Some ascidians from the southern coast of Madagascar collected during the “AtimoVatae” survey

Zootaxa ◽  
2012 ◽  
Vol 3197 (1) ◽  
pp. 1 ◽  
Author(s):  
FRANÇOISE MONNIOT

Surveys of littoral invertebrates along the southern coast of Madagascar have produced the first study of ascidians in this part of the Indian Ocean. Collections were made by SCUBA divers in May and June 2010 down to 25m depth. This region is considered the southern limit for coral reefs but remains diverse biologically. Upwellings and an abundant plankton community particularly favour the abundance of ascidians in this area. Of the 39 species of non-didemnid species described here, eight are new. Ten species are common to South Africa. Other species were for the most part already known from the Mozambique Channel and a few have also been recorded in the western Pacific (either cosmopolitan or introduced).

2021 ◽  
Vol 58 (2) ◽  
pp. 68-100
Author(s):  
Manbir Singh, Dr. Jasdeep Kaur Dhami

The Indian Ocean woven together by transmission of trade, commands the control of majority of the world’s cargo ships, one third of the worlds cargo traffic and two thirds of total world’s oil shipments. The main aim of this paper is to analyse Real GDP, Imports and Exports of Indian Ocean RIM Association Member Nations. Time period of the study is from 1980 to 2019.  Indian Ocean Rim Association for Regional Cooperation (IOR-ARC) contributes 11.7 per cent share in world exports, in case of member nations highest share is of Singapore 2.1 per cent  followed by India and UAE 1.7 per cent, Australia 1.5 per cent, Thailand and Malaysia 1.3 per cent. Indonesia, South Africa, Bangladesh, Oman, Iran, Islamic Republic of, Sri Lanka the share in world exports is less than 1 per cent.  


1978 ◽  
Vol 13 (2) ◽  
pp. 180-193
Author(s):  
Ruth Lapidoth

The strait of Bab al-Mandeb, “the gate of tears” or “the gate of the wailing yard”, joins the high seas of the Gulf of Aden and the Indian Ocean to those of the Red Sea. The name is primarily used by geographers to designate the narrowest part of the passage, between Ras Bab al-Mandeb on the Asian shore and Ras Siyan in Africa. At this point it is bordered on the east by the Yemen Arab Republic (Northern Yemen) and the People's Democratic Republic of Yemen (Southern Yemen), and in the west by the Republic of Djibouti (formerly the French Territory of the Afars and Issas). About 14 miles farther north, where the Red Sea (or, for that matter, the strait) is nearly 20 miles wide, lies the coast of Ethiopia (the province of Eritrea). All the riparians claim a territorial sea of 12 miles, and the Yemen Arab Republic, as well as the People's Democratic Republic of Yemen, also claim jurisdiction for certain purposes in an additional zone of 6 miles.On the eastern shore of the strait of Bab al-Mandeb lies the peninsula of Ras Bab al-Mandeb, which is about 6–10 km. wide. It consists of rocky, volcanic plains with several hills of 200–300 m. The coast of Ras Bab al-Mandeb is surrounded by coral reefs of a width of up to 1500 m. The border between North Yemen and South Yemen passes down the middle of Ras Bab al-Mandeb.


Coral Reefs ◽  
2020 ◽  
Vol 39 (4) ◽  
pp. 977-988
Author(s):  
A. Ebrahim ◽  
T. S. H. Martin ◽  
P. J. Mumby ◽  
A. D. Olds ◽  
I. R. Tibbetts

2004 ◽  
Vol 22 (11) ◽  
pp. 3899-3916 ◽  
Author(s):  
T. H. Seto ◽  
M. K. Yamamoto ◽  
H. Hashiguchi ◽  
S. Fukao

