scholarly journals Arctic on the verge of an ozone hole?

2021 ◽  
Author(s):  
Jayanarayanan Kuttippurath ◽  
Wuhu Feng ◽  
Rolf Müller ◽  
Pankaj Kumar ◽  
Sarath Raj ◽  
...  
Keyword(s):  
Ultra Violet ◽  
Ozone Hole ◽  
The Arctic ◽  
Extreme Weather Events ◽  
Ozone Loss ◽  
Ultra Violet Radiation ◽  
Weather Events ◽  
Antarctic Ozone ◽  
Near Future ◽  
First Time

Abstract. Severe vortex-wide ozone loss in the Arctic would expose nearly 650 million people and ecosystem to unhealthy ultra-violet radiation levels. Adding to these worries, and extreme weather events as the harbingers of climate change, clear signature of an ozone hole (ozone column values below 220 DU) appeared over the Arctic in March and April 2020. Sporadic occurrences of ozone hole values at different regions of vortex for almost three weeks were found for the first time in the observed history in the Arctic. Furthermore, a record-breaking ozone loss of about 2.0–3.4 ppmv triggered by an unprecedented chlorine activation (1.5–2.2 ppbv) matching to the levels of Antarctic ozone hole conditions was also observed. The polar processing situation led to the first-ever appearance of loss saturation in the Arctic. Apart from these, there were also ozone-mini holes in December 2019 and January 2020 driven by atmospheric dynamics. The large loss in ozone in the colder Arctic winters is intriguing and that demands rigorous monitoring of the region. Our study suggests that the very colder Arctic winters in near future would also very likely to experience even more ozone loss and encounter ozone hole situations, provided the stratospheric chlorine levels still stay high there.

scholarly journals Discovery of a New Ozone Hole over the Tropics

2022 ◽  
Author(s):  
Qing-Bin Lu
Keyword(s):  
Lower Stratosphere ◽  
Global Climate ◽  
Ground Level ◽  
Ozone Hole ◽  
The Arctic ◽  
Ozone Loss ◽  
Global Concern ◽  
Antarctic Ozone ◽  
Stratospheric Cooling ◽  
The Tropics

Abstract This paper reveals a new ozone hole that exists in the lower stratosphere over the tropics (30°N-30°S) across the seasons since the 1980s, where an ozone hole is defined as an area of ozone loss larger than 25% compared with the undisturbed atmosphere. The depth of this all-season tropical ozone hole is comparable to that of the well-known springtime ozone hole over Antarctica, while its area is about seven times that of the latter. At the center of the deepest tropical or Antarctic ozone hole, approximately 80% of the normal ozone value is depleted, whereas annual mean ozone depletion in the lower stratosphere over the tropics due to the coldest temperature is about 1.6 times that over Antarctica and is about 7.7 times that over the Arctic. The whole-year ozone hole over the tropics could cause a serious global concern as it can lead to increases in ground-level ultraviolet radiation and affect 50% of Earth's surface area, which is home to approximately 50% of the world's population. Moreover, since ozone loss is well-known to lead to stratospheric cooling, the presence of the all-season tropical ozone hole and the seasonal polar ozone holes is equivalent to the formation of three ‘temperature holes’ in the global lower stratosphere. These findings will play a far-reaching role in understanding fundamental atmospheric processes and global climate change.

scholarly journals The Antarctic ozone hole during 2014

2019 ◽  
Vol 69 (1) ◽  
pp. 1
Author(s):  
Paul B. Krummel ◽  
Andrew R. Klekociuk ◽  
Matthew B. Tully ◽  
H. Peter Gies ◽  
Simon P. Alexander ◽  
...  
Keyword(s):  
Polar Vortex ◽  
Ultra Violet ◽  
Ozone Hole ◽  
Ultra Violet Radiation ◽  
Hole Making ◽  
Antarctic Ozone ◽  
The Antarctic ◽  
Violet Radiation ◽  
Antarctic Ozone Hole

