CHAPTER 1
UPPER-AIR OBSERVATIONS
INTRODUCTION
In this chapter, we discuss the different types of
upper-air observations in addition to the primary upper-
air observation equipment used by the Navy and Marine
Corps. We also discuss how to identify information in
the various upper-air code forms. Finally, we discuss
the TEMP and PILOT codes that are used to
disseminate upper-air observation data and the records
that are maintained for each observation.
UPPER-AIR OBSERVATIONS
LEARNING OBJECTIVES: Recognize the
uses of upper-air observation data. Identify the
different types of upper-air observations.
Determine which types of upper-air
observations are conducted by Navy and
Marine Corps observers. Identify the
publications that govern upper-air observations
and observation codes.
During an upper-air sounding, special instruments
measure different atmospheric elements in the lower
two layers of the atmosphere. These layers are the
troposphere and the stratosphere (fig. l-l). A
meteorological transmitter, known as a radiosonde, is
attached to a balloon and is tracked by ground
equipment. The radiosonde contains sensors that
transmit pressure, temperature, and relative humidity
data to a receiver as the balloon ascends into the
atmosphere. Wind information can also be determined
by tracking the balloon’s movement via radio signal or
optically. The information is processed, encoded, and
then transmitted over automated weather networks.
Upper-air observations are often referred to as upper-air
soundings.
The National Weather Service, U.S. Air Force, and
the U.S. Navy’s meteorological and oceanographic
forecast centers run primary upper-air forecast
programs twice a day based on data received from the
0000Z and 1200Z upper-air soundings. The computer
programs can use data up to 12 hours old. All
observations, regardless of the observation time, are
1-1
used if received within 12 hours after the observation.
Additionally, all transmitted observations, even those
not used in forecasting programs, are automatically
entered in the upper-air climatic data base at the
National Climatic Data Center in Asheville, North
Carolina. This data is used extensively in atmospheric
research.
Locally, upper air observations provide an
immediate vertical profile of the atmosphere and are
invaluable as a forecast tool, particularly for severe
weather and general aviation forecasts.
NAVY/MARINE CORPS UPPER-AIR
PROGRAMS
Upper-air observations are conducted aboard many
naval ships and at many naval and Marine Corps
stations. Aircraft carriers (CVs) and most amphibious
ships (LCC, LHA, LHD, LPHs) routinely conduct
upper-air observations primarily for operational
support. This support includes weather forecasts as well
as refractivity forecasts. Some sites located on islands
or in remote areas are designated Synoptic Upper-air
Observation Sites. These activities routinely conduct
u p p e r - a i r o b s e r v a t i o n s t o s u p p o r t W o r l d
Meteorological Organization (WMO) data collection
requirements, as well as operational commitments.
Mobile Environmental Teams (MET) use portable
equipment aboard ship and at remote shore sites to
conduct upper-air observations in support of
operational and research requirements. Marine Corps
Meteorological Mobile Facility (MMF) members also
use portable equipment and meteorological vans to
conduct upper-air observations to support forces on
temporary deployments.
Normally, all upper-air observations from ships,
designated Synoptic stations, and remote land locations
are encoded and transmitted. Special observations
conducted for training at shore stations may be encoded
but are not usually transmitted.
NOTE: In this chapter, we use altitude and height
only by the strictest definition: height is the vertical
measurement or approximation above the ground level
(AGL); altitude is the vertical measurement or
approximation above mean sea level (MSL). Most
