GEOPHYSICAL ACTIVITY IN 1973

Geophysics ◽  
1974 ◽  
Vol 39 (6) ◽  
pp. 870-886
Keyword(s):  
Far East ◽  
Magnetic Surface ◽  
Western Hemisphere ◽  
Petroleum Exploration ◽  
Eastern Hemisphere ◽  
Surface Work ◽  
Gravity And Magnetic ◽  
Marine Seismic ◽  
Work Up ◽  
Airborne Magnetic

Total worldwide geophysical expenditures soared 16 percent in 1973 to over one billion dollars to continue a 3-year upward trend. This significant increase was due principally to rising expenditures in marine seismic work for petroleum exploration—up 40 percent. Expenditures were up 12 percent for petroleum land seismic work, up 35 percent for gravity and magnetic surface work, and down 27 percent for airborne magnetic work. Miles surveyed were up 14 percent for marine seismic, and up 17 percent for land seismic work. Costs per mile for marine seismic work rose 25 percent to reverse a 5‐year downward trend, but land seismic costs per mile dropped 4 percent. By areas, the Western Hemisphere registered large gains in petroleum seismic work, principally in the U.S. and Canada, while the Eastern Hemisphere dropped slightly with decreases in Europe, Africa, and Australia offsetting gains in Mid‐East and Far East activity.

GEOPHYSICAL ACTIVITY IN 1972

Geophysics ◽  
1974 ◽  
Vol 39 (1) ◽  
pp. 95-109 ◽  
Keyword(s):  
Western Hemisphere ◽  
Petroleum Exploration ◽  
Navigation Systems ◽  
Upward Trend ◽  
Sharp Drop ◽  
Modest Increase ◽  
Eastern Hemisphere ◽  
Marine Seismic ◽  
Work Done ◽  
The U.S

Total worldwide geophysical expenditures increased 3 percent in 1972 to continue an upward trend started in 1971 after a sharp drop in 1970. The modest increase was due principally to rising expenditures in land seismic work for petroleum exploration. Expenditures for petroleum exploration declined for marine seismic work, for airborne surveys, and to a lesser extent for surface gravity/magnetic surveys. However, the total amount of work done—measured in land crew‐months and marine line‐miles—showed little change in 1972. Western Hemisphere work increased significantly in the U.S. and Canada in apparent response to energy shortages. This was offset by declines in Eastern Hemisphere work Of particular note is the continuing 5-year downward trend of marine seismic costs per mile. This can be correlated with the industry’s increasing use of nondynamite methods and improved navigation systems that allow 24 hours/day operations at sea.

GEOPHYSICAL ACTIVITY IN 1956 INTERIM REPORT TO MIDYEAR

Geophysics ◽  
1957 ◽  
Vol 22 (1) ◽  
pp. 104-119
Author(s):  
Homer G. Patrick
Keyword(s):  
World Wide ◽  
Petroleum Industry ◽  
Western Hemisphere ◽  
Interim Report ◽  
Eastern Hemisphere ◽  
Gravity And Magnetic ◽  
Small Decline ◽  
Global Activity

World‐wide activity in geophysical explorations by the petroleum industry, after reaching a record high in 1955, declined by approximately 2 percent in the first six months of 1956. An average of 1098 geophysical crews of all types were employed in the first half of 1956 compared to the 1955 average of 1119 crews. The decline in global activity can be attributed to reductions in the use of the three principal geophysics methods, seismic, gravity and magnetic in the western hemisphere. Increased use of all methods, except magnetic which showed a small decline, was reported in the eastern hemisphere.

Morphological types of spermatheca in Coreidae: bearing on intra-familial classification and tribal-groupings (Hemiptera: Heteroptera)

Zootaxa ◽  
2020 ◽  
Vol 4834 (4) ◽  
pp. 451-501
Author(s):  
DOMINIQUE PLUOT-SIGWALT ◽  
PIERRE MOULET
Keyword(s):  
Western Hemisphere ◽  
Type I ◽  
Type Ii ◽  
Type Iii ◽  
Spermathecal Duct ◽  
Eastern Hemisphere ◽  
Intermediate Part ◽  
Muscular Pump ◽  
Familial Classification

