Martyn Chipperfield

• University of Leeds

Plain Language Summary Around 150 Tg (150 million tons) of water vapor was injected into the stratosphere during the eruption of Hunga Tonga‐Hunga Ha'apai. Water vapor is a greenhouse gas and this increase is expected to have a warming effect in the troposphere, as well causing perturbations in stratospheric chemistry and aerosols. We use an atmosp...

This study investigates the origin of a zonal asymmetry in stratospheric ozone trends at northern high latitudes, identified in satellite limb observations over the past two decades. We use a merged data set consisting of ozone profiles retrieved at the University of Bremen from SCIAMACHY and OMPS‐LP measurements to derive ozone trends. We also use...

Ethylene dichloride (EDC), or 1-2-dichloroethane, is an industrial very short-lived substance (VSLS) whose major use is as a feedstock in the production chain of polyvinyl chloride (PVC). Like other chlorinated VSLS, transport of EDC (or its atmospheric oxidation products) to the stratosphere could contribute to ozone depletion there. However, desp...

We summarise current important and well-established open issues related to the depletion of stratospheric ozone and discuss some newly emerging challenges. The ozone layer is recovering from the effects of halogenated source gases due to the continued success of the Montreal Protocol despite recent renewed production of controlled substances and th...

Ozone is a potent air pollutant in the lower troposphere and an important short-lived climate forcer (SLCF) in the upper troposphere. Studies investigating long-term trends in tropospheric column ozone (TCO3) have shown large-scale spatiotemporal inconsistencies. Here, we investigate the long-term trends in lower tropospheric column ozone (LTCO3, s...

Ozone depletion over the polar regions is monitored each year by satellite- and ground-based instruments. In this study, the vortex-averaged ozone loss over the last 3 decades is evaluated for both polar regions using the passive ozone tracer of the chemical transport model TOMCAT/SLIMCAT and total ozone observations from Système d'Analyse par Obse...

Around 150 Tg (150 million tons) of water vapour was injected into the stratosphere during the eruption of Hunga Tonga-Hunga Ha’apai. We use an atmospheric model to study the residence time of this excess water vapour and its impact on the recent Antarctic ozone hole. The model performance is evaluated by comparison with satellite measurements. Win...

Ozone is a potent air pollutant in the lower troposphere and an important short-lived climate forcer (SLCF) in the upper troposphere. Studies using satellite data to investigate spatiotemporal variability of troposphere ozone (TO3) have predominantly focussed on the tropospheric column metric. This is the first study to investigate long-term spatio...

Monitoring the atmospheric concentrations of greenhouse gases (GHGs) is crucial to improve our understanding of their climate impact. However, there are no long-term profile data sets of important GHGs that can be used to gain a better insight into the processes controlling their variations in the atmosphere. In this study, we apply corrections to...

The sudden leaks from the Nord Stream gas pipelines, which began in September 2022, released a substantial amount of methane (CH4) into the atmosphere. From the IASI instrument onboard EUMETSAT’s MetOp-B, we document the first satellite-based retrievals of column-average CH4 (XCH4) that clearly show the large CH4 plume emitted from the pipelines. T...

This study investigates the origin of the zonal asymmetry in stratospheric ozone trends at northern high latitudes, identified in satellite limb observations over the past two decades. We use a merged dataset consisting of ozone profiles retrieved at the University of Bremen from SCIAMACHY and OMPS-LP measurements to derive ozone trends. We also us...

Depletion of the stratospheric ozone layer remains an ongoing environmental issue, with increasing stratospheric chlorine from very short-lived substances (VSLS) recently emerging as a potential but uncertain threat to its future recovery. Here the impact of chlorinated VSLS (Cl-VSLS) on past ozone is quantified, for the first time, using the UM–UK...

The paper describes the development and performance of the Double Extended Stratospheric–Tropospheric (DEST vn1.0) chemistry scheme, which forms a part of the Met Office's Unified Model coupled to the United Kingdom Chemistry and Aerosol (UM–UKCA) chemistry–climate model, which is the atmospheric composition model of the United Kingdom Earth System...

In the summer of 2018, Europe experienced an intense heatwave which coincided with several persistent large-scale ozone (O3) pollution episodes. Novel satellite data of lower-tropospheric column O3 from the Global Ozone Monitoring Experiment-2 (GOME-2) and Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp satellite showed substantial...

