Hydrology of low latitude Southern Hemisphere land masses

Hydrobiologia ◽  
1985 ◽  
Vol 125 (1) ◽  
pp. 75-83 ◽  
Author(s):  
W. J. R. Alexander
Keyword(s):  
Southern Hemisphere ◽  
Low Latitude

scholarly journals Quasi-biennial and quasi-triennial oscillations in the growth rates of atmospheric chlorofluorocarbons 11 and 12

MAUSAM ◽  
2022 ◽  
Vol 53 (3) ◽  
pp. 349-358
Author(s):  
R. P. KANE
Keyword(s):  
Southern Hemisphere ◽  
Growth Rates ◽  
Southern Oscillation ◽  
Spectral Characteristics ◽  
Linear Increase ◽  
Transport Processes ◽  
Emission Rates ◽  
Low Latitude ◽  
The Difference ◽  
Prominent Peak

The 12-monthly running means of CFC-11 and CFC-12 were examined for 1977-1992. As observed by earlier workers, during 1977-1988, there was a rapid, almost linear increase of these compounds, ~70% in the northern and ~77% in the southern hemisphere. From 1988 up to 1992, growth rates were slower, more so for CFC-11 in the northern hemisphere. Superposed on this pattern were QBO, QTO (Quasi-Biennial and Quasi-Triennial Oscillations). A spectral analysis of the various series indicated the following. The 50 hPa low latitude zonal wind had one prominent QBO peak at 2.58 years and much smaller peaks at 2.00 (QBO) and 5.1 years. The Southern oscillation index represented by (T-D), Tahiti minus Darwin atmospheric pressure, had a prominent peak at 4.1 years and a smaller peak at 2.31 years. CFC-11 had only one significant peak at 3.7 years in the southern hemisphere, roughly similar to the 4.1 year (T-D) peak. CFC-12 had prominent QBO (2.16-2.33 years) in both the hemispheres and a QTO (3.6 years) in the southern hemisphere. For individual locations, CFC-11 showed barely significant QBO in the range (1.95-3.07 years), while CFC 12 showed strong QBO in the range (1.86-2.38 years). The difference in the spectral characteristics of CFC-11 and CFC 12 time series is attributed to differences in their lifetimes (44 and 180 years), source emission rates and transport processes.

Examination of the 2002 major warming in the southern hemisphere using ground-based and Odin/SMR assimilated data: stratospheric ozone distributions and tropic/mid-latitude exchange

2007 ◽  
Vol 85 (11) ◽  
pp. 1287-1300 ◽  
Author(s):  
H Bencherif ◽  
L El Amraoui ◽  
N Semane ◽  
S Massart ◽  
D Vidyaranya Charyulu ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Southern Hemisphere ◽  
Transport Model ◽  
Stratospheric Ozone ◽  
Three Dimensional ◽  
Polar Vortex ◽  
Low Latitude ◽  
Height Range ◽  
Weather Forecasts ◽  
European Centre

Following an exceptionally active winter, the 2002 Southern Hemisphere (SH) major warming occurred in late September. It was preceded by three minor warming events that occurred in late August and early September, and yielded vortex split and break-down over Antarctica. Ozone (O3 and nitrous oxide (N2O) profiles obtained during that period of time (15 August – 4 October) by the Sub-Millimetre Radiometer (SMR) aboard the Odin satellite are assimilated into MOCAGE (Modélisation Isentrope du transport Mésoéchelle de l'Ozone Stratosphérique par Advection), a global three-dimensional chemistry transport model of Météo-France. The assimilated algorithm is a three-dimensional-FGAT built by the European Centre for Research and Advance Training in Scientific Computation (CERFACS) using the PALM (Projet d'Assimilation par Logiciel Multi-méthode) software. The assimilated O3 and N2O profiles and isentropic distributions are compared to ground-based measurements (LIDAR and balloon-sonde) and to maps of advected potential vorticity (APV). The latter is computed by the MIMOSA (Modélisation Isentrope du transport Mésoéchelle de l'Ozone Stratosphérique par Advection) model, a high-resolution advection transport model, using meteorological fields from the European Centre for Medium-Range Weather Forecasts (ECMWF). It is found that O3 concentrations retrieved by the MOCAGE–PALM assimilation system show a reasonably good agreement in the 20–28 km height range when compared with ground-based profiles. This altitude range corresponds to the intersection between the MOCAGE levels (0–28 km) and SMR O3 retrievals (20–50 km). Moreover, comparison of N2O assimilated fields with MIMOSA APV maps indicates that the dramatic split and subsequent break-down of the polar vortex, as well as the associated mixing of mid- and low-latitude stratospheric air, are well resolved and pictured by MOCAGE–PALM. The present study demonstrates also that the tremendous dynamics and associated polar vortex deformations during the 2002-austral-winter have modified ozone and nitrous oxide distributions not only at the vicinity of the polar vortex, but over topics and subtropics as well. PACS Nos.: 92.60.H–, 92.60.Hd, 92.70.Cp, 92.70.Gt

Low-latitude glacial cooling in the Southern Hemisphere from amino-acid racemization in emu eggshells

Nature ◽  
1997 ◽  
Vol 385 (6613) ◽  
pp. 241-244 ◽  
Author(s):  
Gifford H. Miller ◽  
John W. Magee ◽  
A. J. T. Jull
Keyword(s):  
Amino Acid ◽  
Southern Hemisphere ◽  
Low Latitude ◽  
Amino Acid Racemization

scholarly journals Longitudinal Variations of Noontime Thermospheric Winds in Response to IMF Bz Temporal Oscillations: Broken Mean Circulation and Standing Feature

