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
Cloud cover
at night, clouds act as an insulating layer that reradiates longwave energy back to Earth, preventing rapid energy loss to space (can also create warmer nights), during the day, clouds reflect insolation, lowering daily maximum temperatures, shading affect
At any given moment, approximately 50% of Earth is covered by clouds
Clouds are the most variable factor influencing Earth’s radiation budget
High albedo
Land-water heating differences
differences in the degree and way that land and water heat, as a result of contrasts in transmission, transparency, evaporation, mixing, movement, and specific heat capacities, land surfaces heat and cool faster than water
Evaporation - Land-water heating differences
when water evaporates, it changes from liquid to vapour, absorbing heat energy from the immediate environment in the process and storing it as latent heat, resulting in a lowering of temperatures
84% of all evaporation on Earth is from the oceans
Transparency - Land-water heating differences
soils and water differ in their transmission of light: soil ground is opaque; water is transparent. Maximum and minimum daily temperatures for soil surfaces generally occur at the ground level. The transparency of water results in the distribution of available heat energy over a much greater depth and volume, forming a larger reservoir of energy storage than that which occurs on land
Specific heat - Land-water heating differences
the increase of temperature in a material when energy is absorbed (the amount of heat needed to raise the temperature of 1g of 1°C); water has a higher specific heat (can store more heat), cool more slowly than a comparable volume of soil or rock.
day-to-day temperatures near large water bodies tend to be moderated rater than having large extremes
Movement - Land-water heating differences
the movement of currents results in a mixing of cooler and warmer waters, and that mixing spreads the available energy over an even greater volume than if the water were still, reduces temperature difference in water
explain Ocean currents and sea-surface temperatures
along midlatitude and subtropical wast coasts of continents, cool ocean currents flowing toward the equator moderate air temperatures on land
Ocean water is rarely found warmer than 31°C
Warm water adds energy to overlying air through high evaporation rates and transfers of latent heat, leading to warming ex; gulf stream; more water vapour leads to cloud formation, which reflects insolation and produces lower temperature, then reduce evaporation rates, an interesting negative feedback mechanism
SST; sea-surface temperature
It can change the land temperature, and so, we can see different variation of temperature of different city in similar latitude point, because of if they are close to water or not
Gulf Stream
the warm current that moves northward off the east coast of North America, carrying warm water far into the North Atlantic, warming the temperature on land too
Marine effect, or maritime effect
describes locations that exhibit the moderating influences of the ocean on air temperatures, usually along coastlines or on islands
Continental effect or condition of continentality
refers to ares less affected by the sea and, therefore, having a greater temperature range between maximum and minimum temperatures on both a daily and yearly basis
Isotherm
is an isoline - a line along which there is a constant value - that connects points of equal temperature to portray the temperature pattern
how can soil and rock change temperature
Rate varies due to reduced temperature gradient with depth and variation in conductivity of diverse materials comprising soil and rock. The more depth, the less temperature range
Thermal equator
is an isotherm connecting all points of highest mean temperature, roughly 27°C,
Continental effects
Temperature is more pronounce (extreme, hot) over large continents , dominate in the Northern Hemisphere
marine effects
Moderate range temperature, dominate in the Southern Hemisphere
Temperature anomaly
is a difference, or irregularity, found by comparing recorded average annual temperatures against the long-term average annual temperature for a time period selected as the baseline, or base period (the basis for comparison)
For each Celsius degree of global temperature increase
5%-10% changes in precipitation in many regions
3%-10% increases in the amount of rain falling during the heaviest precipitation events
5%-10% changes in flows of streams and rivers (either up or down)
25% decrease in the extent of Arctic summer sea ice
5%-15% reductions in crop yields (as currently grown)
200%-400% increases in the area burned by wildfire in some areas of the Western United States
which years were the three hottest years on record
2014, 2015, 2016, 2016 the hottest
Climate change
cause all the effects of atmospheric warming- these effects vary with location and relate to humidity, precipitation, sea-surface temperatures, severe storms, and many other Earth processes, caused by human activity, ex: positive feedback loop created by Arctic sea-ice melting and temperature rise
not the same thing as global warming, and should not be considered interchangeable
Heat wave
is a prolonged period of abnormally high temperatures, usually, but not always, in association with humid weather, higher humidity, higher heat index, and vice versa
Wind chill
correlates cold and wind speed, stronger wind, lower wind chill index, and vice versa
what combination creates the most heat discomfort for humans
combination of high air temperatures, high humidity, and low winds
why is perspiration not as effective a cooling mechanism as in dry environments
because under humid conditions, the air cannot absorb as much moisture
