A New Blocking Index and Its Application: Blocking Action in the Northern Hemisphere

2006 ◽  
Vol 19 (19) ◽  
pp. 4819-4839 ◽  
Author(s):  
Yina Diao ◽  
Jianping Li ◽  
Dehai Luo
Keyword(s):  
The Other ◽  
Two Dimensional ◽  
Atlantic Sector ◽  
The North ◽  
North Side ◽  
The Pacific ◽  
Different Seasons ◽  
Action Center ◽  
Blocking Event ◽  
Blocking Index

Abstract In this paper, a new two-dimensional blocking index is proposed by defining a difference between the daily 500-hPa geopotenial heights at the reference latitude and its north side. The reference latitude is determined by a composite latitude-dependent 500-hPa geopotenial height of blocking events in different seasons and sectors. The new index can take account of the duration, intensity, propagation, and spatial structure of a blocking event. Using this index, the characteristics (frequency, duration, intensity, and preferred occurrence region) of the blocking action in the North Hemisphere (NH) are investigated using a 42-yr sample of blocking events from the NCEP–NCAR reanalyses. It is found that blocking events in the NH are more frequent in the Atlantic–Europe sector than in the Pacific sector in winter and spring and autumn, but more persistent in the Atlantic–Europe sector than in the Pacific sector for all seasons. Blocking events in the Pacific sector tend to have larger amplitudes than the Atlantic counterparts. In addition, it is shown that in the NH independently occurring blocking events are most frequent, but simultaneously occurring blockings are rather rare, indicating that the blocking events in the NH should be a local phenomenon. On the other hand, a comparison with the existing indices [e.g., Tibaldi and Molteni (TM) index] indicates that in summer and autumn the new index shows similar longitudinal dependency of NH blocking events as does the TM index, but it shows two distinct action centers of blocking events in the Atlantic sector in winter and spring (in which the most frequent one is situated more westward) and an eastward blocking action center in the Pacific sector in spring and autumn, compared to the TM index. In addition, it is found that the new blocking index proposed here shows relatively low blocking frequency for all seasons compared to the TM index, especially in the Atlantic sector in spring and in the Pacific sector in winter and spring, which seems to be in agreement with the result obtained by Pelly and Hoskins using the PV–θ index.

scholarly journals Observations upon the marine barometer, made during the examina­tion of the coasts of New Holland and New Wales, in the Years 1801, 1802, and 1803. By Matthew Flinders, Esq. Com­mander of His Majesty’s Ship Investigator . In a letter to the Right Hon. Sir Joseph Banks, K. B. P. R. S. &c. &c. &c

1832 ◽  
Vol 1 ◽  
pp. 230-232
Keyword(s):  
The State ◽  
The Other ◽  
South Coast ◽  
The South ◽  
South Side ◽  
The North ◽  
North Side ◽  
Northern Half ◽  
Southern Half ◽  
The Right

The chief circumstance that induced Capt. Flinders to think his observations Upon the marine barometer were worthy of attention, was the coincidence that took place between the rising and falling of the mercury, and the setting in of winds that blew from the sea and from off the land, to which there seemed to be at least as much reference as to the strength of the wind or the state of the atmosphere. Our author’s examination of the coasts of New Holland and the other parts of the Terra Australis, began at Cape Leuwen, and con­tinued eastward along the south coast. His observations, which, on account of their length, we must pass over, show, that a change of wind from the northern half of the compass to any point in the southern half, caused the mercury to rise; and that a contrary change caused it to fall. Also, that the mercury stood considerably higher When the wind came from the south side of east and west, than when, in similar weather, it came from the north side.

