Download Weather Maps - Earth Science

Weather Maps Notes #1717
Field –
a 2D or 3D region of space that has
a measurable value at every point
Isolines connect points of equal
value in a given field
Isomaps
ISOTHERMS - LINES THAT CONNECT
POINTS OF EQUAL TEMPERATURE
510-540
Temperature gradient
• How fast the
temperature changes
from one point to
another
• Page 1 in ESRT
• The closer the
isotherms the higher
the gradient
High gradient
Low gradient
Isobars - Lines that connect points of equal
barometric/atmospheric pressure.
Blows from areas of high to low pressure
Named after where it comes from (H)
Speed can be inferred from isobar spacing
Speed increase with altitude.
Why?
Less friction from trees, buildings, ground,
etc.
Fast winds
Slow winds
• The closer the isobars the higher
the pressure gradient and the
faster the wind speed
20-25
knots
0-5
knots
= 50 knots
The Jet Stream - is a current of fast moving air
found in the upper levels of the atmosphere usually
found somewhere between 10-15 km (6-9 miles)
above the earth's surface.
Global winds
Sea Breeze - DAY
Local winds
Land Breeze-NIGHT
Local winds
Pressure Centers
H
L
Wind patterns around “Highs and Lows”
bring about different weather.
High pressure
• Results as cold air
descends from above,
reaches the ground
and spirals outward in
a clockwise direction.
• High pressure
generally brings cool
dry conditions we
refer to as “Fair
skies”.
Low Pressure
• Results from cool air from
a neighboring “High”
circulating along the
ground and pushing
warmer moist air spiraling
upward in a counterclockwise direction.
• “Lows” generally bring
cloudy warm weather.
**The spiraling seen in pressure systems caused by
the Coriolis effect.
Note how the winds blow from
the “High” into the “Low”.
H
L
The Coriolis
Effect
is the apparent
curvature of the path
of an object as it
moves over the
Earth’s surface due
to the
Earth’s Rotation