scholarly journals Global tropospheric ozone variations from 2003 to 2011 as seen by SCIAMACHY

2016 ◽  
Vol 16 (2) ◽  
pp. 417-436 ◽  
Author(s):  
F. Ebojie ◽  
J. P. Burrows ◽  
C. Gebhardt ◽  
A. Ladstätter-Weißenmayer ◽  
C. von Savigny ◽  
...  
Keyword(s):  
South America ◽  
North Atlantic ◽  
Tropospheric Ozone ◽  
Southern Oscillation ◽  
South American ◽  
Quasi Biennial Oscillation ◽  
The Pacific ◽  
The Tropics ◽  
Biennial Oscillation ◽  
South American Continent

Abstract. An analysis of the tropospheric ozone (O3) columns (TOCs) derived from SCIAMACHY limb-nadir-matching (LNM) observations during the period 2003–2011, focusing on global variations in TOC, is described. The changes are derived using a multivariate linear regression model. TOC shows changes of −0.2 ± 0.4, 0.3 ± 0.4, 0.1 ± 0.5 and 0.1 ± 0.2 % yr−1, which are not statistically significant at the 2σ level in the latitude bands 30–50° N, 20° S–0, 0–20° N and 50–30° S, respectively. Tropospheric O3 shows statistically significant increases over some regions of South Asia (1–3 % yr−1), the South American continent (up to 2 % yr−1), Alaska (up to 2 % yr−1) and around Congo in Africa (up to 2 % yr−1). Significant increase in TOC is determined off the continents including Australia (up to 2 % yr−1), Eurasia (1–3 % yr−1) and South America (up to 3 % yr−1). Significant decrease in TOC (up to −3 % yr−1) is observed over some regions of the continents of North America, Europe and South America. Over the oceanic regions including the Pacific, North Atlantic and Indian oceans, significant decreases in TOC (−1 to −3 % yr−1) were observed. In addition, the response of the El Niño–Southern Oscillation (ENSO) and quasi-biennial oscillation (QBO) to changes in TOC for the period 2003–2011 was investigated. The result shows extensive regions, mostly in the tropics and Northern Hemisphere extratropics, of significant ENSO responses to changes in TOC and a significant QBO response to TOC changes over some regions.

Impact of the Quasi-Biennial Oscillation on the boreal winter tropospheric circulation in CMIP5/6 models

2020 ◽  
Author(s):  
Jian Rao ◽  
Chaim Garfinkel ◽  
Ian White ◽  
Chen Schwartz
Keyword(s):  
Pacific Ocean ◽  
Southern Oscillation ◽  
Polar Vortex ◽  
Buoyancy Frequency ◽  
Maritime Continent ◽  
Quasi Biennial Oscillation ◽  
Stratospheric Polar Vortex ◽  
Enso Events ◽  
The Pacific ◽  
Biennial Oscillation

<p>Using 17 CMIP5/6 models with a spontaneously-generated quasi-biennial oscillation (QBO)-like phenomenon, this study explores and evaluates three dynamical pathways for impacts of the QBO on the troposphere: (i) the Holtan-Tan (HT) effect on the stratospheric polar vortex and the northern annular mode (NAM), (ii) the subtropical zonal wind downward arching over the Pacific, and (iii) changes in local convection over the Maritime Continent and Indo-Pacific Ocean. More than half of the models can reproduce at least one of the three pathways, but few models can reproduce all of the three routes. Firstly, most models are able to simulate a weakened polar vortex during easterly QBO (EQBO) winters, in agreement with the observed HT effect. However, the weakened polar vortex response during EQBO winters is underestimated or not present at all in other models, and hence the QBO → vortex → tropospheric NAM/AO chain is not simulated. For the second pathway associated with the downward arching of the QBO winds, seven models incorrectly or poorly simulate the extratropical easterly anomaly center over 20–40°N in the Pacific sector during EQBO, and hence the negative relative vorticity anomalies poleward of the easterly center is not resolved in those models, leading to an underestimated or incorrectly modelled height response over North Pacific. However the other ten do capture this effect. The third pathway is only observed in the Indo-Pacific Ocean, where the strong climatological deep convection and the warm pool are situated. Nine models can simulate the convection anomalies associated with the QBO over the Maritime Continent, which is likely caused by the near-tropopause low buoyancy frequency anomalies. No robust relationship between the QBO and El Niño–Southern Oscillation (ENSO) events can be established using the ERA-Interim reanalysis, and nine models consistently confirm little modulation of the ocean basin-wide Walker circulation and ENSO events by the QBO.</p>

Darwin's Early Notes on Coral Reef Formation

1984 ◽  
Vol 3 (2) ◽  
pp. 160-163 ◽  
Author(s):  
Frederick Burkhardt
Keyword(s):  
Coral Reef ◽  
South America ◽  
Point Of View ◽  
South American ◽  
American Continent ◽  
The Pacific ◽  
The Pacific Ocean ◽  
South American Continent ◽  
Reef Formation ◽  
Water Coral