We review the 2014 Antarctic ozone hole, making use of a variety of ground-based and space-based measurements of ozone and ultra-violet radiation, supplemented by meteorological reanalyses. Although the polar vortex was relatively stable in 2014 and persisted some weeks longer into November than was the case in 2012 or 2013, the vortex temperature was close to the long-term mean in September and October with modest warming events occurring in both months, preventing severe depletion from taking place. Of the seven metrics reported here, all were close to their respective median values of the 1979–2014 record, being ranked between 16th and 21st of the 35 years for which adequate satellite observations exist.

scholarly journals Spatial variations in the warming trend and the transition to more severe weather in midlatitudes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Francisco Estrada ◽  
Dukpa Kim ◽  
Pierre Perron
Keyword(s):  
Radiative Forcing ◽  
Warming Trend ◽  
Severe Weather ◽  
Montreal Protocol ◽  
The Arctic ◽  
Extreme Weather Events ◽  
Jet Stream ◽  
Atmospheric Blocking ◽  
Regional Warming ◽  
Weather Events

AbstractDue to various feedback processes called Arctic amplification, the high-latitudes’ response to increases in radiative forcing is much larger than elsewhere in the world, with a warming more than twice the global average. Since the 1990’s, this rapid warming of the Arctic was accompanied by no-warming or cooling over midlatitudes in the Northern Hemisphere in winter (the hiatus). The decrease in the thermal contrast between Arctic and midlatitudes has been connected to extreme weather events in midlatitudes via, e.g., shifts in the jet stream towards the equator and increases in the probability of high-latitude atmospheric blocking. Here we present an observational attribution study showing the spatial structure of the response to changes in radiative forcing. The results also connect the hiatus with diminished contrast between temperatures over regions in the Arctic and midlatitudes. Recent changes in these regional warming trends are linked to international actions such as the Montreal Protocol, and illustrate how changes in radiative forcing can trigger unexpected responses from the climate system. The lesson for climate policy is that human intervention with the climate is already large enough that even if stabilization was attained, impacts from an adjusting climate are to be expected.

scholarly journals Record-breaking ozone loss in the Arctic winter 2010/2011: comparison with 1996/1997

2012 ◽  
Vol 12 (15) ◽  
pp. 7073-7085 ◽  
Author(s):  
J. Kuttippurath ◽  
S. Godin-Beekmann ◽  
F. Lefèvre ◽  
G. Nikulin ◽  
M. L. Santee ◽  
...  
Keyword(s):  
Transport Model ◽  
Chemical Transport ◽  
The Arctic ◽  
Altitude Range ◽  
Chemical Transport Model ◽  
Model Simulations ◽  
Ozone Loss ◽  
Elevated Ozone ◽  
Record Value ◽  
First Time

Abstract. We present a detailed discussion of the chemical and dynamical processes in the Arctic winters 1996/1997 and 2010/2011 with high resolution chemical transport model (CTM) simulations and space-based observations. In the Arctic winter 2010/2011, the lower stratospheric minimum temperatures were below 195 K for a record period of time, from December to mid-April, and a strong and stable vortex was present during that period. Simulations with the Mimosa-Chim CTM show that the chemical ozone loss started in early January and progressed slowly to 1 ppmv (parts per million by volume) by late February. The loss intensified by early March and reached a record maximum of ~2.4 ppmv in the late March–early April period over a broad altitude range of 450–550 K. This coincides with elevated ozone loss rates of 2–4 ppbv sh−1 (parts per billion by volume/sunlit hour) and a contribution of about 30–55% and 30–35% from the ClO-ClO and ClO-BrO cycles, respectively, in late February and March. In addition, a contribution of 30–50% from the HOx cycle is also estimated in April. We also estimate a loss of about 0.7–1.2 ppmv contributed (75%) by the NOx cycle at 550–700 K. The ozone loss estimated in the partial column range of 350–550 K exhibits a record value of ~148 DU (Dobson Unit). This is the largest ozone loss ever estimated in the Arctic and is consistent with the remarkable chlorine activation and strong denitrification (40–50%) during the winter, as the modeled ClO shows ~1.8 ppbv in early January and ~1 ppbv in March at 450–550 K. These model results are in excellent agreement with those found from the Aura Microwave Limb Sounder observations. Our analyses also show that the ozone loss in 2010/2011 is close to that found in some Antarctic winters, for the first time in the observed history. Though the winter 1996/1997 was also very cold in March–April, the temperatures were higher in December–February, and, therefore, chlorine activation was moderate and ozone loss was average with about 1.2 ppmv at 475–550 K or 42 DU at 350–550 K, as diagnosed from the model simulations and measurements.

