Temperature

a measure of the average speed at which molecules are moving or vibrating.

Temperature scales Freeze Boil Celsius 100 Fahrenheit 32 212 Kelvin 100 Fahrenheit 32 212 Kelvin 273 373

Conversions oF = (1.8 x oC) + 32 oC = 0.56 (oF – 32) K = oC + 273

What Controls temperature? 1. Insolation differences (latitudinal , seasonal, daily) 2. Proximity to water bodies (land/water distribution) 3. Elevation 4. Ocean currents 5. Cloud Cover

1. Insolation a. Latitudinal High latitudes receive less insolation than low latitudes because… sun’s rays are more oblique Day length is variable Net energy surplus in tropics; net energy deficit in polar regions demonstrate

b. Seasonal Changing angle of sun throughout the year changes temperature on a seasonal basis.

c. Daily (diurnally) Changing angle of sun throughout the day changes temperature on a daily basis.

Diurnal temperature pattern Temperature increases as long as net all wave incoming exceeds net all wave outgoing. Min: end of deficit Max: end of surplus

2. Proximity to water bodies Water bodies have a moderating effect on temperature. Maritime locations (coastal, island) have smaller daily and annual ranges in temp than continental locations demonstration

Small effect from Lake Superior on Duluth temperatures Warmer winters, cooler summers near lake vs inland Top of the hill vs. harbor Harbor warmer in fall; cooler in spring Extreme example (May 2009)

3. Elevation Temperature decreases as elevation increases. less mass, less pressure, less absorption

Factors affecting the air temperature of a place: Review: Factors affecting the air temperature of a place: Insolation differences at various latitudes, during seasons, during the course of a day Proximity to big water bodies Elevation Ocean currents Cloud cover

5. Cloud Cover Exert influence on shortwave and longwave exchanges: Very efficient absorbers and emitters of longwave Reduce incoming shortwave High albedo

Net Result: Dampen diurnal temp range Cloudy: uniform temps, small diurnal range Clear: daytime high insolation and nighttime loss of longwave; large diurnal range About cloud measurement

Temperature and Human Comfort Comfort range: air temperature 68 - 77°F Outside comfort range, body will: Perspire Shiver Restrict/increase flow of blood to skin

Hypothermia: Core drops below 95°F Humans are homeothermic Body regulates core temperature to within 3.6°F of 98.6° (95- 102.2) Hypothermia: Core drops below 95°F Violent shaking Lethargy Impaired speech Blurred vision Clumsy

Cardio-respiratory Response Level of Consciousness Degree of Hypothermia Signs and Symptoms Cardio-respiratory Response Level of Consciousness 95 F - Mild Shivering Foot Stomping Normal Withdrawn 90 F - Mild Loss of Coordination Normal to Impaired Confused 85 F - Moderate Lethargy Slow Pulse Sleepy 80 F - Severe Coma Weak Pulse Slow Respirations Irrational if Conscious 78 F - Severe Apparent Death V-Fib/Cardiac Arrest Unconscious

Alcohol adds to danger “Alcohol ingestion increases the risk of acquiring or aggravating hypothermia by causing cutaneous vasodilation (which prevents vasoconstriction), impairment of the shivering mechanism, hypothalamic dysfunction, and a decrease in awareness of environmental conditions”. Part of brain responsible for metabolic functions

treatment Call 911 Get victim to warm place; otherwise don’t move them Remove wet clothing; replace with dry but minimize movement of person Warm core first before extremities Skin-to-skin contact in blanket or sleeping bag Do NOT RUB SKIN If victim can eat, give sweet food or drink (no alcohol or caffeine) Don’t elevate legs Legs are holding cold blood that would return to heart if legs are elevated Don’t give CPR unless not breathing or no pulse Victim may appear dead but can be resuscitated

Frostnip vs. frostbite Frostnip is mild form of frostbite About 4,800 cases of frostbite occur in the United States each year. Frostnip is mild form of frostbite skin looks pale and feels cold, numb and stiff Yellowish or white underlying tissues remain warm and flexible uncomfortable but doesn’t lead to blisters, scarring or permanent damage minor but could lead to frostbite

Third degree frostbite Second degree frostbite Tissue freezes Skin turns white, blue, black or mottled tissues beneath the skin feel hard and frozen. Deep tissue damage to blood vessels, nerves, tendons, muscle May require amputation white or blue skin; feels hard and frozen. blisters after rewarming

Water immersion Can lead to hypothermia much more rapidly than simple cold temperatures Because water is a better conductor of heat than air Ice safety

Wind chill Indoors: Outdoors: Body loses heat by Net radiation (60%) Evaporation from lungs, skin (25%) Outdoors: Radiation Evaporation AND convection

Wind chill equivalent temperature (W.E.T.) Temperature in still air that would correspond to the cooling generated by the combination of temperature and wind Body loses heat at a rate equivalent to conditions induced by calm winds at W.E.T.

Hyperthermia Core goes above 102ºF Collapse Cramps Unconscious Stop sweating Headache, nausea, fatigue

treatment Cool place Liquids (not alcohol or caffeine) Shower, bathe, sponge off with cool water rest

Heat Stroke life threatening! Temp > 104ºF confusion, combativeness, bizarre behavior faintness, staggering strong rapid pulse dry flushed skin, lack of sweating possible delirium or coma

Heat Index Gauges combined effects of temperature and humidity; advise danger of heat stress Comfort depends on ability to lose heat through evaporation Need vapor pressure gradient between skin and air Evaporative cooling decrease as humidity increases Index: gives apparent temperature Temperature in dry air that would cause same level of discomfort

Temperature inversion

Annual March of the Seasons What is range of SSP?