Lecture 2 Flashcards
T OR F
Climate at the local level is more interesting and complex than the regional climatic type might suggest
T
humidity
pressure
a quantity representing the amount of water vapor in the atmosphere or a gas.
the pressure exerted by the weight of the atmosphere,
climate
characteristic values and seasonal patterns of weather elements that in the long term
Climate is a term that relates to the average state of the earth’s atmosphere and incorporates statistics about temperature, humidity, atmospheric pressure and precipitation for a given region over long periods (i.e., 30 or more years).
It is important to include in the description of climate some indication of ____ and _____ and occasional but significant phenomena, such as a mid-January thaw
variability and extremes
Standard climatological practice is to use the most recent __-year averaging interval to construct climatic normals
30
The climate of a location is affected by its: 4
latitude, altitude, terrain conditions and proximity to large bodies of water and their currents
Earth’s climate is driven by energy received from the sun. This energy input, in the form
of ______ radiation, is balanced in the long-term by ________radiation emitted
back into space from earth and its atmosphere.
shortwave
longwave
Earth’s atmosphere is a mixture of different gases. The dominant gases are nitrogen (N2; ___ percent) and
oxygen (O2; __ percent) with the remaining one percent made up of trace gases. The trace gases include relatively small amounts of carbon dioxide (CO2) and other gases (e.g., water vapour (H2O) and methane (CH4)) which absorb longwave radiation and raise the air temperature resulting in what is called the greenhouse effect
78
21
These interactions include positive and
negative feedbacks, which magnify (_____ feedbacks) or reduce (______ feedbacks)
the effect of particular actions.
positive
negative
Incoming solar radiation is approximately ____ W/meter 2
longwave(______) radiation back to the atmos can be reabsorbed and or continue into space
343
infrared
Geographical factors or ______ work together to
shape particular seasonal and long-term climates. Climatic _____ include: (6)
Geographical factors or controls work together to
shape particular seasonal and long-term climates. Climatic controls include:
1• Latitude (seasonally affects solar radiation and length of day);
2• Continentality (relative position with respect to coasts and continental interior);
3• Elevation above sea level (related to atmospheric lapse rate);
4• Prevailing and seasonal large-scale atmospheric circulation features
(determine the transport of heat and moisture, severe weather and other
phenomena);
5• Regional factors (such as warm or cold ocean currents or presence of mountain
ranges);
6• Local and landscape-scale features that affect the surface energy and water
budgets (forests, wetlands, lakes, glaciers or ice fields).
The earth’s rotational axis is tilted with respect to the plane of its orbit around the sun by approximately _____ degrees (Figure 2-4).
The sun appears to be overhead at different latitudes each day, moving seasonally between the Tropic of _______ (23.5 degrees N) and the Tropic of _______ (23.5 degrees S). The sun never appears directly overhead north of 23.5 degrees N or south of 23.5 degrees S.
23.5
cancer
capricorn
The angle that the sun-earth line makes with respect to the equator is called the _______ of the sun, which ranges from +___ degrees to -___ degrees between the northern hemisphere summer solstice (around ______ 21) and winter solstice (around _____ 22). The sun appears directly overhead at the equator and its declination is zero degrees at the equinoxes (21 March and 22 September).
declination
23.5,23.5
june, december
At local noon the altitude of the sun can be determined by this equation:
Altitude = 90 degrees – (______ - _______)
Altitude = 90 degrees – (Latitude - Declination)
Altitude practice questions:
- Determine the solar noon Sun angle at the following locations and dates:
20°S at an equinox ____________________
The Tropic of Cancer at the June solstice __________________ 40°N at
the December solstice ____________________
The equator at the June solstice ____________________ (4 marks)
The declination of the sun on June 21 is +23.5 degrees so at noon at latitude 60o N, the
sun will be ___ degrees above the horizon.