Thermally Driven and Eddy-Driven Jet Variability in Reanalysis

2012 ◽  
Vol 25 (5) ◽  
pp. 1587-1596 ◽  
Author(s):  
Camille Li ◽  
Justin J. Wettstein
Keyword(s):  
Zonal Wind ◽  
Momentum Flux ◽  
Hadley Circulation ◽  
Atlantic Sector ◽  
Wind Variability ◽  
The North ◽  
The Pacific ◽  
Thermally Driven ◽  
Jet Variability ◽  
The North Atlantic Oscillation

Two important dynamical processes influence the extratropical zonal wind field: angular momentum transport by the thermally direct Hadley circulation (thermal-driving T) and momentum flux convergence by atmospheric waves (eddies) that develop in regions of enhanced baroclinicity (eddy-driving E). The relationship between extratropical zonal wind variability and these driving processes is investigated using 40-yr European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-40) data. Indices representing the processes (iT and iE) are defined based on vertically integrated diabatic heating and meridional convergence of the meridional flux of zonal momentum by eddies, respectively. Zonal wind signatures associated with these indices are identified via composite analysis. In the Atlantic sector, zonal wind variability is mainly associated with momentum flux convergence by baroclinic eddies, supporting the established view that the Atlantic jet is primarily eddy driven. In the Pacific sector, zonal wind variability is associated with both driving processes, evidence that the Pacific jet is both thermally driven and eddy driven. The thermally driven Pacific signature reflects changes in jet strength (intensity and longitudinal extent) with some resemblance to the zonal wind anomalies of the Pacific–North America (PNA) pattern. The eddy-driven signature reflects a latitudinal shift of the jet exit region in both sectors that resembles the zonal wind anomalies of the North Atlantic Oscillation (NAO) or West Pacific (WP) patterns.

scholarly journals STUDENT PREPAREDNESS TOWARD MOUNT MERAPI ERUPTION IN SD NEGERI LENCOH IN SELO SUB DISTRICT

GeoEco ◽  
2018 ◽  
Vol 4 (2) ◽  
pp. 127
Author(s):  
Ratih Puspita dewi
Keyword(s):  
Data Collection ◽  
Elementary Students ◽  
Sampling Technique ◽  
The Other ◽  
High Grade ◽  
Public Places ◽  
Student Preparedness ◽  
The North ◽  
North Side ◽  
Data Collection Technique

<p><em>Schools are one of vulnerable public places in case of disaster phenomenon. On the other side, school is a place where the children spend most of their time. It is possible that volcanic eruption occur while children study at school. Selo is one of the sub district of Boyolali district  that located on the north side of Mount Merapi, its location is quite close to the peak of Mount Merapi, it is makes Selo is prone to be affected by Mount Merapi eruption. The aim of this research was to determine the level of student preparedness toward Mount Merapi eruption in SD Negeri Lencoh. The method used in this research was descriptive qualitative. The population in this research were elementary students in the high grade with consideration that student in the high grade were better in understanding to fill out the questionnaire. The sampling technique was purposive sampling technique. The data collection technique was using questionnaire developed by LIPI. The result of this research  was the value of student preparedness level in SD Negeri Lencoh  which was 52.1 so it was conlude as less ready. </em></p>

scholarly journals On the Origin of Planetary-Scale Extratropical Winter Circulation Regimes

2010 ◽  
Vol 67 (5) ◽  
pp. 1382-1401 ◽  
Author(s):  
A. Hannachi
Keyword(s):  
State Space ◽  
North Atlantic ◽  
Clustering Algorithm ◽  
Simultaneous Occurrence ◽  
Atlantic Sector ◽  
Planetary Scale ◽  
The North ◽  
The Pacific ◽  
Winter Circulation ◽  
The Relationship

Abstract Sectorial and planetary-scale winter circulation regimes are studied and the relationship between them is investigated in order to find how much the simultaneous occurrence of sectorial regimes contributes to the occurrence of hemispheric regimes. The strategy is based on the multivariate Gaussian mixture model. The number of components in the model is estimated using two approaches. The first one is based on arguments from order statistics of the mixture proportions and the second uses a more severe test based on reproducibility. The procedure is applied next to the 500-hPa height field over the North Pacific, the North Atlantic, and the Northern Hemisphere using the empirical orthogonal function state space. Two highly significant regimes are found in each case, namely, the Pacific–North America (pattern) (±PNA)–North Atlantic Oscillation (±NAO) for the hemisphere—±PNA for the Pacific sector and ±NAO for the Atlantic sector. The sectorial regimes reflect mainly blocking and no-blocking flows. The results are tested further by applying a spatial clustering algorithm and are found to be consistent, particularly along the regime axes in the system state space. The relationship between hemispheric and sectorial circulation regimes is investigated. The data in each sector are first classified and then the times of simultaneous occurrence of sectorial regimes are identified. A new hemispheric dataset is then obtained by discarding maps corresponding to those co-occurrence times, and a new regime analysis is conducted. The results show that the hemispheric regime behavior has significantly decreased, suggesting that synchronization between sectorial circulation regimes could play an important role in the occurrence of planetary circulation regimes. The interannual variability of regime events is also discussed.

