scholarly journals Temperature variability and trends in the UT-LS over a subtropical site: Reunion (20.8° S, 55.5° E)

2010 ◽  
Vol 10 (17) ◽  
pp. 8563-8574 ◽  
Author(s):  
N. Bègue ◽  
H. Bencherif ◽  
V. Sivakumar ◽  
G. Kirgis ◽  
N. Mze ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Indian Ocean ◽  
Close Agreement ◽  
Temperature Variability ◽  
Lapse Rate ◽  
Minor Effect ◽  
Temperature Changes ◽  
The Indian Ocean ◽  
Main Component ◽  
A Minor

Abstract. This paper mainly focuses on the trends and variability of the UT-LS temperature using radiosonde observations carried out over 16 years (January 1993 to December 2008) from a southern subtropical site, Reunion (20.8° S, 55.5° E), using a linear-regression fitting model. Two kinds of tropopause definitions, namely, cold point tropopause (CPT) and lapse rate tropopause (LRT) are used. In order to characterize and quantify the relationship between regional oceanic forcing and temperature at UT-LS, we took into account the Indian Ocean Dipole (IOD) for the estimation of temperature trends. Results show that the main component is the Annual Cycle (AC), particularly at tropopause (CPT, LRT) and in the lower stratosphere (LS) where more than 26.0±2.4% of temperature variability can be explained by AC. The influence of IOD on the variability of the temperature is at highest ratio at CPT and LS, with respectively 12.3±7.3% and 13.1±5.9%. The correlations between IOD and temperature anomalies at UT-LS are barely significant, which are found to be in close agreement with the results obtained by Rosenlof et al. (2008) over the western tropical Pacific Ocean. The temperature trend in the LS reveals a cooling of about −0.90±0.40 K per decade. The cooling trend at LS is found to be in close agreement with the others studies. Trend estimates in the LS suggest that IOD forcing contributes to increasing cooling by about 0.16±0.05 K per decade. Past works have shown that the additional carbon dioxide increase has a minor effect in the LS, and suggested that other effects than ozone and carbon dioxide changes have to be considered, in order to explain the observed temperature changes in the LS. From this study, we can suggest that the SST changes can be considered also, in addition to effects due to ozone and carbon dioxide changes, in order to explain the observed temperature changes in the LS. As a consequence, our results support the assumption that the Indian Ocean may have a slight impact on temperature variability and on temperature change in the LS over Reunion.

scholarly journals Temperature variability and trend estimates at tropopause and UT-LS over a subtropical site: Reunion (20.8° S, 55.5° E)

2010 ◽  
Vol 10 (4) ◽  
pp. 10113-10143
Author(s):  
N. Bègue ◽  
H. Bencherif ◽  
V. Sivakumar ◽  
G. Kirgis ◽  
N. Mzé ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Temperature Variability ◽  
Lapse Rate ◽  
Temperature Trends ◽  
Oceanic Forcing ◽  
The Indian Ocean ◽  
Cooling Trend ◽  
Main Component ◽  
Cold Point ◽  
The Relationship

Abstract. This paper mainly focuses on the trends and variability of the tropopause and UT-LS temperature using radiosonde observations carried out over 16 years (January 1993 to December 2008) from a southern subtropical site, Reunion Island (20.8° S, 55.5° E), using a linear-regression fitting model. Two kinds of tropopause definitions, namely, cold point tropopause (CPT) and lapse rate tropopause (LRT) are used. In the purpose to characterize and quantify the relationship between the regional oceanic forcing and temperature at tropopause and UT-LS, we take into account the Indian Ocean Dipole (IOD) for the estimation of temperature trends. Results show that the main component is the Annual Oscillation (AO), particularly at tropopause (CPT, LRT) and in the lower stratosphere (LS) where more than 26% of the variability of temperature can be explained by AO. As a result, the influence of IOD on the variability of the temperature is at highest ratio at CPT and LS, with respectively 12.3% and 13.1%. The results show a low correlation between IOD and the temperature anomalies at tropopause (LRT, CPT) and UT-LS, in the range of 0.08–0.15, with the maximum of correlation at CPT (0.15). In addition, trend estimates at CPT and in the LS suggests that the IOD forcing contributes enhancing the rate of cooling of about 0.1 K per decade. Indeed a trend analysis reveals a cooling of about 0.90±0.40 K per decade at LS and a cooling trend of about 0.36±0.48 K per decade at CPT. The cooling trend at LS is found to be in good agreement with the others studies. These results support the assumption that the Indian Ocean may have a slight impact on temperature variability and on temperature change at CPT and in the LS over Reunion.

