Fast and accurate evaluation of geomagnetic field elements at arbitrary points in space

2020 ◽  
Vol 224 (1) ◽  
pp. 181-190
Author(s):  
Kamen G Ivanov ◽  
Pencho Petrushev
Keyword(s):  
Geomagnetic Field ◽  
Reference Ellipsoid ◽  
Harmonic Series ◽  
Accurate Evaluation ◽  
Spherical Harmonic Series ◽  
North East ◽  
The North ◽  
The Earth ◽  
Solid Spherical Harmonics ◽  
High Degree

SUMMARY An algorithm and software are developed for fast and accurate evaluation of the elements of the geomagnetic field represented in high-degree (>720) solid spherical harmonics at many scattered points in the space above the surface of the Earth. The algorithm is based on representation of the geomagnetic field elements in solid ellipsoidal harmonics and application of tensor product needlets. Open source FORTRAN and MATLAB realizations of this algorithm that rely on data from the Enhanced Magnetic Models 2015, 2017 (EMM2015, EMM2017) have been developed and extensively tested. The capabilities of the software are demonstrated on the example of the north, east and down components of the geomagnetic field as well as the derived horizontal intensity, total intensity, inclination and declination. For the range from −417 m under the Earth reference ellipsoid up to 1000 km above it the FORTRAN and MATLAB versions of the software run 465 and 189 times faster than the respective FORTRAN and MATLAB versions of the software using the standard spherical harmonic series method, while the accuracy is less than 1 nT and the memory (RAM) usage is 9 GB.

scholarly journals North Italy: Welcome to the Tropics!

2021 ◽  
Vol 13 (1) ◽  
pp. 215-218
Author(s):  
Federica Veronese ◽  
Francesca Graziola ◽  
Pamela Farinelli ◽  
Elisa Zavattaro ◽  
Vanessa Tarantino ◽  
...  
Keyword(s):  
High Temperatures ◽  
Climate Changes ◽  
Northern Italy ◽  
Larva Migrans ◽  
Cutaneous Larva Migrans ◽  
North East ◽  
The North ◽  
Caucasian Girl ◽  
The Tropics ◽  
High Degree

We describe a case of cutaneous Larva Migrans in an 8-year-old Caucasian girl. The lesion appeared ten days after a bath in the river in a valley in the north-east of Piedmont. The patient was successfully treated with Albendazole 400 mg daily for 5 days. Autochthonous cases are rare, particularly in northern Italy. Probably the high temperatures and the high degree of humidity favored by the climate changes to which Europe is subjected are favorable to the development of larvae. The diagnosis of cutaneous Larva Migrans should, therefore, be considered also in individuals who have not traveled in geographic areas at risk for the climate.

COMPARISON ESTIMATION OF A POTATOES HYBRIDS IN ECOLOGICAL TEST

1970 ◽  
pp. 25-27
Author(s):  
O. N. Bashlakova ◽  
N. F. Sintsova
Keyword(s):  
Late Blight ◽  
Potato Variety ◽  
Selection Process ◽  
New Potato Variety ◽  
North East ◽  
The North ◽  
Federal Research ◽  
Breeding Station ◽  
Final Yield ◽  
High Degree

The research was carried out in 2017-2019 at the experimental field of the North-east Federal Research Center in the nursery of ecological testing of promising potato hybrids. The aim of the study was to identify hybrids for creating a new potato variety with high early productivity and final yield, attractive appearance of tubers and a high degree of resistance to major potato diseases. As the object of research 8 potato hybrids created at the Falenskaya breeding station — FGBNU FANC of the North-East were used: 27-07 (165-00 x 282-97), 62-08 (9326-2 x Zhukovsky early), 90-09 (194-00 x 45-7-17), 109-11 (183-05 x Dina), 170-08 (Sierra x 93.14-99), 172-11 (59-6-33 x Lazar), 179-10 (Dina x 45-7-17), 455-08 (591m-62 x Dubrava). As a standard was used the Nevsky potato variety zoned in the territory of the Kirov region. The evaluation of potato hybrids was carried out according to the guidelines for the technology of potato selection process: phenological observations, plant productivity on the 65th day from planting, final yield. The numbers 90-09, 170-08 and 179-10 with an early yield of 16.4-17.2 t/ha, an adaptability coefficient higher than 1 and a high degree of resistance to late blight were distinguished by the set of features.

