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Lightning is one of the main sources of NOxin the Earth's atmosphere. However, there is a large variability in NOxproduction during the lifetime of thunderstorms. In this study, we used the TROPOspheric Monitoring Instrument (TROPOMI) cloud and NO2research products along with Lightning Mapping Array (LMA) measurements to investigate the possible relation between the amount of NOxproduced per lightning flash and flash channel length in the Ebro Valley. We found that there is a positive relationship between both variables. In turn, the vertical structure of the analyzed lightning flashes indicates that longer flashes could release more LNOxat lower altitudes than shorter flashes, while higher flash rates produce less LNOxper flash. Lightning produces significant amounts of NOxin the Earth's atmosphere. However, the quantity of NOxgenerated during thunderstorms exhibits significant variation. In this study, we used a space‐based instrument called TROPOMI to look at clouds and measure NO2, and we also used a network of antennas called Lightning Mapping Array to map the spatial structure of lightning strikes. Our main goal was investigating if there is a connection between the amount of NOxproduced by lightning and how long the lightning flashes were in the Ebro Valley. We found that there is a positive relationship between the two variables. We also looked at the structure of the lightning flashes and found that longer flashes release more NOxat lower altitudes compared to shorter flashes. Additionally, when there are more frequent lightning flashes, each flash produces less NOx. Lightning Mapping Array data reveals a positive correlation between lightning NOxproduction efficiency and the lightning flash lengthsThe investigation of space‐based data demonstrates a negative correlation between lightning NOxproduction efficiency and flash frequencyMean NOxper flash length obtained in this work vary between 1.9 × 1021and 3.8 × 1021molec NOx/m Lightning Mapping Array data reveals a positive correlation between lightning NOxproduction efficiency and the lightning flash lengths The investigation of space‐based data demonstrates a negative correlation between lightning NOxproduction efficiency and flash frequency Mean NOxper flash length obtained in this work vary between 1.9 × 1021and 3.8 × 1021molec NOx/m

We use height‐resolved and total column satellite observations and 3‐D chemical transport model simulations to study stratospheric ozone variations during 1998–2017 as ozone‐depleting substances decline. In 2017 extrapolar lower stratospheric ozone displayed a strong positive anomaly following much lower values in 2016. This points to large interannual variability rather than an ongoing downward trend, as reported recently by Ball et al. (2018, https://doi.org/10.5194/acp‐18‐1379‐2018). The observed ozone variations are well captured by the chemical transport model throughout the stratosphere and are largely driven by meteorology. Model sensitivity experiments show that the contribution of past trends in short‐lived chlorine species to the ozone changes is small. Similarly, the potential impact of modest trends in natural brominated short‐lived species is small. These results confirm the important role that atmospheric dynamics plays in controlling ozone in the extrapolar lower stratosphere on multiannual time scales and the continued importance of monitoring ozone profiles as the stratosphere changes. Emission of long‐lived chlorine and bromine‐containing ozone‐depleting substances has led to the depletion of the ozone layer, most notably the Antarctic ozone hole. Policy action through the Montreal Protocol has phased out the production of the major long‐lived ozone‐depleting substances. Consequently, stratospheric chlorine and bromine amounts are declining, and we expect the ozone layer to slowly recover. However, although the tropical lower stratosphere is not a region where large ozone loss has so‐far been observed, a recent study by Ball et al. (2018) suggested that ozone there is decreasing, in disagreement with models and expectations of ozone recovery. We use updated observations and an atmospheric model to investigate these issues. First, we use an additional year of observations which show that ozone values in the lower stratosphere increased in 2017, which is a consequence of variations in atmospheric dynamics. Second, our 3‐D model performs well in reproducing the observed ozone variations. Although the model is not perfect, the comparisons suggest that we do have a good understanding of the lower stratospheric ozone. Third, we quantify the role of short‐lived chlorine and bromine compounds, which are not controlled by the Montreal Protocol, on the recent ozone changes. The effect is small. Observations show that lower stratospheric ozone at extrapolar latitudes increased strongly in 2017 relative to a negative anomaly in 2016Model simulations reproduce the observed ozone variations well, and the main driver in the lower stratosphere is atmospheric dynamicsThe contribution of an observation‐based trend in short‐lived chlorine species to recent lower stratospheric ozone variations is small

Since 1995, the Global Ozone Monitoring Experiment (GOME) has measured solar and backscattered spectra in the ultraviolet and visible wavelength range. Now, the extensive data set of the most important calibration parameters has been investigated thoroughly in order to analyze the long-term stability and performance of the instrument. This study focuses on GOME in-flight calibration and degradation for the solar path. Monitoring the sensor degradation yields an intensity decrease of 70% to 90% in 240-316 nm and 35% to 65% in 311-415 nm. The spectral calibration is very stable over the whole period, although a very complex interaction between predisperser temperature and wavelength was found. The leakage current and the pixel-to-pixel gain increased significantly during the mission, which requires an accurate correction of the measured radiance and irradiance signals using proper calibration parameters. Finally, several outliers in the data sets can be directly assigned to instrument and satellite anomalies.

The global ozone monitoring experiment (GOME) was launched in April 1995, and the GOME data processor (GDP) retrieval algorithm has processed operational total ozone amounts since July 1995. GDP level 1-to-2 is based on the two-step differential optical absorption spectroscopy (DOAS) approach, involving slant column fitting followed by air mass factor (AMF) conversions to vertical column amounts. We present a major upgrade of this algorithm to version 3.0. GDP 3.0 was implemented in July 2002, and the 9-year GOME data record from July 1995 to December 2004 has been processed using this algorithm. The key component in GDP 3.0 is an iterative approach to AMF calculation, in which AMFs and corresponding vertical column densities are adjusted to reflect the true ozone distribution as represented by the fitted DOAS effective slant column. A neural network ensemble is used to optimize the fast and accurate parametrization of AMFs. We describe results of a recent validation exercise for the operational version of the total ozone algorithm; in particular, seasonal and meridian errors are reduced by a factor of 2. On a global basis, GDP 3.0 ozone total column results lie between −2% and +4% of ground-based values for moderate solar zenith angles lower than 70°. A larger variability of about +5% and −8% is observed for higher solar zenith angles up to 90°.