They say that location is everything in real estate, and when it comes to measuring urban heat, where you collect your data will have an impact on the accuracy of your results.

A new study out of London illustrates just how important it is to take certain variables into account if you want to get an accurate measurement of urban heat.  In this case, tracking night time urban heat in a park full of trees means that previous measurements may have underestimated the urban heat island effect by as much as 45 percent.

From Pys.org – London heat boost underestimated:

Until now, the effect has been measured by calculating the difference between temperatures in St James’ Park in the city, and Wisley – a rural site just outside the M25.

But new research, published in the journalScience of the Total Environment, found night time temperatures in parks can be up to 4°C cooler than in the streets nearby.  So the St James’ Park measurements might have dramatically underestimated the urban heat island in the capital.

‘In the summer time, built-up areas effectively act like a storage heater,’ says Dr Kieron Doick of Forest Research, the research agency for the UK Forestry Commission, who led the research. ‘They store up heat during the day and release it at night.’

‘The extra heat can pose a real health risk, so it’s important to understand the impact that planning decisions have on temperatures in our cities.’

The study mentioned in this article can be found at:
http://phys.org/news/2014-07-london-boost-underestimated.html