The morphology of the spermatheca is described in 109 species of 86 genera representing all four currently recognised subfamilies of Coreidae, covering the undivided Hydarinae, both tribes of Pseudophloeinae, all three tribes of Meropachyinae and 27 of the 32 tribes of Coreinae. Three types of spermatheca are recognised. Type I is bipartite, consisting only of a simple tube differentiated into distal seminal receptacle and proximal spermathecal duct and lacks the intermediate part present in most Pentatomomorpha, in which it serves as muscular pump. Type II is also bipartite but more elaborate in form with the receptacle generally distinctly wider than the duct. Type III is tripartite, with receptacle, duct and an often complex intermediate part. Four subtypes are recognised within type III. Type I is found only in Hydarinae and type II only in Pseudophloeinae. Type III is found in both Coreinae and Meropachyinae. Subtype IIIA (“Coreus-group”) unites many tribes from the Eastern Hemisphere and only one (Spartocerini) from the Western Hemisphere. Subtypes IIIB (“Nematopus-group”) and IIID (“Anisoscelis-group”) are confined to taxa from the Western Hemisphere and subtype IIIC (“Chariesterus-group”) is found in tribes from both hemispheres. The polarity of several characters of the intermediate part and some of the spermathecal duct is evaluated, suggesting autapomorphies or apomorphies potentially relevant to the classification of Coreidae at the sufamilial and tribal levels. Characters of the intermediate part strongly indicate that the separation of Meropachyinae and Coreinae as currently constituted cannot be substantiated. The tribes Anisoscelini, Colpurini, Daladerini and Hyselonotini are heterogeneous, each exhibiting two subtypes of spermatheca, and probably polyphyletic. Two tribes, Cloresmini and Colpurini, requiring further investigation remain unplaced. This study demonstrates the great importance of characters of the spermatheca, in particular its intermediate part, for research into the phylogeny and taxonomy of Pentatomomorpha. 

scholarly journals Convectively Coupled Equatorial Waves. Part I: Horizontal and Vertical Structures

2007 ◽  
Vol 64 (10) ◽  
pp. 3406-3423 ◽  
Author(s):  
Gui-Ying Yang ◽  
Brian Hoskins ◽  
Julia Slingo
Keyword(s):  
Composite Structures ◽  
Wave Structure ◽  
Wave Theory ◽  
Western Hemisphere ◽  
Equatorial Waves ◽  
Kelvin Wave ◽  
Ambient Flow ◽  
Convectively Coupled Equatorial Waves ◽  
Eastern Hemisphere ◽  
Equatorial Wave

Abstract Multilevel 15-yr ECMWF Re-Analysis (ERA-15) and satellite-observed brightness temperature (Tb) data for the period May–October 1992 are used to examine the horizontal and vertical structures of convectively coupled equatorial waves. Dynamical waves are isolated using a methodology developed previously. Composite structures of convectively coupled equatorial waves are obtained using linear regression/correlation between convection (Tb) and dynamical structures. It is found that the relationship depends on the ambient flow and the nature of the convective coupling, and varies between off-equatorial- and equatorial-centered convection, different hemispheres, and seasons. The Kelvin wave structure in the Western Hemisphere is generally consistent with classic equatorial wave theory and has its convection located in the region of low-level convergence. In the Eastern Hemisphere the Kelvin wave tends to have convection in the region of enhanced lower-tropospheric westerlies and a tilted vertical structure. The Kelvin wave also tends to have a third peak in zonal wind amplitude at 500 hPa and exhibits upward propagation into the lower stratosphere. Lower-tropospheric westward-moving mixed Rossby–gravity (WMRG) and n = 1 Rossby (R1) wave structures and their relationship with convection are consistent with classic equatorial wave theory and the implied lower-tropospheric convergences. In the Eastern Hemisphere the WMRG and R1 waves have first baroclinic mode structures in the vertical. However, in the Western Hemisphere, the R1 wave has a barotropic structure. In the Eastern Hemisphere the R1 wave, like the Kelvin wave, tends to have equatorial convection in the region of enhanced lower-level westerlies, suggesting that enhanced surface energy fluxes associated with these waves may play an important organizing role for equatorial convection in this warm-water hemisphere. In the upper troposphere, eastward-moving Rossby–gravity (EMRG) and n = 1 gravity waves are found in the Eastern Hemisphere, and eastward-moving WMRG and R1 waves are found in the Western Hemisphere, suggestive of Doppler shifting of waves by the ambient flow.

Aschersonia aleyrodis. [Descriptions of Fungi and Bacteria].

