Lietuvos teritorijos geomagnetinio lauko parametrų ir jų kitimo nustatymas

Abstract

Determination of Earth geomagnetic field parameters and research of their variation is an actual and complex problem of natural science. It is related to knowledge of the state of natural physical system outer parameters of present geophysical and geodynamical processes. Variation of geomagnetic field is continuous process evident in different Earth surface places but in different ways. It can be determined by precise measurements. Precise repeated observations of geomagnetic field parameters at repeat stations is one of basic methods. For determination of certain epoch geomagnetic field parameters, detailed information on geomagnetic field and its variations is necessary. Data of geomagnetic field research is used for solution of different theoretical and practical tasks. Data is important for solving tasks of navigation, geophysics, geodynamics, explorations of minerals. According requirements of NATO and ICAO (International Civil Aviation Organization) – parameters of geomagnetic field are presented on the topographic maps and navigation charts of the air ports. Compass or director is used in geodesy for orientation, when instrument arrow is oriented along lines of geomagnetic field. Information on geomagnetic declination is necessary for direction determination in this case. Value of declination and its annual change is presented on topographical maps. Geomagnetic and gravimetric data are useful for exploration of minerals. Gravity value and geomagnetic induction help us to determine position and depth of minerals. Geomagnetic field data is useful for geodynamic research when Earth crust movements are related to processes going inside of the Earth. For above mentioned activities is necessary an accurate and constantly updated information on geomagnetic field parameters and their secular variations. Determination of geomagnetic field parameters and their variation in time has attracted interest of scientists from many natural and technical fields of science (geophysicists, geologists, surveyors) and resulted in their collaboration during last decades. Geomagnetic field secular variations is a slow natural process therefore quality research results are not available in sufficient quantities, therefore present precise observation results will be valuable for analysis of long-term changes of geomagnetic field. New theoretical and practical research is necessary for precise observations. Research methods should be developed and improved. Geomagnetic field parameters in Lithuania were determined more than 60 years ago. Secular variations of geomagnetic field parameters were not investigated therefore such research is important to be performed.