Sovereignty in a Minor Key

2021 ◽  
Vol 33 (1) ◽  
pp. 41-61
Author(s):  
Thomas Blom Hansen
Keyword(s):  
Twentieth Century ◽  
Eighteenth Century ◽  
Indian Ocean ◽  
Western Europe ◽  
Nation State ◽  
The World ◽  
The Indian Ocean ◽  
Theories Of Sovereignty ◽  
A Minor ◽  
State Form

Abstract Theories of sovereignty in the twentieth century are generally based on a teleological “out-of-Europe” narrative where the modern, centralized nation-state form gradually spread across the world to be the foundation of the international order. In this article, the author reflects on how the conceptualization of sovereignty may change if one begins a global account of modern sovereignty not from the heart of Western Europe but from the complex arrangements of “distributed sovereignty” that emerged in the Indian Ocean and other colonized territories from the eighteenth century onward. These arrangements were organized as multiple layers of dependency and provisional domination, captured well by Eric Beverley's term minor sovereignty. Thinking through sovereignty in a minor key allows us to see sovereignty less as a foundation of states and societies and more as a performative category, emerging in a dialectic between promises of order, prosperity, and law, and the realities of violent domination and occupation.

Seasonal variations in the Indian Ocean along 110°E. I. Hydrological structure of the upper 500 m

1969 ◽  
Vol 20 (1) ◽  
pp. 1 ◽  
Author(s):  
DJ Rochford
Keyword(s):  
Indian Ocean ◽  
Surface Waters ◽  
Water Masses ◽  
Surface Currents ◽  
Temperature Changes ◽  
East Indian ◽  
Hydrological Structure ◽  
The Indian Ocean ◽  
The Tropics ◽  
East Indian Ocean

Tropical and subtropical water masses at surface and subsurface depths were separated by their salinity, temperature, oxygen, and nutrient characteristics. The annual mean depths and latitudinal extent of these water masses were determined. Annual changes in the upper 50 m were generally so small relative to those found in other oceans that advection and mixing must have been less important in their genesis than local climatic changes. There was a barely significant seasonal rhythm in surface phosphate and nitrate, with peak occurrences of each some 6 months apart. At each latitude the permanent thermal discontinuity centred around a particular isotherm varied little in intensity during the year, but rose and fell in accordance with surface currents. The thermocline south of c. 18�S. varied little in depth but greatly in intensity during the summer. The depth of the mixed layer was much less in summer and at all times shallower in the tropics. The depth of this layer was governed more by the accumulation of surface waters by zonal currents and eddies, than by wind stress or convective overturn. Therefore there was little difference from south to north, or month to month, in average nutrient values of this mixed column. The movement of the various surface waters, deduced from salinity and temperature changes during the year, usually agrees with geostrophic currents across 110�E, and ships' observations of surface currents in the south-east Indian Ocean.

Controlled-Atmosphere Storage of Pork Under Carbon Dioxide

1994 ◽  
Vol 57 (12) ◽  
pp. 1088-1093 ◽  
Author(s):  
R. A. HOLLEY ◽  
P. DELAQUIS ◽  
N. RODRIGUE ◽  
G. DOYON ◽  
J. GAGNON ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Shelf Life ◽  
Weight Ratio ◽  
Storage Period ◽  
Physicochemical Characteristics ◽  
Minor Effect ◽  
Psychrotrophic Bacteria ◽  
Physical Measurements ◽  
A Minor ◽  
Atmosphere Storage

Fresh pork loin slices were packaged under three different anoxic atmospheres (100% N2, 100% CO2 and 50% N2 + 50% CO2) and kept at two storage temperatures (−1°C and 4°C) and two pressures (1.0 and 1.2 atm.) in reusable, gas impermeable metal boxes. A gas headspace to meat weight ratio of >31 per kg was maintained. Carbon dioxide concentrations were unchanged (controlled) during storage. Microbiological, biochemical and physical measurements were made during the 3-week storage period. While atmospheric pressure did not have a significant impact on shelf-life, samples stored at −1°C were satisfactory at 21 days in both CO2 treatments. Samples under N2 did not fare so well, showing higher levels of psychrotrophic bacteria after 18 days at −1°C and 14 days at 4°C. Samples kept in N2 at 4°C were spoiled within 2 weeks. Bacterial growth was slowest under 100% CO2, but samples stored under 50%–50% N2–CO2 at 4°C were also observed to be in good microbiological condition at 21 days of storage. Use of CO2-containing atmospheres provided more than 7 extra days of shelf-life at 4°C over that attainable under 100% N2. Shelf-life at −1°C was improved by 3 to 4 days over that at 4°C. Except for the length of time in storage, treatments had only a minor effect on pH, color, water holding capacity and shear force. These physicochemical characteristics were not factors which limited shelf-life.

