Solar Physics 265 (1/2), 245−256, 2010
Topical issue: "Remote sensing of the innner heliosphere"
© Springer Verlag

Inclusion of in-situ velocity measurements into the UCSD time-dependent tomography to constrain and better-forecast remote-sensing observations

B.V. Jackson, P.P. Hick, M.M. Bisi, J.M. Clover and A. Buffington
Center for Astrophysics and Space Sciences, Univ. of California, San Diego, CA


The University of California, San Diego (UCSD) time-dependent tomography program has been used successfully for a decade to reconstruct and forecast coronal mass ejections from interplanetary scintillation observations. More recently, we have extended this tomography technique to use remote-sensing data from the Solar Mass Ejection Imager (SMEI) on board the Coriolis spacecraft; from the Ootacamund (Ooty) radio telescope in India; and from the European Incoherent SCATter (EISCAT) radar telescopes in northern Scandinavia. In this article we demonstrate how in-situ velocity measurements from space-borne instrumentation are used in addition to remote-sensing data to constrain the time-dependent tomographic solution. Adding this information not only yields a far more accurate and better normalized three-dimensional (3-D) remote-sensing fit to in-situ measurements over time, but it also shows the differences between the remote-sensing observations and in-situ measurements within the volume accessed by the spacecraft. Combining remote-sensing observations and in-situ measurements significantly reduces uncertainty in extending the latter measurements to global 3-D reconstructions that are distant in time and space from the spacecraft measurements. At Earth, this can provide a finely-tuned real-time measurement up to the latest time for which in-situ measurements are available, and allows forecasting beyond this more accurate than remote-sensing observations alone allow.