1984 ◽  
Author(s):  
B. L. Brady
Keyword(s):  
Costa Rica ◽  
Geographical Distribution ◽  
Solomon Islands ◽  
Western Hemisphere ◽  
Scale Insects ◽  
Infected Host ◽  
Santo Domingo ◽  
Eastern Hemisphere ◽  
Aschersonia Aleyrodis ◽  
The Relationship

Abstract A description is provided for Aschersonia aleyrodis. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Scale insects (Coccidae) and whitefly (Aleyrodidae). GEOGRAPHICAL DISTRIBUTION: Costa Rica, Cuba, India, Jamaica, Santo Domingo, Solomon Islands, USA. According to Mains (1959) A. aleyrodis is very common in the Western hemisphere whereas A. placenta is common in the Eastern hemisphere. DISEASE: When the genus Aschersonia Montagne was described in 1848 the species were regarded as parasites of the leaves of the plants on which the insect hosts were located and it was only in 1894 that Webber recognized A. aleyrodis as entomogenous. Early work and the relationship with the ascomycete genus Hypocrella is extensively treated and illustrated in colour by Petch (1921). Sutton (1980) states that approximately 50 taxa have been described in the genus which is wholly entomogenous. Infection is mainly of young larvae, but mature larvae and pupae are also attacked. Larvae in the early stages of infection become swollen and by the time that hyphae emerge around the edge of the infected host the latter is already dead.

Comparison of Two Models for Prediction of Seismic Streamer State Using the Ensemble Kalman Filter

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Jan Vidar Grindheim ◽  
Inge Revhaug ◽  
Egil Pedersen ◽  
Peder Solheim
Keyword(s):  
Kalman Filter ◽  
Ensemble Kalman Filter ◽  
Petroleum Exploration ◽  
Drift Angle ◽  
Pde Model ◽  
Survey Line ◽  
Position Data ◽  
Position Prediction ◽  
Increasing Demand ◽  
Marine Seismic

Towed marine seismic streamers are extensively utilized for petroleum exploration. With the increasing demand for efficiency, leading to longer and more densely spaced streamers, as well as four-dimensional (4D) surveys and more complicated survey configurations, the demand for optimal streamer steering has increased significantly. Accurate streamer state prediction is one important aspect of efficient streamer steering. In the present study, the ensemble Kalman filter (EnKF) has been used with two different models for data assimilation including parameter estimation followed by position prediction. The data used are processed position data for a seismic streamer at the very start of a survey line with particularly large cable movements due to currents. The first model is a partial differential equation (PDE) model reduced to two-dimensional (2D), solved using a finite difference method (FDM). The second model is based on a path-in-the-water (PIW) model and includes a drift angle. Prediction results using various settings are presented for both models. A variant of the PIW method gives the overall best results for the present data.

The Doors of America Are Worse Than Shut When They Are Half-Way Open

Unwanted ◽  
2020 ◽  
pp. 43-70
Author(s):  
Maddalena Marinari
Keyword(s):  
Common Ground ◽  
Family Reunification ◽  
Western Hemisphere ◽  
Southern Europe ◽  
Immigration Reform ◽  
Quota System ◽  
Immigration Restriction ◽  
Jewish Immigration ◽  
Eastern Hemisphere ◽  
European Immigration

Chapter 2 offers an account of how Italian and Jewish immigration reform advocates, sensing the inevitability of further restriction, pragmatically decided to work with legislators in the early 1920s to mitigate some of the more punitive features of the national origins quota system. When the literacy test passed in 1917 failed to halt immigration from eastern and southern Europe significantly, restrictionists in and outside of Congress began pushing for quantitative immigration restriction. In 1924, Congress passed the Johnson-Reed Act, which imposed the national origins quota system for immigration from the Eastern Hemisphere and a near ban on immigration from Asia. The only issue on which restrictionist legislators and Italian and Jewish anti-restrictionists could find common ground when it came to immigration reform was family reunification, but legislators refused to budge on the discriminatory national quotas imposed on European immigration. Although scholars usually present the 1920s and 1930s as the height of immigration restriction, these negotiations over family reunification, along with the exemption of the Western Hemisphere from the quota system, allowed for exclusion and inclusion to continue to coexist in U.S. immigration policy.

