Production of Definitive Data from Indonesian Geomagnetic Observatories

Abstract. Measurement of the geomagnetic field in Indonesia is undertaken by the Meteorology, Climatology and Geophysics Agency (BMKG). Routine activities at each observatory include the determination of declination, inclination and total field using absolute and variation measurements. The oldest observatory is Tangerang (TNG), started in 1964, followed by Tuntungan (TUN) in 1980, Tondano (TND) in 1990, Pelabuhan Ratu (PLR) and Kupang (KPG) in 2000 and Jayapura (JAY) in 2012. One of the main obligations of a geomagnetic observatory is to produce final measurements, released as definitive data, for each year and make them widely available both for scientific and non-scientific purposes, for example to the World Data Centre of Geomagnetism (WDC-G). Unfortunately, some Indonesian geomagnetic observatories do not share their data to the WDC and often have difficulty in producing definitive data. In addition, some more basic problems still exist such as low quality data due to man-made or instrumental noise, a lack of data processing knowledge, and limited observer training. In this study, we report on the production of definitive data from Indonesian observatories and some recommendations are provided about how to improve the data quality. These methods and approaches are applicable to other institutes seeking to enhance their data quality and scientific utility for example in main field modelling or space weather monitoring.