So Sun Angle for 20oN at an equinox = 90o
-20o
= 70o
On December solstice, declination is -23.5o
, then SA= 90-|lat-(-23.5o)|
So Sun Angle for 40oN at the December solstice = 90o - |40o-(-23.5o)|= 26.5o
On June solstice day, declination is 23.5º, then SA=90º -|lat-(23.5 º)|
So Sun Angle for Tropic of Cancer at the June solstice = 90o
-|23.5o-(23.5 º)|= 90o
So Sun Angle for the equator at the June solstice = 90o-|0-(23.5 º)|= 66.5o
53.5
For example, at 20 degrees, the
irradiance is only / as great as it would be if the sun were overhead. _____ of the
radiation by the atmosphere further reduces incoming energy.
1/3
absorption
continentality
Water has a greater heat capacity than soil or rock, therefore, land surfaces tend to
warm and cool faster than large bodies of water, especially oceans. This means inland
areas generally have higher summer (and daytime) temperatures and lower winter (and
night-time) temperatures than coastal or island locations at the same latitude, although
average yearly temperatures in both locations may be the same. This effect is known as
continentality.
Elevation
As one moves upward in the free atmosphere and away from the earth’s surface, the
temperature usually decreases. On average this decrease, known as the lapse rate, is
approximately 6.5o C per kilometer. Accordingly, one would expect high elevations to
have lower temperatures than lower elevations, all else being equal. Generally, this is a
correct assumption. However, in northern regions there are large regional and seasonal
variations in lapse rates. In large areas of the north, the lapse rate is much less than the
global average. In winter, the temperature lapse over large areas is reversed so the air
above the surface to a height of several kilometers is warmer than it is near the ground.
This phenomenon, known as a temperature inversion, is mainly due to strong radiative
cooling (i.e., longwave radiation emitted from the earth’s surface into the atmosphere) at
the ground when the sun is low or below the horizon. The relationship of temperature to
altitude is more complicated in high terrain than in the free atmosphere. In mountainous
regions no simple rule applies.
On average this decrease, known as the lapse rate, is
approximately ___ degrees C per kilometer
6.5
Explain why there is a latituinal radiant energy imbalance and how that plays into planetary-scale circulation
Energy received from the sun is most concentrated in the lower latitudes (Figure 2-7). In contrast, longwave energy emitted by the earth into space is more evenly distributed with latitude. This means more energy enters the atmosphere at low latitudes than is lost (a
net energy gain), while at high latitudes more is lost than is gained from the sun (net energy loss). This latitudinal radiant energy imbalance results in excessive atmospheric heating in low latitudes, which sets up horizontal pressure gradients that drive the movement of air (and heat) toward polar regions with corresponding movement of cold air toward the equator. The resulting flow is modified by the earth’s rotation, internal atmospheric dynamics and interactions with topography to produce seasonal and longterm wind and pressure patterns that characterize earth’s planetary-scale circulation.
-The Arctic and Antarctic act as heat sinks where more energy is lost from the surface
and atmosphere to space than is gained from the sun. To balance this loss, heat is
imported to high latitudes by the atmosphere through the exchange of air. Picture an
imaginary wall around the Arctic Circle extending to the top of the atmosphere. The
atmospheric circulation flowing through it would consist of equal exchanges of poleward
and equatorward flowing air. This results in a net import of heat to the polar region as
cold air flows south and warm air flows north. This exchange varies seasonally, is
strongest in winter and is focused on specific pathways or trajectories.
General Circulation of Atmos
.5 main cells from North to south
.7 main winds in order from North to south
- Polar Cell
- Ferrel Cell
- between 2 & 3 is subtropical high pressure zone(30 degrees) - Hadley cells
- Ferrel Cell
- Polar Cell
PFHFP= POLAR FRONT HIDES POLAR FRONT
- Polar Front
- Westerlies
- NorthEast Trade winds
- Doldrums
- SouthEast Trade Winds
- Westerlies
- Polar Front
PWNDSWP
Polar Front
winds in the north polar region are shown as mainly from the northeast, converging with the westerlies in a subpolar zone of low pressure, the Polar Front
On average about __ percent of energy that reaches the surface is absorbed at the surface (Table 2-2). About __ percent is reflected back to
space by the surface and atmosphere, which is referred to as the earth’s ____ _____.
