COVID‐19 Crisis Reduces Free Tropospheric Ozone Across the Northern Hemisphere

Geophysical Research Letters, Journal Year: 2021, Volume and Issue: 48(5)

Published: Feb. 10, 2021

Abstract Throughout spring and summer 2020, ozone stations in the northern extratropics recorded unusually low free troposphere. From April to August, from 1 8 kilometers altitude, was on average 7% (≈4 nmol/mol) below 2000–2020 climatological mean. Such ozone, over several months, at so many stations, has not been observed any previous year since least 2000. Atmospheric composition analyses Copernicus Atmosphere Monitoring Service simulations NASA GMI model indicate that large 2020 springtime depletion Arctic stratosphere contributed less than one‐quarter of tropospheric anomaly. The anomaly is consistent with recent chemistry‐climate simulations, which assume emissions reductions similar those caused by COVID‐19 crisis. related appear be major cause for reduced 2020.

Language: Английский

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Unprecedented decline in summertime surface ozone over eastern China in 2020 comparably attributable to anthropogenic emission reductions and meteorology

Environmental Research Letters, Journal Year: 2021, Volume and Issue: 16(12), P. 124069 - 124069

Published: Nov. 29, 2021

Abstract China’s nationwide monitoring network initiated in 2013 has witnessed continuous increases of urban summertime surface ozone to 2019 by about 5% year −1 , among the fastest trends recent decade reported Tropospheric assessment report. Here we report that levels averaged over cities eastern China decrease 5.5 ppbv May–August 2020 compared levels, representing an unprecedented reduction since 2013. We combine high-resolution GEOS-Chem chemical model and eXtreme Gradient Boosting (XGBoost) machine learning quantify drivers this reduction. estimate changes anthropogenic emissions alone 3.2 (2.9–3.6) (57% total reduction) 2.5 ∼ three key city clusters for mitigation. These reductions appear be driven decreases both nitrogen oxides (NO x ) volatile organic compounds, likely reflecting stringent emission control measures implemented The Chinese Ministry Environmental Ecology summer 2020, as supported observed decline tropospheric formaldehyde (HCHO) dioxides 2 from satellite bottom-up estimates. Comparable emission-driven reduction, wetter cooler weather conditions 2.3 (1.9–2.6) (43%). Our analyses indicate current strategies can effective mitigation yet tracking future is essential further evaluation. study also reveals important potential mechanism-based, state-of-art atmospheric models with improve attribution drivers.

Language: Английский

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Ozone Anomalies in the Free Troposphere During the COVID‐19 Pandemic

Geophysical Research Letters, Journal Year: 2021, Volume and Issue: 48(16)

Published: Aug. 16, 2021

Abstract Using the CAM‐chem Model, we simulate response of chemical species in free troposphere to scenarios primary pollutant emission reductions during COVID‐19 pandemic. Zonally averaged ozone Northern Hemisphere spring and summer is found be 5%–15% lower than 19‐yr climatological values, good agreement with observations. About one third this anomaly attributed reduction scenario air traffic pandemic, another surface emissions, remainder 2020 meteorological conditions, including exceptional springtime Arctic stratospheric depletion. For combined reductions, overall northern hemisphere tropospheric June less 5 ppb below 400 hPa, but reaches 8 at 250 hPa. In Southern Hemisphere, related by 4%–6% were masked comparable increases due other changes 2020.

Language: Английский

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Global Climate

Bulletin of the American Meteorological Society, Journal Year: 2022, Volume and Issue: 103(8), P. S11 - S142

Published: Aug. 1, 2022

Caption: Lightning discharges appear in various colours depending on the scatter of light inside thundercloud and atmosphere.The intracloud lightning centre to be white with a bluish tint, cloud-to-ground discharge below appears orange.The right hand side exhibits green tint that is attributed unique composition hydrometeors thundercloud.The photo was taken late evening 10 September 2013, near Tarragona northeastern Spain.

Language: Английский

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Impact of the COVID‐19 Economic Downturn on Tropospheric Ozone Trends: An Uncertainty Weighted Data Synthesis for Quantifying Regional Anomalies Above Western North America and Europe

AGU Advances, Journal Year: 2022, Volume and Issue: 3(2)

Published: March 4, 2022

Abstract This study quantifies the association between COVID‐19 economic downturn and 2020 tropospheric ozone anomalies above Europe western North America, their impact on long‐term trends. Anomaly detection for an atmospheric time series is usually carried out by identifying potentially aberrant data points relative to climatological values. However, detecting from sparsely sampled ozonesonde profiles (once per week at most sites) challenging due ozone's high temporal variability. We first demonstrate challenges summarizing regional trends based independent multiple nearby profiling stations. then propose a novel regional‐scale anomaly framework generalized additive mixed models, which accounts sampling frequency inherent uncertainty associated with each vertical profile set, measured ozonesondes, lidar or commercial aircraft. method produces monthly resolution that reports surface middle‐stratosphere under unified framework, can be used quantify during downturn. By incorporating extensive aircraft frequently Europe, we show complex interannual variability of adequately captured our modeling approach. The results free negative in are profound since benchmark year 1994 both positive over 1994–2019 diminished regions anomalies.

