledge of the lightning-induced nitrogen oxides (LNOx) source is important for understanding and predicting the nitrogen oxides and ozone distributions in the troposphere and their trends, the oxidising capacity of the atmosphere, and the lifetime of trace gases destroyed by reactions with OH. This knowledge is further required for the assessment of other important NOx sources, in particular from aviation, the stratosphere, and from surface sources, and for understanding the possible feedback between climate changes and lightning. This paper reviews more then 3 decades of research. The review includes laboratory studies as well as surface, airborne and satellite-based observations of lightning and of NOx and related species in the atmosphere. Relevant data available from measurements in regions with strong LNOx influence are identified, including recent observations at midlatitudes and over tropical continents where most lightning occurs. Various methods to model LNOx at cloud scales or globally are described. Previous estimates are re-evaluated using the global annual mean flash frequency of 44±5 s−1 reported from OTD satellite data. From the review, mainly of airborne measurements near thunderstorms and cloud-resolving models, we conclude that a "typical" thunderstorm flash produces 15 (2–40)×1025 NO molecules per flash, equivalent to 250 mol NOx or 3.5 kg of N mass per flash with uncertainty factor from 0.13 to 2.7. Mainly as a result of previous global model studies for various LNOx parameterisations tested with related observations, the best estimate of the annual global LNOx nitrogen mass source and its uncertainty range is (5±3) Tg a−1 in this study. An accuracy of order 1 Tg a−1 or 20%, as necessary in particular for understanding tropical tropospheric chemistry, is still a challenging goal.

DC3 brought together simultaneous measurements of storm kinematics, structure, electrical activity, and chemistry to improve our knowledge of how thunderstorms affect the chemical composition of the troposphere.

Abstract. The first global tropospheric forecasts of O3 and its precursors have been used in the daily flight planning of field measurement campaigns. The 3-D chemistry-transport model MATCH-MPIC is driven by meteorological data from a weather center (NCEP) to produce daily 3-day forecasts of the global distributions of O3 and related gases, as well as regional CO tracers. This paper describes the forecast system and its use in three field campaigns, MINOS, CONTRACE and INDOEX. An overview is given of the forecasts by MATCH-MPIC and by three other chemical weather forecast models (EURAD, ECHAM, and FLEXPART), focusing on O3 and CO. Total CO and regional CO tracers were found to be the most valuable gases for flight planning, due to their relatively well-defined anthropogenic source regions and lifetimes of one to a few months. CO was in good agreement with the observations on nearly all the flights (generally  r > 0.7, and the relative RMS differences for the deviations from the means was less than 20%). In every case in which the chemical weather forecasts were primarily responsible for the flight plans, the targeted features were observed. Three forecasted phenomena are discussed in detail: outflow from Asia observed in the Mediterranean upper troposphere during MINOS, outflow from North America observed in the middle troposphere over northern Europe during CONTRACE, and the location of the "chemical ITCZ'' over the Indian Ocean during INDOEX. In particular it is shown that although intercontinental pollution plumes such as those observed during MINOS and CONTRACE occur repeatedly during the months around the campaigns, their frequency is sufficiently low (~10--30% of the time) that global chemical weather forecasts are important for enabling them to be observed during limited-duration field campaigns. The MATCH-MPIC chemical weather forecasts, including an interface for making customized figures from the output, are available for community use via http://www.mpch-mainz.mpg.de/~lawrence/forecasts.html.

[1] The eruption of the Eyjafjallajökull volcano, Iceland, in April and May 2010 caused unprecedented disruptions of European air traffic showing that timely monitoring of volcanic ash and SO 2 dispersion as well as the corresponding plume heights are important for aviation safety. This paper describes the observations of SO 2 and BrO columns in the eruption plume and the determination of the SO 2 plume height using the GOME-2 satellite instrument. During the eruptive period in May 2010, SO 2 total columns of up to $20 DU and BrO columns of $7.7 Â 10 13 molec/cm 2 were detected. The BrO/SO 2 ratio estimated from the GOME-2 observations of the Eyjafjallajökull eruption varies from 1.1 Â 10 À4 to 2.1 Â 10 À4. The SO 2 plume heights estimated from the GOME-2 observations on 5 May range from 8-13 km and mostly agree within 1-3 km with visual observations, radar data and modeling results. Furthermore, the GOME-2 SO 2 observations are compared with in situ measurements of the DLR Falcon aircraft on 17 and 18 May 2010 and with Brewer instruments at Valentia, Ireland and Hohenpeissenberg, Germany. The SO 2 columns derived from the Falcon profile measurements range from 0.6-4.7 DU and the comparison with the GOME-2 measurements shows a good agreement, mainly within 1 DU. The Brewer observations at Hohenpeissenberg also agree well with the GOME-2 measurements with a daily average SO 2 column of $1.3 DU during the overpass of the SO 2 cloud on 18 May, whereas the Brewer instrument at Valentia shows up to 50% higher SO 2 columns ($8 DU) on 11 May.Citation: Rix, M., P. Valks, N. Hao, D. Loyola, H. Schlager, H. Huntrieser, J. Flemming, U. Koehler, U. Schumann, and A. Inness (2012), Volcanic SO 2 , BrO and plume height estimations using GOME-2 satellite measurements during the eruption of