49
30
planetary albedo
Unlike shortwave
radiation, which passes easily through the atmosphere, nearly all longwave radiation is
absorbed in the atmosphere producing the _________ effect
greenhouse
_____ ____ is the surface which has the highest albedo effect
Fresh Snow 0.70-0.90
Fundamental principle of Conservation of energy
Over time there is a
balance between the total shortwave energy received by the earth (atmosphere and
surface) and the amount of longwave and reflected shortwave radiation returning to
space.
Energy Budget
Exchanges of energy in different parts of the global climate system can be viewed in
terms of an energy budget.
Surface albedo= __/__
The surface albedo is equal to K↑ divided by K↓. The lower the albedo the greater the amount of solar radiation available to heat the surface.
K↓ and K↑ are…
incoming and reflected shortwave radiation terms
L↑ is _____ radiation from the ______ and L↓ is…
longwave, surface
the proportion of atmospheric longwave radiation
directed to the surface.
Q=__-__-__+__
K↓, K↑,L↑, L↓
net radiation Q*
-* being the algebraic sum of the four radiation terms
When net radiation is equal to __, there is a
balance among various short- and longwave terms. If Q* is positive, the surface is ______. If Q* is negative, the surface is ______.
0
heating
cooling
Radiation is not the only way energy is exchanged at the surface. Three other heat transfer processes work to offset net radiation
1• QS is heat conducted down into or up from the ground;
2• QH is sensible heat associated with the upward movement or convection of air
that warms and rises after contact with the ground; and
3• QE is latent heat flow associated with evaporation of water at the surface,
melting or sublimation of snow, and thawing of permafrost (negative when water
is condensing or ground is freezing).
surface energy budget=
QE(latent heat) and Q(net radiation)
ex: A simple example is the difference between a wet surface where energy is used to evaporate the water (QE), and a dry surface where energy heats the air (QH) and ground (QS). If net radiation is assumed to be positive and equal for both surfaces, air above the dry surface will be warmer than air above the moist surface.
QE(latent heat) is the product of
QE is the product of latent heat of vaporization (LV) and E, the mass of water vapor
being evaporated
Bowen Ratio
The table introduces the Bowen Ratio, which is simply the ratio QH(sensible heat)/QE(latent heat) and indicates what proportion of available energy heats the air relative to that used to evaporate water from the surface.
Factors that contribute to seasonal variation in net radiation and various energy balance
components for the north are described below.
- Winter
- Spring
- Summer
- Fall
1.The sun is below the horizon for most of the winter season. During periods when the sun is above the horizon, the combination of low sun angle, short day length and high surface albedo ensure net radiation is low. The small quantity of available energy is used
to melt or sublimate snow and ice and/or evaporate water from open water surfaces. Little or no energy is available to warm the ground surface; therefore, cold air temperatures characterize winter.
2.Sun angle and day length increase during the spring season. This serves to increase net all-wave radiation. Much of the available energy is used initially to melt and sublimate snow and ice on the surface. Once the snow and ice cover is removed, surface albedo is
reduced by the presence of dark-coloured surfaces. Increased absorption of radiation provides energy to heat the ground surface, raise air temperature, evaporate water and begin to thaw permafrost. Air temperature gradually increases throughout the spring.
- The sun is above the horizon for most of the summer season. The combination of high sun angle, long day length and low surface albedo ensure net radiation is high. A small portion of available energy is used to remove remaining snow and ice on the ground
surface. The remainder of available energy heats the ground surface, evaporates water, raises air temperature and continues thawing permafrost, which leads to the development of the permafrost active layer.
4.Sun angle and day length decrease during the fall season. This decreases net all-wave radiation reducing energy available to heat the ground surface, raise air temperature, evaporate water and sustain thawing of permafrost. Longwave radiative surface cooling begins leading to progressive cooling of air temperature and refreezing of the active layer of permafrost.
