Are recent storms the consequence of climate change?

This is always a hot media topic when we experience severe weather.

Since weather is the result of the Earth system trying to breakdown temperature gradients between equator and pole, it does not follow that and overall increase in global temperature will lead to more vigorous weather.  Downhill skiers go fast because of the gradient they ski on, the same gradient could be found high in the mountains as well as near the valley bottom.

Sadly, the issue if complex and not understood fully yet.

There is no school maths correlation equation:

y=mx+c

with y=storm\ intensity and x=climate\ change .

It was never going to be that simple yet byte size media demands such simplicity.  Contemplation of the equations of dynamics on the surface of a rotating sphere subject to chaotic dynamics make this unsurprising.  Computed calculations use curtailed floating point numbers, numerical weather prediction  cannot even work with true values for irrational numbers like \pi and e and the departure from such values could trigger a ‘butterfly effect’.  Sometimes a better maths and science education is required to understand how much we don’t know.

Recent work has been done to try and define the meaning of questions and develop a framework for answers:

http://www.nap.edu/catalog/21852/attribution-of-extreme-weather-events-in-the-context-of-climate-change

and

http://link.springer.com/article/10.1007/s40641-016-0033-y/fulltext.html

As an operational meteorologist and synoptic weather watchers, I warm to Shepherd’s ‘storyline’ approach to analysis.   Successful application in this area would lead to communicable cause and effect discussions.

The conclusion on the question posed, for now, is that we have low confidence in ‘Understanding of physical mechanisms that lead to changes in extremes as a result of
climate change’ as well as in sufficient ‘Quality/Length of the observational record’ to make the judgments anyway.

Anthropomorphic climate changes is accepted, but this particular question remains unanswered.

 

 

Storm Katie over the North Sea

This majestic satellite picture of the meteorological event of Easter 2016 comes courtesy of Dundee Satellite Receiving Station

This majestic satellite picture of the meteorological event of Easter 2016 comes courtesy of Dundee Satellite Receiving Station

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Jet-stream Cirrus from warp and weft of Atlantic air currents illustrate traditional forecast rules of thumb

One of the tricky things about meteorology is that it happens in three dimensions above the surface of a rotating sphere.  In fact, if you add in time, it is four dimensional.  Yet we only have two dimensional graphics from which to build our understanding of it; its rather like building the picture of a garden viewed only through the narrow gaps in boundary fence.

This featured picture has a stable south westerly jet-stream flow aloft, marked by cirrus which weaves itself across a lower level unstable north westerly from the direction of Cape Farewell, the southern tip of Greenland.  Such differential motion of low and high level clouds give rise to traditional seagoing forecast rules of thumb and allow an observer to detect whether they are ahead or astern of a storm.  Of course, a peek at the ships log might tell them that.

Jet stream is shown here from Earthnullschool’s 250mb streamlines.  This matches the shape of the cirrus in the satellite picture above.

250mb stream lines, 29 Mar 16, ENS.
250mb stream lines, 29 Mar 16, ENS.

Whilst below the 1000mb streamlines are:

1000 mb flow, 29 Mar 16, ENS
1000 mb flow, 29 Mar 16, ENS

In this case, cumulus at lower levels moves from the north west whilst cirrus at high levels comes from the south west.  The area does lie to the south west of the complex Atlantic low in the aftermath of storm Katie and pressure is building heralding more settled weather to come.

Storm Katie mixes up the Atlantic air

 

The meteorological event of the day, storm Katie, gives a dramatic signature on all the various meteorological graphics.  MODIS channel 22 at 280230, Earthnullschool surface winds and UKMO surface analysis 280000 presented above.

Surface wind flow from Earthnullschool shows the intense wind field over SE UK, squeezed ahead of the vortex, but the NW’ly surge of air from Denmark Straits is perhaps the most striking element of this graphic.

The storm is a snag in a larger complex depression which mixes cold air from the pole to the West and warm air up to the East.  By this method, the atmosphere does its job of breaking down the temperature gradient from equator to pole and illustrates one of the keys to meteorology.