Abstract Nitrogen oxides (NO x = NO + 2 ) are produced during combustion processes and, thus may serve as a proxy for fossil fuel‐based energy usage and coemitted greenhouse gases other pollutants. We use high‐resolution nitrogen dioxide data from the Ozone Monitoring Instrument (OMI) to analyze changes in urban levels around world 2005 2014, finding complex heterogeneity changes. discuss several potential factors that seem determine these First, environmental regulations resulted large...

Abstract. Ozone depletion by chlorofluorocarbons (CFCs) was first proposed Molina and Rowland in their 1974 Nature paper. Since that time, the scientific connection between ozone losses CFCs other depleting substances (ODSs) has been firmly established with laboratory measurements, atmospheric observations, modeling studies. This science research led to implementation of international agreements largely stopped production ODSs. In this study we use a fully-coupled...

Differences between two ensembles of Goddard Earth Observing System Chemistry‐Climate Model simulations isolate the impact North Pacific sea surface temperatures (SSTs) on Arctic winter climate. One ensemble extended season forecasts is forced by unusually high SSTs in Pacific, while second are low. High – Low differences consistent with a strengthened Western atmospheric teleconnection pattern, and particular, weakening Aleutian This relative change tropospheric circulation inhibits...

The impact of increased stratospheric chlorine, averted by controls imposed the Montreal Protocol, is studied using UKCA chemistry‐climate model. We contrast an atmosphere with 9 ppbv Cl y , which could have occurred ∼2030, present‐day loading (3.5 ppbv), and consider response climate to resulting ozone perturbations, disregarding radiative additional CFCs. Ozone columns decline everywhere, impacts in both polar regions. chlorine leads a strengthening Southern Annular Mode, versus reference,...

The effect of El Niño‐Southern Oscillation (ENSO) on the frequency and character Northern Hemisphere major mid‐winter stratospheric sudden warmings (SSWs) is evaluated using a meteorological reanalysis data set comprehensive chemistry‐climate models. There an apparent inconsistency between impact opposite phases ENSO seasonal mean vortex SSWs: Niño leads to anomalously warm, La Niña cool, polar state, but both lead increased SSW frequency. A resolution this paradox here proposed: region in...

Abstract. Despite the record ozone loss observed in March 2011, dynamical conditions Arctic stratosphere were unusual but not unprecedented. Weak planetary wave driving February preceded cold anomalies polar lower and a relatively late breakup of vortex April. La Niña westerly phase quasi-biennial oscillation (QBO) 2011. Though these are generally associated with stronger mid-winter, respective do persist through March. Therefore, QBO-westerly cannot explain In contrast, positive sea surface...

Lack of national data on water-related ecosystems is a major challenge to achieving the Sustainable Development Goal (SDG) 6 targets by 2030. Monitoring surface water extent, wetlands, and quality from space can be an important asset for many countries in support SDG reporting. We demonstrate potential Earth observation (EO) country reporting Indicator 6.6.1, ‘Change extent over time’ identify considerations using these The spatial ecosystems, partial within investigated seven countries....

Abstract This study is the first to identify a robust El Niño–Southern Oscillation (ENSO) signal in Antarctic stratosphere. Niño events between 1979 and 2009 are classified as either conventional “cold tongue” (positive SST anomalies Niño-3 region) or “warm pool” Niño-4 region). The 40-yr ECMWF Re-Analysis (ERA-40), NCEP, Modern Era Retrospective–Analysis for Research Applications (MERRA) meteorological reanalyses used show that Southern Hemisphere stratosphere responds differently these two...

Atmospheric concentrations of hydrofluorocarbons (HFCs) are projected to increase considerably in the coming decades. Chemistry climate model simulations forced by current projections show that HFCs will impact global atmosphere increasingly through 2050. As strong radiative forcers, tropospheric and stratospheric temperatures, thereby enhancing ozone-destroying catalytic cycles modifying atmospheric circulation. These changes lead a weak depletion ozone. Simulations with NASA Goddard Space...

Satellite observations and chemistry‐climate model experiments are used to understand the zonal structure of tropical lower stratospheric temperature, water vapor, ozone trends. The warming in upper troposphere over past 30 years is strongest near Indo‐Pacific warm pool, while trend western central Pacific much weaker. In stratosphere, these trends reversed: historical cooling pool weakest Pacific. These variations stronger than zonal‐mean response boreal winter. Targeted with a demonstrate...

The Northern Hemisphere (NH) stratospheric signals of eastern Pacific (EP) and central (CP) El Niño events are investigated in stratosphere-resolving historical simulations from phase 5 the Coupled Model Intercomparison Project (CMIP5), together with role stratosphere driving tropospheric teleconnections NH climate. large number each composite addresses some previously reported concerns related to short observational record. results shown here highlight importance seasonal evolution for...

