Solar cycle, seasonal, and asymmetric dependencies of thermospheric mass density disturbances due to magnetospheric forcing

Abstract. Short-term upper atmosphere variations due to magnetospheric forcing are very complex, and neither well understood nor capably modeled due to limited observations. In this paper, mass density variations from 10 years of GRACE observations (2003–2013) are isolated via the parameterization of annual, local solar time (LST), and solar cycle fluctuations using a principal component analysis (PCA) technique. The resulting residual disturbances are investigated in terms of magnetospheric drivers. The magnitude of high-frequency (δ < 10 d) disturbances reveals unexpected dependencies on the solar cycle, seasonal, and an asymmetric behavior with smaller amplitudes in June in the south polar region (SPR). This seasonal modulation might be related to the Russell–McPherron (RM) effect. Meanwhile, we find a similar pattern, although less pronounced, in the northern and equatorial regions. A possible cause of this latitudinal asymmetry might be the irregular shape of the Earth's magnetic field (with the north dip pole close to Earth's rotation axis, and the south dip pole far from that axis). After accounting for the solar cycle and seasonal dependencies by regression analysis to the magnitude of the high-frequency perturbations, the parameterization in terms of the disturbance geomagnetic storm-time index Dst shows the best correlation, whereas the geomagnetic variation Am index and merging electric field Em are the best predictors in terms of time delay. We test several mass density models, including JB2008, NRLMSISE-00, and TIEGCM, and find that they are unable to completely reproduce the seasonal and solar cycle trends found in this study, and show a clear overestimation of about 100 % during low solar activity periods.

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Solar-cycle, seasonal, and asymmetric dependencies of thermospheric mass density disturbances due to magnetospheric forcing

10.5194/angeo-2019-78 ◽

2019 ◽

Author(s):

Andres Calabia ◽

Shuanggen Jin

Keyword(s):

Principal Component Analysis ◽

Solar Cycle ◽

High Frequency ◽

Mass Density ◽

Principal Component ◽

Component Analysis ◽

Upper Atmosphere ◽

Local Solar Time ◽

Short Term ◽

Solar Time

Abstract. Short-term upper atmosphere variations due to magnetospheric forcing are very complex, and neither well understood nor capably modelled due to limited observations. In this paper, mass density variations from 2003–2013 of GRACE observations are isolated through the parameterization of annual, Local-Solar-Time (LST), and solar-cycle fluctuations using a Principal Component Analysis (PCA) technique and investigated in terms of magnetospheric drivers. The magnitude of high-frequency (

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Heavy minerals in the Wajid Sandstone from Abha-Khamis Mushayt area, southwestern Saudi Arabia: implications on provenance and regional tectonic setting

GeoArabia ◽

10.2113/geoarabia090477 ◽

2004 ◽

Vol 9 (4) ◽

pp. 77-102 ◽

Cited By ~ 3

Author(s):

Mahbub Hussain ◽

Lameed O. Babalola ◽

Mustafa M. Hariri

Keyword(s):

Saudi Arabia ◽

Tectonic Setting ◽

Principal Component ◽

Heavy Mineral ◽

Heavy Minerals ◽

Coarse Grained ◽

Distribution Data ◽

The South ◽

Quartz Content ◽

The North

ABSTRACT The Wajid Sandstone (Ordovician-Permian) as exposed along the road-cut sections of the Abha and Khamis Mushayt areas in southwestern Saudi Arabia, is a mediun to coarse-grained, mineralogically mature quartz arenite with an average quartz content of over 95%. Monocrystalline quartz is the dominant framework grain followed by polycrystalline quartz, feldspar and micas. The non-opaque heavy mineral assemblage of the sandstone is dominated by zircon, tourmaline and rutile (ZTR). Additional heavy minerals, constituting a very minor fraction of the heavies, include epidote, hornblende, and kyanite. Statistical analysis showed significant correlations between zircon, tourmaline, rutile, epidote and hornblende. Principal component R-mode varimax factor analysis of the heavy mineral distribution data shows two strong associations: (1) tourmaline, zircon, rutile, and (2) epidote and hornblende suggesting several likely provenances including igneous, recycled sedimentary and metamorphic rocks. However, an abundance of the ZTR minerals favors a recycled sedimentary source over other possibilities. Mineralogical maturity coupled with characteristic heavy mineral associations, consistent north-directed paleoflow evidence, and the tectonic evolutionary history of the region indicate a provenance south of the study area. The most likely provenances of the lower part (Dibsiyah and Khusayyan members) of the Wajid Sandstone are the Neoproterozoic Afif, Abas, Al-Bayda, Al-Mahfid, and Al-Mukalla terranes, and older recycled sediments of the infra-Cambrian Ghabar Group in Yemen to the south. Because Neoproterozic (650-542 Ma) rocks are not widespread in Somalia, Eritrea and Ethiopia, a significant source further to the south is not likely. The dominance of the ultrastable minerals zircon, tourmaline and rutile and apparent absence of metastable, labile minerals in the heavy mineral suite preclude the exposed arc-derived oceanic terrains of the Arabian Shield in the west and north as a significant contributor of the sandstone. An abundance of finer-grained siliciclastic sequences of the same age in the north, is consistent with a northerly transport direction and the existence of a deeper basin (Tabuk Basin?) to the north. The tectonic and depositional model presented in this paper differs from the existing model that envisages sediment transportation and gradual basin filling from west to east during the Paleozoic.

