Chapter 9 Flashcards
(24 cards)
sensible heat
Heat energy that can be measured by a thermometer and thus potentially sensed by humans.
orographic uplift
The forced uplift of an air mass because of the presence of a topographic obstruction. This uplift also causes the cooling of the air mass. If enough cooling occurs condensation can occur and form into orographic precipitation. Also called orographic lifting.
Tropical Moist Climates
These are very warm climates found in the tropics that experience high quantities of precipitation. The primary distinguishing characteristic of these climates is that all months have average temperatures above 18°C (64°F).
Dry Climates
These are climates that experience little precipitation during most of the year. Further, potential losses of water from evaporation and transpiration greatly exceed atmospheric input of precipitation.
Koppen Climate Classification System
System that uses monthly precipitation and temperature data and total annual precipitation data to classify a location’s climate into one of five main categories: Tropical Moist Climates (A); Dry Climates (B); Moist Mid-latitude Climates with Mild Winters; (C) Moist Mid-Latitude Climates with Cold Winters (D); and Polar Climates (E).
Moist Mid Latitude Climates with Cold Winters
In these climates, summer temperatures are warm and winters are cold. The primary distinguishing characteristic of these climates is that the average temperature of the warmest month exceeds 10°C (50°F), and the average temperature of the coldest month is below -3°C (27°F).
Polar Climates
These climates have very cold winters and summers, with no real summer season. The primary distinguishing characteristic of these climates is the warmest month has an average temperature below 10°C (50°F)
Highland Climates
These are climates that are strongly influenced by the effects of altitude. As a result, the climate of such locations is rather different from places with low elevations at similar latitudes.
Glacial Ice Deposits
Fluctuations in climate can be determined by the analysis of gas bubbles trapped in the ice which reflect the state of the atmosphere at the time they were deposited, the chemistry of the ice (concentration or ratio of major ions and isotopes of oxygen and hydrogen), and the physical properties of the ice.
Biological Marine Sediments
Climate change can be evaluated by the analysis of temporal changes in fossilized marine fauna and flora abundance, morphological changes in preserved organisms, coral deposits, and the oxygen isotopic concentration of marine organism
Inorganic Marine Sediments
This type of proxy data includes clay mineralogy, aeolian terrestrial dust, and ice rafted debris
Pleistocene
Geologic epoch from about 2.588 million to 11,700 years ago. During this span of time extensive areas of land in the Northern Hemisphere at the high and middle latitudes where covered with glacial ice. One of two epochs during the Quaternary Period. Sometimes called the Ice Age. See International Commission on Stratigraphy for most recent version of the geologic time scale
Ice Age
Time when glaciers dominate the landscape of the Earth. The last major ice age was during the Pleistocene Epoch.
Holocene Epoch
Geologic epoch from about 10,000 years ago to today. During this period glaciers retreated because of a warmer global climate. Time of modern humans. One of two epochs during the Quaternary Period.
Younger Dryas Period
A cold period during the generally mild Holocene Epoch that occurred from about 10,000 - 8,500 BC. Scientists speculate that this cooling may have been caused by the release of fresh water trapped behind ice on North America into the North Atlantic Ocean
Climactic Optimum
Warmest period during the Holocene Epoch. This period is dated from about 7,000 to 3,000 BC. During this time, average global temperatures were 0.3 to 0.6°C (0.5 to 1.1°F) warmer than they were during the the period 1961-1990. Also called Hypsithermal, Altithermal, Holocene Optimum, Holocene Thermal Maximum, and Holocene Megathermal
Medieval Warm Period
A period of relatively warmer climate that occurred in northern Europe, the North Atlantic, southern Greenland, and Iceland from about the 900 to 1200 AD.
Little Ice Age
A climatically defined period roughly from 1550 to 1850 AD. During this period, global temperatures were at their coldest since the beginning of the Holocene
global warming
Warming of the Earth’s average global temperature because of an increase in the concentration of greenhouse gases. A greater concentration in greenhouse gases in the atmosphere is believed to result in an enhancement of the greenhouse effect.
proxy data
Data that measures the cause and effect relationship between two variables indirectly.
Milankovitch cycles
suggests changes in the Earth’s climate maybe explained by variations in solar radiation received at the Earth’s surface. These variations are due to the combined effects of three different cyclical changes in the geometric relationship between the Earth and the Sun.’ precession, solstices, equinoxes, obliquity, eccentricity
eccentricity
variations in the shape of the Earth’s orbit around the Sun
precession of the equinox
Wobble in the Earth’s polar axis. This motion influences the timing aphelion and perihelion over a cyclical period of 23,000 years.
Obliquity
The tilt of the Earth’s polar axis as measured from the perpendicular to the plane of the Earth’s orbit around the Sun. One cycle of obliquity takes on average 41,040 years. Over the last 5 million years, the angle of the Earth’s tilt has varied from 22.0 to 24.5°. Current obliquity is 23.4°, however, a value of 23.5 is commonly used for simplicity.
