The physical quantities calculated from HMI filtergrams exhibit small but important systematic errors related to the SDO orbital velocity that show up in line-of-sight (LOS) doppler velocity V LOS…

The National Aeronautics and Space Administration Shared Services Center awarded a $133,088.88 Project Grant to the Association of Universities for Research in Astronomy, Inc. (AURA) under the Science (CFDA 43.001) federal grant program.

The grant funding supports work to address systematic errors in physical quantities calculated from Helioseismic and Magnetic Imager filtergrams aboard the Solar Dynamics Observatory spacecraft. Specifically, AURA will analyze and correct for small but important biases related to the spacecraft's orbital velocity that manifest as errors in reported line-of-sight Doppler velocity, magnetic field strength, and vector field values. Addressing these errors, which include approximately 1% scale errors in velocity and periodic variations in reported magnetic field measurements, will enhance analyses relying on frame-to-frame differences in solar magnetic field properties such as energy and helicity transport. Outcomes are due to the agency by March 31, 2022.

The physical quantities calculated from HMI filtergrams exhibit small but important systematic errors related to the SDO orbital velocity that show up in line-of-sight (LOS) doppler velocity V LOS magnetic field M and the vector field B. Results show a C. 1% not-quite-linear scale error in velocity and somewhat larger 24- and 12-hour periodic variations in reported magnetic field values. Though small they are systematic and hinder some analyses of some solar quantities that depend on frame-to-frame differences in the reported magnetic field such as energy and helicity transport through the…