Abstract. The influence of intraseasonal variation (ISV) on convective activities over Sumatera (or Sumatra) is studied by using data derived from the Equatorial Atmosphere Radar (EAR), the Boundary Layer Radar (BLR), the surface weather station, the Geostationary Meteorological Satellite (GMS), and NCEP/NCAR reanalysis. In June 2002, convective activities over the Indian Ocean, the maritime continent, and the western Pacific were significantly modulated by the ISV. Blackbody brightness temperature observed by GMS (TBB) showed that two super cloud clusters (SCCs) developed over the Indian Ocean (70-90° E) in the first half of June 2002, and propagated eastward from the Indian Ocean to the western Pacific. Convective activities were enhanced over the western Pacific (130-160° E) in the latter half of June 2002. Convergence at 1000hPa, which prevailed over the Indian Ocean in the first half of June 2002, propagated eastward to the western Pacific in the latter half of June 2002. Zonal wind observed by EAR and surface pressure observed at the observation site suggested the existence of a Kelvin-wave-like structure of ISV. From temporal variations of TBB, zonal wind at 850hPa, and vertical shear of horizontal wind between 700 and 150hPa, we classified the observation periods into the inactive phase (1-9 June), active phase (10-19 June), and postwesterly wind burst phase of ISV (20-26 June). During the inactive phase of ISV, convective activities caused by local circulation were prominent over Sumatera. Results of radar observations indicated the dominance of convective rainfall events over the mountainous area of Sumatera during the inactive phase of ISV. During the active phase of the ISV, cloud clusters (CCs), which developed in the convective envelope of SCC with a period of 1-2 days, mainly induced the formation of convective activities over Sumatera. Results of radar observations indicated that both convective and stratiform rainfall events occurred over the mountainous area of Sumatera during the active phase of ISV. In the postwesterly wind burst phase of ISV, convective activities were suppressed over Sumatera. Features of convective activities found over Sumatera generally agreed well with those found in Tropical Ocean and Global Atmosphere/Coupled Ocean-Atmosphere Response Experiment (TOGA COARE). However, local circulation played an important role in the formation of convective activities over Sumatera in the inactive phase of ISV.


2009 ◽  
Vol 22 (2) ◽  
pp. 201-216 ◽  
Author(s):  
Lina Zhang ◽  
Bizheng Wang ◽  
Qingcun Zeng

Abstract The impact of the Madden–Julian oscillation (MJO) on summer rainfall in Southeast China is investigated using the Real-time Multivariate MJO (RMM) index and the observational rainfall data. A marked transition of rainfall patterns from being enhanced to being suppressed is found in Southeast China (east of 105°E and south of 35°N) on intraseasonal time scales as the MJO convective center moves from the Indian Ocean to the western Pacific Ocean. The maximum positive and negative anomalies of regional mean rainfall are in excess of 10% relative to the climatological regional mean. Such different rainfall regimes are associated with the corresponding changes in physical fields such as the western Pacific subtropical high (WPSH), moisture, and vertical motions. When the MJO is mainly over the Indian Ocean, the WPSH shifts farther westward, and the moisture and upward motions in Southeast China are increased. In contrast, when the MJO enters the western Pacific, the WPSH retreats eastward, and the moisture and upward motions in Southeast China are decreased. It is suggested that the MJO may influence summer rainfall in Southeast China through remote and local dynamical mechanisms, which correspond to the rainfall enhancement and suppression, respectively. The remote role is the energy propagation of the Rossby wave forced by the MJO-related heating over the Indian Ocean through the low-level westerly waveguide from the tropical Indian Ocean to Southeast China. The local role is the northward shift of the upward branch of the anomalous meridional circulation when the MJO is over the western Pacific, which causes eastward retreat of the WPSH and suppressed moisture transport toward Southeast China.


1992 ◽  
Vol 45 (3) ◽  
pp. 329-343 ◽  
Author(s):  
Sun Guangqi

Zheng He was the greatest navigator in China's history and he conducted major oceanic voyages, before the western ‘Age of Discovery’, at a time when the Portuguese under Prince Henry were just beginning to feel their way down the coast of Africa. Under the orders of Emperor Yongle and then Emperor Xuande in the Ming Dynasty, Zheng He led a fleet which was the greatest in the world in the fifteenth century and made, in all, seven expeditions to the Western Ocean from 1405 to 1433. His fleet sailed across most of the sea areas of the Western Pacific Ocean and the Indian Ocean, and visited more than thirty Asian and African countries and regions. This paper will mainly discuss the extraordinary achievements of Zheng He's expeditions and their navigational technology, and will also briefly evaluate their role in navigational history.


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