ESS 11 Exam 3
The "A" climates are some of the wettest on Earth. Do any of the "A" climates have a dry season? If so, which ones?
Am: monsoonal with short dry season and rest year rainy Aw: distinct dry season (seasonal subtropical high pressure)
How do the semi-permanent Sub-Tropical Highs and cold ocean currents help determine the location of deserts and other dry climates?
Cold ocean currents + sub-tropical highs = desert.
What is the most important factor responsible for seasons on Earth?
Earth's tilt on its axis
What are typical impacts from El Nino in North America? Southeast Asia?
Changes in patterns of precipitation and temperature. Severe drought and massive food shortage
Define climate and the climate system including the various 'spheres' of the climate system.
Climate - long term atmospheric conditions in a region Earth's climate includes interactions of: Atmosphere - all air/gases surrounding Earth Hydrosphere - all water on Earth Geosphere - all rock/subsurface on Earth Biosphere - all life on Earth Cryosphere - all ice on Earth Climate system - exchanges of energy and moisture between these spheres
Define both climate and climate change. Why is it difficult to observe climate change?
Climate is the long-term statistical properties of the atmosphere for an area. Climate change is the change in global or regional climate patterns, in particular a change apparent from the mid to late 20th century onwards and attributed largely to the increased levels of atmospheric carbon dioxide produced by the use of fossil fuels. It is difficult to observe climate change because he consequences of changing the natural atmospheric greenhouse are difficult to predict. Climate change models can mimic modern conditions only if human forcing is taken into account.
Describe cloud feedbacks to human-induced greenhouse gas warming.
Clouds reflect solar radiation (promotes cooling) and absorbs upwelling longwave (promotes warming). Which radiative effect above "wins" is uncertain as is response of cloud frequency to warming. Positive or negative feedback unclear and extent uncertain Some research estimates suggest positive cloud feedback but range of estimate is large (10 to 50% amplification).
Describe the variation in the climate of North America east of the Rocky Mountains vs west of the front range of the Rockies.
East of the Rockies is low variation due to flat topography whereas West of the Rockies is extremely variable due to the small channels and passes within the mountains allowing the wind to change directions and the climate to vary more as altitude changes over a short distance.
Define eccentricity. What is the impact of eccentricity on Earth's climate?
Eccentricity is changes in the shape of the earth's orbit around the sun. If there is no eccentricity to Earth's orbit, then Earth will remain at the same distance from the sun throughout the year, therefore producing no climate change, seeing as how the Earth's orbit would be perfectly circular around the sun. On the other hand, if Earth's orbit has a very high eccentricity, Earth would be very close to the sun (compared to a perfectly circular orbit) during two opposite seasons, and very far away from the sun during the other two opposite seasons. This effect can be seen by analyzing any ellipse, and observing how flat or how skinny the ellipse becomes as its eccentricity increases.
Define and describe ENSO (El Nino and Southern Oscillation). Be sure to define the Southern Oscillation and explain its relationship to El Nino.
El Nino and Southern Oscillation = ENSO Southern Oscillation - is the atmospheric component of El Niño This component is an oscillation in surface air pressure between the tropical eastern and the western Pacific Ocean waters. El Niño has lower pressure over Tahiti and higher pressure in Darwin. La Niña has higher pressure in Tahiti and lower in Darwin.
List the five primary climate controls.
Elevation, latitude, location, landforms, prevailing winds and ocean currents
Describe what the process of 'remnant landforms' is and explain how it can be used as proxy data for climate studies
All of Earth's landforms are the end result of processes that build up and wear down features at the surface. Mechanisms for eroding and depositing material include the movement of water, the slow-moving ice sheets expanding across the surface, wave action along coastlines, wind, and floating icebergs carrying land debris. These mechanisms leave characteristics that scientists can use as evidence to infer climatic conditions at the time of erosion or deposition.
Identify & describe the Maunder minimum and explain its relationship to the Little Ice Age.
An absence of sunspots was well observed from 1645 to 1715. The so-called "Maunder minimum" coincided with a cool climatic period in Europe and North America: "Little Ice Age" The Maunder Minimum was not unique. Increased medieval activity Correlated with climate change.
