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)
2 per decade (0.767–0.812 million km 2 per decade for the extent) for the 1992–2012 period. High-frequency algorithms obtained a decrease of 0.766–0.978 million km 2 per decade in the area and 0.758–0.814 million km 2 per decade in the extent over the period 1992–2012. Results for all the algorithms have close agreement on the strength of the negative trend(More)
Climate policy needs to address the multidecadal to centennial time scale of climate change. Although the realization of short-term targets is an important first step, to be effective climate policies need to be conceived as long-term programs that will achieve a gradual transition to an essentially emission-free economy on the time scale of a century. This(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)
[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)