Darwin's letters and some rough notes found in his field notebooks of 1835 confirm the statement in his Autobiography that he had formulated his theory of coral reef formation before the Beagle left South America and before he had seen a coral reef. His geological observations having convinced him of the elevation of the South American continent, Darwin predicted that evidence of a compensatory gradual subsidence of the Pacific Ocean floor would be found in the existence of shallow-water coral genera in the Pacific reef formations. The first draft of the theory was written on board the Beagle shortly after seeing the reefs of Moorea in November 1835. After visiting the Cocos (Keeling) Islands he wrote a summary of his view in a letter of April 1838, in which he expressed his conviction that he had found an explanation which would "put some of the facts in a more simple and connected point of view, than that in which they have hitherto been considered".

scholarly journals Sixteen Years of Measurements of Ozone over Athens, Greece with a Brewer Spectrophotometer

Oxygen ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 32-45
Author(s):  
Kostas Eleftheratos ◽  
Dimitra Kouklaki ◽  
Christos Zerefos
Keyword(s):  
North Atlantic ◽  
Total Ozone ◽  
Southern Oscillation ◽  
Quasi Biennial Oscillation ◽  
The North ◽  
Satellite Retrievals ◽  
Brewer Spectrophotometer ◽  
The North Atlantic ◽  
The North Atlantic Oscillation ◽  
Biennial Oscillation

Sixteen years (July 2003–July 2019) of ground-based measurements of total ozone in the urban environment of Athens, Greece, are analyzed in this work. Measurements were acquired with a single Brewer monochromator operating on the roof of the Biomedical Research Foundation of the Academy of Athens since July 2003. We estimate a 16-year climatological mean of total ozone in Athens of about 322 DU, with no significant change since 2003. Ozone data from the Brewer spectrophotometer were compared with TOMS, OMI, and GOME-2A satellite retrievals. The results reveal excellent correlations between the ground-based and satellite ozone measurements greater than 0.9. The variability of total ozone over Athens related to the seasonal cycle, the quasi biennial oscillation (QBO), the El Nino Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), the 11-year solar cycle, and tropopause pressure variability is presented.

How Does the Quasi-Biennial Oscillation Affect the Boreal Winter Tropospheric Circulation in CMIP5/6 Models?

2020 ◽  
Vol 33 (20) ◽  
pp. 8975-8996 ◽  
Author(s):  
Jian Rao ◽  
Chaim I. Garfinkel ◽  
Ian P. White
Keyword(s):  
Pacific Ocean ◽  
Southern Oscillation ◽  
Polar Vortex ◽  
Buoyancy Frequency ◽  
Maritime Continent ◽  
Quasi Biennial Oscillation ◽  
Stratospheric Polar Vortex ◽  
Enso Events ◽  
The Pacific ◽  
Biennial Oscillation

AbstractUsing 17 CMIP5 and CMIP6 models with a spontaneously generated quasi-biennial oscillation (QBO)-like phenomenon, this study explores and evaluates three dynamical pathways for impacts of the QBO on the troposphere: 1) the Holtan–Tan (HT) effect on the stratospheric polar vortex and the northern annular mode (NAM), 2) the subtropical zonal wind downward arching over the Pacific, and 3) changes in local convection over the Maritime Continent and Indo-Pacific Ocean. More than half of the models can reproduce at least one of the three pathways, but few models can reproduce all of the three routes. First, seven models are able to simulate a weakened polar vortex during easterly QBO (EQBO) winters, in agreement with the HT effect in the reanalysis. However, the weakened polar vortex response during EQBO winters is underestimated or not present at all in other models, and hence the chain for QBO, vortex, and tropospheric NAM/AO is not simulated. For the second pathway associated with the downward arching of the QBO winds, 10 models simulate an inconsistent extratropical easterly anomaly center over 20°–40°N in the Pacific sector during EQBO, and hence the negative relative vorticity anomalies poleward of the easterly center is not present in those models, leading to no consensus on the height response over the North Pacific between those models and the reanalysis. However, the other seven models do capture this effect. The third pathway is only observed in the Indo-Pacific Ocean, where the strong climatological deep convection and the warm pool are situated. Seven models can simulate the convection anomalies associated with the QBO over the Maritime Continent, which is likely caused by the near-tropopause low buoyancy frequency anomalies. No robust relationship between the QBO and El Niño–Southern Oscillation (ENSO) events can be established using the JRA55 reanalysis, and 10 models consistently confirm little modulation of the ocean basinwide Walker circulation and ENSO events by the QBO.

scholarly journals Climatology and Long-Term Trends in the Stratospheric Temperature and Wind Using ERA5

2021 ◽  
Vol 13 (23) ◽  
pp. 4923
Author(s):  
Michal Kozubek ◽  
Jan Laštovička ◽  
Radek Zajicek
Keyword(s):  
North Atlantic ◽  
Middle Atmosphere ◽  
Southern Oscillation ◽  
Quasi Biennial Oscillation ◽  
Stratospheric Temperature ◽  
Wind Climatology ◽  
Long Term Trends ◽  
The Impact ◽  
Biennial Oscillation