Accurate quantification of long-term trends in stratospheric ozone can be challenging due to their sensitivity to natural variability, the quality of the observational datasets, and non-linear changes in forcing processes as well as the statistical methodologies. Multivariate linear regression (MLR) is the most commonly used tool for ozone trend an...

Atmospheric methane (CH4) is the second most important anthropogenic greenhouse gas and has a 20-year global warming potential 82 times greater than carbon dioxide (CO2). Anthropogenic sources account for ~60 % of global CH4 emissions, of which 20 % come from oil & gas exploration, production and distribution. High-resolution satellite-based imagin...

Plain Language Summary Strong volcanic eruptions, such as the 1991 eruption of Mt Pinatubo, inject a large amount of SO2 directly into the stratosphere, thereby enhancing the stratospheric aerosol layer and causing a short‐term climatic perturbation. Another substantial part of the climatic influence is the change in stratospheric water vapor (SWV)...

We present a comparison of atmospheric transport models that simulate carbonyl sulfide (COS). This is part II of the ongoing Atmospheric Transport Model Inter‐comparison Project (TransCom–COS). Differently from part I, we focus on seven model intercomparison by transporting two recent COS inversions of NOAA surface data within TM5‐4DVAR and LMDz mo...

Carbonyl sulfide (OCS) has emerged as a valuable proxy for photosynthetic uptake of carbon dioxide (CO2) and is known to be important in the formation of aerosols in the stratosphere. However, uncertainties in the global OCS budget remain large. This is mainly due to the following three flux terms: vegetation uptake, soil uptake and oceanic emissio...

Using state-of-the-art satellite ozone profile products, and chemical transport model, we provide an updated estimate of the tropospheric ozone radiative effect (TO3RE) and observational constraint on its variability over the decade 2008–2017. Previous studies have shown the short-term (i.e. a few years) globally weighted average TO3RE to be 1.17±0...

Tropical forests such as the Amazonian rainforests play an important role for climate, are large carbon stores and are a treasure of biodiversity. Amazonian forests have been exposed to large-scale deforestation and degradation for many decades. Deforestation declined between 2005 and 2012 but more recently has again increased with similar rates as...

The Tibetan Plateau (TP, approximately 27.5–37.5° N, 75.5–105.5° E) is the highest and largest plateau on Earth with a mean elevation of over 4 km. This special geography causes strong surface solar ultraviolet radiation (UV), with potential risks to human and ecosystem health, and which is controlled by the local total column ozone (TCO). The El N...

We give a personal perspective on recent issues related to the depletion of stratospheric ozone and some newly emerging challenges. We first provide a brief review of historic work on understanding the ozone layer where we highlight some work from the late Paul Crutzen as a contribution to the special issue in his honour. We then review the status...

Ozone is a potent air pollutant in the lower troposphere and an important short-lived climate forcer (SLCF) in the upper troposphere. Studies using satellite data to investigate spatiotemporal variability of troposphere ozone (TO3) have predominantly focussed on the tropospheric column metric. This is the first study to investigate long-term spatio...

Anthropogenic emissions of methane (CH4) have made a considerable contribution towards the Earth's changing radiative budget since pre-industrial times. This is because large amounts of methane are emitted from human activities, and the global warming potential of methane is high. The majority of anthropogenic fossil methane emissions to the atmosp...

In contrast to the general stratospheric ozone recovery following international agreements, recent observations show an ongoing net ozone depletion in the tropical lower stratosphere (LS). This depletion is thought to be driven by dynamical transport accelerated by global warming, while chemical processes have been considered to be unimportant. Her...

Ozone depletion over the polar regions is monitored each year by satellite and ground-based instruments. In this study, the vortex-averaged ozone loss over the last three decades is evaluated for both polar regions using the passive ozone tracer of the chemical transport model TOMCAT/SLIMCAT and total ozone observations from Système d'Analyse par O...

We present a comparison of atmospheric transport models that simulate carbonyl sulfide (COS). This is part II of the ongoing Atmospheric Transport Model (ATM) Inter-comparison Project (TransCom–COS). Differently from part I, we focus on seven model intercomparison by transporting two recent COS inversions of NOAA surface data within TM5-4DVAR and L...

Hydrogen cyanide (HCN) is an important tracer of biomass burning, but there are significant uncertainties in its atmospheric budget, especially its photochemical and ocean sinks. Here we use a tracer version of the TOMCAT global 3-D chemical transport model to investigate the physical and chemical processes driving the abundance of HCN in the tropo...

