Modeling the Effect of Potential Nitric Acid Removal During Convective Injection of Water Vapor Over the Central United States on the Chemical Composition of the Lower Stratosphere

Clapp, C. E.; Anderson, James G.

doi:10.1029/2018jd029703

Cited by 5 publications

(4 citation statements)

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“…water vapour budget in the atmosphere, impact the exchange processes between the troposphere and stratosphere, and affect the surface energy balance (Roewe and Liou, 1978;Berry and Mace, 2014;Dessler et al, 2016). Although difficult to observe, the presence of SICs has been found and discussed in a number of studies (Clodman, 1957;Sandhya et al, 2015). However, due to the intricacy of atmospheric processes, the precise mechanisms for the formation and existence of SICs under different atmospheric conditions are not fully understood.…”

Section: Introductionmentioning

confidence: 99%

“…Empirical evidence for the existence of SICs at midlatitudes was found from in situ measurements (Murgatroyd and Goldsmith, 1956;Clodman, 1957;Bartolome Garcia et al, 2021), ground-based lidar observations (Keckhut et al, 2005;Noël and Haeffelin, 2007), and satellite data (Spang et al, 2015;Homeyer et al, 2017). Sassen and Campbell (2001) showed that about 5 %-7.5 % of cirrus cloud tops are located above the tropopause over Salt Lake City, Utah, in the winter season based on a 10-year high cloud data set at the University of Utah Facility for Atmospheric Remote Sensing.…”

Section: Introductionmentioning

confidence: 99%

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Empirical evidence for deep convection being a major source of stratospheric ice clouds over North America

et al. 2021

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Abstract. Ice clouds in the lowermost stratosphere affect stratospheric water vapour and the Earth's radiation budget. The knowledge of its occurrence and driving forces is limited. To assess the distribution and possible formation mechanisms of stratospheric ice clouds (SICs) over North America, we analysed SIC occurrence frequencies observed by the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) instrument during the years 2006 to 2018. Possible driving forces such as deep convection are assessed based on Atmospheric Infrared Sounder (AIRS) observations during the same time. Results show that at nighttime, SICs are most frequently observed during the thunderstorm season over the Great Plains from May to August (MJJA) with a maximum occurrence frequency of 6.2 %. During the months from November to February (NDJF), the highest SICs occurrence frequencies are 5.5 % over the north-eastern Pacific and western Canada and 4.4 % over the western North Atlantic. Occurrence frequencies of deep convection from AIRS, which includes storm systems, fronts, mesoscale convective systems, and mesoscale convective complexes at midlatitude and high latitude, show similar hotspots like the SICs, with highest occurrence frequencies being observed over the Great Plains in MJJA (4.4 %) and over the north-eastern Pacific, western Canada, and the western North Atlantic in NDJF (∼ 2.5 %). Both, seasonal patterns and daily time series of SICs and deep convection show a high degree of spatial and temporal relation. Further analysis indicates that the maximum fraction of SICs related to deep convection is 74 % over the Great Plains in MJJA and about 50 % over the western North Atlantic, the north-eastern Pacific, and western Canada in NDJF. We conclude that, locally and regionally, deep convection is the leading factor related to the occurrence of SICs over North America. In this study, we also analysed the impact of gravity waves as another important factor related to the occurrence of SICs, as the Great Plains is a well-known hotspot for stratospheric gravity waves. In the cases where SICs are not directly linked to deep convection, we found that stratospheric gravity wave observations correlate with SICs with as much as 30 % of the cases over the Great Plains in MJJA, about 50 % over the north-eastern Pacific and western Canada, and up to 90 % over eastern Canada and the north-west Atlantic in NDJF. Our results provide a better understanding of the physical processes and climate variability related to SICs and will be of interest for modellers as SIC sources such as deep convection and gravity waves are small-scale processes that are difficult to represent in global general circulation models.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Empirical evidence for deep convection being a major source of stratospheric ice clouds over North America

et al. 2021

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“…The reaction efficiency of HCl+ClONO 2 can be affected not only by different types of surfaces (e.g., organic aerosols and PSCs), but also by water vapor content and pressure, which vary with altitude ( 34 ), which has been suggested as a potential midlatitude ozone depletion mechanism ( 35 , 36 ). We therefore expand the focus to the range of altitudes from 14.5 to 18.5 km for 2020, 2021, and 2012 ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Stratospheric chlorine processing after the 2020 Australian wildfires derived from satellite data

Wang

Solomon

Stone

2023

Proc. Natl. Acad. Sci. U.S.A.