What is the significance of the Arctic and Antarctic Circles?
Arctic Circle, parallel, or line of latitude around the Earth, at approximately 66°30′ N. The Antarctic Circle is the southern counterpart of the Arctic Circle, where on any given date conditions of daylight or darkness are exactly opposite.
Which primary climate classification depends solely on the amount of precipitation received?
B- Dry
Describe the relative frequency of warm periods vs. cold ice ages during Earth's climate over the last 2.5 billion years, as well as the last ~400,000 years.
Brief cold ice ages interrupted a generally warm climate, about 10-20% of the time in the last 2.5 billion years. For most of Earth's history, climate was 5-15°C warmer than present. For 20,000 years, global temperatures warmed by more than 5°C (9°F). Massive releases of carbon dioxide and methane from multiple sources led to the so-called Paleocene-Eocene Thermal Maximum (PETM).
Define and describe the Milankovitch cycles in earth-sun orbital mechanics and explain their relationship to natural climate change. Be sure to identify and describe the three properties of the Earth's orbit that explain natural climate change on the 20,000 to 100,000 year time frame.
Milankovitch cycles refer to regular natural variations in the Earth's orbit around the sun. Serbian astrophysicist in 1920's who studied effects of solar radiation on the irregularity of ice ages. Likely played important role in expansion and retreat of glaciers during Pleistocene, especially as they relate to seasonality. E.g., low seasonality - warmer winter means more water vapor to make more snow and cooler summers promote less melting. Changes in shape of the earth's orbit around sun: Eccentricity (100,000 years) Wobbling of the earth's axis of rotation: Precession (22,000 years) Changes in the tilt of earth's axis: Obliquity (41,000 years)
Which primary climate type (Tropical, Dry, Mild Midlatitude, Severe Midlatitude, or Polar) has the great temperature difference between summer and winter? Why?
Mild Midlatitude. The coldest month of the year has an average temperature higher than -3°C (27°F) but below 18°C (64°F). Summers can be hot.
Define and describe the 'Little Ice Age' and the causes of this cold period.
More recently, 'Little Ice Age' - 1400 to 1850 AD - cold period recorded for Western Europe - Alpine Glaciers Advanced (but not a true ice age) - Temperatures fell by 0.5° C to 1° C (0.9° to 1.8° F) - Shortened growing periods for agriculture
Describe positive and negative feedbacks and provide examples of each
Negative: feedback acts to inhibit further change in a variable. Positive: feedback acts to magnify further change in a variable. Examples: Ice-albedo, water vapor and clouds, atmosphere-biosphere interactions, and ocean-atmosphere interactions.
Do you expect numerous severe thunderstorms in the severe midlatitude climates? What makes the severe midlatitude climates "severe" in name?
No. Severe means very cold winters.
List and describe a few effects (or impacts) of temperature related variables associated with global warming in the last century
Number of days with frost has decreased over many parts of the midlatitude regions. Decrease in extreme cold and extreme warm events have become more frequent. Snow cover has decreased in most areas and has mostly been driven by increasing temperature. From 1901 to 2002 the maximum extent of seasonally frozen ground declined by about 7 percent in the Northern Hemisphere.
Define obliquity. What is the impact of obliquity on Earth's climate?
Obliquity is the changes in the tilt of earth's axis. Obliquity does not influence the total amount of solar radiation received by the Earth, but affects the distribution of insolation in space and time. As obliquity increases, so does the amount of solar radiation received at high latitudes in summer, whilst insolation decreases in winter.
What is the main driver for the direction that surface ocean currents flow?
Surface currents are mainly driven by surface winds
List and describe the secondary classification (or climate sub-zones) associated with each primary climate zone. Again, it's not necessary to memorize the letters. Just be aware of what properties differentiate climate sub-zones within each primary climate zone.
