TemperatureTemperature

A. A. Statistical AnalysisStatistical Analysis

1. ______________Temperature: Average of the highest and lowest temperature for a day.

2. Daily Temperature : Difference between the highest and lowest temperatures for a day.

3. Monthly Temperature: Average of each of the daily average temperatures for a month.

4. Annual Temperature: Average of the each of the average monthly temperatures for a year.

5. Annual Temperature : Difference between the highest and lowest average monthly temps for a year.

Average Daily

Range

Average

Average

Range

B.B. Measuring TemperatureMeasuring Temperature

1. ______________(a) Different substances react to

temperature changes differently.

(b) Liquid-in glass thermometer

Thermometers

c. c. Maximum and Minimum Maximum and Minimum ThermometersThermometers

• Maximum Thermometer: – As temperature rises, mercury expands and is forced

through the constriction which prevents a return of mercury into the bulb when temperature falls

• Minimum Thermometer: – A small dumbbell-shaped index in a low density liquid (alcohol)

is pulled toward the bulb as the temperature drops and the column shortens.

– The index remains at the lowest temperature reached as liquid drains past it when temperature rises. It must be mounted horizontally

2. _________strip:

a. Two metals expand and contract unequally when heated or cooled.

b. Causes the strips to curl.c. The change corresponds to the change in temperature

Bimetal

3. _____________

a. A _______________thermometerb. Changes in the curvature of the bimetal strip move a

pen arm.c. Pen marks temperatures on a calibrated chart that is

attached to a clock-driven, rotating drum

recording

Thermograph

ThermogramThermogram

4. ___________ Thermometers

a. Thermisters (thermal resister): (1) Resistance to current is temperature dependent.(2) Higher temp = higher resistance, resulting in a reduction in flow of

current

b. Measures flow of electricity which is calibrated in degrees of temperature.

c. Commonly used in thermostats and radiosondes.

Electrical

5.5. Location of ThermometersLocation of Thermometers

a. Inaccurate readings could result from placement (e.g. near a heat radiating surface or in the Sun)

b. Ideal placement is in an _________________.

•Standard NWS shelter constructed of white pine, louvered on all sides.•Provides protection from Sun, wind, and precipitation.

instrument shelter

C. Temperature ScalesC. Temperature Scales

A quantitative measurement of temperature A quantitative measurement of temperature requires scales based in requires scales based in fixed points fixed points which which

are reference pointsare reference points.

1. Fahrenheit Scale1. Fahrenheit Scale

a. Devised by German physicist Daniel Fahrenheit in 1714

b. Fixed Points(1) point = lowest

temperature of a mixture of ice, water, and common salt.

(2) point = human body temperature (he used 96o).

(3) ___________is 32 degrees (melting point of ice) and 212 degrees (boiling point of water) called the point and point respectively.

ice

Range

steam

Zero

Second

2. Celsius Scale2. Celsius Scalea. Devised by Swedish astronomer

Anders Celsius in 1742

b. Scale

c. Fixed Points(1) Zero Point = 0 degrees (melting

point for water)

(2) Second Point 100 degrees (boiling point for water)

(3) Also called centigrade but now referred to as Celsius in honor of its inventor.

Decimal

3.3. Kelvin ScaleKelvin Scalea. Developed by Scottish

mathematician and physicist Lord Kelvin in the mid 1800's.

b. The scale. c. Used for some scientific endeavorsd. Fixed Points

(1) Uses 100 degrees between the melting point of ice and boiling point of water.

(2) Ice point = 273 (3) Zero point represents the

theoretical temperature, absolute zero.

e. No negative valuesf. Degrees Kelvin are called Kelvins

which are abbreviated as K, with no degree symbol used (ex. 273 K).

absolute

If Temperature is provided in degrees Celsius, convert to degrees Fahrenheit

Two degree increments

One degreeincrements

Conversions:Conversions:Celsius -Fahrenheit RelationshipCelsius -Fahrenheit Relationship

oF = (1.8 x oC) +32

oC = oF – 32

1.8

Celsius-Kelvin ConversionsCelsius-Kelvin Conversions

oC = K - 273

K = oC + 273

D.D. Map Representation of TemperatureMap Representation of Temperature

1. ________Modelsa. Weather information at a particular point is

transmitted and plotted on a surface map at that station’s location. The arrangement of the data around the station location is called a station model and is standardized by international agreement

Station

The Station ModelThe Station Model

b. Plotting Temperature on a Station Modelb. Plotting Temperature on a Station Model

1. Temperature is plotted in the upper ____ of the circle.

2. Always plotted in degrees ___________

3. Units (oF) are __________.

left

Fahrenheitomitted

Practice ExamplesPractice Examples

• Plot a temperature of 40o F.

• Plot a temperature of 12o C.