Depletion of the stratospheric ozone layer remains an ongoing environmental issue, with increasing stratospheric chlorine from Very Short-Lived Substances (VSLS) recently emerging as a potential but uncertain threat to its future recovery. Here the impact of chlorinated VSLS on past ozone is quantified, for the first time. using the UM-UKCA chemist...

Accurate quantification of long-term trends in stratospheric ozone can be challenging due to their sensitivity to natural variability, the quality of the observational datasets, non-linear changes in forcing processes as well as the statistical methodologies. Multivariate linear regression (MLR) is the most commonly used tool for ozone trend analys...

Plain Language Summary Iodine has the potential to cause stratospheric ozone depletion. Small satellites (<10 kg) in low Earth orbit require electric propulsion to prolong their time in orbit, and there is strong interest in replacing the rare gas propellant (Xe or Kr) with I2. Here we estimate the potential impact of thermosphere iodine injection...

Exposure to air pollution is a leading public health risk factor in India, especially over densely populated Delhi and the surrounding Indo-Gangetic Plain. During the post-monsoon months, the prevailing north-westerly winds are known to influence aerosol pollution events in Delhi, by advecting pollutants from agricultural fires as well as from loca...

Monitoring the atmospheric concentrations of greenhouse gases (GHGs) is crucial in order to improve our understanding of their climate impact. However, there are no long-term profile data sets of important GHGs that can be used to gain a better insight into the processes controlling their variations in the atmosphere. Here, we merge chemical transp...

We present a comparison of atmospheric transport model (ATM) simulations for carbonyl sulfide (COS), within the framework of the atmospheric tracer transport model intercomparison project “TransCom‐COS.” Seven ATMs participated in the experiment and provided simulations of COS mixing ratios over the years 2010–2018, using state‐of‐the‐art surface f...

Siberia is one of the world's major food production bases areas and a climate-sensitive region, where summer precipitation has shown decreasing, increasing, and renewed decreasing trends in recent decades. However, the external factors driving the long-term trend in precipitation are not yet understood. Here we find that summer precipitation in Sib...

Summer precipitation variations substantially impact food production and wildfire frequency in Siberia, exhibiting trends of decrease, increase, and subsequent decrease in recent decades. Nonetheless, the external factors contributing to these long-term precipitation patterns remain unclear. Our findings reveal a strong connection between stratosph...

Atmospheric methane (CH4) concentrations are rising which is expected to lead to a corresponding increase in its global seasonal cycle amplitude (SCA), the difference between its seasonal maximum and minimum values. Spatially-varying changes in the SCA could indicate long-term persistent variations in the seasonal sources and sinks but such SCA cha...

Tropical forests such as the Amazonian rainforests play an important role for climate, are large carbon stores and are a treasure of biodiversity. Amazonian forests are being exposed to large scale deforestation and degradation for many decades which declined between 2005 and 2012 but more recently has again increased with similar rates as in the 2...

In the summer of 2018, Europe experienced an intense heat wave which coincided with several persistent large-scale ozone (O3) pollution episodes. Novel satellite data of lower tropospheric column O3 from the Global Ozone Monitoring Experiment-2 (GOME-2) and Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp satellite showed substantia...

Wetlands are the largest natural source of methane. The ability to model the emissions of methane from natural wetlands accurately is critical to our understanding of the global methane budget and how it may change under future climate scenarios. The simulation of wetland methane emissions involves a complicated system of meteorological drivers cou...

The paper describes the development and performance of the Double Extended Stratospheric-Tropospheric (DEST vn1.0) chemistry scheme, which forms a part of the Met Office’s Unified Model coupled to the United Kingdom Chemistry and Aerosol (UM-UKCA) chemistry-climate model, the atmospheric composition model of the United Kingdom Earth System Model (U...

We use a tracer version of the TOMCAT global 3-D chemical transport model to investigate the physical and chemical processes driving the abundance of hydrogen cyanide (HCN) in the troposphere and stratosphere over the period 2004–2016. The modelled HCN distribution is compared with version 4.1 of the Atmospheric Chemistry Experiment - Fourier Trans...

As discussed above, and supported by extensive literature, there is no robust, credible observational evidence for substantial ozone depletion (i.e., an “ozone hole”) in the tropics. It is well known that climatological total ozone in the tropics is much lower than that in the mid-latitudes (e.g., Sahai et al., 2000; Weber et al., 2022). Satellite...

