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Wide-Latitude Substorm Study - October 1998

Experiment Overview

WLS Events

Diagnostic Data

Millstone Hill Data

Realtime Data

John Foster's Homepage

April 98 (WLS98) Campaign

April 97 WLS Campaign

WLS 98: Hot News

In response to halo CME 1998 October 15. geomagnetic disturbance began promptly on Oct 19, 1998.

AP index heading into the Oct 98 WLS period exhibits 27-day recurrence period indicating good chances for disturbed conditions during the planned campaign

LASCO and EIT observed a halo CME 1998 October 15. Movies and Images.

The ionospheric effects of a sharp reversal in the IMF By component on OCtober 19, 1998 were examined in detail with the Millstone Hill Radar.

A strong disturbance took place during World Day operations on September 25, 1998, exactly one solar rotation prior to the scheduled October 98 WLS campaign. This occurred in response to a strong flare during the recurrent activity interval.

WLS 98: Overview

The Wide-Latitude Substorm Study has been organized by the NSF/UAF community as a research interval directed towards providing distributed observations of ionospheric parameters and electrodynamics through coordinated incoherent scatter radar (ISR) observations during active conditions. This WLS experiment will use a floating operating schedule with the pre-selected (nominal) dates for the campaign October 19-21, 1998.
A very-successful WLS campaign was conducted in April 1997 ( WLS97) and provided extensive observations of a storm sequence which resulted in visible ionospheric effects of the northern US.
Global ISR coverage of this WLS event was very good. Jicamarca, Irkutsk, Kharkov, Arecibo, Sondrestrom, and ESR successfully covered the core period 10/19-21/98 and Millstone Hill operated 10/18-22/98. The EISCAT Tromso radar was down and did not participate.
The October 98 WLS interval started at 20 UT on 10/18/98 in response to a halo CME on 10/15. Activity began shortly after 00 UT on 10/19 and the entire day was quite disturbed (Ap = 52). The regular WLS World Day began at 16 UT on the 19th.
The IMF/SW observed at ACE indicated the effects of a magnetic cloud, with strongly negative and very steady Bz through the 19th. By comparison, the 20th was only moderately disturbed, with a strong substorm taking place near 18 UT.
The regular WLS World Day ended at 16 UT on the 21st. A good NH-viewing POLAR UVI interval followed the scheduled WLS end time and the Millstone Hill and Irkutsk radars extended operations through that period. a well-defined substorm occurred 17UT - 19 UT on 10/21/98.
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Millstone Radar Oct98 Observations

WLS98 Individual Scans
Oct 19th disturbance: variation of Velocity with latitude
Oct 19th disturbance: variation of Ne with latitude
Oct 19th disturbance: variation of Te with latitude
Oct 19th sector boundary: Sharp change in Phi (IMF) @ 14:10 UT from ACE observations.
Oct 19th sector boundary: Sharp change in high-latitude convection and density structure from Millstone observations.
Oct 19th sector boundary: Millstone LOS Velocity @ 12 AZ shows pronounced sector reversal during TX outage ~15:30 UT.
Oct 19th sector boundary: Millstone Density shifts equatorward as sector-dependent convection changes.
Oct WLS zenith data: Ne.
Oct WLS zenith data: Electron Temperature.
Oct WLS zenith data: Upward Velocity.
Oct WLS postion mode: Velocity to the North.
Oct WLS Elevation Scan: Latitude Variation of Ne, Te, N-S Velocity @ 400 km altitude.

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Millstone Radar Individual Scans

Azimuth Scan Density: 21 UT 10/18 - 14 UT 10/19.

Azimuth Scan Density: 14 UT 10/19 - 10 UT 10/20.

Azimuth Scan Density: 10 UT 10/20 - 04 UT 10/21.

Azimuth Scan Density: 10 UT 05/21 - 20 UT 10/21.

Azimuth Scan Velocity: 21 UT 10/18 - 14 UT 10/19.

Azimuth Scan Velocity: 14 UT 10/19 - 10 UT 10/20.

Azimuth Scan Velocity: 10 UT 10/20 - 04 UT 10/21.

Azimuth Scan Velocity: 10 UT 05/21 - 20 UT 10/21.

Elevation Scan Density: 20 UT 10/18 - 14 UT 10/19.

Elevation Scan Density: 14 UT 14/19 - 09 UT 10/20.

Elevation Scan Density: 09 UT 14/20 - 05 UT 10/21.

Elevation Scan Density: 05 UT 14/21 - 20 UT 10/21.

Elevation Scan Electron Temperature: 20 UT 10/18 - 14 UT 10/1.

