Chapter 5 Geography

Average internal human body temperature

38.6 C

Temperature anomaly

A difference found by comparing recorded average annual temperatures against the long0term average annual temperature for a time period selected as the baseline - 2012 was the hottest year ever in US

Temperature

A measure of the average kinetic energy of individual molecules in matter - measure of heat - heat transfer can occur without a change in temp when a substance changes state

Wind-chill factor

Enhanced rate at which body heat is lost to the air - risk: frostbite, hypothermia - wind chill index does not account for sunlight intensity, a person's physical activity, or use of protective clothing

Specific heat

Heat capacity of a substance - energy needed to increase the temperature of water is greater than for an equal volume of land - specific heat of water is about four times that of soil

Temperature and Southern/Northern hemispheres

High sun altitudes and longer days in the Southern Hemisphere cause summer weather conditions; lower Sun altitudes and short days in the Northern hemisphere associated with winter - isotherms on the January - Summer dominates North/Winter dominates Southern - continental effects dominate in North, marine effects dominate in South

Fahrenheit

Ice Melting point: 32 F Water freezing point: 32 to -40 R Boiling point: 212 F

Single most important influence on temperature variations

Insolation - also influence temperature: latitude, altitude, elevation, cloud cover, land-water heating differences

Isotherm

Isoline - a line along which there is a constant value - that connects points of equal temperature to portray the temperature pattern, about 27 C - useful for the spatial analysis of temperatures - generally trend east-west, are parallel to the equator, and interrupted by the presence of landmasses

Thermal equator

Isotherm connecting all points of highest mean temperature, roughly 27 C - In North, isotherms shift toward equator as cold air chills the continental interiors - more moderate temps occur over oceans

Arctic Ocean temps

July is "summer" in the Arctic Ocean, sea-ice melting

Snow line and Temperature

Lower limit of permanent snow and indicates where winter snowfall exceeds the amount of snow lost through summer melting and evaporation - function both of latitude and elevation and related to local microclimate conditions

Marine effect

Maritime effect, refers to the moderating influences of the ocean and usually occurs in locations along coastlines or on islands

Satellites

Measure land-surface temperatures (land skin temperature), heating of the land surface and is often much hotter than the air around your body - record the heating of the ground from insolation and other heat flows - tend to be highest in dry environments with clear skies and surfaces with low albedo that absorb solar radiation

Celsius

Melting point: 0 C Boiling: 100 C

Kelvin

Melting point: 273 K Boiling point: 373 K Size of one Kelvin unit = one Celsius degree

Largest average annual temperature ranges

Occur at subpolar locations within the continental interiors of North America and Asia

Hottest places on Earth

Occur in Northern Hemisphere deserts during July, caused by clear skies, strong surface heating, virtually no surface water, and few pants

Antarctica temps

Summer is in December and January - coldest and highest landmass - in July, nights are 24 hours long - coldest temperatures are usually in August

Altitude and Temp

Temperatures decrease with increasing altitude - normal lapse are of temp change with altitude is 6.4 C/1000 M or 3.5 F/1000 Ft. - density of the atmosphere decreases with increasing altitude (density of the atmosphere at an elevation of 5500 m is about half that at sea level) - mountainous areas experience lower temps than regions near sea level

Global Climate Observing System

coordinates the reading and recording of temperatures among countries worldwide

Apparent temperature

general term for the outdoor temperature as it is perceived by humans - humidity and wind affect apparent temperature

Gulf Stream

warm current that moves northward off the east coast of North America, carrying warm water into the North Atlantic - higher ocean temps produce higher evaporation rates, and more energy is dissipated from the ocean as latent heat - more water vapor leads to cloud formation, which reflects insolation and lowers temperatures (negative feedback)

Absolute zero

- 0 absolute temp, the temp at which atomic and molecular motion in matter completely stops - negative 273 celsius, -59.4 Fahrenheit, 0 kelvin

Evaporation and Temperature

- 84% of all evaporation on Earth is from the oceans - as surface water evaporates, it absorbs energy from the immediate environment, resulting in a lowering of temperatures - land affected less by evaporative cooling than water

Continental effect

- Condition of continentality, refers to the greater range between maximum and minimum temperatures on both a daily and yearly basis that occurs in areas inland from the ocean

3 Expressions of Temperature

- Daily mean temperature: average of hourly readings taken over a 24-hour day - Monthly mean: total of daily mean temperatures for the month divided by the number of days in the month - annual temperature range: expresses difference between lowest and highest monthly mean temperatures for a given year

Ocean currents and Temperature

- along midlatitude and subtropical west coats, cool ocean currents flowing toward the equator moderate air temperatures on land

Cloud cover and Temperature

- at any moment, approx 50% of Earth covered by clouds - colder temps on a clear night, especially during dawn (coldest time of the day) - at night, clouds act as an insulating layer, presence of clouds raises night temperatures - during day, clouds lower temperatures reflecting insolation

Soil temperatures

- below the surface, even at shallow depths, temperatures remain about the same throughout the day - ex. beach: surface sand may be painfully hot, but as you dig in your toes it is cooler

Elevation and temp

- height of a point on Earth's surface above some plane of reference - high elevations, surfaces gain and lose energy rapidly to the atmosphere - average air temps are lower, nighttime cooling is greater, temp range between day and night is greater than at low elevations - temp difference between areas of sunlight and shadow is greater at high elevation than at sea level

Latitude and Temp

- insolation is more intense than at higher latitudes where the Sun is never directly overhead - intensity of incoming solar radiation decreases away from the equator and toward the poles - sun angle and daylight drive seasonal effect of latitude on temperature

Thermometer

- sealed glass tube containing a fluid that expands and contracts according to whether heat is added or removed - mercury: freezes at -39 C - alcohol thermometers preferred in colder climates

Water movement and Temperature

- the movement of currents results in a mixing of cooler and warmer waters which spreads the available energy over an even greater volume - vertical direction - land loses its energy more readily than does moving reservoir of oceanic energy

Land-water heating differences and Temperature

The physical differences between land - land heats and cools faster than water

Transparency and Temperature

When light reaches a body of water, it penetrates because of water's transparency (water is clear and light passes through it) - distribution of available heat energy forms a larger reservoir of energy storage than that which occurs on land

Humidity

presence of water vapor in the air - the higher the amount of water vapor, the higher the relative humidity

Heat wave

prolonged period of abnormally high temperatures usually in association with humid weather