Targeted experiments with a comprehensive chemistry‐climate model are used to demonstrate that seasonality and the location of peak warming sea surface temperatures dictate response stratospheric water vapor El Niño. In boreal spring, Niño events in which temperature anomalies eastern Pacific lead at tropopause above warm pool region, subsequently more (consistent previous work). However, fall early winter, also during anomaly is found mainly central Pacific, qualitatively different: changes...

Abstract Comprehensive chemistry‐climate model experiments and observational data are used to show that up half of the satellite era early springtime cooling trend in Arctic lower stratosphere was caused by changing sea surface temperatures (SSTs). An ensemble forced only SSTs is compared an which both observed chemically radiatively active trace species changing. By comparing two ensembles, it shown warming Indian Ocean, North Pacific, Atlantic tropical Pacific have strongly contributed...

Abstract. The Goddard Earth Observing System Chemistry-Climate Model, Version 2 (GEOS V2 CCM) is used to investigate the response of Antarctic stratosphere (1) warm pool El Niño (WPEN) events and (2) sensitivity this phase QBO. A new formulation GEOS CCM includes an improved general circulation model internally generated quasi-biennial oscillation (QBO). Two 50-yr time-slice simulations are forced by repeating annual cycles sea surface temperatures ice concentrations composited from observed...

Successful simulation of the breakup Antarctic polar vortex depends on representation tropospheric stationary waves at Southern Hemisphere middle latitudes. This paper assesses in two new chemistry‐climate models (CCMs). The stratospheric version UK Chemistry and Aerosols model is able to reproduce observed timing breakup. Version 2 Goddard Earth Observing System (GEOS V2) typical CCMs that breaks up too late; 10 hPa, mean transition easterlies 60°S delayed by 12–13 days as compared with...

Warm pool El Niño (WPEN) events are characterized by positive sea surface temperature (SST) anomalies in the central equatorial Pacific. Under present‐day climate conditions, WPEN generate poleward propagating wavetrains and enhance midlatitude planetary wave activity, weakening stratospheric polar vortices. The late 21st century extratropical atmospheric response to is investigated using Goddard Earth Observing System Chemistry‐Climate Model (GEOSCCM), version 2. GEOSCCM simulations forced...

Abstract The National Oceanic and Atmospheric Administration’s (NOAA) Weather Service (NWS) has been providing national, regional, local climate services for more than 20 years. NWS building blocks consist of service provision infrastructure, partnership outreach, discovery user needs requirements, delivery at local, tribal levels. To improve services, the program accelerated engagement through customer surveys, workshops, collaborations. Since 2002, annual Climate Prediction Applications...

Abstract. Ozone depletion by chlorofluorocarbons (CFCs) was first proposed Molina and Rowland in their 1974 Nature paper. Since that time, the scientific connection between ozone losses CFCs other depleting substances (ODSs) has been firmly established with laboratory measurements, atmospheric observations, modeling research. This science research led to implementation of international agreements largely stopped production ODSs. In this study we use a fully-coupled...

As countries take action to mitigate global warming, both by ratifying the UNFCCC Paris Agreement and enacting Kigali Amendment Montreal Protocol manage hydrofluorocarbons (HFCs), it is important consider relative importance of pertinent greenhouse gases distinct structure their atmospheric impacts, how timing potential gas regulations would affect future changes in temperature ozone. HFCs should be explicitly considered upcoming climate ozone assessments, since chemistry-climate model...

Abstract. A Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM) simulation with strong tropical non-orographic gravity wave drag (GWD) is compared to an otherwise identical near-zero GWD. The GEOSCCM generates a quasi-biennial oscillation (QBO) zonal wind signal in response peak GWD that resembles the and climatological mean precipitation field. modelled QBO has frequency amplitude closely observations. As expected, improves of winds enhances subtropical stratospheric...

To disentangle the combined effect of CO 2 and O 3 changes on both large-scale circulation global distribution ozone, we have conducted four idealised climate change experiments using a version Met Office's Unified Model (UM) with well-resolved middle atmosphere parameterised stratospheric ozone chemistry, imposing changes. Focusing northern hemisphere compare our model results respect to existing observations process-oriented quantities involving in particular slope loss-PSC volume...

Abstract This study is the first to assess sensitivity of mid‐winter Arctic stratosphere variability in width quasi‐biennial oscillation (QBO). Differences between a pair idealised simulations with simplified chemistry–climate model are examined. The QBO appears have equal influence on as does phase (i.e. Holton‐Tan mechanism). In model, wider acts like preferential shift towards easterly QBO. That is, average, associated weaker vortex and enhanced total ozone at high latitudes. Copyright ©...

This study examines trends in Antarctic temperature and A PSC , a proxy for the area of polar stratospheric clouds, an ensemble Goddard Earth Observing System (GEOS) chemistry‐climate model (CCM) simulations 21st century. selection greenhouse gas, ozone‐depleting substance, sea surface scenarios is used to test trend sensitivity these parameters. One scenario compare two versions GEOS CCM. An extended austral winter season examined detail. In May, June, July, expected future increase CO 2...