40

62

2. Isotherms2. Isothermsa. ____________ connecting points of equal temperature.b. The larger the range in temperatures, the larger the

interval used on the map.

Example using a 10o F interval

40

63

50

61

38

4440

46

34

57

66

50

40

49

68

Isolines

40

50

60Infer the 60o F isotherm’s location, even though no 60o F value is Plotted on the map

United States Isotherm MapUnited States Isotherm Map

E. E. Factors that Cause Temperatures to Factors that Cause Temperatures to Vary from Place to PlaceVary from Place to Place

1. 1. Land and WaterLand and Watera. Differential___________________: A mass of soil

heats and cools _______than an equal mass of water.

heating and coolingfaster

b. Land is opaque and water is more _________________(1) Heat is absorbed by land only at the ________________, within

the top few centimeters.(2) Solar radiation penetrates to greater depths in water, to depths

of several meters.

transparentsurface

C.C. Water is highly mobile.Water is highly mobile.

(1) _______________ currents can distribute heat throughout a ______________mass.

(2) Heat remains near the __________of land. No mixing can occur

Convection

surfacegreater

d.d. Specific HeatSpecific Heat(1) The specific heat of liquid water is more than three

times____________ than for land.

(1) Water requires__________ heat to raise its temperature the same amount as an equal quantity of land

greater

more

2.2. Geographic LocationGeographic Location

a. Coastal Locations vs. Inland Locations(1) Coastal regions have their yearly temperatures ___________by

the nearby presence of a body of water.(2) Coastal regions will have ____________yearly temperature

ranges than inland regions(a) ___________ summer temperatures(b) ___________winter temperatures

moderated

smaller

CoolerWarmer

b.b. Windward Coast vs. Leeward CoastWindward Coast vs. Leeward Coast

(1) Windward: Prevailing winds from the ocean will result in a _________annual temperature range

(2) Leeward: __________ temperature range because winds do no carry the ocean’s influence on shore.

smallerLarger

Prevailing

Winds

c.c. LatitudeLatitude

(1) On the average, as latitude increases average annual temperature _____________

(2) Higher latitudes also have a greater annual temperature __________.

decreases

range

Global Annual Temperature RangesGlobal Annual Temperature Ranges

ClimographsClimographs

d. Northern Hemisphere vs. Southern Hemisphered. Northern Hemisphere vs. Southern Hemisphere

(1) The Southern Hemisphere has a_____________ percentage of water than the Northern Hemisphere (81% covered - 20 percent more than the N. Hemisphere).

(2) __________ temperature variations in the Southern Hemisphere.

greater

Smaller

3.3. AltitudeAltitude

a. As altitude increases, average annual temperature ____________.b. Increased altitude results in a _______daily temperature range

because the greater intensity of insolation due to the less dense air.

Quito, Ecuador is highin the Andes Mountains

Guayaquil, Ecuadoris near sea level.

decreaseslarger

4. Ocean Currents

a. Currents moving towards lower latitudes are ______.b. Currents moving away from the equator are ________.c. Caused by frictional drag on the surface by _______.d. Affect coastal areas

coldwarmwindwind

Ocean CurrentsOcean Currents

5.5. Cloud CoverCloud Cover

a. During the day, clouds __________ insolation back to space.b. At night, minimum temperature will not fall as low. Clouds ________

terrestrial radiation and emit a portion of it toward the surface.c. Clouds _________the daily temperature range.

reflectabsorb

reduce

F. Temperature Data F. Temperature Data ApplicationsApplications

1. __________Degree Days1. __________Degree Days

a. Evaluates energy demand and consumption

b. Assumes that heating is not required in a building when the daily mean temperature is 65o F (18.3o C) or higher.

HeatingHeating

c. Each degree of temperature lower than 65o F equals one heating degree day.d. Subtract the daily mean below 65o F from 65o F.e. Amount of heat required to maintain a desired temperature in a building is proportional to the number of heating degree days (a linear relationship).f. Heating “season” is July 1 through June 30 and heating degree days are cumulative

1000’s oF

2. ________Degree Days2. ________Degree Days

a. Evaluates amount power required to cool a buildingb. Uses 65o F as the base temperature by subtracting this

number from the daily mean temperature.

Cooling

1000’s oF

3. ________ Degree Days3. ________ Degree Days

a. Helps determine the approximate date when crops will be ready for harvest.

b. Difference between the daily mean temperature and the base temperature of the crop (minimum temperature required for it to grow).

c. It accumulates with the onset of the growing season

GrowingGrowing

4. Wind Chill4. Wind Chill

1. Wind cools the body (increase evaporation, a cooling process, from the skin).

2. Estimate of human discomfort.

• New Chart effective November 2001• Accounts for wind effects at face level• More accurately portrays body heat-loss estimates• Tested on human subjects• Includes a frostbite indicator