Global Water Cycle
5 BASIC STEPS in system
The global water cycle describes how water on earth moves from various “compartments” (ocean, atmosphere, snow and ice, lakes and streams, soil moisture and ground water) and the physical processes involved (Figure 2-10). No significant amount of water appears in or is lost to the system. Water is a finite but renewable resource.
Water falls as PRECIPITATION (rain and snowfall). It is temporarily HELD in the soil or seasonal snow covering the land, glaciers or sea ice. Water then moves as
RUNOFF into streams, perhaps to groundwater, and eventually to the ocean. Energy from
the sun drives the return flow from the land and ocean to the atmosphere through the
processes of EVAPORATION and TRANSPIRATION.
Less than _____ percent of the earth’s water is in the atmosphere
0.001
If all water in the atmos rained out at one time, it would cover the entire earth to approximately a ___ cm depth. Since the earth’s average yearly precipitation is approximately ___ cm, water must cycle many
times per year.
2.5 cm
100 cm
drainage basin(also called a _______)
drainage basin (also called a watershed), which is a land area where precipitation runs off into streams, rivers, lakes and reservoirs and eventually the ocean. Water may fall as snow and be held until it melts in the spring or be held for decades or centuries as ice in a glacier. A drainage basin can be delineated on a map by tracing a line along the highest elevations that enclose a stream and its tributaries (i.e., a drainage divide).
drainage devide
A drainage basin can be delineated on a map by tracing a line along the highest elevations that enclose a stream and its tributaries (i.e., a drainage divide).
two largest river basins moving poleward
The largest rivers basins, the Lena River in Russia
and the Mackenzie River in Canada, contain thousands of smaller drainage basins
It is possible to discuss water movement in budget terms because of the conservation
of mass principle
__-__=__
P – E = R
More simply P-E=R
-because storge is assumed to be zero when averaged
It is possible to discuss water movement in budget terms because of the conservation of mass principle. Outflows from part of the system must equal inflows plus or minus any change in the amount of water storage in a compartment. For example, the mass of
water discharged from the mouth of a river (R) is equal to the precipitation that falls on it (P) less the mass of water evaporated or transpired (E) plus or minus any change in water stored in various parts of the drainage basin (ΔS).
runoff ration= __/__
The runoff ratio R/P indicates the
proportion of precipitation that runs off directly to streams rather than infiltrating into the
soil to be transpired by vegetation.
In the Arctic, a high runoff ratio is associated with
large areas of impenetrable _______ within the basin
permafrost
____ runoff ratio means that less water is absorbed into the surface
high
5 major rivers that flow into the arctic
five major rivers that flow into the Arctic, the Mackenzie and Yukon in North America, and the three largest in Asia, the Ob, Yenisey and Lena Rivers.
-Ob least ammount of runoff because of least ammount of permafrost
pack ice
landfast ice
multiyear ice
open ocean takes on a cover of drifting pack ice
while protected coasts and bays have landfast ice (Figure 2-11) of varying extent, which grows several metres thick by spring.
In the central Arctic Ocean
and part of the Canadian Arctic Archipelago, ice persists into the following winter
The area of ice-covered ocean reaches its maximum of approximately 15 million km2 in _____ when seasonal warming slows and reverses ice growth. The ice
melts and contracts to about half the area by late ______
March
september
Is ice growth and example of negative or positive feedback loop?
Another type of feedback occurs as water bodies freeze in the fall. Once formed, ice cover reduces convective loss of heat to the atmosphere from the water, allowing air to cool further and ice to grow downward. However, as ice thickens heat loss to the
atmosphere decreases as does the rate of ice growth. Thickening ice works against ice growth, a negative feedback, which sets an upper limit on how thick multiyear ice becomes.