Pacific Slope Cretaceous bivalves: eight venerid species

1993 ◽  
Vol 67 (6) ◽  
pp. 965-979 ◽  
Author(s):  
L. R. Saul
Keyword(s):  
New Species ◽  
North America ◽  
Southern California ◽  
New Genus ◽  
Baja California ◽  
The Other ◽  
New Genera ◽  
The North ◽  
The Pacific ◽  
Pacific Slope

Four new venerid species from the Cretaceous of the North American Pacific Slope are described and four previously described species are reassigned. Of the new species, two are allotted to new genera: Rhaiphiale based upon Rhaiphiale pharota n. sp. and Egrona based upon Egrona fallax n. sp., both Turonian in age and from southern California. The other new species are Loxo quintense n. sp., of late Maastrichtian age from California, and Paraesa cedrina n. sp., late Albian in age from Baja California, Mexico. The previously described species “Meretrix” arata Gabb, 1864, Turonian, and “?Meretrix” fragilis Gabb, 1869, late Maastrichtian, are placed in the new genus Callistalox; “Meretrix” lens (Gabb, 1864), Campanian age, and Flaventia zeta Popenoe, 1937, Turonian, are provisionally assigned to Paraesa Casey, 1952. This is the first identification of Paraesa from the Pacific Slope of North America. No species of Flaventia Jukes-Brown, 1908, is now known in Pacific Slope faunas.

scholarly journals The Fishes collected by the “Huxley” from the North Side of the Bay of Biscay in August, 1906

1907 ◽  
Vol 8 (1) ◽  
pp. 1-5
Author(s):  
L. W Byrne
Keyword(s):  
The Other ◽  
Bay Of Biscay ◽  
East Atlantic ◽  
North East ◽  
The North ◽  
North Side

Only one species met with on this cruise appears to have been previously undescribed.Although all the other species were already known from similar localities in the North-east Atlantic, attention may be called to an interesting series of the young of Synaphobranchus pinnatus and to the capture of numerous young examples of Onus biscayensis.When compared with the results of the hauls taken by H.M.S. Research, a little farther south and over very much deeper soundings, the list of species taken by the Huxley is chiefly remarkable for the entire absence of Stomias boa, Gonostoma microdon, and G. bathyphilum, the range of none of which seems to extend into waters as shallow as those fished by the Huxley.

scholarly journals I. A Letter from John Gage, Esq. F.R.S., Director, to Hudson Gurney, Esq. F.R.S. V.P. &c. containing an account of further discoveries of Roman sepulchral relics at the Bartlow Hills

Archaeologia ◽  
1839 ◽  
Vol 28 (1) ◽  
pp. 1-6 ◽  
Author(s):  
John Gage
Keyword(s):  
The Other ◽  
The South ◽  
The North ◽  
North Side ◽  
The Hill

Lord Maynard having directed a further excavation to be made at the Bartlow hills, a gallery was commenced early in April last on the north side of the south barrow. This hill, according to the plan, is about thirty-five feet high, the diameter having been computed at ninety feet, but it exceeds a hundred. The gallery was constructed in the same manner as that opened in 1835 in the largest barrow, and had reached the centre of the hill on the 16th April, upon which day I inspected it in company with Lord Braybrooke and the Honourable Captain Percy. It extended fifty-two feet, and we observed that the tumulus was formed, like the largest barrow, of earth and chalk, in horizontal strata. Our arrival took place shortly after the workmen had broken in upon a hollow, where we gladly anticipated the finding a sepulchral deposit, appearances heing much the same as those observed on first opening the cavity in the centre of the other barrow.