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Multi-trait Analysis of Agroclimate Variations During the Growing Season in East-Central Poland (1971-2005)

International Agrophysics ◽

10.1515/intag-2015-0021 ◽

2015 ◽

Vol 29 (2) ◽

pp. 213-219 ◽

Cited By ~ 1

Author(s):

Elżbieta Radzka ◽

Katarzyna Rymuza

Keyword(s):

Principal Component Analysis ◽

Air Temperature ◽

Meteorological Data ◽

Principal Component ◽

Growing Season ◽

Component Analysis ◽

The South ◽

East Central ◽

Central Poland ◽

The North

Abstract The work is based on meteorological data recorded by nine stations of the Institute of Meteorology and Water Management located in east-central Poland from 1971 to 2005. The region encompasses the North Podlasian Lowland and the South Podlasian Lowland. Average values of selected agroclimate indicators for the growing season were determined. Moreover, principal component analysis was conducted to indicate elements that exerted the greatest influence on the agroclimate. Also, cluster analysis was carried out to select stations with similar agroclimate. Ward method was used for clustering and the Euclidean distance was applied. Principal component analysis revealed that the agroclimate of east-central Poland was predominantly affected by climatic water balance, number of days of active plant growth, length of the farming period, and the average air temperature during the growing season (Apr-Sept). Based on the analysis, the region of east-central Poland was divided into two groups (areas) with different agroclimatic conditions. The first area comprized the following stations: Szepietowo and Białowieża located in the North Podlasian Lowland and Biała Podlaska situated in the northern part of the South Podlasian Lowland. This area was characterized by shorter farming periods and a lower average air temperature during the growing season. The other group included the remaining stations located in the western part of both the Lowlands which was warmer and where greater water deficits were recorded.

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Antarctic studies of the coupled ionosphere-m agnetosphere system

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1989.0036 ◽

1989 ◽

Vol 328 (1598) ◽

pp. 271-287 ◽

Cited By ~ 13

Keyword(s):

Solar Wind ◽

Polar Region ◽

Experimental Methods ◽

Future Research ◽

The South ◽

Valuable Contribution ◽

Longitudinal Structure ◽

The North ◽

High Latitude Ionosphere ◽

Per Se

The southern polar region offers many significant advantages over its northern counterpart for studies of the interactions of the solar wind, magnetosphere, ionosphere and thermosphere. These mainly arise from the much wider separation of the geographic and geomagnetic poles in the south compared with the north. These displacements lead to hemispheric asymmetries and to considerable longitudinal structure in the high-latitude ionosphere and magnetosphere, which is particularly striking in the south. Examples of these effects are given. In addition, observations of geospace from Antarctica have made a valuable contribution per se . Suitable illustrations are provided from invariant latitude ca . 45° to the invariant pole. Possible areas for future research, and the experimental methods that are likely to be used to overcome the logistical difficulties, are discussed.

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Inverse regional responses to climate change and fishing intensity by the recreational rockfish (Sebastes spp.) fishery in California

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f04-203 ◽

2004 ◽

Vol 61 (12) ◽

pp. 2499-2510 ◽

Cited By ~ 5

Author(s):

William A Bennett ◽

Kimy Roinestad ◽

Laura Rogers-Bennett ◽

Les Kaufman ◽

Deb Wilson-Vandenberg ◽

...

