Editing Rain gauge (section)

===Pluviometer of intensities===
[[File:Pluviograf Jardi.jpg|thumb|Pluviometer of intensities (1921)]]
The '''pluviometer of intensities''' (or Jardi's pluviometer) is a tool that measures the average intensity of rainfall in a certain interval of time. It was initially designed to record the rainfall regime in Catalonia but eventually spread throughout the world.<ref name="East1967">{{cite book|title=Water Resources Series|url=https://books.google.com/books?id=l24qAAAAMAAJ&q=Royal+observatory+HongKong+jardi|access-date=23 October 2011|year=1967|publisher=United Nations}}</ref>
{{Blockquote | style=font-size:100% | ''It employs the principle of [[feedback]]&nbsp;... the incoming water pushes the buoy upwards, making the lower "adjusting conic needle" to let pass the same amount of water that enters into the container, this way&nbsp;... the needle records on the drum the amount of water flowing through it at every moment—in mm of rainfall per square meter. ''}}
It consists of a rotating drum that rotates at constant [[speed]], this drum drags a graduated sheet of cardboard, which has the [[time]] at the [[Abscissa and ordinate|abscissa]] while the y-axis indicates the [[height]] of rainfall in [[rain|mm of rain]]. This height is recorded with a pen that moves vertically, driven by a buoy, marking on the paper the [[rain]]fall over time. Each cardboard sheet is usually used for one day.

As the rain falls, the water collected by the funnel falls into the container and raises the buoy that makes the pen arm rise in the vertical axis, marking the cardboard accordingly. If the rainfall does not vary, the water level in the container remains constant, and while the drum rotates, the pen's mark is more or less a horizontal line, proportional to the amount of water that has fallen. When the pen reaches the top edge of the recording paper, it means that the buoy is "up high in the tank" leaving the tip of the conical needle in a way that uncovers the regulating hole, ''i.e.'', the maximum flow that the apparatus is able to record. If the rain suddenly decreases, making the container (as it empties) quickly lower the buoy, that movement corresponds to a steep slope line that can reach the bottom of the recorded cardboard if it stops raining.

The rain gauge of intensities allowed precipitation to be recorded over many years, particularly in Barcelona (95 years), apart from many other places around the world, such as Hong Kong.<ref name = "East1967" /><ref name="KongOffice1974">{{cite book |author=T. Y. Chen |title=Comparison of Jardi and Workman Rate-of-Rainfall Gauges |url=http://www.hko.gov.hk/publica/tnl/tnl018.pdf |access-date=23 October 2011 |year=1974 |publisher=Royal Observatory, Hong Kong |url-status=live |archive-url=https://web.archive.org/web/20150924045406/http://www.hko.gov.hk/publica/tnl/tnl018.pdf |archive-date=24 September 2015 }}</ref>