Wednesday, 20 January 2016

The wettest month ever

One of the variables which is recorded on each Community Science Environmental Monitoring site in rainfall level.

To do this, volunteers install an automated rain gauge. This works by channeling water which falls on the surface of a bucket down a funnel into a tipper mechanism. Each time the tipper fills, an automatic logger records 1 'event'. Each event (i.e. tip) equates to 0.2mm of rain, so if you know how many times the tipper has tipped you can work out how much rain has fallen and when.

Inside the rain gauge -  the tipper mechanism is visible in the middle

As you may know, December 2015 holds the overall UK prize for the wettest month since records began. So how much rain did we record?

The graph below shows the daily amount of rain that fell on our site near Holme (West Yorkshire) throughout December - downloaded from the rain gauge by the volunteers who look after the site.

The wettest days were the 12th and the 26th - both recording over 50mm of rain -  and as you might remember the heavy rainfall around both storms 'Desmond' and 'Eva' (Boxing day) caused extensive flooding in areas of Cumbria,Yorkshire and Lancashire - and equate to these readings.

December rainfall at Holme EM site (mm)

The total which fell on this site in December was 294.8mm, this compares to 230mm which was the average UK total for the month, and 137mm which was the figure for England. More information about December's weather can be found on the Met Office website.