Editing Rain gauge (section)

===Tipping bucket rain gauge===
[[File: Exterior tipping bucket.JPG|thumb|The exterior of a tipping bucket rain gauge]]
[[File: Interior tipping bucket.JPG|thumb|The interior of a tipping bucket rain gauge]]

The tipping bucket rain gauge consists of a funnel that collects and channels the precipitation into a small [[seesaw]]-like container. After a pre-set amount of precipitation falls, the lever tips, dumping the collected water and sending an electrical signal. An old-style recording device may consist of a pen mounted on an arm attached to a geared wheel that moves once with each signal sent from the collector. In this design, as the wheel turns the pen arm moves either up or down leaving a trace on the graph and at the same time making a loud "click".

The tipping bucket rain gauge is not as accurate as the standard rain gauge, because the rainfall may stop before the lever has tipped. When the next period of rain begins it may take no more than one or two drops to tip the lever. This would then indicate that a pre-set amount has fallen when only a fraction of that amount has actually fallen. Tipping buckets also tend to underestimate the amount of rainfall, particularly in snowfall and heavy rainfall events.<ref>Groisman, P.Y. (1994): "[http://ams.allenpress.com/perlserv/?request=get-abstract&doi=10.1175%2F1520-0477(1994)075%3C0215:TAOUSP%3E2.0.CO%3B2 The Accuracy of United States Precipitation Data]" [[Bulletin of the American Meteorological Society]] '''75'''(2): 215–227.</ref><ref>{{cite web|url=http://www.usbr.gov/pn/agrimet/precip.html|title=AgriMet Pacific Northwest Region - Bureau of Reclamation|first=Bureau of|last=Reclamation|website=www.usbr.gov|url-status=live|archive-url=https://web.archive.org/web/20081025193858/http://www.usbr.gov/pn/agreement/precip.html|archive-date=2008-10-25}}</ref> The advantage of the tipping bucket rain gauge is that the character of the rain (light, medium, or heavy) may be easily obtained. Rainfall character is decided by the total amount of rain that has fallen in a set period (usually 1 hour) by counting the number of pulses during that period. Algorithms may be applied to the data as a method of correcting the data for high-intensity rainfall.

[[File: Tipping Bucket Recorder.JPG|thumb|left|Tipping bucket rain gauge recorder]]
[[File: Close up chart.JPG|thumb|left|Closeup of a tipping bucket rain gauge recorder chart]]

Modern tipping rain gauges consist of a plastic collector balanced over a pivot. When it tips, it actuates a switch (such as a [[reed switch]]) which is then electronically recorded or transmitted to a remote collection station.

Tipping gauges can also incorporate elements of weighing gauges whereby a [[strain gauge]] is fixed to the collection bucket so that the exact rainfall can be read at any moment. Each time the collector tips, the strain gauge (weight sensor) is re-zeroed to null out any drift.

To measure the ''water equivalent'' of frozen precipitation, a tipping bucket may be heated to melt any ice and snow that is caught in its funnel. Without a heating mechanism, the funnel often becomes clogged during a frozen precipitation event, and thus no precipitation can be measured. Many [[Automated airport weather station#Automated Surface Observing System (ASOS)|Automated Surface Observing System (ASOS)]] units use heated tipping buckets to measure precipitation.<ref>"[http://www.nws.noaa.gov/asos/tipbuck.htm The Tipping Bucket Rain Gauge] {{webarchive|url=https://web.archive.org/web/20110629133314/http://www.nws.noaa.gov/asos/tipbuck.htm |date=2011-06-29 }}." [[National Weather Service]].</ref>