none 10.1190/1.3279792 Society of Exploration Geophysicists Society of Exploration Geophysicists 186 40921506 5981 2025121113255845500 10.1190 2025-12-11T18:26:05Z 2010-01-27T18:02:39Z 21 Geophysics 1942-2156 0016-8033 2010 01 01 2010 75 1 Majid Beiki 1Uppsala University, Department of Earth Sciences, Geophysics, Uppsala, Sweden. E-mail: Majid.Beiki@geo.uu.se; Mehrdad.Bastani@geo.uu.se; Laust.Pedersen@geo.uu.se. Mehrdad Bastani 1Uppsala University, Department of Earth Sciences, Geophysics, Uppsala, Sweden. E-mail: Majid.Beiki@geo.uu.se; Mehrdad.Bastani@geo.uu.se; Laust.Pedersen@geo.uu.se. Laust B. Pedersen 1Uppsala University, Department of Earth Sciences, Geophysics, Uppsala, Sweden. E-mail: Majid.Beiki@geo.uu.se; Mehrdad.Bastani@geo.uu.se; Laust.Pedersen@geo.uu.se. Abstract We introduce a new technique to level aerogeophysical data. Our approach is applicable to flight-line data without any need for tie-line measurements. The technique is based on polynomial fitting of data points in 1D and 2D sliding windows. A polynomial is fitted to data points in a 2D circular window that contains at least three flight lines. Then the same procedure is done inside a 1D window placed at the center of the 2D window. The leveling error is the difference between 1D and 2D polynomial fitted data at the center of the windows. To demonstrate the reliability of the method, it was tested on a synthetic aeromagnetic data set contaminated by some linear artifacts. Using the differential polynomial fitting method, we can remove the linear artifacts from the data. The method then was applied to two real airborne data sets collected in Iran. The leveling errors are removed effectively from the aeromagnetic data using the differential polynomial fitting. In the case of helicopter-towed electromagnetic (HEM) data, the polynomial fitting method is used to level the measured real (in-phase) and imaginary (quadrature) components, as well as the calculated apparent resistivity. The HEM data are sensitive to height variations, so we introduce an average-height scaling method to reduce the height effect before leveling in-phase and quadrature components. The method also is effective in recovering some of the attenuated anomalies. After scaling, the differential polynomial fitting method was applied to the data and effectively removed the remaining line-to-line artifacts. 2010 01 01 2010 01 27 2010 L13 L23 10.1190/1.3279792 https://pubs.geoscienceworld.org/geophysics/article/75/1/L13/261303/Leveling-HEM-and-aeromagnetic-data-using https://pubs.geoscienceworld.org/seg/geophysics/article-pdf/75/1/L13/3219416/gsgpy_75_1_L13.pdf https://pubs.geoscienceworld.org/seg/geophysics/article-pdf/75/1/L13/3219416/gsgpy_75_1_L13.pdf http://geophysics.geoscienceworld.org/cgi/doi/10.1190/1.3279792 Geophysics Bandy 55 885 1990 10.1190/1.1442903 Direct method for determining constant corrections to geophysical survey lines for reducing mis-ties Cheesman 1998 HEMRES2 GX documentation (online Help for the amplitude-altitude resistivity inversion algorithm in Oasis montaj software) Exploration Geophysics Davis 37 355 2006 10.1071/EG06355 Pendulum swing in airborne HEM systems Journal of Geophysical Research Foster 75 1507 1970 10.1029/JB075i008p01507 Statistical estimation of systematic errors at intersections of aeromagnetic survey data Geophysics Fraser 37 518 1972 10.1190/1.1440277 A new multicoil aerial electromagnetic prospecting system Geophysics Huang 73 3 F83 2008 10.1190/1.2836674 Airborne geophysical data leveling based on line-to-line correlations Geophysics Huang 64 378 1999 10.1190/1.1444542 Airborne resistivity data leveling Geophysics Huang 66 148 2001 10.1190/1.1444889 Mapping of the resistivity, susceptibility and permittivity of the earth using a helicopter-borne electromagnetic system AGSO Journal of Australian Geology & Geophysics Luyendyk 17 31 1997 Processing of airborne magnetic data Geophysics Mauring 71 1 L5 2006 10.1190/1.2163912 Leveling aerogeophysical data using a moving differential median filter Journal of Applied Geophysics Siemon 67 206 2009 10.1016/j.jappgeo.2007.11.001 Levelling of helicopter-borne frequency-domain electromagnetic data Exploration Geophysics Valleau 31 584 2000 10.1071/EG00584 HEM data processing — a practical overview Geophysics Yarger 46 1148 1978 10.1190/1.1440884 Diurnal drift removal from aeromagnetic data using least squares