Studies on the origin, evolution and distribution of the Gramineae. I. The tribe Andropogoneae

1958 ◽  
Vol 6 (2) ◽  
pp. 116 ◽  
Author(s):  
W Hartley
Keyword(s):  
Climatic Factors ◽  
Western Hemisphere ◽  
Western India ◽  
High Concentration ◽  
Cytological Evidence ◽  
Origin And Evolution ◽  
Eastern Hemisphere ◽  
Winter Temperatures ◽  
The Tropics ◽  
World Distribution

From a study of the grass flora of some 300 regions, a world distribution map of the grass tribe, Andropogoneae, has been prepared. This map shows that the Indo-Malaysian region is relatively rich in species of the tribe, with zones of high concentration in western India and in southern Indonesia. The relative species density falls off rapidly in passing from the tropical to the temperate zones, and is lower in the western than in the eastern hemisphere. Climatic factors are of major importance in determining the distribution pattern. Winter temperatures are of special significance in temperate regions, while there is a striking relationship between high midsummer rainfall and relative abundance of species of Andropogoneae in the tropics and subtropics. In general, the geographical survey supports conclusions drawn from taxonomic and cytological evidence regarding the origin and evolution of the tribe, but with greater emphasis on climate as a significant factor. The Andropogoneae have had a long evolutionary history in the eastern hemisphere, but have spread more recently to the western hemisphere, where they have not yet attained their full development.

Changes in the 300-mb North Circumpolar Vortex, 1963–2001

2006 ◽  
Vol 19 (12) ◽  
pp. 2984-2994 ◽  
Author(s):  
James K. Angell
Keyword(s):  
El Niño ◽  
El Nino ◽  
Western Hemisphere ◽  
Quasi Biennial Oscillation ◽  
Circumpolar Vortex ◽  
Eastern Hemisphere ◽  
University Of Berlin ◽  
El Chichón ◽  
Vortex Size ◽  
El Chichon

Abstract The mean monthly polar stereographic map analyses of the Free University of Berlin terminated at the end of 2001. This paper summarizes the changes in size of the 300-mb north circumpolar vortex, and quadrants, for the full period of record, 1963–2001, where the size has been defined by planimetering the area poleward of contours in the jet stream core. A contracted vortex has tended to be a deep vortex in winter but a shallow vortex in summer. During 1963–2001 there was a statistically significant decrease in vortex size of 1.5% per decade, the decrease in size of Western Hemisphere quadrants being twice that of Eastern Hemisphere quadrants. A significant increase in Arctic Oscillation (AO) index accompanies the significant decrease in vortex size, but since the vortex contracts appreciably in all four seasons, whereas the positive trend in the AO index is mainly in winter, the vortex cannot serve as a proxy for the AO index. The evidence for vortex contraction at the time of the 1976–77 regime shift is not conclusive, but there is good evidence for a 6% increase in vortex size due to the 1991 Pinatubo eruption. There is little change in vortex size following the 1982 El Chichon eruption, however. Because on average there is a significant 4% contraction of the vortex following an El Niño, it is proposed that the vortex expansion to be expected following the 1982 El Chichon eruption has been contravened by the contraction following the strong 1982–83 El Niño. There is little relation between vortex size and phase of the quasi-biennial oscillation (QBO), and the evidence for a contracted vortex near 11-yr sunspot maxima is tenuous because the vortex record extends through only three full sunspot cycles. There is a highly significant tendency for opposite vortex quadrants 0°–90°E and 90°W–180° to vary in size together, indicating either a pulsating polar vortex or the propagation of planetary wavenumber 2.

scholarly journals Influence of the Arctic Circumpolar Vortex on the Mass Balance of Canadian High Arctic Glaciers

2007 ◽  
Vol 20 (18) ◽  
pp. 4586-4598 ◽  
Author(s):  
Alex S. Gardner ◽  
Martin Sharp
Keyword(s):  
Mass Balance ◽  
Regime Shift ◽  
High Arctic ◽  
Western Hemisphere ◽  
The Arctic ◽  
Glacier Mass Balance ◽  
Canadian High Arctic ◽  
Circumpolar Vortex ◽  
Eastern Hemisphere ◽  
Air Temperatures

Abstract Variability in July mean surface air temperatures from 1963 to 2003 accounted for 62% of the variance in the regional annual glacier mass balance signal for the Canadian High Arctic. A regime shift to more negative regional glacier mass balance occurred between 1986 and 1987, and is linked to a coincident shift from lower to higher mean July air temperatures. Both the interannual changes and the regime shifts in regional glacier mass balance and July air temperatures are related to variations in the position and strength of the July circumpolar vortex. In years when the July vortex is “strong” and its center is located in the Western Hemisphere, positive mass balance anomalies prevail. In contrast, highly negative mass balance anomalies occur when the July circumpolar vortex is either weak or strong without elongation over the Canadian High Arctic, and its center is located in the Eastern Hemisphere. The occurrence of westerly positioned July vortices has decreased by 40% since 1987. The associated shift to a dominantly easterly positioned July vortex was associated with an increased frequency of tropospheric ridging over the Canadian High Arctic, higher surface air temperatures, and more negative regional glacier mass balance.

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