A: f, m, w 2nd letter indicates when dry season occurs - Af: no dry season at all - Am: monsoonal with short dry season and rest year rainy - Aw: distinct dry season (seasonal subtropical high pressure) BW: true deserts and BS: semi-deserts C or D: 2nd letter signifies timing of dry season - f: no dry season - s: dry summer - w: dry winter ET: polar tundra and EF: polar covered by glaciers If present, 3rd letter represents temperature regime
Describe the greenhouse effect and its role in the Earth system's energy budget.
Addition to or subtraction from heat on Earth Incoming radiation from Sun shorter wavelengths Outgoing radiation from Earth longer wavelengths Rates of energy absorption and re-radiation must be equal when in equilibrium
Explain how volcanoes can modify the climate. Identify the approximate effect of recent volcanoes on global temperature (note: don't need to remember exact values - just approximate range)
As noted earlier, volcanic eruptions can increase stratospheric aerosols Volcano releases sulfuric gases that transform chemically to form aerosols Can increase atmospheric albedo directly by increased aerosol backscatter and indirectly by increase in reflectivity of clouds Net cooling Recent examples: El. Chichón (Mexico) in April 1982 Decreased global temperatures by 0.2° C (0.4° F) Mt. Pinatubo (Philippines) in June 1991 Global mean tropospheric temperature decrease of 0.7° C (1.6 °F)
How do the semi-permanent High pressure cells relate to the location of Earth's deserts?
At the Equator, the sun's rays are perpendicular with the Earth's surface; solar heating is intense. Air is heated at the equator, ascends, and is replaced by inrushing air. As the heated air moves upward, it is gradually cooled. Cool air, with a lower saturation point, is capable of holding less moisture within than warm air. (Equatorial air is very moist). Desert formation in these particular latitudes is primarily due to complex global air-circulation patterns caused by the rotation of the earth on its axis (earth moves at great speed near the equator and slowly near the poles), the seasonal tilting of the earth in relation to the sun, and other factors.
Identify the two primary variables used for climate classification
Average temperature and precipitation
List and briefly describe the five primary Koeppen System climatic zones. Note, it is not necessary to memorize the letter abbreviations for the primary climate zones (or secondary sub-zones). If the letter abbreviations are used on the exam, they will be provided with the actual climatic zone first for clarity.
A—Tropical. Climates in which the average temperature for all months is greater than 18°C (64°F). Almost entirely confined to the region between the equator and the tropics of Cancer and Capricorn. B—Dry. Potential evaporation exceeds precipitation. C—Mild Midlatitude. The coldest month of the year has an average temperature higher than -3°C (27°F) but below 18°C (64°F). Summers can be hot. D—Severe Midlatitude. Winters have at least occasional snow cover, with the coldest month having a mean temperature below -3°C (27°F). Summers are typically mild. E—Polar. All months have mean temperatures below 10°C (50°F). H- Highlands - for representing mountainous regions
Describe deforestation and desertification and explain how these human-induced changes to the land surface could potentially impact climate.
Deforestation: large tracts of land cleared of trees. - reduces evapotranspiration and changes surface energy budget. - Less energy involved in evaporation resulting in higher surface temperatures and less precipitation. - Decomposition of vegetation leads directly to increased CO2, a greenhouse gas. - Indirect increase in CO2. Desertification: alteration of arid/semi-arid land surfaces by overgrazing cattle, poor agricultural practices, deforestation. - Loss of natural vegetation.
Describe the direct and indirect effects of aerosols on climate.
Direct: scattering and absorption of solar and infrared radiation Indirect: Serve as cloud condensation nuclei (CCN) affecting cloud development.
List and briefly describe some typical global and regional impacts during ENSO events.
Disastrous effects of 1982-1983 El Nino: 1.Australia-Drought and devastating brush fires 2.Indonesia, Philippines-Crops fail, starvation follows 3.India, Sri Lanka-Drought, fresh water shortages 4.Tahiti-6 tropical cyclones 5.South America-Fish industry devastated - decrease in nutrients off Peru- fewer fish (anchovy) 6.Across the Pacific-Coral reefs die 7.Colorado River basin-Flooding, mud slides 8.Gulf states-Downpours cause death, property damage 9.Peru, Ecuador-Floods, landslides 10.Southern Africa-Drought, disease, malnutrition
Where are the various dry climates located, and why do they occur where they do?
