Monthly Archives: August 2014

26. SDO/HMI Multi-height Dopplergrams

Contributed by Kaori Nagashima. Posted on August 15, 2014

Multi-height Doppler velocity maps from two layers separated by 50 km are obtained from combinations of currently recorded HMI filtergrams. Using synthetic data of spectral line profiles produced in a convective environment, we test the ability to recover vertical velocity fields at different heights.

25. Solar Flare Forecasting Using HMI Vector Magnetic Field Data with a Support Vector Machine Algorithm

Contributed by Sebastien Couvidat. Posted on August 11, 2014

We attempt to forecast M- and X-class solar flares using a support vector machine algorithm and 4 years of HMI vector magnetic field data. With the true skill statistic as the preferred metric to estimate the algorithm performances, we obtain good predictive abilities. This may be partly due to fine-tuning the algorithm for this purpose, and to a choice of 13 SHARP parameters obtained from vector magnetograms.