Arctic ozone loss in early spring and its impact on the stratosphere-troposphere coupling

Abstract. The empirical relationship found between column-integrated Arctic ozone loss and the potential volume of polar stratospheric clouds inferred from meteorological analyses is recalculated in a self-consistent manner using the ERA Interim reanalyses. The relationship is found to hold at different altitudes as well as in the column. The use of a PSC formation threshold based on temperature dependent cold aerosol formation makes little difference to the original, empirical relationship. Analysis of the photochemistry leading to the ozone loss shows that activation is limited by the photolysis of nitric acid. This step produces nitrogen dioxide which is converted to chlorine nitrate which in turn reacts with hydrogen chloride on any polar stratospheric clouds to form active chlorine. The rate-limiting step is the photolysis of nitric acid: this occurs at the same rate every year and so the interannual variation in the ozone loss is caused by the extent and persistence of the polar stratospheric clouds. In early spring the ozone loss rate increases as the solar insolation increases the photolysis of the chlorine monoxide dimer in the near ultraviolet. However the length of the ozone loss period is determined by the photolysis of nitric acid which also occurs in the near ultraviolet. As a result of these compensating effects, the amount of the ozone loss is principally limited by the extent of original activation rather than its timing. In addition a number of factors, including the vertical changes in pressure and total inorganic chlorine as well as denitrification and renitrification, offset each other. As a result the extent of original activation is the most important factor influencing ozone loss. These results indicate that relatively simple parameterisations of Arctic ozone loss could be developed for use in coupled chemistry climate models.

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Brief communication "Stratospheric winds, transport barriers and the 2011 Arctic ozone hole"

Nonlinear Processes in Geophysics ◽

10.5194/npg-19-687-2012 ◽

2012 ◽

Vol 19 (6) ◽

pp. 687-692 ◽

Cited By ~ 6

Author(s):

M. J. Olascoaga ◽

M. G. Brown ◽

F. J. Beron-Vera ◽

H. Koçak

Keyword(s):

Maintenance Phase ◽

Early Spring ◽

Ozone Hole ◽

The Arctic ◽

Late Winter ◽

Boreal Winter ◽

Meridional Transport ◽

Transport Barrier ◽

Cold Temperatures ◽

Ozone Loss

Abstract. The Arctic stratosphere throughout the late winter and early spring of 2011 was characterized by an unusually severe ozone loss, resulting in what has been described as an ozone hole. The 2011 ozone loss was made possible by unusually cold temperatures throughout the Arctic stratosphere. Here we consider the issue of what constitutes suitable environmental conditions for the formation and maintenance of a polar ozone hole. Our discussion focuses on the importance of the stratospheric wind field and, in particular, the importance of a high latitude zonal jet, which serves as a meridional transport barrier both prior to ozone hole formation and during the ozone hole maintenance phase. It is argued that stratospheric conditions in the boreal winter/spring of 2011 were highly unusual inasmuch as in that year Antarctic-like Lagrangian dynamics led to the formation of a boreal ozone hole.

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ILAS observations of chemical ozone loss in the Arctic vortex during early spring 1997

Geophysical Research Letters ◽

10.1029/1999gl010794 ◽

2000 ◽

Vol 27 (2) ◽

pp. 213-216 ◽

Cited By ~ 22

Author(s):

Y. Sasano ◽

Y. Terao ◽

H. L. Tanaka ◽

T. Yasunari ◽

H. Kanzawa ◽

...

Keyword(s):

Early Spring ◽

The Arctic ◽

Ozone Loss

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A closer look at Arctic ozone loss and polar stratospheric clouds

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-6681-2010 ◽

2010 ◽

Vol 10 (3) ◽

pp. 6681-6712 ◽

Cited By ~ 1

Author(s):

N. R. P. Harris ◽

R. Lehmann ◽

M. Rex ◽

P. von der Gathen

Keyword(s):

Nitric Acid ◽

Climate Models ◽

Empirical Relationship ◽

Early Spring ◽

Polar Stratospheric Clouds ◽

Chlorine Nitrate ◽

Ozone Loss ◽

Near Ultraviolet ◽

Chlorine Monoxide ◽

Stratospheric Clouds

Abstract. The empirical relationship found between column-integrated Arctic ozone loss and the volume of polar stratospheric clouds inferred from meteorological analyses is updated and examined in more detail. The relationship is found to hold at different altitudes as well as in the column. Analysis of the photochemistry leading to the ozone loss shows that the early winter activation is limited by the photolysis of nitric acid. This step produces nitrogen dioxide which is converted to chlorine nitrate which in turn reacts with hydrogen chloride on any polar stratospheric clouds to form active chlorine. The rate-limiting step is the photolysis of nitric acid: this occurs at the same rate every year and so the interannual variation in the ozone loss is caused by the extent and persistence of the polar stratospheric clouds. In early spring the ozone loss rate increases as the solar insolation increases the photolysis of the chlorine monoxide dimer. However the length of the ozone loss period is determined by the photolysis of nitric acid which also occurs in the near ultraviolet. As a result of these compensating effects, the amount of the ozone loss is principally limited by the extent of original activation rather than its timing. In addition a number of factors, including the vertical changes in pressure and total inorganic chlorine as well as denitrification and renitrification, offset each other. As a result the extent of original activation is the most important factor influencing ozone loss. These results indicate that relatively simple parameterisations of Arctic ozone loss could be developed for use in coupled chemistry climate models.

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Evidence for slowdown in stratospheric ozone loss: first stage of ozone recovery

Nature ◽

10.1038/news030728-5 ◽

2003 ◽

Keyword(s):

Stratospheric Ozone ◽

Ozone Loss

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Early spring mycobiota of pine litter needles.

Czech Mycology ◽

10.33585/cmy.63204 ◽

2011 ◽

Vol 63 (2) ◽

pp. 153-161 ◽

Cited By ~ 1

Author(s):

Ondřej Koukol

Keyword(s):

Early Spring

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EVALUATION OF CLOVERS ON SANDY COASTAL SOIL

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.1977.39.1500 ◽

1977 ◽

pp. 130-138 ◽

Cited By ~ 1

Author(s):

W.M. Williams ◽

L.B. Anderson ◽

B.M. Cooper

Keyword(s):

New Zealand ◽

Drought Stress ◽

Sandy Soil ◽

White Clover ◽

Plant Material ◽

Red Clover ◽

Early Spring ◽

Commercial Cultivars ◽

Mediterranean Origin ◽

Winter Annual

In evaluations of clover performances on summer-dry Himatangi sandy soil, it was found that none could match lucerne over summer. Emphasis was therefore placed on production in autumn-winter- early spring when lucerne growth was slow. Evaluations of some winter annual clover species suggested that Trifolium spumosum, T. pallidum, T. resupinatum, and T. vesiculosum would justify further investigation, along with T. subterraneum which is already used in pastures on this soil type. Among the perennial clover species, Kenya white clover (7'. semipilosum) showed outstanding recovery from drought and was the only species to produce significantly in autumn. However, it failed to grow in winter-early spring. Within red clover, materials of New Zealand x Moroccan origin substantially outproduced the commercial cultivars. Within white clover, material from Israel, Italy and Lebanon, as well as progeny of a selected New Zealand plant, showed more rapid recovery from drought stress and subsequently better winter growth than New Zealand commercial material ('Grasslands Huia'). The wider use of plant material of Mediterranean origin and of plants collected in New Zealand dryland pastures is advocated in development of clover cultivars for New Zealand dryland situations.

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