The MANA Magnetometer Array, and Magnetic Observations Across New Zealand From 2024

Abstract This paper describes the Magnetometer Array for New Zealand Aotearoa, or MANA, completed in 2023. The network consists of five new variometer sites to complement the existing Eyrewell geomagnetic observatory. Here, we describe the technical details and capabilities of the network, including the hardware and software used. Data products include the standard 1 s cadence magnetic field time series (and up to 130 Hz upon request), as well as the MANA website used to monitor geomagnetic storms ( https://solartsunamis.otago.ac.nz/mana/data/ ). We also report on observations from the MANA network as an example of the network operating, specifically from the 10–12 May and 10–12 October 2024 geomagnetic storms. The 10–12 May 2024 “Gannon” storm was the largest geomagnetic storm observed in New Zealand since 1994, and hence is of particular interest, with a maximum recorded of 478 nT/min at Awarua and 321 nT/min at Eyrewell (exceeding the previous maximum of 191 nT/min in November 2001). The 10–12 October geomagnetic storm was a smaller event, with more variable magnetic field observations across New Zealand and was the fifth largest since 1994 in terms of . This storm had a maximum recorded of 202 nT/min at Awarua, while simultaneously, a spike of only 40 nT/min was observed at Eyrewell. The local maxima for each of these storms occurred roughly 10 hr after the global maxima. Significant differences between the local H30‐ and global Hpo‐indices indicated that localized phenomena were driving these events, most likely substorms.