Final Exam Emphasized Topics Flashcards
Polar Front Theory
- Stationary Front
- Frontal Wave
- Open Wave
- Mature (initial occlusion)
- Advanced occlusion
- Cutoff cyclone
Rossby waves are:
Long waves
Corriolis force is stronger at ___ making winds faster
Ridges
Wind slows during ___
Wind speeds up during ___
- Convergence
- Divergence
What is the Rossby Redox
- Short waves move faster
- Short waves are embedded in the background of longwaves and are much more active
How do short waves cause storms (cyclones)?
- Begins with stationary polar front and a steady flow above
- As the shortwave moves through the upper air flow, convergence and divergence generate high and low centers
- This starts. the polar front moving, generating a warm front with air moving N and cold front where it moves S
- Storm dissipates when the surface low isolates from the upper air divergence
Barotropic/ Baroclinic
- Temperature contours and isoheights are parallel
- no advection = Wind transported horizontally by the wind
Baroclinic Instability
- Short wave pushes south across temperature contours
- Cold air is transported into region of convergence deepening the trough
- Warm air is brought into region of divergence, strengthening the ridge
Cooling air ___, whereas warm air ___
compresses down
Warm air expands up
Numerical Weather Prediction (NWP)
Considers:
- domain size
- resolution
- initial conditions
- model assumptions
Watch
Atmospheric conditions are favorable for hazardous weather although location and time are uncertain
Warning
Hazardous weather is actually occuring or imminent within the forecast area
What developes a tropical disturbance into a tropical cyclone
- Warm sea surface
- Adequate Coriolis effect: 5 degrees from the equator
- weak vertical wind shear: no strong upper tropospheric flow
- humid air in mid troposphere
What does the saffir simpson scale measures…
Rates tropical storm strength on a scale from 1-5
Easterly Waves
- Travel east to west in the trade winds
- troughs in mid-latitude upper flow - winds slows when entering easterly wave
- Convergence -> wind increases when exiting easterly waves
- Divergence -> low level convergence causes upward motion
Requirements for tropical storm/cyclone formation
- Storm is powered by latent heat release in clouds
- adequate coriolis effect provides rotation
- weak verticle wind sher required allowing deep vertical orginization and development
- Moist mid-troposhere
Hurricanes weaken or die when…
They loose their source of moist air by moving over land, or over colder water
- this reduces the supply of latent het that powers the storm
How does cyclic flow in the lower troposphere, becoming anticyclonic in the upper troposphere
Wind are strongest in the lower troposphere, then decrease in the upper troposphere until they turn and circulate in the opposite direction at the top of the storm
Cyclostrophic Flow
Pressure-gradient + Coriolis effect + friction = V2/R
- At the eye wall of a hurricane
- pressure gradient much larger than friction
- weak Coriolis
- parcels move rapidly in a tight circle
- parcels cannot make ny further inward progress, so winds in the eye are weak
True or False: the eye of the storm is almost cloud free
True
Cyclostrophic Radius
some air descends to replace eye air fed into base of eye wall clouds
What are the pressure trends as the eye approaches
pressure drops as the eye approaches and winds peak near the eye wall
Storm Surges
- strong onshore winds
- shallow sloped shore
- narrowing bay
- high tide
Region of Maximum heating
- Where the solar altitude angle reaches 90 degrees
- varies between the tropic of cancer and the tropic of capricorn
Describe the intertropical convergence zone (ITCZ)
Low pressure area where trade winds converge and air rises causing intense convective precipritation
The Doldrums
ITCZ
- unreliable winds, frequent rain
Horse Latitudes
- Lack of wind
- lack of preciprittion
- subtropical highs
Why are deserts found in the horse latitudes
due to the lack of wind and precipitation
Why are rainforests found at the ITCZ
due to the frequent rain
Why does the ITCZ shift with the seasons?
- The sun moves with the seasons
- this moves the source of max sensible and latent heat at the bottom of our thermally driven circulation
What is the trade wind inversion
- What aspect of tropical climate does it help to explain
- layer where T increases with height
- Air stops rising: clouds stay as cumulus and do not develop into thunderstorm clouds (cumulonimbus)
What forms trade winds
- Subsiding air (subsidence inversion)
- profile of air descent in region of high pressure -> subsidence decreases close to surface can not continue descent
Why is there a large seasonal shift in the ITCZ over southern asia
- It has to do with the monsoon wind system -> seasonally change
What is the monsoon wind system
giant land/sea breeze
- seasonal reversal of winds
Describe the development of a “sea breeze”
Day time
- land heats more rapidly than water
- warmer air expands over land and lifts upper pressure surfaces
- Divergence over land and convergence over sea
surface flow from sea to land = sea breeze
Describe the development of land breeze
Night time
- land cools more rapidly than water
- land air column shrinks and upper pressure surface descends
- convergence aloft over land
- divergence aloft over sea
land surface pressure increases
- sea surface pressure decreases
- surface flow from land to sea
Monsoon circulation - winter
winter - land colder than ocean -> giant land breeze -> augments the northernly trade winds (dry season) -> ITCZ stays south
Monsoon circulation - summer
land warmer than ocean -> giant sea breeze -> augments the southernly trade winds (wet season) -> ITCZ moves north
Southern Oscillation
pressure gradient that oscillates from weaker to stronger with an irregular period
El nino
- occurs with a weak SOI
- warm phase of southern oscillation
- alterations in P pattern and winds
- warm water sloshes towards south america
La nina
- Occurs with a strong SOI
- cool phase of the southern oscillation
- warm water pushed towrds indonesi
Primary sources of air pollution
- enter atmosphere directly
- hazardous ir pollutants (toxic at low conc. emitted by accident
- criteria air contaminants - allowed but regulated
Secondary air pollutants
- form due to reaction between primary pollutants and other air components
Name the 6 criteria air contaminants
- Ammonia
- carbon monoxide
- volatile organic compounds
- sulfer oxides
- nitrogen oxides
- particulate matter
Ammonia main sources
Agricultural livestock, fertilizer application
Carbon monoxide main sources
transportation
Volatile organic compounds
transportation, oil and gas, solvent use
Sulfer oxides
mining, coal fire power generators
nitrogen oxides
transportation, oil and gas
particulate matter
wood combustion, diesel use
increased wind speed has what effect on air pollution?