Dry climates occur in areas where potential evapotranspiration is greater than precipitation. 30% of Earth's land surface is classified as a dry climate. Semideserts are transitional zones that separate the true deserts from adjacent climates. They are also called steppe climates, with reference to the associated vegetation type consisting of short grasses. The two-tiered system of categorization yields four types of dry climates: subtropical desert, subtropical steppe, midlatitude desert, and midlatitude steppe.
Describe the current global climate temperature vs the last 2.5 billion years
Due to meteorological data/stations on the increase, more climate data is available for the last century. Have seen rapid warming in recent decades Global warming is not the only climate trend in the last hundred years. Precipitation exhibits variability from year to year and from place to place. Long-term changes must be very large.
Explain the impact of El Nino to trade winds, ocean circulations (including the tilt of thermocline and upwelling of cold water on S. American coast), SSTs, and locations of rising/subsiding or stormy/clear air.
During El Nino trade winds slacken E-W tilt of thermocline & upwelling of cold water are reduced. SST rises in central/eastern equatorial Pacific Changes Walker Circulation
What factor other than annual precipitation is involved in a climate being defined as dry?
Evapotranspiration
What was the primary cause for the "year without a summer" in 1816?
Evidence suggests that the anomaly was predominantly a volcanic winter event caused by the massive 1815 eruption of Mount Tambora in April in the Dutch East Indies (known today as Indonesia). This eruption was the largest in at least 1,300 years (after the hypothesized eruption causing the extreme weather events of 535-536), and perhaps exacerbated by the 1814 eruption of Mayon in the Philippines.
Define (i.e. compare and contrast) an external and internal forcing associated with the Earth system. Identify whether a particular forcing agent is internal or external.
External Forcing: The agent of change is outside of the Earth-atmosphere system Internal Forcing: The agent of change is within the Earth-atmosphere system itself
Identify and describe the impact of El Nino and La Nina on hurricane activity in the Atlantic and Eastern Pacific basins.
Fewer hurricanes in Atlantic Basin during El Nino due to stronger vertical wind shear and greater atmospheric stability there. More hurricanes in Atlantic Basin during La Nina due to weaker vertical wind shear and less atmospheric stability there.
How accurately have GCMs predicted Earth's global temperature over the past 20 years?
General Circulation Models (GCM's) - The average amount of warming predicted by the IPCC GCM's for three 20-year time periods. - Research will help to better understand the impact of human activity, and new information will be obtained to help better understand climate change. Large uncertainty in GCM outcomes: - need more research to improve models and observations (for validation) of the atmosphere
Describe the term 'global dimming' and explain how it can counteract the forcing effects of increased greenhouse gases.
Global dimming: reduction of solar radiation reaching the Earth's surface due to absorption and backscattering of sunlight by human-induced tropospheric aerosols Net effect of increased tropospheric aerosols is reduction of surface temperatures globally E.g., 1970 to 1990 amount of solar radiation reaching Earth's surface decreased several percent due to increased aerosols or air pollution Radiative cooling due to anthropogenic aerosols can 'mask' (or counteract) radiative warming simultaneously occurring due to greenhouse gases
What is the Greenhouse Effect? Would there be life on Earth without the Greenhouse Effect? How can humans amplify the Greenhouse Effect?
Greenhouse effect keeps Earth's surface habitable. Incoming heat energy is shorter wavelengths. Longer wavelengths some trapped, some escape, net warming effect. There would not be life on earth without the Greenhouse effect. Humans can amplify the Greenhouse effect from Anthropogenic contributions of CO2 via fossil-fuel burning.
Identify and describe the two primary severe midlatitude climates: 'Humid Continental' and 'Subarctic'. Be able to differentiate between the two primary severe midlatitude climates. If given a climograph of temperature and precipitation, evaluate which of the two primary severe midlatitude climates is represented
Humid Continental (Dfa, Dfb, Dwa, Dwb): - Severe Midlatitude Climates • Very cold winters. • Large continental areas. • Evenly distributed annual precipitation. - Humid Continental (Dfa, Dfb, Dwa, Dwb) • Eastern continents of 40°N-55°N. • Warm to hot summers and cold winters. • Abundant annual precipitation. Subarctic (Dfc, Dfd, Dwc, Dwd): - Contains the coniferous boreal forest (taiga—Asia). - Warm, short summers and extremely cold winters. - Low annual precipitation with the moistest season being summer.