Keyword(s):

Principal Component ◽

Fishing Effort ◽

Interactive Effects ◽

Catch Per Unit Effort ◽

The South ◽

Annual Fish ◽

Ocean Climate ◽

The North ◽

Regional Responses ◽

Over Time

The interactive effects of ocean climate and fishing pressure on nearshore rockfishes (Sebastes spp.) were examined using historical commercial passenger fishing vessel catch records from California. Principal component analysis was used to characterize the dominant patterns in catch per unit effort (CPUE) over time (19571999) and space (10′ latitude × 10′ longitude blocks). Ocean climate explained 60% of the variation in CPUE and revealed opposite responses in northern and southern California. In warm El Niño years, CPUE was 4.2 times higher in the north and 1.8 times lower in the south. CPUE responded similarly to low-frequency climate shifts by increasing in the north and decreasing in the south after 19761977. Four geographic regions responded as discrete units to environmental forcing and fishing intensity: North, Central, South, and Channel Islands. Over time, annual fish landings declined sharply in the South, with fishing effort remaining stationary and high relative to that in the other regions. In the North, landings and fishing effort remained tightly coupled, with effort an order of magnitude lower than in the South. These findings support a management strategy for nearshore rockfishes in California based on regional responses to ocean climate and fishing intensity.

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The Increasing Trend of Black Carbon and Organic Carbon in Jordan During the Period of 2007 to 2018

Nature Environment and Pollution Technology ◽

10.46488/nept.2021.v20i03.004 ◽

2021 ◽

Vol 20 (3) ◽

Author(s):

K. M. Hamasha

Keyword(s):

Organic Carbon ◽

Black Carbon ◽

Mass Concentration ◽

Mass Density ◽

Carbonaceous Aerosol ◽

The South ◽

Surface Mass ◽

The North ◽

Scattering Measurements ◽

Increasing Trend

During the last decades, carbonaceous aerosol extinctions such as black carbon and organic carbon extinctions exhibit an increasing trend across the globe. Measurements of carbonaceous aerosol in Jordan were done using satellite data during the period 2007 to 2018. These measurements were done in four locations of Jordan - Irbid in the north, Amman and Az-Zarqa in the middle, and Ma’an in the south. Black carbon extinction in Jordan increased slightly (slope = 0.0001) during this period, while organic carbon extinction increased slightly (slope = (0.7 – 10) x10-5) in three locations and decreased slightly in one location (Irbid location (slope = -2x10-5)). Organic carbon extinction measurements were greater than black carbon extinction measurements in all locations with varying ratios depending on the location of the measurements. Black carbon and organic carbon scattering measurements have the same behavior as extinction, with larger values in the north and smaller values in the south. Scattering values of organic carbon are larger than black carbon scattering values. Scattering values of organic carbon increased slightly in all locations (slope = 0.0001) while scattering values of black carbon decreased in three locations (Irbid, Amman, and Ma’an) and increased in one location (Az-Zarqa). Column mass density and surface mass concentration measurements show that organic carbon had larger values than black carbon in all locations besides that both organic carbon and black carbon had values decreasing when we go from north to south.

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Time-Latitude Prominence and the Green Corona Distribution Over the Solar Activity Cycle

International Astronomical Union Colloquium ◽

10.1017/s0252921100048132 ◽

1998 ◽

Vol 167 ◽

pp. 484-487 ◽

Cited By ~ 2

Author(s):

M. Minarovjech ◽

M. Rybanský ◽

V. Rušin

Keyword(s):

Solar Activity ◽

Solar Cycle ◽

High Latitude ◽

Activity Cycle ◽

Solar Activity Cycle ◽

North Pole ◽

Latitudinal Distribution ◽

The South ◽

The North

AbstractWe present a distribution of prominences over the solar cycle activity. There are found both polar and equatorial branches of prominences that migrate in opposite directions. Prominences of the high-latitude crown migrate, starting in the minimum of the cycle, towards the poles, which they reach at the maximum of the cycle and then decay. The equatorward-migrating branch of prominences appears also in the minimum of the cycle at mid-latitudes and disappears at the end of the cycle. The distribution of the prominences is compared with a time-latitudinal distribution of the green corona. It is assumed that the polar branches in cycle 23 will reach the poles in 2002 (the north pole) and 2003 (the south one), respectively.