Trichlorofluoromethane (CFC-11) is the second most important chlorofluorocarbons (CFCs) in the Earth’s atmosphere. CFCs are long-lived chemicals which were exclusively produced by the industry and broadly used as aerosol spray propellants, refrigerants, inflating and insulating agents in the production of foam materials, as well as solvents. CFCs a...

Anthropogenic emissions of methane (CH4) make up a considerable contribution towards the Earth’s radiative budget since pre-industrial times. This is because large amounts of methane are emitted from human activities and the global warming potential of methane is high. The majority of anthropogenic fossil methane emissions to the atmosphere origina...

The atmospheric concentration of CFC-11 (CCl3F) has declined in response to the phase-out of its production by the Montreal Protocol. Nevertheless, this atmospheric concentration decline suffered a slow-down around 2012 due to emissions from non-reported production. Since CFC-11 is one of the most important ozone-depleting chlorofluorocarbons (CFCs...

Indonesia is seasonally affected by intense fire events, often driven by El Ni\ no events. These events release substantial amounts of carbon stored in the soil as peat into the atmosphere, affecting the air quality and the atmospheric composition of the region and on a global scale. During the 2015 El Ni\ no event, a strong enhancement of Indonesi...

Indonesian peatlands are seasonally cleared to prepare the carbon rich soil for agriculture, enhancing the fire risk. Once burned, peats emit a large quantity of trace gases, including hydrogen cyanide (HCN). During 2015, El Niño amplified the already dry condition causing one of the most intense fire seasons in recent decades ever observed in Indo...

The Montreal Protocol is successfully protecting the ozone layer. The main halogen gases responsible for stratospheric ozone depletion have been regulated under the Protocol, their combined atmospheric abundances are declining and ozone is increasing in some parts of the atmosphere¹. Ozone depletion potentials2–4, relative measures of compounds’ ab...

Impacts of chlorinated very short-lived substances (Cl-VSLS) on stratospheric chlorine budget over the first two decades of the 21st century are assessed using the Met Office’s Unified Model coupled to the United Kingdom Chemistry and Aerosol (UM-UKCA) chemistry–climate model; this constitutes the most up-to-date assessment and the first study to s...

We use TOMCAT, a 3-dimensional (3D) offline chemical transport model (CTM) forced by two different meteorological reanalysis data sets (ERA-Interim and ERA5) from the European Centre for Medium-Range weather Forecasts (ECMWF) to analyse seasonal behaviour and long-term trends in stratospheric ozone and mean age of air. The model-simulated ozone var...

We present a novel approach to derive indirect global information on the hydroxyl radical (OH), one of the most important atmospheric oxidants, using state-of-the-art satellite trace gas observations (key sinks and sources of OH) and a steady-state approximation (SSA). This is a timely study as OH observations are predominantly from spatially spars...

Atmospheric hydrogen cyanide (HCN) is one of the most abundant cyanides in the global atmosphere. Understanding its physical and chemical nature is important considering its influence on the nitrogen cycle. The key processes driving tropospheric HCN variability are biomass burning, as the main source, and ocean uptake, as the main tropospheric sink...

Hydrogen cyanide (HCN) is one of the most abundant cyanides present in the global atmosphere, and is a tracer of biomass burning, especially for peatland wildfires. In this work we present observations of HCN during the 2015 Indonesian peatland fires from the IASI (Infrared Atmospheric Sounding Interfer-ometer) satellite instrument. We also investi...

The Arctic has experienced several extreme springtime stratospheric ozone depletion events over the past four decades, particularly in 1997, 2011 and 2020. However, the impact of this stratospheric ozone depletion on the climate system remains poorly understood. Here we show that the stratospheric ozone depletion causes significant reductions in th...

We use the TOMCAT 3-dimensional (3D) off-line chemical transport model (CTM) forced by two different meteorological reanalysis datasets (ERA-Interim and ERA5) from the European Centre for Medium-Range weather Forecasts (ECMWF) to study stratospheric ozone trends and variability. The model-simulated ozone variations are evaluated against two observa...

We have implemented a new stratospheric ozone model in the European Centre for Medium-Range Weather Forecasts (ECMWF) system and tested its performance for different timescales to assess the impact of stratospheric ozone on meteorological fields. We have used the new ozone model to provide prognostic ozone in medium-range and long-range (seasonal)...

