Transcript North Carolina Landforms, Weather, and Climate

North Carolina Landforms,
Weather, and Climate
Tom Shields
NCST 2000
(Fall 2001)
Landforms
Regions of North Carolina
• Coastal Plain
– Two main subregions:
• Outer Coastal Plain
• Inner Coastal Plain (includes Sandhills)
• Piedmont
• Mountains
Major Geographic Regions
Geographic View
Coastal Plains
• Features of the Coastal Plain
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Barrier Islands
Coastal Plain Terraces
Pocosins
Carolina Bays
Barrier Islands
Coastal Plain Terraces
Oceanic
Invasion
of the
South
The Formation of a Pocosin
A Typical Pocosin Profile
Carolina Bays
Piedmont
• Drained by a number of rivers, including the Dan,
Tar, Neuse, Cape Fear, Yadkin, and Catawba
Mountains
• Main chains of mountain ranges running
from northeast to southwest
• Other chains run between the main chains,
creating coves, basins, and valleys.
Mountain Ranges
Weather and Climate
Climatic Considerations
• Geographic Considerations
– Air Masses
– Elevation
– Bodies of Water
• Climatic Concerns
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Temperature
Precipitation
Sunshine
Frost
Air
Masses
Affecting
North
Carolina
Types of Precipitation
• Orographic Precipitation
• Convectional Precipitation
• Cyclonic Precipitation
Orographic Precipitation
• Occurs in the mountains and western piedmont
• Tropical air mass reaches the mountains and cools
adiabatically as it rises along the mountains.
• When it reaches the dew point (100% humidity), it results
in rain or snow.
Adiabatic
• adiabatic: describing a process in which there is
no transfer of heat into or out of the system in
question.
• saturation-adiabatic process: an adiabatic process
in which the air is maintained at saturation by the
evaporation or condensation of water substance,
the latent heat being supplied by or to the air
respectively; the ascent of cloudy air, for example,
is often assumed to be such a process.
Convectional Precipitation
• Primarily a warm weather phenomena—isolated summer
thunderstorms.
– Most summer rain comes from convectional precipitation.
• The heat of day on the air and land heats an already warm
maritime tropical air mass.
• As the heated and moist air rises, it cools and its water
vapor turns into rain.
Cyclonic Precipitation
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Conventional low pressure storms.
Generally move west to east across the United States.
Generally fall, winter and spring in North Carolina.
Warm fronts tend to provide light, prolonged precipitation.
Cold fronts tend to provide brief, heavy showers.
Exceptional Weather
• Tornados
• Hurricanes
Climatic Measures
• Average Temperatures
• Frost-Free Seasons
• Average Annual Rainfall
January Average Temperatures
July Average Temperatures
Average Frost Free Days
Average Annual Precipitation
Geography and Climate
Sample Situations
Human Effects on Geography
• In the 1800s (and earlier) eastern North Carolina's
economy affected the landscape:
– Naval Stores—use of region’s longleaf pine for timber
and tar:
• Some barrier island forests harvested to the point of
deforestation.
• Parts of the coastal plains destroyed by insect infestations,
burnings, windstorms, etc., once trees were cut with V’s to
drain sap for tar.
– Draining of swamps:
• Drained for farming and rice growing.
• Draining lowered water levels in rivers and allowed for major
forest fires.
Affects of Climate on History
• In 1998, scientists discovered by
measuring tree rings in bald
cypresses that in the late 16th and
early 17th centuries, two major
droughts occurred:
1606-12
– 1587-89—the worst drought in the
last 800 years.
– 1606-12—the driest seven-year
period in the last 800 years.
1587-89