scholarly journals Differences in Arctic and Antarctic PSC occurrence as observed by lidar in Ny-Ålesund (79° N, 12° E) and McMurdo (78° S, 167° E)

2005 ◽  
Vol 5 (8) ◽  
pp. 2081-2090 ◽  
Author(s):  
M. Maturilli ◽  
R. Neuber ◽  
P. Massoli ◽  
F. Cairo ◽  
A. Adriani ◽  
...  
Keyword(s):  
Large Fraction ◽  
Particle Surface ◽  
The Arctic ◽  
Ozone Loss ◽  
Polar Stratospheric Cloud ◽  
Antarctic Ozone ◽  
Stratospheric Cooling ◽  
Hole Dimensions ◽  
Activation Rates ◽  
The Relationship

Abstract. The extent of springtime Arctic ozone loss does not reach Antarctic ``ozone hole'' dimensions because of the generally higher temperatures in the northern hemisphere vortex and consequent less polar stratospheric cloud (PSC) particle surface for heterogeneous chlorine activation. Yet, with increasing greenhouse gases stratospheric temperatures are expected to further decrease. To infer if present Antarctic PSC occurrence can be applied to predict future Arctic PSC occurrence, lidar observations from McMurdo station (78° S, 167° E) and NyÅlesund (79° N, 12° E) have been analysed for the 9 winters between 1995 (1995/1996) and 2003 (2003/2004). Although the statistics may not completely cover the overall hemispheric PSC occurrence, the observations are considered to represent the main synoptic cloud features as both stations are mostly situated in the centre or at the inner edge of the vortex. Since the focus is set on the occurrence frequency of solid and liquid particles, the analysis has been restricted to volcanic aerosol free conditions. In McMurdo, by far the largest part of PSC observations is associated with NAT PSCs. The observed persistent background of NAT particles and their potential ability to cause denoxification and irreversible denitrification is presumably more important to Antarctic ozone chemistry than the scarcely observed ice PSCs. Meanwhile in Ny-Ålesund, ice PSCs have never been observed, while solid NAT and liquid STS clouds both occur in large fraction. Although they are also found solely, the majority of observations reveals solid and liquid particle layers in the same profile. For the Ny-Ålesund measurements, the frequent occurrence of liquid PSC particles yields major significance in terms of ozone chemistry, as their chlorine activation rates are more efficient. The relationship between temperature, PSC formation, and denitrification is nonlinear and the McMurdo and Ny-Ålesund PSC observations imply that for predicted stratospheric cooling it is not possible to directly apply current Antarctic PSC occurrence to the Arctic stratosphere. Future Arctic PSC occurrence, and thus ozone loss, is likely to depend on the shape and barotropy of the vortex rather than on minimum temperature alone.

scholarly journals Why Are Siberian Temperatures Plummeting While the Arctic Warms?