Describe and explain the ice-albedo feedback to human-induced greenhouse gas warming
Ice-albedo feedback (positive feedback) - Ice cover affects global albedo - Ice has a higher albedo than most other natural surfaces Expansion ice > increased albedo > reduced insolation > cooling Retreat of ice coverage > decreased albedo > increased insolation > warming
Describe the role of atmosphere-ocean General Circulation Models (GCMs) in identifying the cause of climate change and estimating a projection of future climate.
Identifying the causes of climate change: - Observing changes to particular causes and in making predictions about possible futures, climate science relies heavily on so-called Atmosphere-Ocean General Circulation Models (GCMs) (or global climate model) - GCMs are mathematical representations of the Earth atmosphere-ocean-land system that run on supercomputers.
Define and describe La Nina and compare and contrast it with El Nino. Define the Southern Oscillation during La Nina conditions.
In La Nina conditions SST in the central and eastern equatorial Pacific is unusually cold & easterly trade winds are unusually strong La Nina conditions sometimes occur in the year following an El Nino event (e.g. 1988 followed 1987 El Nino)
Explain the difference between a positive and negative feedback in the climate system.
Internal feedback processes of system can modify impact of change in external factors on system Positive feedback - enhance initial change Negative feedback - counteract initial change
Identify and describe the three mild midlatitude climates: 'Mediterranean', 'Humid Subtropical', and 'Marine West Coast'. Be able to differentiate between the three mild midlatitude climate zones. If given a climograph of temperature and precipitation, evaluate which of the three mild midlatitude climate zones is represented.
Mediterranean (Csa, Csb): - Distinct summer dry period due to subtropical high interactions. - Winter precipitation varies while temperatures are mild. - Mild to hot summers Humid Subtropical (Cfa, Cwa): - Eastern continental areas of the lower midlatitudes. - Long, hot, and muggy summers. - Abundant precipitation primarily the result of convection. - Winter temperatures are lower than those of Mediterranean climates. - The occurrence of frost and snow decreases toward the lower latitudes, but even south Florida is not completely immune. Marine West Coast (Cfb, Cfc): - Marine west coasts climates occur poleward of Csb. - Cold ocean current influence with mild summers and winters. - Often has fog and/or low cloud cover. - High frequency of rain days with low annual totals.
Discuss how geographic factors such as latitude and altitude influence the distribution of temperature across Earth's surface.
Low latitude locations experience only small temperature changes through the year as these location recieve nearly constant amounts of solar radiation. Location farther poleward experience larger annual temperature ranges as solar radiation values flux due to Earth-sun geometry. Because temperatures typically decrease with increasing altitude in the troposphere, higher altitude locations are typically cooler than lower altitude locations. However, because altitude refers to height above mean sea level without considering the elevation of landmasses below, this may be misleading. In sum, locations far above Earth's surface experience minimal fluxes in temperature as compared to locations directly below, and nearer the Earth's surface. Would you
Define and describe the Walker Circulation in terms of sea level pressure, surface winds, sea surface temperatures (SSTs), rising/sinking air (or presence of relatively stormy or clear regions) in the equatorial Pacific Ocean. El Nino vs. La Nina
Mean ascent (rising air), and low surface pressure, over warmest SST associated with deep convection (T-storms) Subsidence (sinking air), and high surface pressure, in non-convection regions (clear skies) Equatorial trades blow from high to low pressure, thus the easterly trade winds blow from east to west In La Nina conditions SST in the central and eastern equatorial Pacific is unusually cold & easterly trade winds are unusually strong
Explain how ocean deposits and ice cores are used as proxy data for climate studies. Note that for both of them, ratios of oxygen isotopes are used.
