CHAPTER 2
SURFACE OBSERVATION EQUIPMENT
INTRODUCTION
As a surface aviation weather observer, you must
have a thorough knowledge of the equipment used in the
observation process.
This chapter will guide you
through the various types of equipment used to conduct
a surface aviation weather observation, both ashore and
aboard ship. Both primary and backup systems are
covered.
AUTOMATIC WEATHER STATIONS
LEARNING OBJECTIVE: Describe the major
components and characteristics of the
Automated Surface Observing System
(ASOS), the Shipboard Meteorological and
Oceanographic Observing System (SMOOS),
and the meteorological buoy.
Automatic weather stations are electronic packages
that sample, record, and display or transmit weather
information to a collection site or user. In the mid-
1970's, several systems were introduced that could
measure temperature, wind, pressure, and precipitation.
By the early 1980's, sensors were developed that could
determine sky cover and visibility. In the mid-1980's
remote observation sites were in use, providing full
spectrum observation data via satellite and phone lines.
In 1988, installation was started on a network of
Automatic Meteorological Observation Stations
(AMOS) in the Pacific to support the Joint Typhoon
Warning Center. In the late 1990's, we will see more of
these automatic weather stations installed.
The automated weather stations in use by the Navy
and Marine Corps at shore stations are called
Automated Surface Observing Systems (ASOS), while
the equipment system used for shipboard observations
is called the Shipboard Meteorological and
Oceanographic Observing System (SMOOS). The
widely used meteorological buoys are also a type of
fully automated weather stations.
AUTOMATED SURFACE OBSERVING
SYSTEM (ASOS)
The Automated Surface Observing System (ASOS)
is a configuration of fully automated observation
equipment that will replace observation equipment at
all shore stations. These automated systems are
currently being installed. The AN/GMQ-29
semiautomatic weather station, the AN/GMQ-32
transmissometer system, the AN/GMQ-13 cloud height
set, and the AN/UMQ-5 wind-measuring set will be
replaced. The ASOS automatically collects, processes,
and error checks observation data and formats. In
addition, ASOS automatically displays, archives, and
reports weather elements included in a surface weather
observation.
Display and Control Terminal
The ASOS equipment consists of several
components that look very much like a standard desk-
top computer. The heart of an ASOS is the acquisition
control unit (ACU). The ACU receives data by radio
link from up to three data collection packages (DCPs).
The DCPs are located near the sensors at the touchdown
end of a runway and get raw data from individual
sensors via a fiber-optic link.
Inside the meteorological office, a computer
keyboard and video monitor serve as an interactive user
terminal that allows the observer to both receive data
and send commands to the ACU. A computer-style
printer prints out selected data and observations. The
system is also equipped with an audio alarm and a
microphone that is used to record supplements to the
voice-produced telephone weather report. Telephone
and radio modems are used to link the system with
various users, maintenance personnel, and on-line
weather reporting circuits. A liquid crystal display
(LCD) display maybe located in the control tower to
keep the air traffic controllers informed of the latest
weather conditions. Software menus guide the user
through entry of supplemental observation data, file
maintenance, and other procedures.
The ASOS provides several types of data for
various requirements. The product outputs are as
follows:
Complete weather observations updated each
minute
Wind speed and direction updated every 5
seconds
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