ACE News #8: Inauguration of the ACE Real-Time Solar Wind System

On 21 January 1998 The Real-Time Solar Wind (RTSW) system developed by NOAA's Space Environment Center became operational. These data will be used to assist NOAA in forecasting space weather, including geomagnetic storms. From its location near the L1 point 1.5x10^6 km sunward of Earth, ACE can provide up to an hour warning of solar wind structures including coronal mass ejections. In brief, ACE broadcasts the RTSW data in the low bit rate mode 21 hours per day, and NOAA receives real time data from NASA during the time of the downlink (~3 hours per day). This means that it is possible to have 24 hour per day coverage every day. During the last year NOAA worked with several partners to develop a ground system that could deliver the data continuously. Currently, there are two dedicated ground systems, one at the Communications Research Laboratory in Japan and the other at the Rutherford-Appleton Laboratory in Great Britain. A third partner is NASA, which provides data to NOAA during the science data downlink. The U.S. Air Force is the fourth partner. This network is capable of delivering the necessary coverage most of the time.

Within the RTSW data stream there are raw data from four instruments: MAG, SWEPAM, EPAM, and SIS. The data are received, processed, and placed into operations within 5 minutes of leaving ACE! NOAA has placed this data set on their web page ( as both plots and listings. An example of one of the plots is shown above for the last six hours received while typing this report. This plot displays the magnetic field data from MAG in the top two panels and solar wind data from SWEPAM in the bottom three panels. Also provided are energetic particle data from EPAM and SIS.

The system was inaugurated during a ceremony at NOAA's Boulder, Colorado headquarters that was attended by ~100 members of the scientific community, including officials from NOAA, NASA, the U.S. Air Force, and the Japanese Communications Research Laboratory.

....contributed by Ron Zwickl, NOAA

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Last modified 26 January 1998, mrt
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