On the computation and approximation of ultra-high-degree spherical harmonic series

2006 ◽  
Vol 81 (9) ◽  
pp. 603-615 ◽  
Author(s):  
Christopher Jekeli ◽  
Jong Ki Lee ◽  
Jay H. Kwon
Keyword(s):  
Spherical Harmonic ◽  
Harmonic Series ◽  
Spherical Harmonic Series ◽  
High Degree

The Day the Earth Shook: The Sumatra–Andaman Earthquake 2004

2013 ◽  
Author(s):  
Mike Searle
Keyword(s):  
Indian Ocean ◽  
Plate Boundary ◽  
Chandler Wobble ◽  
North West ◽  
North East ◽  
The North ◽  
Tilted Surface ◽  
The Earth ◽  
The Indian Ocean ◽  
Length Of The Day

At 00.58 GMT (7.58 local time) on Sunday, 26 December 2004 a massive earthquake occurred off the north-west coast of Sumatra. The earthquake measured between magnitude 9.0 and 9.3 on the Richter scale with its epicentre at 3.32oN, 95.85oE, and occurred at a depth of approximately 30 kilometres. It was the second largest earthquake recorded since instrumental records began and was the deadliest natural disaster in recorded history. The earthquake and the resulting tsunami are estimated to have killed at least 228,000 people across fifteen countries bordering the Indian Ocean. The worst affected countries were Indonesia, Sri Lanka, India, Thailand, Burma, the Maldives, and Somalia. The earthquake occurred on the subduction zone interface between the down-going Indian Ocean plate and the overriding Burma–Andaman–Sumatra plate. It ruptured approximately 1600 kilometres’ length of the plate boundary from Sumatra all the way north to the Burmese coast, travelling at 2–3 kilometres per second. Aftershocks continued unrelentingly for over four months after the earthquake, several reaching magnitude 7.5 as far north as the northern Andaman Islands. The seismic waves indicated a thrust fault earthquake that tilted the surface up to the south-west and down to the north-east. The ground surface was elevated as much as 11 metres at the epicentre, with the tilted surface sinking up to one metre further to the north-east, offshore Sumatra. During the rupture, the Burma plate slipped as much as 15 metres horizontally as the Indian Ocean plate slipped beneath. The force of the quake perceptibly shifted the Earth’s axis, raised sea level globally and speeded Earth’s rotation. It has been suggested that the earthquake shortened the length of the day by 2.68 microseconds, because of the decrease in oblateness of the Earth. The earthquake caused the Earth to wobble on its axis by up to 2.5 cm in the direction of 145o east longitude. The natural ‘Chandler wobble’, a small motion in the Earth’s axis of rotation (the motion that occurs when the spinning object is not a perfect sphere) can be up to 9 metres over 433 days, so this eventually offsets the comparatively minor wobble produced by the earthquake.

IV. Extract of a letter from Mr. William Arderon, F. R. S. to Mr. Henry Baker, F. R. S. containing observations on the precipices or cliffs on the North-East Sea-Coast of the Country of Norfolk

1746 ◽  
Vol 44 (481) ◽  
pp. 275-284
Keyword(s):  
East Sea ◽  
North East ◽  
The North ◽  
The Earth ◽  
Sea Coast

Dear Sir , Since my last, my leisure Hours have been Chiefly employed in visiting and examining many Places where i had Reason to believe I might find some Things curious in the mineral or fossil Kingdom; and I have enjoyed an inexpressible Satisfaction, in observing the great Variety of Subjects that demanded my Attention, and made every Pit or Fracture of the Earth, every Stratum of Sand, or Bed of Clay, every Flint or Pebble, strive, as it were, with each other, in producing something to oblige and reward me for my Trouble.

Intertidal ostracod (Crustacea: Ostracoda) abundance and assemblage structure within and between four shores in north-east England

1999 ◽  
Vol 79 (6) ◽  
pp. 1045-1051 ◽  
Author(s):  
Susan L. Hull
Keyword(s):  
Cluster Analysis ◽  
East Coast ◽  
Tidal Elevation ◽  
North East ◽  
The North ◽  
Significant Difference ◽  
Exposed Shore ◽  
High Degree ◽  
Degree Of Similarity ◽  
Ostracod Species