Eos ◽  
2018 ◽  
Vol 99 ◽  
Author(s):  
Kimberly Cartier
Keyword(s):  
Climate Models ◽  
Extreme Weather ◽  
The Arctic ◽  
Extreme Weather Events ◽  
Weather Events ◽  
Stratospheric Circulation

The answer involves the intricacies of stratospheric circulation, which, if better represented in climate models, could help predict extreme weather events in Siberia and elsewhere.

scholarly journals Exceptional loss in ozone in the Arctic winter/spring of 2019/2020

2021 ◽  
Vol 21 (18) ◽  
pp. 14019-14037
Author(s):  
Jayanarayanan Kuttippurath ◽  
Wuhu Feng ◽  
Rolf Müller ◽  
Pankaj Kumar ◽  
Sarath Raj ◽  
...  
Keyword(s):  
Climate Change ◽  
Ultraviolet Radiation ◽  
Extreme Events ◽  
Atmospheric Dynamics ◽  
The Arctic ◽  
Large Loss ◽  
Ozone Loss ◽  
The Antarctic ◽  
First Time

Abstract. Severe vortex-wide ozone loss in the Arctic would expose both ecosystems and several millions of people to unhealthy ultraviolet radiation. Adding to these worries, and extreme events as the harbingers of climate change, exceptionally low ozone with column values below 220 DU occurred over the Arctic in March and April 2020. Sporadic occurrences of low ozone with less than 220 DU at different regions of the vortex for almost 3 weeks were found for the first time in the observed history in the Arctic. Furthermore, a large ozone loss of about 2.0–3.4 ppmv triggered by an unprecedented chlorine activation (1.5–2.2 ppbv) matching the levels occurring in the Antarctic was also observed. The polar processing situation led to the first-ever appearance of loss saturation in the Arctic. Apart from these, there were also ozone-mini holes in December 2019 and January 2020 driven by atmospheric dynamics. The large loss in ozone in the colder Arctic winters is intriguing and demands rigorous monitoring of the region.

scholarly journals From Theory to Field Evidence: Observations on the Evolution of the Settlements of an Earthfill Dam, over Long Time Scales

2019 ◽  
Vol 4 (4) ◽  
pp. 65 ◽  
Author(s):  
Pytharouli ◽  
Michalis ◽  
Raftopoulos
Keyword(s):  
Extreme Weather Events ◽  
Field Evidence ◽  
Weather Events ◽  
Long Time ◽  
Clay Core ◽  
Earthfill Dams ◽  
Downstream Communities ◽  
Flooding Events ◽  
First Time

Unprecedented flooding events put dams and downstream communities at risk, as evidenced by the recent cases of the Oroville and Whaley bridge dams. Empirical models may describe expected ‘normal’ dam behaviour, but they do not account for changes due to recurring extreme weather events. Numerical modelling provides insights into this, but results are affected by the chosen material properties. Long-term field monitoring data can help with understanding the mechanical behaviour of earthfill dams and how this is affected by the environment over decades. We analyse the recorded settlements for one of the largest earthfill dams in Europe. We compare the evolution of these settlements to the reservoir level, rainfall, and the occurrence of earthquakes for a period of 31 years after first impoundment. We find that the clay core responds to the reservoir fluctuations with an increasing (from 0 to 6 months) time delay. This is the first time that a change in the behaviour of a central clay core dam, as observed from field data, is reported in the international literature. Seepage rates, as recorded within the drainage galleries, are directly affected by cumulative rainfall depths exceeding 67 mm per fortnight.

The CO2 balance of a boreal fen is more sensitive to drought than surrounding forests

2020 ◽  
Author(s):  
Mats Nilsson ◽  
Joshua Ratcliffe ◽  
Anne Klosterhalfen ◽  
Peng Zhao ◽  
Jinchu Chi ◽  
...  
Keyword(s):  
Boreal Forests ◽  
Vapour Pressure Deficit ◽  
Weather Conditions ◽  
Pine Forest ◽  
Extreme Weather Events ◽  
Boreal Peatlands ◽  
Weather Events ◽  
Co2 Balance ◽  
First Time ◽  
Boreal Landscape