2020 ◽  
Author(s):  
Kedeng Zhang ◽  
Hui Wang ◽  
Wenbin Wang ◽  
Jing Liu ◽  
Jie Gao
Keyword(s):  
Southern Hemisphere ◽  
Periodic Oscillation ◽  
Meridional Wind ◽  
Field Configuration ◽  
Low Latitude ◽  
Ionosphere Model ◽  
Atmospheric Disturbances ◽  
Longitudinal Variations ◽  
Ionospheric Electric Field ◽  
Mean Circulation

Abstract By using coupled magnetosphere-thermosphere-ionosphere model, we explore the longitudinal/UT differences of the dayside neutral wind in response to the 60 min periodic oscillation of interplanetary magnetic field (IMF) Bz. The southward propagation of the travelling atmospheric disturbances (TADs) in meridional wind stands at about 20º MLat, which is related to the geomagnetic field configuration, neutral temperature and electron density changes. The meridional wind travels continuously from high to low latitude in the western southern hemisphere, while they are broken into pieces in the eastern southern hemisphere. The broken mean circulation is induced by the stronger roles of the ion drag than the pressure gradient. The ion drag shows obvious longitudinal differences associated with the penetration of the ionospheric electric field during the oscillation of IMF Bz.

METEOSAT Water Vapor Channel and a Low-Latitude Vortex

1982 ◽  
Vol 63 (7) ◽  
pp. 747-750
Author(s):  
N. E. Davis
Keyword(s):  
Water Vapor ◽  
Southern Hemisphere ◽  
Cyclonic Circulation ◽  
Low Latitude ◽  
Vapor Channel ◽  
The North ◽  
Low Latitudes ◽  
Upper Level ◽  
Set Up

METEOSAT water-vapor (5.7–7.1 μm) images are used to illustrate the formation of a low-latitude, upper-level vortex over NE Brazil in February 1979. Winds derived from cloud motions over three consecutive half-hourly METEOSAT infrared (10.5–12.5 μm) images show that the basic cause of the development is the disruption of an upper trough penetrating into low latitudes from the north. Cross-equatorial flow is set up and a cyclonic circulation appears in the southern hemisphere.

scholarly journals Perumegabalanus calziai gen. et sp. nov., a new intertidal megabalanine barnacle from the early Miocene of Peru

2019 ◽  
Vol 294 (2) ◽  
pp. 197-212 ◽  
Author(s):  
Giovanni Coletti ◽  
Alberto Collareta ◽  
Giulia Bosio ◽  
Mario Urbina-Schmitt ◽  
John Buckeridge
Keyword(s):  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Intertidal Zone ◽  
New Taxon ◽  
Low Latitude ◽  
Shallow Marine ◽  
Lower Miocene ◽  
Tropical Environments ◽  
Early Diversification ◽  
Marine Nearshore

Living members of the tribe Austromegabalanini are large balanid barnacles (Crustacea: Cirripedia: Neobalanoformes) that live in temperate and cold waters of the Southern Hemisphere. During the Neogene, however, the austromegabalanines also inhabited the Northern Hemisphere, as well as some low- latitude tropical environments. This paper describes a new taxon of austromegab-alanines, Perumegabalanus calziai gen. et sp. nov., from the shallow-marine, nearshore, lower Miocene (19 to 17 Ma, Burdigalian) deposits of the Chilcatay Formation (East Pisco Basin, southern Peru). Among austromegabalanines, this new taxon is characterised by the presence of thick, ornamented, multitubiferous parietes, where the parietal tubes are irregularly partitioned by auxiliary sep - ta; in addition, the sheath is vesicular. Based on morphofunctional considerations, the peculiar shell architecture of P. calziai is here interpreted as well-suited for an existence in the intertidal zone. In the Chilcatay strata, two taxa of Austromegabalanini (i. e., Austromegabalanus carrioli and P. calziai) coexist, representing some of the geologically oldest records of austromegabalanines worldwide – an observation that strongly supports the hypothesis of a circum-equatorial origin and early diversification for this successful lineage of acorn barnacles.

scholarly journals Astrometry and Spectra Classification of Near Earth Asteroids with Lijiang 2.4m Telescope

2017 ◽  
Vol 12 (S330) ◽  
pp. 413-414
Author(s):  
X. L. Zhang ◽  
B. Yang ◽  
J. M. Bai
Keyword(s):  
Sea Level ◽  
Southern Hemisphere ◽  
High Accuracy ◽  
Spectral Classification ◽  
Low Latitude ◽  
Tracking Mode ◽  
Near Earth Asteroids ◽  
Near Earth Objects

AbstractThe Lijiang 2.4m telescope of Yunnan Observatories is located at longitude E100°01′51″, latitude N26°42′32″ and height 3250m above sea level (IAU code O44). Because of low latitude of the site, long-focus system and planetary tracking mode of telescope, high accuracy positioning and spectral classification of the near Earth objects (NEAs) especially in the Southern Hemisphere can be studied with the Lijiang 2.4m telescope. As a set of observational campaigns organized by the GAIA-FUN-SSO, astrometry of several near Earth asteroids including (367943) Duende and (99942) Apophis were made with Lijiang 2.4m telescope during 2013. From December 12, 2015, spectra of three near earth asteroids were also observed with the YFOSC terminal attached to the Lijiang 2.4m telescope. This paper will give the detailed introduction of Lijiaing 2.4m telescope and observational results of near Earth asteroids obtained with it.

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