Discussing modifications to Station XML format to accommodate the needs of mobile stations associated with current EarthsScope-Oceans Initiatives

Over the last 5 years, Petrobras has been running the PMBAS-BS project collecting hydroacoustic data allowing them to monitor the sea life near the platform, co-existing with its Exploration and Production operation. PMBAS-BS has so far accumulated a dataset of Sea Glider campaigns and a series of mooring lines with acoustic sensors. This work focused on integrating this dataset into a SeisComp system that allowed the processing of PMBAS-BS data together with data from the Brazilian Seismographic Network (RSBR). The major issue faced by the team is the handling of the metadata. A concept that is widely agreed upon is that seismographic instrumentation operates in Epochs during which some instrumentation parameters are immutable. A different approach is faced inside EarthScope-Oceans initiatives where the acoustic sensors monitoring the oceans associated with the MERMAID platform are moving instrumentation. Such a paradigm is also applicable to ARGO platforms, Sea Gliders, and other ocean monitoring instruments, i.e. they are launched at a certain point over the Earth and constantly change their position with time that has a direct impact since the coordinates of the metadata Station (MERMAID) is rapidly changing with time. When they surface, they collect a new coordinate that is true only for the instant. Supporting this kind of metadata involves understanding the coordinates as sampled data and not epochs, as adopted on land instrumentation. The normal sampling rate of coordinates ranges from a sample per week to a sample per month. Recently the International Federation of Digital Seismograph Networks (FDSN) working group V approved the GeoCSV proposal, as an approach to handle Rapidly Changing Metadata (RCM) in the EarthScope-Oceans environment. While GeoCSV was a simple solution to allow the initial data to be shared inside the FDSN framework, it is viewed as an intermediate step focussed on Metadata capture.  GeoCSV with the RCM will be merged within the current Station XML structure and thereby the RCM will become a subelement of current StationXML and not stored in a separate GeoCSV file. The process of developing this next version of StationXML that incorporates RCM will be closely coordinated with FDSN Working Group II that oversees the SEED format along with Station XML. In this work we intend to present at least one manner that the EarthScope-Oceans consortium believes that the GeoCSV information could be rendered inside the Station XML.