Manchester’s Urban Heat Island on March 6th 2009
We waited a long time for the forecast weather conditions to look right for us to run the Manchester Urban Heat Island experiment. We needed a clear, calm night with a late sunrise in order to be able to get the best data.
Despite weather conditions that turned out not to be ideal, the data collected by hundreds of school pupils, weather enthusiasts and members of the general public around Manchester have allowed us to construct a very interesting picture of Manchester’s urban heat island. There are clear ‘hot spots’ in central Manchester and central Stockport. Even more interestingly, when we compared the data collected with a land use map of Manchester, we found a clear relationship between temperature and land use. Although there are large error bars, it is clear that some land uses, such as storage and manufacturing, are considerably warmer than low density residential areas and farmland.
The weather on the day
Although the night started clear and calm, and the high pressure conditions persisted well into the day, a thick later of stratocumulus had developed across much of Manchester by 6am. There was a significant break in this cloud cover over central Manchester. Unfortunately, this cloud cover meant that the SCORCHIO plane was not able to collect data on the day.
How has the data been quality controlled?
We have taken out any data that was obviously wrong – this may have been due to a postcode or grid reference that was supplied incorrectly, a temperature measurement that was very different from those geographically near it (typically more than 2 standard deviations from the average of the surrounding points), or a measurement that had obviously been made on the wrong day or at a very different time of day.
By comparison with time series of data from a few weather stations around Manchester (including data available from wunderground, the Met Office, various members of the Climatological Observers Link and weather stations monitoring road conditions around Manchester), we corrected the data to account for the general increase in temperature across the morning. Sunrise was at 0644 on the 6th March 2009.
We obviously converted any readings in F to ºC, but did not try to correct for the cooling affect of altitude.
Over 1000 data points were collected. 454 of these were used in the results above.
If you use this data in schools for project work, why not send some of the work to us, and we can put it up on the website?
Would you like to be involved in helping us measure the Urban Heat Island of your town and city? Please contact us.
BBC Manchester web article.
Find out more about urban heat islands.