Triplicate samples of rockpool algae were collected at each of three tidal elevations (upper, mid and low) from four shores on the north-east coast of England. Two moderately exposed (Ravenscar, the exposed shore at Filey Brigg), and two moderately sheltered (Selwicks Bay, the sheltered shore at Filey Brigg) shores were sampled during one week of spring tides during June 1996. A total of 6866 individual ostracods comprising of 26 ostracod species were recovered from the algal samples. Some species showed significant differences in abundance with tidal elevation across the four shores, e.g. Hirschmannia viridis was significantly more abundant in the upper shore pools. Other species, e.g. Heterocythereisalbomaculata, showed no significant difference in abundance either with tidal elevation or between shores. Significant differences in abundance occurred between shores at a given tidal height in some species, e.g. Semicytherura nigrescens was absent from Selwicks Bay but abundant on the remaining shores. Other species had markedly disjunct distributions, e.g. Callistocythere badia only occurred in the exposed upper shore pools at Filey Brigg. Ostracods were significantly less abundant in the low shore pools. Cluster analysis showed that low shore samples had a high degree of similarity between the four shores whereas the upper and mid-shore samples clustered primarily to shore. A two-way ANOSIM indicated that there was a significant difference in assemblage similarity between the four shores and also between the different tidal elevations.

A Minoan shaft-grave in the bank with Hogarth's Tombs (Knossos Survey 16)

1959 ◽  
Vol 53 ◽  
pp. 283-283
Author(s):  
Sinclair Hood
Keyword(s):  
Building Blocks ◽  
The West ◽  
Early Christian ◽  
North East ◽  
The North ◽  
Low Field ◽  
The Earth ◽  
Usual Manner ◽  
East End ◽  
High Bank

What seemed to be the covering slabs of a tomb were noticed by the School's foreman, Manoli Markoyiannakis, exposed in the low field bank which forms the southern continuation of the high bank with the Geometric tombs dug by Hogarth and Payne, a couple of metres north of the path running eastwards across the base of the Kefala ridge past the Hellenic tower (BSA 52 (1957) 244ff.). During the course of the School's excavation of the early Christian building on the neighbouring Sanatorium site in 1953 Dr. N. Platon, Ephor of Antiquities for Crete, kindly gave me permission to examine the slabs, which were found to cover a grave roughly rectangular in shape and measuring 1·60 × 0·70 at the bottom (Fig. 1). The grave's floor was only 1·15 at the west end and 1·60 at the east below the modern surface of the rock; but the surface here must have once stood much higher, and have worn away owing to erosion.The three large slabs over the grave were blocks of dressed limestone. That at the east end (A) had a ‘branch’ sign (L. 0·25, max. W. 0·13), boldly carved with broad shallow V-shaped grooves, on the upper exposed face in the north-east corner (Fig. 1, Plate 66d). The joints between the three slabs were carefully wedged with small stones. In the grave below them was a clean fill of kouskouras, the soft white chalky rock of the area, containing a few nondescript Minoan sherds. The cover slabs with the smaller stones wedged in the joints between them seemed to be in place; but the earth below contained small lumps of rock, as if the grave had been deliberately filled before the cover slabs were laid in position. This agrees with what has been observed in the case of other Minoan shaft-graves in the Gypsades cemetery (see p. 219). At the bottom of the grave were the scanty remains of a skeleton, lying on its back with the knees flexed and originally perhaps raised in the usual manner (see p. 218). Although the cover slabs appeared to be in position, and the grave undisturbed, nothing was found with the skeleton. The grave is, however, like other similar shaft-graves at Knossos, presumably Late Minoan, and perhaps early rather than late in the period. The cover slabs may well be old building blocks, and they and the ‘branch’ sign carved on one of them may therefore be considerably earlier than the grave.

scholarly journals THE USE OF GEOMAGNETIC FIELD MODELS IN MAGNETIC SURVEYS

Geophysics ◽  
1975 ◽  
Vol 40 (4) ◽  
pp. 621-629 ◽  
Author(s):  
Robert D. Regan ◽  
Joseph C. Cain
Keyword(s):  
Numerical Model ◽  
Secular Variation ◽  
Geomagnetic Field ◽  
Harmonic Series ◽  
Magnetic Survey ◽  
Reference Field ◽  
Main Field ◽  
International Geomagnetic Reference Field ◽  
Spherical Harmonic Series ◽  
Geomagnetic Field Models

Global geomagnetic field models, usually computed from spherical harmonic series, are becoming more important in the reduction of magnetic surveys. When used correctly, a numerical model of sufficient complexity, including adequate secular variation correction, provides a suitable representation of the regional field. The best known and most widely used of the available field models is the International Geomagnetic Reference Field (IGRF). However, the IGRF may not be suitable for the reduction of all magnetic survey data because of its imperfect fit to the main field, particularly since 1968.

Sign in / Sign up

Export Citation Format

Share Document