Oceanic Deposits: - Scientists extract deep cores of material that have been deposited over long periods, with more recent material constantly burying older material. - Cores include the bones and shells of plankton and other animal life. - The information contained in the oxygen in the calcium carbonate is most important for determining past climates. Ice Cores: -Scientists determine oxygen ratios for deep ice cores obtained from the Greenland and Antarctic ice sheets and from alpine glaciers at lower latitudes. -Ice cores are used to obtain temperature data from isotope ratios, and provide information on the past chemistry of the atmosphere and on the incidence of past volcanic eruptions. -Oxygen isotope ratio: 18O/16O ("heavy/light") -Snow fall under relatively warm conditions contains a greater amount of the heavier isotope -Concentrations of carbon dioxide (CO2) and trace gases like methane (CH4) trapped in bubbles of ice -Provide long term record of varying levels
Define paleoclimate and proxy data for characterizing it. List several possibly sources of proxy data for past climates
Paleoclimate - climates of the past Proxy data - indirect evidence using natural recorders of climate variability -Oceanic deposits -Remnant landforms -Ice cores -Coral reefs -Pollen (past vegetation) -Tree rings -Historical documents
Define precession. What is the impact of precession on Earth's climate?
Procession is the wobbling of the earth's axis of rotation. Axial precession makes seasonal contrasts more extreme in one hemisphere and less extreme in the other. Currently perihelion occurs during winter in the Northern Hemisphere and in summer in the Southern Hemisphere. This makes Southern Hemisphere summers hotter and moderates Northern Hemisphere seasonal variations.
Describe how solar output can be a source of natural climate change and explain how sunspots are related to solar output and can be used as a proxy
Solar energy changes: variable energy from the sun over time, luminosity, sunspots. Solar variations: Sunspots correlate with solar activity. More sunspots = more solar energy Sunspot numbers increase and decrease over an 1 year cycle. The sun is 0.1 to 0.2% brighter when solar activity is high.
How does the semi-permanent ITCZ relate to the location of rain forests?
Starting at the equator are the rainiest climates on earth, the tropical rain forest (Af) and tropical monsoon (Am). The tropical rain forest is noted to for its high, year-round rain fall that often exceeds 100 inches in a year. The copious rainfall is a product of the warm moist air masses that converge into the low pressure belt that straddles the equator and uplifted by convection. The monsoon climate in Africa, like the Asian monsoon, has a notable dry period during the low sun season. The dry period is due to the presence of the subsiding air of the subtropical high, while the wet season is due to the presence of the ITCZ and moisture-bearing trade winds along the coast.
Identify and describe the four types of dry climates: 'Subtropical Desert', 'Subtropical Steppe', 'Midlatitude Desert', and 'Midlatitude Steppe'. Be able to differentiate between the four dry climate zones. If given a climograph of temperature and precipitation, evaluate which of the four dry climate zones is represented.
Subtropical Deserts (BWh): - Largest deserts are located in BWh climates. - Occur on the western sides of continents. - Areas with atmospheric subsidence and high pressure. - High daily temperature ranges with low dew points and humidity. Subtropical Steppe (BSh): - High aridity. - High precipitation and temperature variability. - Large temperature ranges. - Extreme summer temperatures. - Summer precipitation. Midlatitude Deserts (BWk): - Extreme continentality and/or rain shadows create the BWk climate. - Very high temperature ranges. - Summer temperatures are very hot. - Nighttime and winter temperatures are very cool. - Higher humidity and precipitation than subtropical deserts. Midlatitude Steppe (BSk): - A transition zone. - BSk climates have the same temperature characteristics as the midlatitude deserts. - BSk climates have higher annual average precipitation than deserts.
Explain the difference between a surface current and a density current in the ocean.
Surface Currents: - in the upper 1000m - Driven by wind that results from temperature contrast - AKA global currents Density Currents: - Driven by Density - More dense water sinks and where they circulate for 500 to 2000 years
If the tilt of Earth's axis were 10° (instead of 23.5°), where would we find the Arctic and Antarctic Circles? Would this cause a change in the perihelion and aphelion?
