Sunday, 9 March 2014

Winter? what is that? (says the Englishman)

I'm sure we have all sat in a room at some point and tried to guess what the temperature is ... and usually a guess that's roughly within 20°C plus or minus.  Maybe it was back at school when the heating had broken and below a certain temperature, class had to be cancelled (I was this fortunate only once!).  Or maybe, you are like this guy with his funky headwear, trying to figure out how many layers you need.  

Either way, I realised I don't have too much difficulty in working out the temperature... mainly because I'm surrounded by 10 different sensors that are capable of recording data every second on air temperature and relative humidity of my little secluded hideaway.  I don't want make it sound like the Bat-Cave or anything.... but its the TomCave! (trademark).  

...ok, so it's the old boiler house at the University which has more dust than equipment... but either way its my little hideaway spot.  

Basically, in preparation for some fieldwork in the Alps next month, I need to test all of my temperature sensors and the logging systems before installing them on the glacier.  In order to accurately understand the temperature differences across a glacier when it begins to melt, I have to make sure all the sensors are reading approximately the same temperature under a (more) controlled environment.  Thus, the TomCave acts as a nice spot, sheltered from the effects of wind, but with a nice window to allow the sensors to record a daily cycle of temperature under impact of the sun (and how they all respond to this change).  

What we get is this:

The graph here shows the typical cycle of air temperature with peaks between midday and around 3-4pm as would be expected.  Interestingly during the 6th March (the fourth 'peak') the difference between the high daytime value and the night time low is very little.  This would suggest a cloudy, overcast day which persisted during the night, trapping the outgoing heat from the earths surface.  But the crazy thing to notice, is the dates and the associated temperatures... I think we should have all noticed (in the UK and over parts of Euro-Scandinavia) what a crazily mild winter we have had, with warm-ish temperatures and endless rain.  Highs of 15.5°C at the end of this graph support this early onset of spring (if winter ever came at all) assuming we ignore the start of this graph where I held my hand on the sensor just to.... test science and such (hence the 21.5°C maximum at the start).  
Fellow people from Minnesota and parts of the US that I know would argue very differently the case of the disappearing winter.  As this guy and his crazy dress sense indicates, the presence of the Polar Vortex over the US and Canada this winter has given them something to grumble about, perhaps even deny climate change on the grounds that its gone a bit colder this year.  

A brief BBC News overview in case you have been living in a hole, or perhaps you got frozen solid at the beginning of it, and having recently thawed, you are wondering what the hell happened.  .  

Either way, considering the maximum temperature between 1981-2010 at Tynemouth is recorded as 9°C, the presence of 15.5 at the beginning of the month seems pretty significant. (Historical data source: MetOffice:  

Personally, I'm waiting for a small, cold snap of winter weather before spring becomes fully incorporated into the mood and dress sense of Newcastle's population (excluding the night time experience :S ).  

I digress!.... Looking back the same graph but more zoomed in:

The air temperature during the day of March 5th (middle peak on first graph) measured at 10 minute intervals is expressed by the main black and blue lines, with the boxes showing the maximum and minimum values recorded within those 10 minute intervals.  The lines show some very minor variations between two sensors which are under near-identical conditions.  However these differences are less than one tenth of a degree, which is a reasonable similarity of measure considering the manufacturer indicates an accuracy within a twentieth of a degree (0.2) of these sensors.  

This will need to be tested under alternate conditions before being installed on the glacier in April when all the temperature loggers are in the same place (half currently being in Italy already).  But that is a job for the near future.  

I will be very interested to see the range of temperatures found during this field season in comparison with the general findings of previous studies, if this (European) winter is anything to go by.  However the differences between the air temperature measured in the TomCave and those measured above a glacier surface are something to consider... more on that next week.  


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