brings cleaner air and dilutes the concentration of a pollutant
how does an unstable environment affect pollution
- pollutants rise, mix, and disperse downwind
How does stable environment affect pollution
- shallow mixing depth and pollutants are trapped within inversion.
Elevated Subsidence Inversion
Down Slope of a mountain causes sinking of air, which results in subsidence inversion
What sort of plume would arise during a clear night with poor vertical mixing (stable)
Fanning shape that spreads in the horizontal, but not vertical
What plume type would you expect to arise during a clear day with good vertical mixing? (unstable)
Looping plume type where the plume rises and sinks rapidly and is widespread cross the vertical
What type of plume would you expect to arise on a cloudy day or night with modest mixing? (neutral)
Coning plume type that is spread evenly in both the vertical and horizontal creating a cone shape
Sigma Z is the measurement of __ plume dimension
Vertical
Sigma y is the measurement of ___ plume dimension
horizontal
True or False: Ozone is a secondary air pollutant?
true
What causes ground level ozone smog?
- Sunshine (UV to dissociate NO2)
- Warmth
- southernly winds that import extra O3, VOCs and NOx
What are the 4 main green house gases, and their sources
- carbon dioxide - fossil fuel use, land use change
- Methane - agricultural activities, waste and energy
- Nitrous Oxide - agriculture and fertilizer
- Fluorinated gases - industrial processes and refridgeration
Name 2 factors that govern climate
- Effect on global energy budget (changes in energy coming in or going out)
- Internal interactions and feedback effects (ocean and air circulation)
Millennial Time Scale - Eccentricity
The variation in the earth’s distance from the sun
Millennial Time scale - Obliquity
Earth’s tilt on its axis
Millennial Time scale - Precession
Wobble in the earths axis that changes the position of hemispheres and there distance from the sun
In winter for the ice age…
Higher radiation -> more evap. -> more clouds -> more snow
In summer for an ice age…
Weaker radiation -> less snow melt
Cold starts with… (Millennial Time scale)
- high eccentricity
- small tilt
- Big E-S distance in summer (NH)
Cold ends with… (Millennial Time scale)
- lower eccentricity
- bigger tilt
- smaller E-S distance (NH)
Do sunspots increase the total amount of sun radiation or decrease it? why?
Sunspots emmit less radiation, but around them there is more radiation being emmited there fore they increase amount of solar radiation emmited
Why are there uncertainties due to instrumental record?
- changes in the accuracy of sensors over time
- changes in location of stations
- changes in land use around stations (urbanization)
- lack of observation over oceans and poles
Positive feedback ___ change, where as negative feedback ___ change
enhances, decreases
Polar Amplification
More warming in higher latitude regions due to albedo feedback
What evidence is there for climate change? (4)
- sea level rise
- warming oceans
- globally water vapor in the atmosphere has increased at a rate consistant with prediction climate models
- global T rise
How is the jet stream changing due to climate change?
- the decrease in temperature contrast has causes weaker jet stream creating a wavy omega pattern
General Circulation Models/ Global Climate Models (GCM):
Computer programs that simulate how components of the climate system work and interact
- use 3D grid
- similar to numericl weather forecasting models
- used to understand how climate changed in the past and how it will change in the future
Radiative Forcing:
Any change in average net radiation that is due to some change in the climate system is called radiative forcing
Units for radiative forcing
+ means…
- means…
energy surplus = warming
energy deficit = cooling
Does the following have positive or negative feedback: Ice albedo
+
Does the following have positive or negative feedback: CO2 and/or methane released from permafrost
+
Does the following have positive or negative feedback: CO2 and/or methane released from/to vegetation causing
1. more growth
2. more fire
- -
- +
Does the following have positive or negative feedback: Water vapour from
1. ocean evaporation
2. From vegetation
- +
- -
Does the following have positive or negative feedback:
1. Thick low clouds
2. thin high clouds
- -
- +
Does the following have positive or negative feedback: Ocean feedbacks
1. increased T = increase photosynthesis
2. freshening sea water/ slowing of the Atlantic conveyer belt
- -
- -
According to polar front theory, when does a storm begin to dissipate?
When the low pressure center on the surface becomes isolated from upper air divergence
How is the strength of trade winds determined?
By the pressure gradient between Tahiti (high P) and Darwin (low P)
Describe the bergeron-findestein process (process of growing ice crytsals)
- Water vapour pressure gradient between supercooled droplet and ice crystal
- Vapour is pushed from drop to ice crystal due to pressure difference
- this increases evaporation
- droplet is consumed by ice crystal.
