| Term |
Explanation |
| Above
Mean Sea Level (AMSL) |
Any
height above the mean sea level. See: Mean Sea Level
below. |
All
Time Records -
Record High Temperature |
Highest
temperature recorded during 1 day |
All
Time Records -
Warmest Day |
Highest
averaged temperature in a 12 hour period (6am - 6pm) |
| Aphel
(aphelion) |
Farthest
from the sun |
| Apogee |
Farthest
from the earth |
| Barometer
corrected to MSL |
Adjustment
made to allow for the height the barometer is above MSL |
| Base
18 degrees/degree days |
How
many days the temperature was below 18C (65F). See: http://www.energylens.com/articles/degree-days
for a fuller explanation. |
| Cloud
base |
Lowest
level of visible cloud or the height at which clouds may form |
|
Dew point |
The
temperature point at which air is cooled causing water vapour to condense
out into water |
| Dry
bulb thermometer |
Ordinary
thermometer. See: wet bulb thermometer below. |
| FSU
buoys |
These
are instruments which collect weather and ocean data within the
world's oceans. They measure such things as air temperature at the
ocean surface, water temperature, wave height, dominant wave period,
barometric pressure, wind speed (steady and gusting) and wind direction.
The
buoys transmit this data via satellite communications to meteorological
centres for use in weather forecasting and climate study. Both moored
buoys and drifting buoys (drifting in the open ocean currents) are
used. Data obtained from Florida
State University (FSU).
|
| Humidity |
The
amount of water vapour in the air |
| Mean
Sea Level (MSL) |
Mean
sea level (MSL) is the average (mean) height of the sea, with reference
to a suitable reference surface. Defining the reference level, however,
involves complex measurement, and accurately determining MSL can prove
difficult. See: Wikipedia
explanation |
| METAR |
This
is a world-wide recognised format for reporting weather information
and is predominantly used by pilots as a part of a pre-flight weather
briefing. It is also used by meteorologists who use it to assist in
weather forecasting. |
| Moon
– age |
How
many days into the lunar phase, i.e. since last new moon |
| Moon
– new |
Beginning
of a new lunar phase (no moon visible with naked eye) |
| Moon
– first quarter |
Half
the moon is visible (right side if in northern hemisphere) |
| Moon
– full |
Whole
moon visible |
| Moon
– last quarter |
Half
the moon is visible (left side if in northern hemisphere) |
| Perigee |
Nearest
to the earth |
| NOAA |
National
Oceanic and Atmospheric Administration |
| Perihel
(perihelion) |
Nearest
to the sun |
| Precipitation |
The
falling to earth of any form of water (rain, sleet, snow, mist or
hail) |
| Temperature
– apparent |
What
the temperature actually feels like taking into account temperature,
wind and humidity, e.g. if it's windy it will feel colder than the
measured air temperature. |
UTC
(Coordinated Universal Time) |
In casual
terms GMT (Greenwich Mean Time) and UTC are considered the same. |
| Wet
bulb thermometer |
A thermometer
that has its bulb wrapped with a wet muslin covering. A wet bulb temperature
will be lower than a dry bulb due to the effect evaporation. See:
Wikipedia
explanation |
| Windrun |
Product
of wind speed and time. For example, if the wind had been blowing
at 2 m.p.h. for 6 hours that would give a windrun value of 12 miles |
| Wind
chill |
Cooling
effect of exposed skin caused by the wind |