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The 2019 to 2020 Australian summer wildfires injected an amount of organic gases and particles into the stratosphere unprecedented in the satellite record since 2002, causing large unexpected changes in HCl and ClONO 2 . These fires provided a novel opportunity to evaluate heterogeneous reactions on organic aerosols in the context of stratospheric chlorine and ozone depletion chemistry. It has long been known that heterogeneous chlorine (Cl) activation occurs on the polar stratospheric clouds (PSCs; liquid and solid particles containing water, sulfuric acid, and in some cases nitric acid) that are found in the stratosphere, but these are only effective for ozone depletion chemistry at temperatures below about 195 K (i.e., largely in the polar regions during winter). Here, we develop an approach to quantitatively assess atmospheric evidence for these reactions using satellite data for both the polar (65 to 90°S) and the midlatitude (40 to 55°S) regions. We show that heterogeneous reactions apparently even happened at temperatures at 220 K during austral autumn on the organic aerosols present in 2020 in both regions, in contrast to earlier years. Further, increased variability in HCl was also found after the wildfires, suggesting diverse chemical properties among the 2020 aerosols. We also confirm the expectation based upon laboratory studies that heterogeneous Cl activation has a strong dependence upon water vapor partial pressure and hence atmospheric altitude, becoming much faster close to the tropopause. Our analysis improves the understanding of heterogeneous reactions that are important for stratospheric ozone chemistry under both background and wildfire conditions.

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“…Midlatitude ozone is mainly affected by an increase in heterogeneous chemistry, which increases ClO x (= Cl + ClO + 2 • Cl 2 O 2 ) and reduces NO x (= NO+NO 2 +NO 3 +2•N 2 O 5 ) (Pitari et al, 2014;Heckendorn et al, 2009). The increase in ClO x , which causes ozone destruction in the ClO x cycle (Stolarski and Cicerone, 1974;Rowland and Molina, 1975), is balanced by the reduction in NO x , which reduces ozone destruction in the NO x cycle (Crutzen, 1970;Johnston, 1971), until the middle of this century (Pitari et al, 2014). In the subsequent decades, the decrease in ODSs would result in a general increase in stratospheric ozone (Pitari et al, 2014).…”

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confidence: 99%

Potential of future stratospheric ozone loss in the mid-latitudes under climate change and sulfate geoengineering

Robrecht

Vogel

Tilmes

et al. 2020

Preprint

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Abstract. The potential of heterogeneous chlorine activation in the mid-latitude lowermost stratosphere during summer is a matter of debate. The occurrence of heterogeneous chlorine activation through the presence of aerosol particles could cause ozone destruction. This chemical process requires low temperatures and is accelerated by an enhancement of the stratospheric water vapour and sulfate amount. In particular, the conditions present in the lowermost stratosphere during the North American Summer Monsoon season (NAM) are expected to be cold and moist enough for causing the occurrence of heterogeneous chlorine activation. Furthermore, the temperatures, the water vapour mixing ratio and the sulfate aerosol abundance are affected by future climate change and by the potential application of sulfate geoengineering. Hence, both future scenarios could promote this ozone destruction process. We investigate the likelihood for the occurrence of heterogeneous chlorine activation and its impact on ozone in the lowermost stratospheric mixing layer between tropospheric and stratospheric air above central North America (30.6–49.6° N, 72.25–124.75° W) in summer for conditions today, at the mid and at the end of the 21st century. Therefore, the results of the Geoengineering Large Ensemble Simulations (GLENS) for the lowermost stratospheric mixing layer between tropospheric and stratospheric air are considered together with 10 day box-model simulations performed with the Chemical Lagrangian Model of the Stratosphere (CLaMS). In GLENS two future scenarios are simulated: the RCP8.5 climate change scenario and a geoengineering scenario, where sulfur is additionally injected in the stratosphere to keep the global mean surface temperature from changing. In the GLENS simulations, the mixing layer will warm and moisten in both future scenarios with a larger effect in the geoengineering scenario. The likelihood for chlorine activation to occur in the mixing layer is highest in the years 2040–2050 if geoengineering is applied, accounting for 3.3 %. In comparison, the likelihood for conditions today is 1.0 %. At the end of the 21st century, the likelihood of this ozone destruction process to occur decreases. We found that 0.1 % of the ozone mixing ratios in the mixing layer above central North America is destroyed for conditions today. A maximum ozone destruction of 0.3 % in the mixing layer occurs in the years 2040–2050 if geoengineering is applied. Comparing the southernmost latitude band (30–35° N) and the northernmost latitude band (44–49° N) of the considered region, we found a higher likelihood for the occurrence of heterogeneous chlorine activation in the southernmost latitude band, causing a higher impact on ozone as well. However, the ozone loss process is found to have a minor impact on the mid-latitude ozone column with not more than 0.1 DU today or in the future scenarios.

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Modeling the Effect of Potential Nitric Acid Removal During Convective Injection of Water Vapor Over the Central United States on the Chemical Composition of the Lower Stratosphere

Cited by 5 publications

References 158 publications

Empirical evidence for deep convection being a major source of stratospheric ice clouds over North America

Empirical evidence for deep convection being a major source of stratospheric ice clouds over North America

Stratospheric chlorine processing after the 2020 Australian wildfires derived from satellite data

Potential of future stratospheric ozone loss in the mid-latitudes under climate change and sulfate geoengineering

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