Monthly values of absolutely measured geomagnetic components (D, I, H, Z, F) of Coimbra observatory in the period1866-2015

Monthly values of the absolutely measured geomagnetic components D, I, H, Z, F for the period 1866-2015 of Coimbra observatory. Different combinations of three magnetic elements were used to fully specify the geomagnetic field vector: the HDI components were measured in 1866-1951; HDZ in 1951-2006; and DIF in 2006-2015. It should also be noted that the monthly values of the first period (1866-1951) are based exclusively on the averages of absolute measurements (made on average 3 per month), while from 1951 onwards the monthly averages were calculated from the hourly averages obtained from the magnetograms after baseline calibration.