<p>The boreal zone is one of the most carbon-dense biomes in the world and is comprised of a highly interconnected mosaic of forest and wetlands which are warming at a rate several times the global average with extreme weather events, such as droughts, becoming increasingly common. At the ecosystem scale, both forests and peatlands are often vulnerable to drought-induced carbon loss, however, the relative resilience of these two ecosystems within the boreal landscape is not well understood. Here we study the effect of the 2018 drought on CO<sub>2</sub> fluxes in two boreal forests and a boreal peatland within <20km radius, i.e. experiencing the same weather conditions. The peatland displayed the strongest response to the drought, with the site becoming a net annual source for CO<sub>2</sub> for the first time in 17 years, with the CO<sub>2 </sub>sink slow to recover after the drought broke. In contrast, the response of the forests was mixed, a  spruce/pine forest on glacial till remained unaffected by the drought, whereas a nearby pine forest, situated on drier sandy soil, responded strongly to vapour pressure deficit and declining soil moisture content, decreasing with CO<sub>2</sub> uptake weakening, but still allowing the forest to function as a CO<sub>2</sub> sink. In contrast to the bog, the pine forest CO<sub>2</sub> sink quickly recovered following the end of the drought. We conclude that boreal peatlands are likely to be the most vulnerable component of the boreal landscape to drought and that soil type is likely to play a role in regulating the response of boreal forests.</p>

scholarly journals Stratospheric ozone loss in the Arctic winters between 2005 and 2013 derived with ACE-FTS measurements

2019 ◽  
Vol 19 (1) ◽  
pp. 577-601 ◽  
Author(s):  
Debora Griffin ◽  
Kaley A. Walker ◽  
Ingo Wohltmann ◽  
Sandip S. Dhomse ◽  
Markus Rex ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Stratospheric Ozone ◽  
Polar Vortex ◽  
The Arctic ◽  
Estimation Methods ◽  
Mixing Ratio ◽  
Total Column Ozone ◽  
Ozone Loss ◽  
Column Ozone ◽  
First Time

Abstract. Stratospheric ozone loss inside the Arctic polar vortex for the winters between 2004–2005 and 2012–2013 has been quantified using measurements from the space-borne Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS). For the first time, an evaluation has been performed of six different ozone loss estimation methods based on the same single observational dataset to determine the Arctic ozone loss (mixing ratio loss profiles and the partial-column ozone losses between 380 and 550 K). The methods used are the tracer-tracer correlation, the artificial tracer correlation, the average vortex profile descent, and the passive subtraction with model output from both Lagrangian and Eulerian chemical transport models (CTMs). For the tracer-tracer, the artificial tracer, and the average vortex profile descent approaches, various tracers have been used that are also measured by ACE-FTS. From these seven tracers investigated (CH4, N2O, HF, OCS, CFC-11, CFC-12, and CFC-113), we found that CH4, N2O, HF, and CFC-12 are the most suitable tracers for investigating polar stratospheric ozone depletion with ACE-FTS v3.5. The ozone loss estimates (in terms of the mixing ratio as well as total column ozone) are generally in good agreement between the different methods and among the different tracers. However, using the average vortex profile descent technique typically leads to smaller maximum losses (by approximately 15–30 DU) compared to all other methods. The passive subtraction method using output from CTMs generally results in slightly larger losses compared to the techniques that use ACE-FTS measurements only. The ozone loss computed, using both measurements and models, shows the greatest loss during the 2010–2011 Arctic winter. For that year, our results show that maximum ozone loss (2.1–2.7 ppmv) occurred at 460 K. The estimated partial-column ozone loss inside the polar vortex (between 380 and 550 K) using the different methods is 66–103, 61–95, 59–96, 41–89, and 85–122 DU for March 2005, 2007, 2008, 2010, and 2011, respectively. Ozone loss is difficult to diagnose for the Arctic winters during 2005–2006, 2008–2009, 2011–2012, and 2012–2013, because strong polar vortex disturbance or major sudden stratospheric warming events significantly perturbed the polar vortex, thereby limiting the number of measurements available for the analysis of ozone loss.

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