Elevation Scan Electron Temperature: 14 UT 10/19 - 09 UT 10/20.

Elevation Scan Electron Temperature: 09 UT 14/20 - 05 UT 10/21

Elevation Scan Electron Temperature: 05 UT 14/21 - 20 UT 10/21

Elevation Scan Velocity: 20 UT 10/18 - 14 UT 10/19.

Elevation Scan Velocity: 14 UT 14/19 - 09 UT 10/20.

Elevation Scan Velocity: 09 UT 14/20 - 05 UT 10/21.

Elevation Scan Velocity: 05 UT 14/21 - 20 UT 10/21.

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Diagnostic Data: October 1998 WLS Experiment

Ap Index for interval leading up to Oct98 campaign
IMF from ACE for Oct 98 campaign.
IMF from WIND for Oct 98 campaign.
SW Protons from WIND for Oct 98 campaign.
Ap Index for interval leading up to Oct98 campaign
Oct 19 98: arrival of Solar Wind disturbance with strongly southward Bz.
SW data for 1st complete day of WLS experiment from ACE (10/19/98).
ACE IMF data for for Oct 20 98.
Oct 19 98: intensification of electrojet currents driven by southward Bz (G. Rostoker's CANOPUS page).
Oct 19 98: POLAR UVI images 1207 UT and 0722 UT.
Oct 19 98: Solar wind parameters at disturbance onset ACE IMF.
Oct 19 98: Solar wind parameters at disturbance onset WIND IMF.
Oct 19 98: Solar wind parameters at disturbance onset WIND Protons.
Oct 19 98: Substorm intensification at Sodankyla early on 10/19 UT.

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Substorm Events during the 1998 WLS Campaign

Substorm at ~18UT October 20, 1998
- Oct 20 98: Substorm intensification near 18:00 UT seen at Sodankyla.
- Oct 20 98: Substorm signature in Northward turning of WIND IMF Bz near 18:00 UT.
- Oct 20 98: Substorm signature in Millstone Hill position-mode data at 15 EL.
- Oct 20 98: Substorm signature in Millstone Hill position-mode data at 60 EL.
- Oct 20 98: Millstone azscan observed enhanced convection near noon during 18 UT substorm.
- Oct 20 98: Sondrestrom Radar enhanced convection velocities during 18 UT substorm.
- Oct 20 98: Irkutsk Radar enhanced ion temperature during 18 UT substorm.
Substorm at ~18UT October 21, 1998
- Oct 21 98: POLAR UVI images of substorm onset (16:55 UT - 18:13 UT) and substorm decay (17:51 UT - 19:02 UT) on 21 Oct 98.
- Oct 21 98: Millstone azscan observed enhanced convection near noon
- Oct 21 98: Sondrestrom Radar enhanced convection velocities.
- Oct 21 98: Sondrestrom Radar velocities @ 2 latitudes
- Oct 21 98: WIND IMF parameters near substorm onset.
- Oct 21 98: WIND SWE protons.

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September 25, 1998 Disturbance

Sep 25 98: Strong disturbance with Kp=9 occurs in response to solar disturbance during recurrent-activity interval one month prior to planned campaign.
Sep 25 98: Global auroral activity follows onset near 02 UT.
Sep 25 98: Millstone Local density and electron temperature indicate the rapid formation of a deep ionospheric trough at the latitude of intense convection > 1500 m/s.
Sep 25 98: Solar Wind Disturbance is associated with a dropout of ACE SW plasma detector (comparison with WIND observations indicates dropout at the time of high-speed stream arrival).
Sep 25 98: IMF disturbance included increase in |B| and fluctuating Bz.
Interplanetary data from ACE for recent MLTCS experiment
Recent daytime ionogram from the Millstone site

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Real-Time Data Plots

Realtime data for the Oct98 WLS experiment are availble through this site and through a separate Real-Time Prediction page incorporating several useful links to real-time data spources. The Millstone Hill Madrigal database features Realtime Data from MHO Radar.

Millstone Radar Local F-Region Measurements
Latest Millstone elevation scan data
Latest Millstone azimuth scan data
Latest Millstone digisonde data
Real-time solar wind/IMF data from ACE through NOAA/SEC server
Real-time SuperDARN Convection Pattern
Canadian Magnetometer data from CANOPUS Chain
Latest Magnetometer data from Sodankyla
Current RT auroral image from POLAR UVI
Current RT auroral image from POLAR VIS
Current Month's Dst Index

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http://www.haystack.edu/~jcf/oct98.htm -- Revised: May 21, 1999.jcf@haystack.mit.edu