This study analyses long-term trends in temperature and wind climatology based on ERA5 data. We study climatology and trends separately for every decade from 1980 to 2020 and their changes during this period. This study is focused on the pressure levels between 100–1 hPa, which essentially covers the whole stratosphere. We also analyze the impact of the sudden stratospheric warmings (SSW), North Atlantic Oscillation (NAO), El Nino Southern Oscillation (ENSO) and Quasi-biennial oscillation (QBO). This helps us to find details of climatology and trend behavior in the stratosphere in connection to these phenomena. ERA5 is one of the newest reanalysis, which is widely used for the middle atmosphere. We identify the largest differences which occur between 1990–2000 and 2000–2010 in both temperature climatology and trends. We suggest that these differences could relate to the different occurrence frequency of SSWs in 1990–2000 versus 2000–2010.

Ocean Coasts and Continental Shelves

2007 ◽  
Author(s):  
José Araya-Vergara
Keyword(s):  
South America ◽  
Atlantic Coast ◽  
South American ◽  
The South ◽  
South American Plate ◽  
The Pacific ◽  
Analytical Perspective ◽  
Oceanic Plates ◽  
The 1960S ◽  
The Tropics

Suess (1900) provided the first scientific treatment of the South American coast from a tectonic perspective when he distinguished between the Atlantic and Pacific structural styles on opposite sides of the continent. Inman and Nordstrom (1971) later complemented this approach by relating these styles to the concepts of plate tectonics that had emerged during the 1960s. Useful keys to understanding South American coastal processes and sediment supplies were then offered by Davies (1977) and Potter (1994), respectively, while regional accounts of South American coastal landforms were made by specialists in books edited by Bird and Schwartz (1985) and Schwartz (2005). Clapperton (1993) reviewed Quaternary coastal morphogenesis. Coastal sites of scientific importance and historical coastline changes were discussed by Bird and Koike (1981) and Bird (1985). This chapter focuses on the principal factors involved in coastal evolution and morphogenesis, describes key regional landforms, and proposes a new analytical perspective for South America’s coasts by introducing a hierarchical system within coastal groups. The main coastline of South America is approximately 31,100 km long, of which 10,400 km face the Pacific Ocean, 16,700 the open Atlantic Ocean, and the remaining 4,000 km the more sheltered Caribbean Sea. Of the total length, approximately two-thirds lie within the tropics, ensuring that physical and ecological responses to ocean-atmosphere circulation systems involving the Intertropical Convergence Zone dominate these coasts. The remaining one third of the coast beyond the tropics is dominated during part or all of the year by temperate westerly conditions, which become increasingly cool and stormy toward the continent’s southern tip. The origins of the present coast reflect the tectonic forces that have affected the South American plate over the past 200 million years, augmented by relative sea-level changes associated with changing global (eustatic) ocean volume and regional (isostatic) crustal adjustments. The Atlantic coast of South America owes its broad outline to the separation of the continent from neighboring parts of Gondwana that began more than 200 Ma (million years ago). The Pacific and Caribbean coasts have a more complex history, related to the progressive interaction of the westwardmoving South American plate with four oceanic plates with which it has come into contact).

scholarly journals Global and zonal tropospheric ozone variations from 2003–2011 as seen by SCIAMACHY

2015 ◽  
Vol 15 (17) ◽  
pp. 24085-24130 ◽  
Author(s):  
F. Ebojie ◽  
J. P. Burrows ◽  
C. Gebhardt ◽  
A. Ladstätter-Weißenmayer ◽  
C. von Savigny ◽  
...  
Keyword(s):  
North America ◽  
Linear Regression ◽  
South America ◽  
Tropospheric Ozone ◽  
South American ◽  
Multivariate Linear Regression Model ◽  
American Continent ◽  
The South ◽  
South American Continent ◽  
Ozone Variations

Abstract. An analysis of the tropospheric ozone (O3) columns (TOCs) derived from SCIAMACHY limb-nadir-matching (LNM) observations during 2003–2011, focusing on the zonal and global variations in TOC is described. The changes are derived using a multivariate linear regression model. TOC shows a change of −0.2 ± 0.4 % yr−1, 0.3 ± 0.4 % yr−1, 0.1 ± 0.5 % yr−1 and 0.1 ± 0.2 % yr−1, which are not statistically significant at the 2 σ level in the latitude bands 30–50° N, 20° S–0, 0–20° N and 50–30° S, respectively. Tropospheric O3 shows statistically significant increases over some regions of South Asia (1–3 % yr−1), the South American continent (up to 2 % yr−1), Alaska (up to 2 % yr−1) and around Congo in Africa (up to 2 % yr−1). Significant increase in TOC is derived from the continental outflows including those of Australia (up to 2 % yr−1), Eurasia (1–3 % yr−1) and the South America (up to 3 % yr−1). Significant decrease in TOC (up to −3 % yr−1) is observed over some regions of the continents of North America, Europe and South America. Over the Oceanic regions, significant decrease in TOC of about −2 % yr−1 is observed over the outflows of Europe and North America.

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