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Many general circulation models (GCMs) predict that high latitude environments will experience substantial warming over the next 100 years, which will be particularly pronounced during the winter months. Precipitation is also expected to increase but there is uncertainty as to the amount and spatial variation. The flora and fauna of the arctic and subarctic regions, together with indigenous people, such as the Saami, are particularly vunerable to rising temperatures and changing precipitation. Mean monthly temperature and precipitation data were examined for the last 100 years for northern Finland. These data were further analysed for the first and second half of the 20th century. There was no discernible warming trend between 1876 and 1993, but a significant annual warming (r=0.344, ρ<0.05) occurred in the period 1901–1945, together with a significant summer warming (r=0.381, ρ<0.05). Warming has occurred consistently in May and June over the last 100 years and there appears to be a current (i.e. post 1990) annual trend, mostly due to winter warming. The greatest temperature anomaly increase for the period 1901–1945 was in the winter months (+0.72°C). The degree of temperature variation in the winter is greater than in the summer and has risen from 3.98°C for December in the period 1901–1945 to 4.37°C in the period 1946–1990. This is attributed to the recent high variability in the North Atlantic Oscillation (NAO) Index. Annual precipitation has increased significantly during the period 1880–1993. The period 1946–1990 was wetter than 1901–1945, with greater variability particularly in the summer months, which contribute most to the annual precipitation in Lapland. Copyright © 2000 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

Dedicated experiments have been performed in KSTAR Ohmic plasmas to investigate the detailed physics of the rotation reversal phenomena. Here we adapt the more general definition of rotation reversal, a large change of the intrinsic toroidal rotation gradient produced by minor changes in the control parameters (Camenen et al 2017 Plasma Phys. Control. Fusion59 034001), which is commonly observed in KSTAR regardless of the operating conditions. The two main phenomenological features of the rotation reversal are the normalized toroidal rotation gradient () change in the gradient region and the existence of an anchor point. For the KSTAR Ohmic plasma database including the experiment results up to the 2016 experimental campaign, both features were investigated. First, the observations show that the locations of the gradient and the anchor point region are dependent on . Second, a strong dependence of on is clearly observed in the gradient region, whereas the dependence on , , and is unclear considering the usual variation of the normalized gradient length in KSTAR. The experimental observations were compared against several theoretical models. The rotation reversal might not occur due to the transition of the dominant turbulence from the trapped electron mode to the ion temperature gradient mode or the neoclassical equilibrium effect in KSTAR. Instead, it seems that the profile shearing effects associated with a finite ballooning tilting well reproduce the experimental observations of both the gradient region and the anchor point; the difference seems to be related to the magnetic shear and the value. Further analysis implies that the increase of in the gradient region with the increase of the collisionality would occur when the reduction of the momentum diffusivity is comparatively larger than the reduction of the residual stress. It is supported by the perturbative analysis of the experiments and the nonlinear gyrokinetic simulations. The absence of the sign change of even when a much lower collisionality is produced by additional electron cyclotron heating brings further experimental support to this interpretation. [ABSTRACT FROM AUTHOR]

Experiments of electron cyclotron resonance heating (ECH) power scan in KSTAR tokamak clearly demonstrate that both the cutoff density for non-local heat transport (NLT) and the threshold density for intrinsic rotation reversal can be determined by the collisionality. We demonstrate that NLT can be affected by ECH, and the intrinsic rotation direction follows the changes of NLT. The cutoff density of NLT and threshold density for rotation reversal can be significantly increased by ECH. The poloidal flow of turbulence in core plasma is in the electron and the ion diamagnetic direction in ECH plasmas and high density OH plasma, respectively. The auto-power spectra of density fluctuation are almost the same in the outer region for both ECH and OH plasmas. On the other hand, the divergence in density fluctuation spectra at high frequency range between OH and ECH plasma is clearly observed in core region. The features of linear confinement and saturated confinement also appeared in ECH plasma, which is similar to the linear ohmic confinement (LOC) mode and saturate ohmic confinement (SOC) mode. All these observations in macroscopic parameters and micro fluctuations suggest a possible link between the macro phenomena and the structural changes in turbulence mode. [ABSTRACT FROM AUTHOR]