What equipment does a Cooperative Station use?
A cooperative weather observer uses different equipment dependant
on the type of station he or she is at. Typically, and at a minimum,
all observers have a rain gage with a few having a thermometer.
Observing sites are placed in one or more of the following networks:
- The "a" network is the basic climatic network
of the NWS, and specifically support climatological operations,
and are the backbone of the Nations Climatic database. These sites
observe 24 hour maximum and minimum temperatures and 24 hour precipitation
totals. Included in the "a" network are stations in
the historical climatology network (HCN), which must have at least
80 years of records.
- The "b" network is specifically designed to
support hydrologic operations and are used primarily to support
hydrologic operations. These sites always report 24 hour precipitation
totals with many also take river level readings.
- The "ab" sites support both Climatological
and hydrological programs of the NWS.
- The "c" stations were setup to act as meteorological
sites and to supplement the "a" and "b" network.These
sites support ther issuance of warnings and forecasts programs.
All sites play important roles in the daily operations of the National
Temperature and Temperature Shelters
||Some cooperative observers use the Cotton Region Shelter (CRS)
to record maximum and minimum temperature data. A CRS is typically
a wooden structure with louvered sides, a slotted bottom and
solid top. It is usually made of pine, painted white, and sits
atop a wooden or metal base, 5 to 6 feet above the ground. Some
shelters have an electric fan in it to allow for better circulation
during light wind conditions.
Thermometers used in a CRS are two basic types: Alcohol and
Mercury. Alcohol thermometers are used to record the minimum
temperatures. Minimum thermometers have a small bar embedded
in the liquid which is pulled down the tube as the temperature
falls. As the temperature warms again and the liquid moves
back up the tube, the bar remains at the "minimum"
which allows the observer to read the lowest temperature.
Mercury thermometers are used to record the maximum temperature.
Maximum thermometers have a small break near the base of the
well of liquid at the bottom of the thermometer. So as the
temperature falls from the high, this break in the liquid
keeps the liquid in place at its high point. The observer
then twirls the thermometers in a rack which rejoins the mercury
or sends the bar back to the top of the liquid, resetting
them for another days recording.
|Electronic Temperature Equipment |
||Another and newer type of thermometer is the
Maximum Minimum Temperature System or MMTS. An MMTS is an electronic
thermometer not too different from the type you buy at the local
electronics store. The MMTS is a thermistor housed in a shelter
which looks similar to a bee hive. This design is similar in
functionality to the CRS.
|Currently the MMTS requires a cable to connect
the sensor with the display. Future plans call for wireless
devices which would eliminate many of the problems currently
associated with the cabled systems.
|Precipitation Gauges |
There are several types of gages used but the two basic types are
recording and non-recording.
|| The most common is the non-recording gauge called a Standard
Rain Gauge (SRG). Typically the SRG is a metal cylinder with
a funnel on top and a plastic measuring tube in the middle.
The measuring tube can handle up to 2.00 inches of rain before
overflowing into the larger outer cylinder. During the winter,
the observer removes the funnel and inner tube and allows the
snow to collect in the outer tube. The observer then melts the
snow and measures it, getting an accurate water equivalent to
||Another type of precipitation gauge is the recording
gauge. The most common type is the Fisher/Porter (F&P) gauge,
developed by the Belfort instrument Company. The Fisher /Porter
gauge (as the one pictured below) 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.
|Snowfall and Snow Depth
Observers also report the amount of snow and the depth of newly
fallen and existing snow. This can be a difficult task, especially
in windy conditions. Observers must use experience and the guidelines
provided by the NWS.
In some instances snowfall measurement is an estimation at best.
To help the observer, a snowboard may be used. The snowboard
is simply a piece of plywood, typically 3 feet square with a
ruler attached in the middle. The snowboard sits in an open
space and as the name implies, is covered with snow. The observer
then measures the amount of newly fallen snow every 6 hours,
brushing off the "old" snow when finished.
Communications and observations
There are several methods available to the CWO to send data
to the NWS. Some observers call information to the office
using a toll free number. Others use a programmable telephone
or a PC based program. The newsest and most preferred method
is via a web based reporting system. All the observer provided
data is coded in a special format which NWS computers can
read and decipher, allowing the viewing of this data both
graphically and in a tabular format.
The Coop weather observer plays an extremely important part
in the role of the National Weather Service. The data they
collect are used in a wide variety of applications: Agriculture,
Industry, city planning, litigation, and studies about long
term climatological events such as El Nino and La Nina. Coop
observers are truly unsung heros who's dedication needs to
be celebrated and their efforts sung from the heights.
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