Emardson R.,SP Technical Research Institute of Sweden |
Jarlemark P.,SP Technical Research Institute of Sweden |
Jarlemark P.,Chalmers University of Technology |
Johansson J.,SP Technical Research Institute of Sweden |
Radio Science | Year: 2013
Traveling ionospheric disturbances (TIDs) appear as medium-scale TIDs at midlatitudes and as polar cap patches at high latitudes. Both can have a negative impact on Global Navigation Satellite Systems (GNSS) measurements, although the amplitude is of tenths of a total electron content unit (TECU), 1 TECU = 1016 el m-2. Due to their spatial extension, they affect GNSS measurements using receivers separated with distances up to ∼1000 km. We present statistical measures of the ionospheric spatial variability as functions of time in solar cycle, annual season, and time of day for different geographical locations in Europe. In order to perform this spatial characterization of the ionosphere, we have used archived GPS data from a 13 year period, 1999-2011, covering a complete solar cycle. We find that the ionospheric spatial variability is larger for the northern areas than for the southern areas. This is especially pronounced at solar maximum. For the more northern areas, the ionospheric variability is greater during nighttime than during daytime, while for central Europe, the variability is larger during daytime. At solar maximum, the variability is larger during the months October and November and smaller in June and July. Key Points We present statistical measures of ionospheric spatial variability over Europe The variability is larger for northern areas than for southern areas Nighttime effects dominate in the north, while daytime effects dominate in the south ©2013. American Geophysical Union. All Rights Reserved.
Corrosion and Materials | Year: 2011
Traditionally copper based antifouling coatings (mostly Cuprous Oxide) have not been used on aluminium hulls due the concern that corrosion of the hull will occur due to the electrochemical potential differences between the cuprous oxide and the aluminium hull. Recent laboratory investigation and a review of field experience has shown that there are other factors that are important to be properly controlled to avoid corrosion.