Magnetic field gradient tensor time series

<strong>Description of dataset:</strong> CDF dataset contains 4-monthly time series of the magnetic field gradient tensor elements, the secular variation field gradient tensor elements, and their associated error estimates, all provided in a global grid of 300 Geomagnetic Virtual Observatories. <br> GVOs from Swarm satellite data (extending to 2022): SW_OPER_GVOBS_4M_2_20140301T000000_20220301T000000_0202.cdf<br> GVOs from CHAMP satellite data: CH_OPER_GVOBS_4M_2_20010301T000000_20100701T000000_0201.cdf <br> The ReadMe.txt file provides details on the datasets and how these are made, version, changelog. In addition, the script GVOgradient_ex.ipynb provides a simple example of how to load and plot the CDF files in Python. <br> The algorithms used to derive the GVO gradient data products are explained in detail in the reference below. <br> <strong>Reference:</strong> Hammer, M. D, Finlay, C. C, and Olsen, N. (2021) 'Secular Variation Signals in Magnetic Field Gradient Tensor Elements derived from satellite-based Geomagnetic Virtual Observatories', <em>Geophysical Journal International</em>, Vol.229, Issue 3, June 2022, 2096–2114