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New constraints on the geometry of the Lac Bouchette gabbro – anorthosite from magnetotellurics and magnetics

Canadian Journal of Earth Sciences ◽

10.1139/e95-110 ◽

1995 ◽

Vol 32 (9) ◽

pp. 1365-1377 ◽

Cited By ~ 6

Author(s):

R. L. Kellett

Keyword(s):

High Frequency ◽

Seismic Reflection ◽

Fault Zones ◽

The South ◽

Grenville Province ◽

Magnetotelluric Soundings ◽

The North ◽

Geophysical Study ◽

Magnetic Modelling ◽

Tectonic Boundaries

A cross section of the resistivity structure through the Lac Bouchette gabbro–anorthosite provides a new image of the thin-skinned geometry of an allochthonous terrane in the western Grenville Province of Canada. Two-dimensional inversion of high-frequency magnetotelluric soundings and magnetic modelling indicate that the gabbro–anorthosite is a 1.5 km thick slice bounded by conductive thrust faults. Graphite, which is present at the margins of the gabbro–anorthosite and in the metasedimentary Réservoir Cabonga terrane to the south, is the most likely source of the enhanced electrical conductivity in the fault zones. The southern margin of the gabbro–anorthosite dips at about 15° to the south beneath the Réservoir Cabonga terrane. The gabbro–anorthosite can be divided into a highly magnetic gabbroic body in the south, a less magnetic metagabbro in the north, and a thin anorthositic lense in the centre. The combination of closely spaced magnetotelluric soundings and magnetic modelling provides independent constraints for gravity and seismic reflection studies in progress. The geometry of the Lac Bouchette gabbro–anorthosite, revealed by this geophysical study, supports a hypothesis that some gabbro–anorthosites behave as competent blocks adjacent to the major tectonic boundaries of the Grenville Province.

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V.—The Inclination of Overfolds in Relation to the Larger Folds in which they are Contained

Geological Magazine ◽

10.1017/s0016756800133965 ◽

1907 ◽

Vol 4 (11) ◽

pp. 506-509 ◽

Cited By ~ 1

Author(s):

George Hickling

Keyword(s):

The South ◽

Tectonic Structure ◽

Great Uncertainty ◽

The North ◽

Apparent Thickness ◽

Region I ◽

Constant Direction ◽

History Of ◽

True Structure ◽

Possible Cause

While spending a few days recently examining the sections on the North Devon coast, with a view to obtaining a clearer conception of the tectonic structure of that region, I was deeply impressed by the great number of minor overfolds and with the great uncertainty in the relations of the various beds thereby brought about. In many cases where the dip appears to be constantly to the south, through a considerable thickness of strata, closer examination shows repeated isoclinal folds. The western face of Little Hangman Hill at Combe Martin exhibits such a condition very well. Throughout the whole coast which I examined, from Combe Martin to the southernmost part of Bideford Bay, the axes of the minor folds are inclined to the north in this way, so as to frequently produce the appearance of steady southern dip and greatly to increase the apparent thickness of the strata. In speculating as to the possible cause of the constant direction in which the axes of these folds are inclined, an explanation occurred to me which I believe to be the correct one, and which may be applied generally to a large number of cases. As I have been unable to find it in the works I have been able to consult, it may be desirable to publish it, since it may aid considerably the elucidation of the true structure and history of complicated districts.

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The evolution of Jupiter polar cyclones

10.5194/egusphere-egu21-16226 ◽

2021 ◽

Author(s):

Alessandro Mura ◽

Christina Plainaki ◽

Giuseppe Sindoni ◽

Alberto Adriani ◽

Davide Grassi ◽

...

Keyword(s):

Polar Region ◽

Infrared Camera ◽

Polar Regions ◽

The South ◽

The North ◽

Rest Position ◽

North Polar ◽

The Stability ◽

Westward Drift ◽

Juno Mission

JIRAM (the Jovian InfraRed Auroral Mapper) is an infrared camera and spectrometer on board Juno. JIRAM operates in the 2-5 &#956;m spectral range and is built to observe both Jupiter's infrared aurora and its atmosphere. Since 2016, JIRAM has performed several observations of the polar regions of the planet, thanks to the unique orbital design of the Juno mission.&#160; In the north polar region, Juno discovered, in 2017, the presence of an eight-cyclone structure around a single polar cyclone; to the south, a polar cyclone is surrounded by five circumpolar cyclones. The stability of these structures has been monitored for almost 4 years. Recent observations, made at the end of 2019, showed that the configuration of the South Pole has temporarily changed: the structure moved in a hexagon for a few months, before returning to its original pentagonal shape. To the north, there are significant hints that the octagonal shape may have been lost for a similar period of time. We find that all cyclones show a very slow, westward drift as a rigid ensemble, and, in addition, they oscillate around their rest position with similar timescales. These oscillations seem to propagate from cyclone to cyclone. The implications of these transient deviations from the symmetrical forms, which appear to be an apparent condition of equilibrium, are discussed.

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