The Arctic Circle would be at a latitude of 80 degrees N; the Antarctic Circle would be at 80 degrees S. The Tropic of Cancer would be at a latitude of 10 degrees N; the Tropic of Capricorn would be at 10 degrees S.
Define and describe the fundamental basis of the Koeppen climate classification system and the atmospheric properties upon which it depends.
The Koeppen climate classification system is based on natural vegetation types as indicators of average temperature and precipitation. Uses a letter system for abbreviations First capital letter is the primary climate (A-E) Second (and other following) letters are to further subdivide the primary climates into sub-climates
Describe the evolution of trade winds and SST's in the equatorial Pacific Ocean during a strong El Nino event.
Thermocline and wind patterns during the normal Walker Circulation. Cooler, nutrient rich water moves upward from below along the South American coast. Thermocline, Upwelling, & El Nino Thermocline and wind patterns during the normal El Nino - Southern Oscillation (ENSO) conditions Cooler, nutrient rich water does not "upwell" to the ocean surface. Warm surface water piles up along the South American Coast. So during these ENSO events, the equatorial tropical east Pacific water is about 2°C warmer than typical
Are the mild midlatitude climates really mild? Explain.
They are compared to Severe Midlatitude climates.
Despite their low latitudes, tropical climates are not among the hottest on Earth. Why not?
They have continuous availability of moisture on their surface area. On hot days, this moisture gets evaporated. This prevents the surface from getting hot.
Why do ocean temperatures change (heat up and cool down) so slowly compared to the atmosphere?
Throughout the day, the ocean absorbs heat from the sun and during the night the ocean holds in the heat permitting only small changes in temperature.
Identify and describe the 'Tropical Wet', 'Monsoonal' and 'Tropical Wet and Dry' climate zones in the tropics. Be able to differentiate between the three tropical climate zones. If given a climograph of temperature and precipitation, evaluate which of the three tropical climate zones is represented.
Tropical Wet (Af): Even precipitation through year - High humidity - Temperatures: Highs = low 30°C (80°F)/Lows = low 20°C (70°F) Monsoonal (Am): - Monsoonal climates are considered the transition climate between tropical wet and tropical wet dry climates. - Precipitation does not occur as steadily throughout the year in a monsoonal climate as it does in a tropical wet climate. - Some months experience heavy rainfall while others are nearly dry. - The wet months in monsoonal climates yield far more rain than does the wettest month for tropical wet climates. Tropical Wet and Dry (Aw) : - Tropical wet and dry climates occur along the poleward sides of the tropics and border dry climates on one side and tropical wet climates on the other. - Low sun dry period. - Unreliable precipitation. - Savanna vegetation consists mainly of grasses with widely separated trees or clumps of trees.
Identify and describe the two polar climates: 'Tundra' and 'Ice Cap'. Be able to differentiate between the two primary polar climates. If given a climograph of temperature and precipitation, evaluate which of the two primary polar climates is represented.
Tundra (ET): - Polar Climates • Very high • Very cold. - Tundra (ET) • Named for vegetation (tundra). • Severe winters. • Mild summers of long daylight. • Permafrost (permanently frozen layer below the surface) region. Ice Cap (EF): - Constant ice cover. - Greenland and Antarctica. - Warmest monthly temperatures are less than 0°C. - Katabatic winds influence this climate. - Low precipitation totals.
How often do El Nino conditions generally occur?
Typical ENSO period is every 3-7 years, but with significant irregularity
Define ocean upwelling and the thermocline. How does El Nino and La Nina impact upwelling off the South American coast?
Upwelling - wind-driven motion of cooler and nutrient-rich water from deep ocean up to surface Cooler, nutrient rich water does not "upwell" to the ocean surface. Warm surface water piles up along the South American Coast.
Explain how volcanoes and land configuration on the continental scale (e.g., plate tectonics) can be associated with natural climate change.
Volcanic eruptions. Volcanic ejecta may block sunlight. Need many eruptions in short time period to have longer term impacts on climate. Not observed in recent history. Movement of Earth's Plates. Plate tectonics gradually change the configurations of the mountains and oceans. Mountain building and land erosion affect climate over geologic time. Change ocean circulation. Extremely slow process. Climate change would be very gradual over millions of years. Linked to Pleistocene Ice Age, Little Ice Age, Medieval Warm Period.
