chapter 5 Flashcards
Apparent temperature
outdoor temperature as it is perceived by humans,
Factors affecting apparent temperature
water vapour (content of the air), and wind
Wind-chill factor
quantifies the enhanced rate at which body heat is lost to the air, as wind speeds increase, heat loss from the skin increases, and the wind-chill factor rises
Wind-chill temperature index
a chart plotting the temperature we feel as a function of actual air temperature and wind speed, accurate tool for assessing the dangers to humans from winter winds and freezing temperatures
Frostbite
the lower wind-chill values on the chart present a serious freezing hazard
Hypothermia
a condition of abnormally low body temperature that occurs when the human body is losing heat faster than it can be produced
Temperature
is a measure of the average kinetic energy of individual molecules in matter, a measure of sensible heat energy present in the atmosphere and other media
*not a form of energy, but is related to the amount of energy in a substance
Absolute zero, or ) absolute temperature
the temperature at which atomic and molecular motion in. Matter completely stops (-273° Celsius, -459,67° Fahrenheit, and 0 Kelvin
Fahrenheit
Daniel G. Fahrenheit, a German physicist, melting point of ice at 32°F, separated by 180 subdivisions from the boiling point of water at 212°F
Celsius
Swedish astronomer Anders Celsius, melting point of ice at 0°C and the boiling temperature of water at sea level at 100°C, diving his scale into 100 degrees using a decimal system
Kelvin
British physicist Lord Kelvin, temperatures readings proportional to the actual kinetic energy in a material, melting point for ice is 272K, and its boiling point of water is 373K, 100 units higher, one Kelvin unit is the same size as one Celsius degree
Thermometer
measure the air temperature
Mercury thermometers
mercury freezes at -39°C
Alcohol thermometers
alcohol freezes at -112°C
instrument to measure day to day temperature
Standard instrument shelters contain a thermistor, which measures temperature by sensing the electrical resistance of a semiconducting material
Satellites
measure land-surface temperature (LST)
Temperature depends on what
on latitude, altitude and elevation, cloud cover, and land-water heating differences, the effects of human activity are altering some of there natural controls on temperature
Latitude
variation in these two factors - sun angle and daylength - throughout the year drive the seasonal effect of latitude on temperature
Altitude and Elevation
temperature decrease with increasing altitude above Earth’s surface, as the atmosphere thins, it contains less sensible heat
Altitude
refers to airborne objects or heights above Earth’s surface
Elevation
refers to the height of a point on Earth’s surface above some plane of reference, such as elevation above sea level
what happen at high elevation
At high elevation the temperature range between day and night is greater than at low elevations, and the difference between areas of sunlight and shadow is greater
Slope/hill aspect
direction slope is facing, flat no aspect, south facing receive most insolation
Slope/hill angle
determines angle of incident radiation, influence varies diurnally and seasonally