scholarly journals The chain tower in Kyrenia’s harbour, Cyprus

X ◽  
2020 ◽  
Author(s):  
Alessandro Camiz ◽  
Marika Griffo ◽  
Seda Baydur ◽  
Emilia Valletta
Keyword(s):  
Middle Ages ◽  
Structure From Motion ◽  
Eastern Mediterranean ◽  
Historical Research ◽  
The Other ◽  
The North ◽  
Golden Horn ◽  
North Side ◽  
A Chain ◽  
The City

In the Middle Ages a chain suspended between two towers defended the entrance of Kyrenia’s little harbour, like the chain across the Golden Horn in Constantinople. William de Oldenburg, who visited Cyprus in 1211 during the reign of King Hugh I, referred to Kyrenia as “a small town well-fortified, which has a castle with walls and towers”. He perceived the chain tower as part of Kyrenia’s fortification system in that time. The Byzantines had already fortified the city, but in the thirteenth century, during the Longobard war, before the siege of the city, Frederick II’s party, under the direction of Captain Philippo Genardo, improved the defences of the city. The chain tower is still visible today in the north side of the old Kyrenia harbour. It consists of an 8,15 m diameter cylindrical tower and a 1,5 m diameter pillar on top of it. The tower was supporting a chain attached on the other side to another structure. The fortifications on the north side terminated against the harbour in a square tower or bastion holding the chain to be raised and lowered by means of a windlass. The paper includes the digital photogrammetric survey of the chain tower using a structure from motion software, the historical research and the comparison with other coeval harbour defence constructions of the eastern Mediterranean.

Crustal structure of the hawaiian ridge near gardner pinnacles

1960 ◽  
Vol 50 (4) ◽  
pp. 563-573
Author(s):  
George G. Shor
Keyword(s):  
Crustal Structure ◽  
Seismic Refraction ◽  
Pacific Basin ◽  
The North ◽  
North Side ◽  
The Pacific ◽  
Oceanic Sediments ◽  
Hawaiian Ridge ◽  
Volcanic Islands ◽  
Mohorovičić Discontinuity

ABSTRACT A series of seismic refraction profiles has been made across a flat bank at Gardner Pinnacles (a pair of volcanic islets on the western Hawaiian Ridge) down the side of the ridge and across the adjacent deep to the floor of the Pacific basin. The ridge is composed principally of material with velocities typical of volcanic islands. The high-velocity oceanic crust, found in the oceanic areas adjacent, extends beneath the ridge and up into the center of the rise. The total crustal section is thickened and the Mohorovičić discontinuity depressed beneath the deep as well as beneath the ridge. The smooth “archipelagic apron” on the north side of the ridge has at most 20 meters of sediment over a layer with a velocity of 3 km/sec, which could be volcanic and is definitely of higher velocity than normal oceanic sediments.

A Russian Visit to the Spanish Franciscans in California, 1836

1953 ◽  
Vol 9 (4) ◽  
pp. 453-458
Author(s):  
George O. Schanzer
Keyword(s):  
Cold War ◽  
Pacific Coast ◽  
Common Knowledge ◽  
The Other ◽  
Early Nineteenth Century ◽  
Spanish Speaking ◽  
The North ◽  
The Pacific ◽  
History Of ◽  
The Military

The History of the Early contacts between the Russians and the Spanish-speaking people in this hemisphere remains to be written. A few of these meetings are common knowledge. Miranda’s visit to the Russia of Catherine the Great has been treated frequently; Concepción de Argüello’s tragic love for the Russian Rezanov became a traditional theme. Obviously, in California, where the two civilizations met, contacts were numerous. With very few exceptions they were reported as incidents of friction. Bancroft’s History of California (XIX, Chapters 4, 14 and 28) and Engelhardt’s The Missions and Missionaries of California convey the impression that the Russians were aware of the military weakness of the Spanish outposts and that the Spanish, later Mexican, leaders were generally apprehensive of the designs of their neighbors to the North. On the other hand, the friendly reception accorded by the Spanish Franciscans to Rezanov’s companion, Langsdorff, and the latter’s favorable comments on the friars’ achievements are known. Another instance of peaceful relations whose record somewhat belies the concept of an early nineteenth-century “cold war” on the Pacific coast is almost unknown.

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