History of Zanzibar to 1890

2020 ◽  
Author(s):  
Abdul Sheriff
Keyword(s):  
Indian Ocean ◽  
Industrial Revolution ◽  
East African ◽  
East African Coast ◽  
Swahili Coast ◽  
Cape Of Good Hope ◽  
15Th Century ◽  
The Indian Ocean ◽  
City States ◽  
A Minor

The East African or Swahili coast is at the confluence between the continental world of Africa and the maritime world of the Indian Ocean, giving rise to a cosmopolitan culture. The Zanzibar archipelago is geographically at the center of the East African coast, and was ideally located in terms of the monsoons for trade and social interaction with the African mainland as well as across the Indian Ocean. The first golden age of the Zanzibar archipelago blossomed from the middle of the first millennium ce when transoceanic connections began to be forged between the western seaboards of the Indian Ocean as far as China in the east. It was spearheaded by Unguja Ukuu, followed by a number of ports on Pemba and Unguja, including Kizimkazi with its unique 12th-century Kufic inscription. The Portuguese intervened from the 15th century to monopolize and divert Indian Ocean trade to Europe via the Cape of Good Hope, although they did not succeed. Nevertheless, they disrupted the former patterns of trade and social interactions in the Indian Ocean. After the Portuguese interlude, the Swahili civilization tried to recover its initiative, but it could no longer hold its own. The Swahili city states had to seek assistance from Oman. Zanzibar developed as the seat of a vast commercial empire in the 19th century based on the clove economy on the islands and commerce that extended from the Indian to the Atlantic Ocean, and a vast hinterland that extended as far as the African Great Lakes. It flourished, but it could not withstand the onslaught of the European colonial powers in their scramble for Africa to monopolize its natural resources and markets for their industrial revolution. With the colonial partition of Africa, Zanzibar was reduced to a minor British protectorate by 1890.

Hazy clouds: Making black carbon visible in climate science

2021 ◽  
pp. 135918352199486
Author(s):  
Vasundhara Bhojvaid
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Indian Ocean ◽  
Black Carbon ◽  
Indian Subcontinent ◽  
Climate Science ◽  
Diesel Emissions ◽  
The Indian Ocean

In 1995, a multimillion-dollar experiment – the Indian Ocean Experiment – discovered a dark mass of polluting air hovering above the Indian subcontinent. This mass of air was termed a cloud and found to be composed of a high amount of black carbon that was judged to be the second biggest threat to climate change after carbon-dioxide. In this article, an attempt is made to trace the life of black carbon by documenting its changing forms since the experiment. It emerges that the changing forms allow for the movement of air – smoke from traditional cookstoves and vehicular diesel emissions in India lead to the formation of the cloud – and reveal how an ethnography of air can be undertaken.

scholarly journals Otolith δ18O Composition as a Tracer of Yellowfin Tuna (Thunnus albacares) Origin in the Indian Ocean

Oceans ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 461-476
Author(s):  
Iraide Artetxe-Arrate ◽  
Igaratza Fraile ◽  
Jessica Farley ◽  
Audrey M. Darnaude ◽  
Naomi Clear ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Secondary Ion Mass Spectrometry ◽  
Multinomial Logistic Regression ◽  
Adult Population ◽  
Equatorial Indian Ocean ◽  
Isotopic Signature ◽  
Yellowfin Tuna ◽  
Thunnus Albacares ◽  
The Indian Ocean ◽  
A Minor

Yellowfin tuna of the Indian Ocean is overfished, and a better understanding of the stock structure is needed to enable sustainable management. Here, otolith δ18O values of young-of-the-year fish from known nursery areas of the equatorial Indian Ocean (West, Central and East) were used to establish a reference isotopic signature to predict the origin of sub-adult and adult individuals. Sub-adult tuna otolith δ18O values from Reunion Island were similar to the West nursery signature, but otolith δ18O values of sub-adults from Pakistan were unlike any of the nurseries sampled. Therefore, δ18O values from the Pakistan area samples were considered an additional nursery source for predicting the origin of adult tuna, using a multinomial logistic regression classification method. The western equatorial area was the most productive nursery for three fishing grounds sampled, with a minor contribution of Pakistan-like origin fish. Contribution of Central or East nurseries to the adult population was negligible. One adult otolith was analysed by secondary ion mass spectrometry along the otolith growth transect and results were compared with an isoscape approach to infer lifetime movements. This study is an important first step towards understanding the spatial structure and connectivity of the species.

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