Ola M. Johannessen

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A continuous data set of Greenland Ice Sheet altimeter height from European Remote Sensing satellites (ERS-1 and ERS-2), 1992 to 2003, has been analyzed. An increase of 6.4 +/- 0.2 centimeters per year (cm/year) is found in the vast interior areas above 1500 meters, in contrast to previous reports of high-elevation balance. Below 1500 meters, the(More)
—In this paper, sea ice in the Central Arctic has been classified in synthetic aperture radar (SAR) images from ENVISAT using a neural network (NN)-based algorithm and a Bayesian algorithm. Since different sea ice types can have similar backscattering coefficients at C-band HH polarization, it is necessary to use textural features in addition to the(More)
Passive and active acoustic measurements are effective and unique approaches to ocean observation. Both approaches have techniques that are well-established and suitable for immediate deployment as part of an operational observing system. Many of these techniques exploit the remarkable ability of low-frequency sounds to traverse great distances in the(More)
[1] In the Indian Ocean, in situ data are sparse both in time and space. Therefore, numerical models are one of the major tools for further understanding of the ocean circulation. We have implemented, validated, and done a 40 year simulation experiment forced by synoptic atmospheric data by using the Miami Isopycnic Coordinate Ocean Model (MICOM) not(More)
The role and contribution of satellite data in operational oceanography is reviewed, with emphasis on northern European seas. The possibility to observe various ocean parameters and processes by existing satellite sensors, such as optical instruments, infrared radiometers, passive Ž. microwave radiometers, and active microwave systems altimeter,(More)
The overall objective of this investigation is to gain an improved understanding of the ocean circulation and variability in the Indian Ocean in response to the monsoon system, by integrated use of radar altimeter data and numerical modeling. Speciic objectives are to study the model's ability to reproduce the seasonal circulation, transport of currents and(More)
Passive and active acoustic measurements are effective and unique approaches to ocean observation. Both approaches have techniques that are well-established and suitable for immediate deployment as part of an operational observing system. Many of these techniques exploit the remarkable ability of low-frequency sounds to traverse great distances in the(More)