Treeline= This limit corresponds approximately to the end of the zone above which _____
temperatures average less than __ degrees C.
july
10
Landscapes include natural features and _____ elements.
cultural
North Pole represent less than __ percent of the earth’s area and approximately ____ of
this area is ocean
10
half
Most of the North(of 60 degrees) is classified as= 4
EF=Ice cap
ET=Tundra
DFC=subarctic
DWD=subarctic
Large masses of air containing heat, moisture and
pollutants move from middle to higher latitudes in _______ depressions that follow favored tracks, especially in the North Atlantic sector between Greenland and Scandinavia (Figure 2-19).
cyclonic
Although cyclonic storms are mainly a mid-latitude
phenomenon many move northward bringing heat and moisture to affect the Subarctic
and Arctic regions.
Polar Lows
Not all Arctic storms come from the south. Polar lows are intense, short-lived storm systems that form over ocean areas along the boundary between cold and warmer waters, as in the Labrador Sea and Norwegian Barents Seas. Polar lows bring strong winds, rapid temperature change and heavy precipitation that usually falls as snow
Temperature and Precipitation patherns in nORTH
COMPARE CONTINENT TO MARITIME
Figure 2-16 shows summer and winter temperature patterns for the Arctic, averaged over a number of years. Winter temperatures are coldest in the continental interiors (Siberia) and warmest in areas influenced most strongly by relatively warm ocean
currents and storm tracks associated with the North Atlantic Ocean (Norwegian and Barents Seas). Summer temperatures are highest in the continental interiors, remaining most depressed over the Greenland Ice Cap and the Arctic Ocean.
Precipitation is relatively low across much of the North, compared with the global average of approximately 1,050 mm per year (Pidwirny, 2006). Major river basins shown in Table 2-4 average approximately 400 to 500 mm of precipitation annually. Winter and summer precipitation amounts over the Arctic are indicated in Figure 2-17. Polar desert regions of the High Arctic experience less than 30 mm in July (200 mm annually), while coastal areas adjacent along principal storm tracks receive more than 1,000 mm annually with the greatest amounts in the fall and winter.
arcctic haze
This haze is a form of pollution composed of
aerosols, which are microscopic liquid or solid particles that come from natural and
anthropogenic sources.
stable atmosphere
can result in two things if combined with atmospheric pollutants trapped as surface
In many areas, particularly inland valleys, winter is a season of relatively light winds and low surface temperatures creating stable atmos at ground level
- As a result, emissions composed of gases and particles are trapped near ground-level causing reduced visibility and respiratory problems for people in these
areas. - Where sufficient moisture is present in the emissions and the temperatures are below – 35 oC, ice fog can form
DEFINITION FUN
- Biomes:
- Cyclonic Depression:
- Greenhouse Effect:
- Heat Capacity:
- Lapse Rate:
- Latent Heat of Vaporization:
- Longwave Radiation:
- Planetary Albedo:
- Shortwave Radiation:
- Stable Atmosphere:
- Transpiration:
1.are climatically and geographically defined as similar climatic conditions on the earth, such as communities of plants, animals and soil organisms and are often referred to as ecosystems.
2.an area of low atmospheric pressure characterized by inward spiraling winds that rotate anticlockwise in the northern hemisphere and clockwise in the
southern hemisphere.
3.a process by which radiation emitted from the earth’s surface is absorbed by atmospheric greenhouse gases (e.g., water vapour, carbon dioxide) and is
re-emitted in all directions.
- a measurable physical quantity that characterizes the amount of heat required to change a substance’s temperature by a given amount.
- in physical geography, the rate of change of any atmospheric variable withaltitude, especially atmospheric temperature.
- the amount of heat required to convert a unit mass of a liquid at its boiling point into vapour without an increase in temperature.
- electromagnetic radiation with wavelengths greater than 4 microns (1 micron = 1 µm = 1 x 10-6 metres).
8.the fraction of solar radiation that is reflected by the earth atmosphere system and returned to space mostly by back scatter from clouds in the
atmosphere.
- electromagnetic radiation with wavelengths between 0.4 to 4.0 microns.
- the atmosphere is considered stable when it does not support, in any way, the movement of air molecules upward for a defined area or location.
- a process in which the water vapour escapes through plant leaves into the atmosphere.
