WMOD00549

• Title: Testing of Satellite Uplinked Remote Surface Weather Stations in the Sierra Nevada
• Date: 6/19/1978
• Weather Modification - Doc Type: Report

The CDCP is controlled by an internal micro-
processor. All control parameters are entered
into the microprocessor by means of a test set
at the time a station is activated. The CDCP
unit, power supplies, and sensor interface elec-
tronics are housed in a weatherproof enclosure
mounted on the meteorological tower 'above the
expected maximum snowpack. The CDCP has 256
locations of 4-bit Random Access Memory (RAM),
of which 207 are dedicated to data storage. The
information stored in RAM is automatically trans-
mitted each hour to the Geostationary Operational
Environmental Satellite (GOES) at l350W. Three
complete sets of hourly observations are held in
memory. As new data are acquired, the oldest set
of data is automatically removed from memory.
The entire memory contents are transmitted during
each transmission event. Therefore, three sets
of hourly observations, present and past 2 hours,
are transmitted each hour.

Power for AESOP stations is supplied from,commer-
cial 120 VAC with standby battery backup. For
remote applications, an optional solar panel is
available to provide an independent power source.

3.0 AESOP SENSORS

Hourly observations of wind speed, wind direction,
temperature, humidity, pressure, and precipita-
tion are automatically taken, temporarily stored
and automatically transmitted via the GOES satel-
lite link.

The MRI Model 1022 wind set is used in the AESOP
stations for sensing wind speed and direction.
The sensor consists of a cup and vane using a
cOJlllllon crossarm for mounting. Sensor range and
resolutions are 0-5400 and 2.110 respectively for
direction; and 0-160 KmPH and 0.63 KmPH respec-
tively for the speed. The wind equipment is
mounted on a 10-meter meteorological tower.

The temperature sensor (Thermilinear Component
'44203.) is manufactured by Yellow Springs Instru-
ment Company. The range and accuracy of the sen-
sor are -30 to 50 .C and ~0.2 .C respectively.
The sensor provides a linear response over the
entire range. Both the temperature and humidity
sensors are mounted in a ventilated radiation
shelter located at the 7.5-m level on the sta-
tion tower.

The humidity sensor is an electric hygrometric
circuit element which senses changes in relative
humidity by changes in impedance.

The precipitation sensor (Catalog No. 6071,
Series high capacity) is manufactured by the
Belfort Instrument Company. It is specially
equipped with a potentiometric output. This gage
with its 750-mm (30-inch) capacity and double
the standard orifice area was selected because
of high snowfall rates expected at the Sierra
sites. The gages are located on a separate tri-
pod stand placed 5 meters from the tower and ele-
vated to a height of 4 meters above ground at the
Blue Canyon site and 6 meters above ground at the
Snow Lab site. The gages also have a chart
recording capability which provides a direct com-
parison with telemetered data. Resolution of the
telemetered precipitation data was limited to

~.
"

- --".:;)

approximately 3.3 mm due to the 8-bit input to
the CDCP.

The pressure sensor (Model 2014) is manufactured
by H. E. Sostman Company. Its range and accuracy
are up to 23 363 Pascals (6.9 in Hg) and 0.12 per-
cent of range respectively. However, in order to
obtain high resolution and yet maintain an ade-
quate range, the AESOP pressure sensors are pres-
ently set for 3386 Pascals (1 in Hg) range which
provides digital resolution to approximately
13 Pascals (0.0039 in Hg)~' The pressure sensor
is mounted in a weatherproof housing directly
below the main electronics enclosure.

4.0 INTERFACE AND INTEGRATING ELECTRONICS

The electronic interface circuitry provides exci-
tation to sensors, buffering to protect CDCP
inputs and integrating circuits. Averaging inter-
vals and formats conform to standards set forth
in both the Federal Meteorological Handbook of
Surface Observations and the design manual for
the National Oceanic and Atmospheric Administra-
tion's Remote Automatic Meteorological Observa-
tion Station (RAMOS). Buffer amplifiers are
provided for each input line of the CDCP to
afford maximum protection from static potential
buildup or nearby lightning strikes and to pro-
vide input range adjustment.

5.0 DATA PATH

As previously stated, the data are transmitted
from the AESOP's each hour up to the GOES satel-
lite over the equator at l3SoW. The satellite
then relays the data to the direct readout ground
station at Wallops Island, Virginia. The data
are then relayed to the World Weather Building,
Camp Springs, Maryland, where the first data sort
is accomplished. Next, the data are relayed to
the National Meteorological Center, Suitland,
Maryland, where the data are merged with other
weather data and then sent to the Bureau of Recla-
mation's Engineering and Research Center, Denver,
Colorado. Figure 2 summarizes the AESOP data
path.

/ j

~~~~
" -'" " ...........

A.[SOP-Automaflc[n..ron....n'aISairfa"OIIH..QtionPlolform
~-Rad,otro",I'''n,o"
GOES -GtoHol'OnotjOp''llI,onol En..ronmtMol Satfll>to
WAL - Wollo~~ hlnnd. ',11'1'"'0
- H'9",~.rdtl)ltlputuh".

HESS -~"o"ol EIW,tan""ntol S/lI,ll1h Stn'CI
Hlote -Hol'onoltr,l.teoroIo9'CoICfftt.rSu'flond....oryloftd
wwe - Wllrld -'O'M' l"nldl'" Camp 50'""9', Morrlo~d.
OOflER.En4'n..r'"ICIfI(I!teuordClfttfrO'....'r.Colorodo
SC?? -SlIrroCDOwroit,,,P'iloIPrOjlct

Figure 2. AESOP Data Path.

Once the data are archived in the Engineering and
Research Center's computer, they are immediately
available for operational use to all users of

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