Describe warm and cold surface currents in the ocean
Warm Currents: - Driven by winds (temperature) - Flow away from the equator towards the poles Cold Currents: - Driven by winds (temperature) - Flow away from the poles and towards the equator
Why is London, UK so much warmer than most of Canada for the same latitude?
Warm currents are around the UK while Canada is surrounded by cold currents. Warm ocean currents bring warmer water poleward, thereby making areas farther north more temperate.
What is the role of ocean currents in the distribution of heat on Earth?
Warm ocean currents bring warmer water poleward, thereby making areas farther north more temperate. Cold ocean currents bring colder water equatorward, thereby making areas farther south more temperate Warm ocean currents = more water vapor in the air, thus adjacent land masses are more humid & receive more rainfall Cold ocean currents = less water vapor in the air, thus adjacent land masses are less humid & receive less rainfall
How might changes in ocean currents impact changes regional, hemis., & global climate?
Warming temperatures and sea levels: - Increase in global temperatures can raise mean sea level by expansion of warmer ocean waters and melting of glaciers and release of water to oceans. - Sea-level rise feedbacks to climate via changes to ocean surface currents, movement of deep ocean water, and proportion of land vs. ocean. Changes in ocean circulation: - Glacier melting adds freshwater to ocean. - Fresh water from glacier melting can change/disrupt thermohaline circulations - ocean circulations driven by temperature and salinity variations
Why isn't upwelling an important process in the Gulf Stream?
Water sinks in the Gulf Stream. Downwelling happens here, not upwelling.
List the major greenhouse gases in the atmosphere and their percentage of the total amount of greenhouses gases in the atmosphere. Which gas is the most abundant greenhouse gas in Earth's atmosphere?
Water vapor (60%), CO2 (3.6%), Methane (9% of the remaining 1.4%), Nitrous Oxide (5% of the remaining 1.4%), CFCs (2% of the remaining 1.4%), Ozone. Most abundant is water vapor.
Which two gases are the most effective at absorbing longwave radiation?
Water vapor and carbon dioxide
Explain how past vegetation (e.g., pollen and tree rings) can be used as proxy data to characterize past climate.
When vegetation occupies a region, some of its pollen and spores can be deposited and preserved indefinitely in lake beds or bogs. Much information about past climates extending back for several thousand years can also be obtained from tree rings.
How do the semi-permanent low pressure and the ITCZ help determine the location of tropical rain forests?
Wherever the semi-permanent low pressure cell and ITCZ are located will not experience a dry season and will be tropical rainforests.
List the all of the primary Atlantic Ocean and Pacific Ocean currents that impact North America, South America, Europe, & Africa, and know whether these are warm ocean currents or cold ocean currents. These include, but are not limited to, the following: a) North Equatorial Current b) Benguela Current c) North Pacific Current d) Alaskan Current e) South Equatorial Current f) Humboldt / Peruvian Current g) California Current h) Antarctic Current i) Gulf Stream j) Brazilian Current k) Labrador Current l) Canary Current m) North Atlantic Drift n) West Wind Drift
a) warm current b) cold current c) warm current d) warm current e) warm current f) cold current g) cold current h) cold current i) warm current j) warm current k) warm current l) cold current m) warm current n) cold current
Describe the general trend of greenhouse gases that have potential human-caused sources from pre-industrial times (say before 1750) to present times.
see graph in lecture 14
Be able to identify the following climates from their climographs: Marine West Coast Humid Sub-Tropical Humid Continental Tropical Wet Mediterranean Desert
see lecture 12
Rank the various human-caused greenhouses gases in terms of present concentration, how much infrared absorption per molecule (i.e., how strong a greenhouse gas it is) and relative contribution to increasing the greenhouse effect. (Note: you do NOT have to memorize exact numbers for concentration or absorption/molecule but have a good sense of relative comparison (which is more abundant, which is stronger).
see table lecture 14
