Interhemispheric Studies

Through AON and PAntOS

Vladimir PapitashviliDepartment of Atmospheric, Oceanic and Space Sciences

University of Michigan

IPY Cluster Project #63Heliosphere Impact on Geospace

Kick-off Workshop, Finnish Meteorological InstituteHelsinki, Finland, 5-9 February 2007

GEOSPACE: Solar Wind and Earth’s Magnetosphere

Courtesy of NASA

Solar Wind and Interplanetary Magnetic Field, Earth’s Magnetosphere, Plasmasphere, and Ionosphere

Complex, Coupled System with the Mass & Energy Transfer

Magnetic conjugacy studies are of general interest because of their implications concerning the processes that electrically couple the magnetosphere and ionosphere. … Four major categorizations seem to occur :

1.clearly conjugate features implying similar topologies and precipitation patterns;

2.conjugate features implying similar topologies, but with distinct differences in precipitation characteristics;

3.features that occur in both hemispheres but at different MLT; and

4.features that appear in only one hemisphere.

J. S. Murphree and J. D. Craven “Evaluation of the High Latitude Magnetic Conjugacy of Auroral Features Based on DE-1 and Viking Data”, AGU Fall Meeting 2001, Abstract #SM32A-0808.

Could Earth’s Polar Regions be Windows to Geospace and to Heliosphere?

What spacecraft can see from geospace?

Jupiter’s Polar Regions

Substorm’s Onset and Theta Aurora in

Opposite Hemispheres: September 18, 2000

Northern Hemisphere• 10-12 MLT • 74-80 degrees• No Theta Aurora

Southern Hemisphere• 11-15 MLT• 80-87 degrees• Theta Aurora

Østgaard et al., GRL, 2003

Substorm Onset in Conjugate Hemispheres

IMAGE Spacecraft Far Ultra Violet Camera &

Wide Imaging Camera

What controls asymmetry of substorm onset locations?

POLAR Spacecraft Visible Imaging System Earth camera

Courtesy of Nikolai Østgaard

All-sky TV data (23:19:30 - 23:23:50 UT, 10 sec interval)September 26, 2003

Exceptionally synchronous discrete auroras over Tjornes (Iceland) and Syowa (Antarctica)over Tjornes (Iceland) and Syowa (Antarctica)

Sato et al., GRL, 2005

What controls the size, shape, and location of conjugate auroral forms?

Polar Caps and Auroral Ovals in Corrected Geomagnetic Coordinates

http://modelweb.gsfc.nasa.gov/models/cgm/North South

with magnetospheric sources added (solid lines)

(dashed lines)

WinterSummer IMF BT = 5 nT

IMF-Dependent Maps of Ground Magnetic Field Perturbations

Papitashvili, V. O., and F. J. Rich, High-latitude ionospheric convection models derived from Defense Meteorological Satellite Program ion drift observations and parameterized by the interplanetary magnetic field strength and direction, J. Geophys. Res., 107, No. A8, 10.1029/2001JA000264, SIA 17(1-13), 2002.

DMSP-based IMF-Dependent Maps of Ionospheric Plasma Convection

http://mist.engin.umich.edu/Northern Summer Southern WinterIMF BT = 5 nT

IMF-Dependent Maps of Field-Aligned Currentshttp://mist.engin.umich.edu

Papitashvili, V. O., F. Christiansen, and T. Neubert, A new model of field-aligned currents derived from high-precision satellite magnetic field data, Geophys. Res. Lett., 29, No. 14, 10.1029/2001GL014207, 2002.

Northern Winter IMF = 5 nT Southern Summer

m R1pc

m + R1

mpc m R1

R1(max)

Φ Φ Φ Φ ΦΦΦ Φ - JJ

DMSP-based Cross-Polar Cap Potential Ratio IMF ~ 0 IMF SouthN. Summer / S. Winter 0.94 0.64S. Summer / N. Winter 0.83 0.88N. Equinox / S. Equinox 0.89 0.90

Cross-polar cap potential drop in the sunlit polar cap is ~15% lower than in the dark cap

Ørsted-based S. Summer S. EquinoxField-Aligned --------------- ---------------Currents Ratio N. Winter N. Equinox Dayside 1.8 1.0Dawn R1/R2 1.5 1.0Dusk R1/R2 1.5 1.0 Nightside 1.0 1.0

R1/R2 field-aligned currents are 1.5 times stronger when they flow in sunlit polar cap

Magnetosphere-Ionosphere Voltage-Current RelationExperiment and Theory

Siscoe et al., JGR, 2002: pc (kV) = 101 21.8 JR1 (MA)

If JR1winter = 1.0 MA & JR1summer = 1.5 MA,

then sum/win = (10133)/(10122) = 68 / 81 = 0.84

MHD-modelled Ionospheric Electrodynamics for the Northern Polar Cap

Ionospheric potentials

Ridley, A. J., The effects of seasonal changes in the ionospheric conductances on magnetospheric field-aligned currents, submitted to Geophys. Res. Letters, October 2006.

