A few days ago I mentioned John Neilsen Gammon’s post about The other half of the USHCN network – precipitation
In that post I had a picture of the standard rain gauge used by Cooperative weather observers in the USA, shown below.
One of the downsides to the cooperative observer network is that fact that you have to read and empty this gauge manually each day, and if you miss a reading, you get a cumulative total of a days and no way to figure out what the previous days reading were.
A dipstick is used to get the rainfall reading.
Some observers I spoke with during the surfacestations.org survey indicated that if they missed a reading, sometimes they’d “fudge” the reading by going back to the local newspaper or other weather stations online nearby to get a reading. I should mention that most observers are very diligent, but stuff happens. People get sick, they get called away by family or business. It is inevitable with such a labor intensive system. NOAA recognizes this problem and on some (but not all) stations they put in a Fisher & Porter automatic recording rain gauge like the one shown below.
Amazingly, it uses an old paper punch strip recorder and the data must be run through a 60′s era tape reader.
The description from NOAA below describes the process.
The most common type of recording precipitation gauge is the Fisher Porter (F&P) gauge, developed by the Belfort instrument Company. The Fisher Porter gauge is designed to work for many years in remote and harsh environments. The F&P gauge weighs the precipitation it collects in a large metal bucket. This bucket sits atop a mechanism which converts the weight of the water into the measuring unit of inches and then, every 15 minutes, punches holes in a paper tape, recording the amount of precipitation. In the winter months the bucket is filled with anti-freeze which allows snow and ice to melt and be accurately measured. The observer removes the tape once a month and sends it to the local NWS Office. After reviewing the data the tape is sent to the National Climatic Data Center for archiving. – Click for larger images
I wonder what the observers do with the bucket of anti-freeze when they are done with it? The list of parts and supplies is quite interesting. Lots to break or run out of. When mechanical failures occur, the observer uses the backup standard rain gauge, but that only works if they remembered to empty it. You can read the manual for Cooperative Observer Network equipment here (PDF)
When I visited NCDC in April 2008, I was told about a crisis that developed over this old apparatus. It seems they can’t get the supplies for the mechanism in it anymore and the paper punch rolls were becoming hard to get. I heard later they had a third party company create a solution; a rebuild kit which you can see details on here (PDF).
It isn’t cheap. I’ve heard the cost to be over $1000 for the rebuild kit. Given what you can see in the NOAA FP rebuild procedures manual, it is easy to see how it could cost so much. I sure travel and labor charges alone add up to about the same as the cost of the equipment, assuming that cost is correct.
But as we know, the government can pay exorbitant amounts of money for simple technology, like hammers and toilet seats. For anyone that might be interested, I have engineered a solution that is small, portable, and quite cost effective. It is also calibrated and NIST traceable.
This unit can be placed anywhere, and log rainfall data for up to a year using the self contained data logger. Simply plug the data logger into the USB port of your Windows PC to download, graph, and export the data using the software provided.
- Mounts to any flat surface, mounting screws included
- Can easily be post mounted with a square wood plate, pole mounting accessories available
- Built in bubble level for level surface alignment
- Self-emptying tipping-bucket design is exceptionally accurate
- Special metalized tipper coating resists mildew and algae growth
- Easy snap on cover, no tools required, rotate and lock into place
- Self contained logging of rainfall – no wires or external counters needed
- Automatic and unattended operation anywhere for a period of up to 1 year
- Long life Lithium battery included
- Choice of 0.1 inch or 0.2 mm metric models
- Internal calibration adjustment of +/- 2% if desired. Pre calibrated at factory
- Comes with software for your PC to download data, works under Windows 2000, XP, Vista & 7
- Data in comma delimited format can be exported to Excel, Databases, graphing programs etc
- Selectable logging intervals from seconds to days, preset from factory for 1 hour intervals
- Stores up to 32,510 rain tips (325.1 inches or 6502 millimeters) of rainfall
- Rugged wide temperature range: -35 to +80°C (-31 to +176°F)
- Rain collector case is made of UV resistant
- Designed to meet the measurement guidelines of the World Meteorological Organization
- Home, school, or business rainfall monitoring
- Remote rainfall monitoring
- Lawn sprinkler delivery monitoring
- Golf courses and other grass management rainfall/irrigation monitoring
- Agricultural rainfall/irrigation monitoring at growing locations
Units come pre-assembled and tested from the factory, ready to deploy, no assembly is required. Mounting screws and leaf/debris strainer is included along with a mounting/placement guide. Tipper unit is locked with a strap during shipping to prevent damage, and can be cut with a scissors or knife prior to deployment. Functionality of the datalogger unit in the field is indicated by flashing red and green LEDs, with an option to flash the red LED every time an event occurs.
Datalogger includes special datalogger software on CD ROM, waterproof cap, long life Lithium battery which allows logging for up to 1 year, and manual.
Sample Data File produced by the Logging Rain Gauge software: Sample_Rain_logger.txt
The data file shows that the logger captures rainfall tips (.01 inch or 0.2 millimeter) per logging interval, in this case hourly:
At $199 USD, it is much more affordable. Details here should you want to get one. If you ever wanted to monitor rain at a location but can’t be there all the time to check it, this unit could be a solution.