Spring 2013 across much of the northern hemisphere mid-latitude landmasses has been notable for extreme cold, record breaking snow falls and severe winter storms. Northern Europe, Scandinavia, Russia, Western and North Canada, North and Eastern USA and NE China and Northern Japan have all been exposed to many more prolonged incursions of cold air from the Arctic than in “normal” years. The blue and green colours on the temperature anomaly map above show areas experiencing a record breaking March of well below average temperatures (“anomalies”), some exceeding an average of 10°C below the temperature expected. The map for 2013 year-to-date looks very similar, so the whole of late winter has been colder. The satellite photo shows widespread snow across the whole northern hemisphere mid-latitudes: a good indication of how extra-ordinary this late winter has been.
So, what is responsible for this extreme late winter weather? Here is a fun round-up of some of the main “suspects” on the Climate Cluedo board: which of them killed Spring 2013? Click on each (as posted!) and find a quick judgement on their culpability in the death of Spring 2013!
- Blocking high pressure / weaker jet stream
- Loss of Arctic sea ice
- Solar activity: sunspot cycles
- Volcanic eruptions
- El Nino / La Nina / ocean currents
- Long term climate change and orbital cycles
- Sudden Stratospheric Warming (started January)
- Human activity (to be dealt with later!)
Thought of some more suspects? Please leave a comment to add them!