Spring Summer Fall Winter

Pedersen conductance

Field-alignedcurrents

MHD-modelled Ionospheric Electrodynamics for the Northern Polar Cap

Cross-polar cap potential

Winter Spring Summer Fall Winter

Maximum of derivedfield-aligned currents

Ridley, A. J., The effects of seasonal changes in the ionospheric conductances on magnetospheric field-aligned currents, submitted to Geophys. Res. Letters, October 2006.

Equinox-Summer = 72 kV

Winter = 83 kV

~15%

Summer = 0.47 A/m2

Equinox-Winter = 0.30 A/m2

~1.6 times stronger

Mapping Magnetopause Reconnection to Conjugate Polar Caps

Northern Winter Solstice for 05 UT

Coleman, I. J., M. Pinnock, and A. S. Rodger, The ionospheric footprint of antiparallel merging regions on the dayside magnetopause, Annales Geophysicae, 18, 511-516, 2000.

Northern Summer Solstice for 17 UT

Note summer merging lines are shorter in length than winter ones

Difference in the merging lines length could be a geometrical effect due to the Earth’s dipole tilt

However, this could be the effect predicted from our sketch for the Hill’s voltage-current relationship

Geomagnetic Conjugacy Greenland West Coast and Eastern Antarctic

P5

P3

P4VOS

Greenland West Coast Magnetometer Chain

~40 CGM meridian (12 stations)

Eastern AntarcticMagnetometer Sites

~40 CGM meridian (6 stations)

65

75

85

60

70

80

BAS LPMs

A81

P2

SPA

P6

P1

SuperDARN Radars and Magnetometers in the Arctic and Antarctic

Existing Planned

NIPR LPM between Syowa & Dome F

U. Michigan LPM test run at South Pole

Syowa

Mission Science Objectives

• Primary What macroscale instability causes substorm onset?

• Secondary How are radiation belt (killer) electrons energized?

• Tertiary Dayside solar wind -magnetosphere coupling processes

THEMIS = Time History of Events and Macroscale Interactions in Substorms

NASA Launch – February 15, 2007

THEMIS – From Geospace to Ground

20 All-Sky Cameras Deployed Across Alaska and Canada

• Onset location and timing relative to boundaries etc.

• Magnetosphere - Ionosphere coupling in substorms

• Auroral signatures of magnetospheric dynamics

• And on and on…

THEMIS and Interhemispheric Conjugacy Studies

THEMIS and Interhemispheric Conjugacy Studies

COMMITTEE ON DESIGNING AN ARCTIC OBSERVING NETWORK

W. Berry Lyons (Chair), The Ohio State University, ColumbusKeith Alverson, Global Ocean Observing System Project Office, IOC/UNESCO,

ParisDavid Barber, Univ. of Manitoba, WinnipegJames G. Bellingham, Monterey Bay Aquarium Research Institute, CaliforniaTerry V. Callaghan, University of Sheffield, UK & Abisko Sci. Res. Station, SwedenLee W. Cooper, University of TennesseeMargo Edwards, University of HawaiiShari Gearheard, Univ. of Western OntarioMolly McCammon, Alaska Ocean Observing System, AnchorageJamie Morison, Polar Science Center, SeattleScott E. Palo, University of Colorado, BoulderAndrey Proshutinsky, Woods Hole Oceano- graphic Institution, MassachusettsLars-Otto Reiersen, Arctic Monitoring and Assessment Programme, Oslo, NorwayVladimir E. Romanovsky, Univ. of AlaskaPeter Schlosser, Lamont-Doherty Earth Observatory, Palisades, New YorkJulienne C. Stroeve, National Snow and Ice Data Center, Boulder, ColoradoCraig Tweedie, University of Texas, El PasoJohn Walsh, University of Alaska, Fairbanks

Out of 18 members, only Scott E. Palo, University of Coloradorepresented STP & Aeronomy

Summary• Observable changes, many of which have regional and global implications, are

underway across the Arctic. • Although the Arctic is not the only region on Earth affected by environmental

change, it … is a region with a limited record of observations … and yet, despite these constraints, rapid and systemic changes have clearly been identified.

• The interconnectedness of physical, biological, chemical, and human components, together with the high amplitude of projected changes, make a compelling argument for an improved observation infrastructure that delivers a coherent set of pan-arctic, long-term, multidisciplinary observations.

• Without such observations, it is very difficult to describe current conditions in the Arctic, let alone understand the changes that are underway or their connections to the rest of the Earth system.

• Without such observations, society’s responses to these ongoing changes and its capability to anticipate, predict, and respond to future changes that affect physical processes, ecosystems, and arctic and global residents are limited.

• This report outlines the potential scope, composition, and implementation strategy for an Arctic Observing Network (AON). Such a network would build on and enhance existing national and international efforts and deliver easily accessible, complete, reliable, timely, long-term, pan-arctic observations.

• The goal is a system that can detect conditions and fundamental variations in the arctic system, provide data that are easily compared and analyzed, and help improve understanding of how the arctic system functions and changes. The network would serve both scientific and operational needs.

Evolution of the Arctic Observing Network

Pan-Antarctic Observations System (PAntOS)