• Content count

  • Joined

  • Last visited

Community Reputation

571 Exceptional

About sebastiaan1973

Profile Information

  • Gender
  • Location
  1. A new study. The relationship between Eurasian snow cover extent (SCE) and Northern Hemisphere atmospheric circulation is studied in reanalysis during 1979-2014 and in CMIP5 preindustrial control runs. In observations, dipolar SCE anomalies in November, with negative anomalies over eastern Europe and positive anomalies over eastern Siberia, are followed by a negative phase of the Arctic Oscillation (AO) one and two months later. In models, this effect is largely underestimated, but four models simulate such relationship. In observations and these models, the SCE influence is primarily due to the eastern Siberian pole, which is itself driven by the Scandinavian pattern (SCA), with a large anticyclonic anomaly over the Urals. The SCA pattern is also responsible for a link between Eurasian SCE anomalies and sea ice concentration (SIC) anomalies in the Barents-Kara Sea. Increasing SCE over Siberia leads to a local cooling of the lower troposphere, and is associated with warm conditions over the eastern Arctic. This is followed by a polar vortex weakening in December and January, which has an AO-like signature. In observations, the association between November SCE and the winter AO is amplified by SIC anomalies in the Barents-Kara Sea, where large diabatic heating of the lower troposphere occurs, but results suggest that the SCE is the main driver of the AO. Conversely, the sea ice anomalies have little influence in most models, which is consistent with the different SCA variability, the colder mean state, and the underestimation of troposphere-stratosphere coupling simulated in these models.
  2. QBO may 8.01 coming from april 13.88 So two more months till we are in the eQBO-zone? Just in time for winter 2018. It takes some time to have an impact.
  3. Yet another winter with a positive NAO. The Finnish guys with the research are proving right. Declining solar activity -> Positive NAO. So, this is the final winter with this correlation for a while.
  4. It's totally normal for the QBO being in the westerly phase this spring. In the summer it will change. Last year was an exception.
  5. No, not that I'm aware of. Meteociel is French, I'm Dutch.
  6. Here you are Steve. Dauwpunt=dewpoint.
  7. This is a plume of Leeuwarden, in the north of the Netherlands. Obviously the EC oper is on the warm side from next weekend on. And the other is the dewpoint of de Bilt.
  8. At day6 UKMO0h performs the best of several models including EC. Altough the differences are not big.
  9. Dewpoint De Bilt for the plume can be found here
  11. Too early. Ian Fergusson tweeted about half februar.
  12. I Think we see the results of the stratospheric warming. Cohen wrote: The immediate response from the PV weakening will likely be increasing tropospheric ridging/positive geopotential height anomalies over northwestern North America directly under the stratospheric ridge and a deep tropospheric polar low under the displaced stratospheric PV over the north slope of Asia. Rising heights over Alaska and Northwest Canada will help force troughing/ negative geopotential height anomalies accompanied by a cooling trend downstream over the Eastern US. Counterclockwise circulation around the polar low over the north slope of Siberia will transport North Atlantic maritime air into western Eurasia including Europe resulting in a trend to milder temperatures across the region. At 192h we see an area of high pressure by Alaska. After that, we have to wait for; However if there are subsequent pulses of WAFz/poleward heat transport this should further weaken the stratospheric PV and nudge it closer to Europe. This could either turn the winds more northerly across Europe or even force the stratospheric PV into Europe. Both of these scenarios would reverse the weather once again across Europe and result in much colder temperatures.
  13. Well. The end of februar 2006 was (very) cold for the continent. Phase 1 and 2 have high pressure displaced to the north. Altough phase 1 less than phase 2.