Improvements, extension and perspectives of the Cluster GRMB (Geospace Region and Magnetospheric Boundary identification) dataset

The purpose of the Geospace Region and Magnetospheric Boundary identification (GRMB) dataset is to provide information on the regions crossed by each of the 4 Cluster spacecraft during the entire mission. The dataset includes 15 labels, among which are: plasmasphere, plasmapause transition region (TR), plasmasheet TR, plasmasheet, lobes, polar regions, magnetopause TR, magnetopause, magnetosheath, bow shock TR, and solar wind and foreshock. The 4 remaining labels are: inside the magnetosphere, outside the magnetosphere, unknown, and no available data. This dataset has been delivered in 2024 to the Cluster Science Archive (CSA) covering the years 2001-2022: https://doi.org/10.57780/esa-85c563c.

We present updates and improvements made since this delivery. First, the available dataset publicly available at the CSA has been extended to the year 2023 and it will be extended to the end of the Cluster scientific mission (30 September 2024) by the end of 2026.

Second, a methodology update is addressing 2 aspects of the original dataset. The first one concerns IN/PLS and IN/PPTR labels following the update of the distance plots for C2, C3 and C4 completed during the first phase of the project. The second one concerns the descriptions of following inside labels: IN/PLS, IN/PPTR, IN/PSTR, IN/PSH, IN/LOB, and IN/POL to reduce the number of observations that could match 2 or more label definitions in the original methodology. The updated methodology is compatible with the original one, meaning that the updated dataset is more homogeneous. The outcome of these updates is illustrated with the years 2001-2002, which are reprocessed and delivered to the CSA in February 2026. Years 2001 to 2005 are not reprocessed to get a more precise dataset during the first years of the mission, when data availability and quality are the highest. This reprocessing shall be completed by the end of 2026.

Another important output of this dataset is to highlight the importance to identify the spacecraft location in term of Geospace environments. We therefore also discuss the possibility for the space plasma scientific community to have a normalized definition of the regions to ease multi-missions studies.