Language: Английский

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Global tropospheric ozone trends, attributions, and radiative impacts in 1995–2017: an integrated analysis using aircraft (IAGOS) observations, ozonesonde, and multi-decadal chemical model simulations

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(20), P. 13753 - 13782

Published: Oct. 25, 2022

Abstract. Quantification and attribution of long-term tropospheric ozone trends are critical for understanding the impact human activity climate change on atmospheric chemistry but also challenged by limited coverage observations in free troposphere where has higher production efficiency radiative potential compared to that at surface. In this study, we examine observed trends, their attributions, impacts from 1995–2017 using aircraft In-service Aircraft a Global Observing System database (IAGOS), ozonesondes, multi-decadal GEOS-Chem chemical model simulation. IAGOS above 11 regions Northern Hemisphere 19 27 global ozonesonde sites have measured increases (950–250 hPa) 2.7 ± 1.7 1.9 ppbv per decade average, respectively, with particularly large lower (950–800 East Asia, Persian Gulf, India, northern South America, Gulf Guinea, Malaysia/Indonesia 2.8 10.6 decade. The simulation driven reanalysis meteorological fields most up-to-date year-specific anthropogenic emission inventory reproduces overall pattern including over tropics 2.1–2.9 Asia 0.5–1.8 weak North Europe, high latitudes both hemispheres, underestimated observations. estimates an increasing trend 0.4 Tg yr−1 burden 1995–2017. We suggest uncertainties early years (e.g., 1995–1999) developing may contribute GEOS-Chem's underestimation trends. sensitivity simulations show changes patterns, equatorward redistribution surface emissions rapid emissions, dominant factors contributing 0.5 yr−1. particular, highlight disproportionately large, previously underappreciated, contribution 0.3 yr−1, mainly due emitting NOx mid-troposphere upper is high. Decreases lower-stratospheric stratosphere–troposphere flux decrease mid-latitudes latitudes. estimate 1995–1999 2013–2017 +18.5 mW m−2, 43.5 m−2 contributed (20.5 alone emissions), highlighting areas strong convection increase effective ozone's greenhouse effect.

Language: Английский

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Attribution of the 2020 surge in atmospheric methane by inverse analysis of GOSAT observations

Environmental Research Letters, Journal Year: 2022, Volume and Issue: 17(9), P. 094003 - 094003

Published: Aug. 5, 2022

Abstract Atmospheric methane mixing ratio rose by 15 ppbv between 2019 and 2020, the fastest growth rate on record. We conduct a global inverse analysis of 2019–2020 Greenhouse Gases Observing Satellite observations atmospheric to analyze combination sources sinks driving this surge. The imbalance increased 31 Tg −1 from representing 36 forcing (direct changes in emissions OH concentrations) budget away steady state. 86% base inversion is increasing (82 ± 18% nine-member ensemble), only 14% decrease tropospheric OH. Half increase Africa (15 ) appears be driven wetland inundation. There also large relative Canada Alaska (4.8 , 24%) that could temperature sensitivity boreal emissions.

Language: Английский

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Quantification of COVID-19 impacts on NO2 and O3: Systematic model selection and hyperparameter optimization on AI-based meteorological-normalization methods

Atmospheric Environment, Journal Year: 2023, Volume and Issue: 301, P. 119677 - 119677

Published: Feb. 27, 2023

Language: Английский

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Response of surface ozone concentration to emission reduction and meteorology during the COVID‐19 lockdown in Europe

Meteorological Applications, Journal Year: 2021, Volume and Issue: 28(3)

Published: May 1, 2021

Abstract The lockdown period (March–May 2020) during the COVID‐19 pandemic in Europe led to a reduction anthropogenic emissions of primary pollutants. For three‐quarters over 1,100 available monitoring stations, average nitrogen dioxide (NO 2 ) concentrations decreased by at least 2.7 μg·m −3 (or 25%) compared with recorded same previous seven years. This was not specific urban or rural areas because relative similar magnitude both areas. ozone (O 3 response differed spatially, positive anomalies Northern and negative Southwestern Europe. Reduced cloudiness related enhanced radiation played significant role increase surface O shifting photochemical partitioning between NO toward more . level total oxidant x = + remained unchanged, except where it decreased. Several episodes lasting few days high oxidants were observed results illustrate complexity atmospheric unprecedented emission

Language: Английский

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NASA GEOS Composition Forecast Modeling System GEOS‐CF v1.0: Stratospheric Composition

Journal of Advances in Modeling Earth Systems, Journal Year: 2022, Volume and Issue: 14(6)

Published: April 19, 2022

The NASA Goddard Earth Observing System (GEOS) Composition Forecast (GEOS-CF) provides recent estimates and 5-day forecasts of atmospheric composition to the public in near-real time. To do this, GEOS system model is coupled with GEOS-Chem tropospheric-stratospheric unified chemistry extension (UCX) represent from surface top atmosphere (0.01 hPa). GEOS-CF described, including updates made UCX mechanism within for improved representation stratospheric chemistry. Comparisons are against balloon, lidar, satellite observations composition, measurements ozone (O

Language: Английский

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