Nitrogen oxides (NOx, NO + NO2) are potent air pollutants which directly impact on human health and which aid the formation of other hazardous pollutants such as ozone (O3) and particulate matter. In this study, we use satellite tropospheric column nitrogen dioxide (TCNO2) data to evaluate the spatiotemporal variability and magnitude of the United...

Atmospheric hydrogen cyanide (HCN) is one of the most abundant cyanides in the global atmosphere. Understanding its physical and chemical nature is important considering its influence on the nitrogen cycle. The key processes driving tropospheric HCN variability are biomass burning, as the main source, and ocean uptake, as the main tropospheric sink...

We use the TOMCAT 3-D chemical transport model with a balanced flux inventory to simulate the global distribution of atmospheric carbonyl sulfide (OCS). This is compared with limb-sounding satellite observations made by the Atmospheric Chemistry Experiment – Fourier Transform Spectrometer (ACE-FTS) and surface flask measurements made worldwide at 1...

High quality long-term data sets of altitude-resolved measurements of the atmospheric composition are important because they can be used both to study the evolution of the atmosphere and as a benchmark for future missions. For the final ESA reprocessing of MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) on ENVISAT (ENViromental SA...

Atmospheric impacts of chlorinated very short-lived substances (Cl-VSLS) over the first two decades of the 21st century are assessed using the UM-UKCA chemistry-climate model; this constitutes the most up-to-date assessment as well as the first study to simulate Cl-VSLS impacts using a whole atmosphere chemistry-climate model. We examine the Cl-VSL...

We present a novel approach to derive indirect global information on the hydroxyl radical (OH), one of the most important atmospheric oxidants, using state-of-art satellite trace gas observations (key sinks and sources of OH) and a steady-state approximation (SSA). This is a timely study as OH observations are predominantly from spatially sparse fi...

Until now our understanding of the 11-year solar cycle signal (SCS) in stratospheric ozone has been largely based on high-quality but sparse ozone profiles from the Stratospheric Aerosol and Gas Experiment (SAGE) II or coarsely resolved ozone profiles from the nadir-viewing Solar Backscatter Ultraviolet Radiometer (SBUV) satellite instruments. Here...

Wetlands are the largest natural source of methane. The ability to model the emissions of methane from natural wetlands accurately is critical to our understanding of the global methane budget and how it may change under future climate scenarios. The simulation of wetland methane emissions involves a complicated system of meteorological drivers cou...

High-quality stratospheric ozone profile data sets are a key requirement for accurate quantification and attribution of long-term ozone changes. Satellite instruments provide stratospheric ozone profile measurements over typical mission durations of 5–15 years. Various methodologies have then been applied to merge and homogenise the different satel...

Atmospheric Hydrogen cyanide (HCN) is one of the most abundant cyanides present in the global atmosphere and, due to its ability to influence the nitrogen cycle and satellite measurements of nitrogen oxides (NOx), understanding its physical and chemical nature are very important. Key processes driving tropospheric HCN variability are biomass burnin...

This paper presents a modelling study on the fate of CHBr3 and its product gases in the troposphere within the context of tropical deep convection. A cloud-scale case study was conducted along the west coast of Borneo, where several deep convective systems were triggered on the afternoon and early evening of 19 November 2011. These systems were sam...

We report on measurements of total bromine (Brtot) in the upper troposphere and lower stratosphere taken during 15 flights with the German High Altitude and LOng range research aircraft (HALO). The research campaign WISE (Wave-driven ISentropic Exchange) included regions over the North Atlantic, Norwegian Sea, and northwestern Europe in fall 2017....

The Pantanal region of Brazil is the largest seasonally flooded tropical grassland and, according to local chamber measurements, a substantial CH4 source. CH4 emissions from wetlands have recently become of heightened interest because global atmospheric ¹³CH4 data indicate they may contribute to the resumption of atmospheric CH4 growth since 2007....

Using multidecadal time series of ground‐based and satellite Fourier transform infrared measurements of inorganic fluorine (i.e., total fluorine resident in stratospheric fluorine reservoirs), we investigate stratospheric circulation changes over the past 20 years. The representation of these changes in five modern reanalyses is further analyzed th...

The 2019/2020 Australian wildfires emitted large quantities of atmospheric pollutant gases and aerosols. Using state‐of‐the‐art near‐real‐time satellite measurements of tropospheric composition, we present an analysis of several emitted trace gases and their long‐range transport, and compare to the previous (2018/2019) fire season. Observations of...