World Distribution of Temperatures

Air Temperature Data: what data are recorded?

Daily MeanDaily Range

Monthly Mean

Annual MeanAnnual Range

Latitude

Controls of Temperature

Sun Angles at Different Latitudes

Geographic Position

Coasts

Temperature controlLand and Water

• Continental climates

• Land water heating– Mobility– Transparency– Evaporation– Specific heat

Land & Water

Ocean Currents

45 degrees N… halfway between equator and pole

Inverewe Gardens .”..This colourful sub-tropical garden owned by the National Trust for Scotland is located further north than Moscow, but thanks to the North Atlantic Drift, all kinds of exotic plants

grow here in 50 acres... Highly recommended.” http://www.scotland-inverness.co.uk/gardens.htm

57.5 degrees North (same latitude as Moscow and Hudson’s Bay… semi-tropical gardens on the coast of Scotland

Altitude

Cloud Cover

Note the influence of clouds… which interrupts the latitudinal patterns

Daily Variations in Air Temperature

Temperature Measurement

Thermometer

Maximum & Minimum Thermometers

Thermograph

Temperature Scales

Wind-Chill Factor

Heat Index

Normal Atmospheric Conditions…

Temperature Inversion… warmer air slides over the cool air at the surface trapping the surface air beneath a very stable upper air mass

Degree Days

• Heating Degree Days

• Growing Degree Days

• Cooling Degree Days

An index of temperature that can be used to assess climatic conditions.

Growing Degree DayBase temperatures (TBase)

• 40F - wheat, barley, rye, oats, flaxseed, lettuce, asparagus

• 45F - sunflower, potato• 50F - sweet corn, corn, sorghum, rice, soybeans,

tomato

• 44F - corn rootworm• 48F - alfalfa weevil• 50F - black cutworm, European corn borer

Calculating GDD

• first find the mean temperature for the day. (This is usually done by taking the high and low temperature for the day, adding them together and dividing by two.)

• If the mean temperature is above Tbase, then the growing degree day amount equals the mean temperature minus Tbase

• For example, if the mean temperature was 75F then the growing degree day amount equals 25, using a Tbase = 50F

• http://www.sws.uiuc.edu/atmos/statecli/FAQ/degree_days.htm

An Example of GDD requirements:

• Field Corn Hybrid Maturity Classification.

• Maturity Days GDD

• Early-season 85-100 2100-2400

• Mid-season 101-130 2400-2800

• Full-season 131-145 2900-3200 • http://www.ces.purdue.edu/extmedia/NCH/NCH-40.html