Dipole tilt angle effects on the latitude of the cusp and cleft/low-latitude boundary layer

Journal Article · Thu Jun 01 00:00:00 EDT 1989 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JA094iA06p06949· OSTI ID:5830971

Newell, P T; Meng, C I ^[1]

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1. Johns Hopkins Univ., Laurel, MD (USA)

A large data set of approximately 12,000 Defense Meteorological Satellite Program satellite F7 crossings of the cusp or the cleft (i.e., the dayside magnetospheric boundary layer) over a 3-year period is studied for seasonal dependence in latitudinal position. A carefully tested algorithm is used to distinguish the various dayside particle precipitation regions and boundaries. It is found that in the 1,100-1,300 MLT sector, the cusp proper exhibits about {minus}0.06{degree} magnetic latitude (MLAT) shift for each degree increase in dipole tilt angle. Thus the difference between the average summer and winter cusp positions is close to 4{degree} MLAT, approximately symmetric about equinox. For the cleft (magnetospheric boundary layer) the variation is smaller. For example, in the 0700-0900 MLT sector the cleft equatorward boundary shift is {minus} 0.027{degree} MLAT/1{degree} dipole tilt. These results are in general agreement with the predictions of empirical magnetospheric magnetic field models. Various ground-based and low-altitude observations can be systematically affected by the seasonal latitudinal shift herein documented.

• OSTI ID: 5830971
• Journal Information: Journal of Geophysical Research; (USA), Vol. 94:A6; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
POLAR CUSP
LATITUDE EFFECT
ALGORITHMS
BOUNDARY LAYERS
CHARGED-PARTICLE PRECIPITATION
DATA ANALYSIS
EARTH MAGNETOSPHERE
GEOMAGNETIC CONJUGACY
SATELLITES
SEASONAL VARIATIONS
EARTH ATMOSPHERE
GEOGRAPHICAL VARIATIONS
LAYERS
MATHEMATICAL LOGIC
VARIATIONS
640201* - Atmospheric Physics- Auroral
Ionospheric
& Magetospheric Phenomena