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Statistical significance of rising and oscillatory trends in global ocean and land temperature in the past 160 years
(Journal article; Tidsskriftartikkel, 2014-03-20)
Various interpretations of the notion of a trend in the context of global warming are discussed, contrasting the difference between viewing a trend as the deterministic response to an external forcing and viewing it as a slow variation which can be separated from the background spectral continuum of long-range persistent climate noise. The emphasis in this paper is on the latter notion, and a general ...
The Hotelling-Lawley trace statistic for change detection in polarimetric SAR data under the complex Wishart distribution
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014-01-27)
In this paper we propose a new test statistic for unsupervised changedetectioninpolarimetricsyntheticapertureradar(PolSAR) data. We work with multilook complex (MLC) covariance matrix data, whose underlying model is assumed to be the scaled complex Wishart distribution. We use the complex kind Hotelling-Lawley (HL) trace statistic for measuring the similarity of two covariance matrices. The sampling ...
20 years of research on the Alcator C-Mod tokamak
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
Improving Doppler frequency estimation from Envisat data
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014-11-06)
This paper shows that Envisat ASAR data are degraded by a small periodic variation in gain between internal calibration cycles of the antenna, which introduces a significant bias when we try to estimate line-of-sight surface velocities from the estimated Doppler frequency shifts. We investigate the impact of the gain problems on the derived surface velocity product and propose a simple correction ...
Long-range memory in internal and forced dynamics of millennium-long climate model simulations
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
Northern Hemisphere (NH) temperature records from a palaeoclimate reconstruction and a number
of millennium-long climate model experiments are investigated for long-range memory (LRM). The models are
two Earth system models and two atmosphere–ocean general circulation models. The periodogram, detrended
fluctuation analysis and wavelet variance analysis are applied to examine scaling properties ...
Magnitude of extreme heat waves in present climate and their projection in a warming world
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
An extreme heat wave occurred in Russia in the summer of 2010. It had serious impacts on humans and natural ecosystems, it was the strongest recorded globally in recent decades and exceeded in amplitude and spatial extent the previous hottest European summer in 2003. Earlier studies have not succeeded in comparing the magnitude of heat waves across continents and in time. This study introduces a new ...
Linear scaling Coulomb interaction in the multiwavelet basis, a parallel implementation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014-08-27)
We present a parallel and linear scaling implementation of the calculation of the electrostatic
potential arising from an arbitrary charge distribution. Our approach is making
use of the multi-resolution basis of multiwavelets. The potential is obtained as the
direct solution of the Poisson equation in its Green’s function integral form. In the multiwavelet
basis, the formally non local ...
Multi-radar observations of polar mesosphere summer echoes during the PHOCUS campaign on 20-22 July 2011
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014-06-27)
During the PHOCUS rocket campaign, on 20-22 July 2011, the observations of polar mesosphere summer echoes (PMSE) were made by three mesosphere-stratosphere-troposphere radars, operating at about 50 MHz. One radar, ESRAD is located at Esrange in Sweden, where the rocket was launched, two other radars, MAARSY and MORRO, are located 250 km north-west and 200 km north of ESRAD, respectively, on the other ...
Monitoring glacier changes using multitemporal multipolarization SAR images
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014)
Simulation of Anti-reflection Coated Carbonaceous Spectrally Selective Absorbers
(Journal article; Tidsskriftartikkel; Peer reviewed, 2014-11-22)