meteorology exam 4: final exam

Relationship between wind speed and “wind pressure”

a slight change in speed can profoundly affect the pressure, for example, a marginal hike in wind speed can lead to a significant surge in wind pressure

How many categories in the Saffir-Simpson scale?

5

What state was hit by the most fatal hurricane in U.S. history?

Texas - the Galveston Hurricane of 1900

Where in a hurricane will the strongest winds and highest storm surges be?

(relative to its direction of movement)

strongest winds found in: eyewall

highest storm surges found in: hurricane landfall on shallow land

What is the #1 cause of fatalities from hurricanes in the U.S.?

storm surge and coastal flooding

What country has suffered >300,000 fatalities in a single tropical cyclone?

Bangladesh - The Bhola Cyclone of 1970

Two causes of storm surge

strong winds and low barometric pressure

Does the WMO believe that there will be more tropical cyclones due to climate change?

yes

Does the WMO believe that tropical cyclones will be more intense due to climate change?

yes

Does the WMO believe that rain rates in tropical cyclones will increase due to climate change?

yes

What landform was highlighted in lecture as being particularly prone to damage during tropical cyclones, and where are they common in the U.S.?

Barrier Islands, common on the east coast of the United States like cities Atlantic City, Miami Beach, Virginia Beach

What are Weather Forecast Offices? How many in SD?

They have designated “county warning areas” and have forecast and warning responsibilities. SD has 3: Sioux Falls, Aberdeen, Rapid City

Are radiosondes on weather balloons launched at the same local time globally, or the same time (UTC) globally?

UTC - coordinated universal time, allows for simultaneous data connection across the globe, local time in each location will vary

Be able to determine wind direction, temperature, and dewpoint from a weather station model (plus pressure as assigned earlier in the review sheet)

wind direction: coming from direction arrow is pointed

temp: upper-left

dewpoint: lower-left

pressure: upper-right or middle-right

How far out do short-range and medium-range forecasts go out?

short-range: 12, 24, 36, 48-hr forecasts

medium-range: 3-7 day extended outlooks

bonus: long-range: 6-10 day, 8-14 day, 30-day, 90-day, multi-seasonal outlooks

What are the basic differences between the NAM and GFS models in terms of how far out they go in time, and the area that they cover?

North American Mesoscale: forecasts every6 hrs out to 3.5 days, 12 km grid that covers North America

Global Forecast System: covers whole globe, first 8 days run at 28 km grid, last 8 days run at 70 km grid

bonus: The European Model: 9km grid

What are ensemble runs, and what is their value?

many numerical runs out of one model or different models, avg. of different forecasts is created

What facility issues severe thunderstorm and tornado watches?

SPC: Storm Prediction Center

General difference between advisory, watch, and warning

watch: conditions are favorable

advisory: hazardous weather is occurring or imminent - but cause inconvenience and could potentially lead to dangerous situations if caution isn’t taken

warning: hazardous weather is occurring or imminent - more severe, threat to life and property requires immediate action

Are the criteria for all advisories/watches/warnings the same everywhere?

no - some are based on localized criteria

What is meant by forecast skill

it describes the accuracy of forecast, accuracy declines rapidly after 48 hrs and is minimal beyond 10 days

Understand the human role in forecasting done by the NWS

meteorologists at the NWS look at computer models and then use their knowledge, experience, and intuition to forecast

Be able to determine the probability of precipitation if you are given a %

confidence precipitation will occur in an area and the % of the area that would be impacted (kept simple so no calculator required)

C x A x 100: confidence of precip occuring x area that would be affected x 100 = PoP - probability of precipitation

ex: 60% confidence, 50% of area = 30% PoP

As a single-station forecasting rule of thumb, what does towering cumulus cloud formation by mid-morning suggest?

this is a forewarning of afternoon thunderstorms

Why is the sky blue and why are sunsets red? (old material revisited)

blue - scattering of blue light, shorter wavelengths

red - sunlight has to travel through more of the earth’s atmosphere when the sun is low in the sky, longer wavelengths

Match processes with simple descriptions of the following light-matter

interactions: reflection, refraction, dispersion, diffraction, and scattering

reflection: internal reflection is light reflecting to stay within a medium

refraction: bending of energy rays as they change speed, bending of light as it passes from one transparent medium into another, how glasses and contacts work

dispersion: different wavelengths refracted at different angles, ex: prism

diffraction: bending of a light wave as it moves along the boundary of an object, for example a water droplet, and produces an interference pattern as light waves bend behind the obstruction, producing color

scattering: molecules and particles in the atmosphere send light waves in different directions

How is light bent relative to the perpendicular of an interface when it slows

down? speeds up?

light rays that enter the water at a ninety degrees are not refracted

when light slows down as it enters a new medium, it bends toward the perpendicular/normal line at the interface

when light speeds up as it enters a new medium, it bends away from the perpendicular

Difference between superior and inferior mirages, and cause. Recognize them in pictures.

superior mirage: light rays reflected from distant object bend more sharply, an object may look reflected

inferior mirage: rays refracted less than normal, object appears lower, looks like it is underneath actually object

so when looking at a pic: superior would be a boat on the left side appearing to also be on the right side. inferior would be a palm tree with clone of it right beneath it on the sand

An understanding of how rainbows form (what light-matter interactions happen in what order)

millions of rain drops act like tiny prisms

First, sunlight is refracted with dispersion

then reflected internally

finally refracted with dispersion again

Two phenomena associated with diffraction

coronas and iridescent clouds

Difference in processes and outcome for secondary rainbow (compared to

primary)

seen eight degrees above primary rainbow, results from two internal reflections, dimmer because some of the light gets lost at each internal reflection, the color spectrum is also reversed

Why are there sometimes two visible halos (answer in most basic sense)?

happens when sunlight or moonlight refracts through ice crystals in high-altitude cirrus clouds, they bend light a specific angle, usually twenty two degrees

when the density of ice crystals is high or the cloud layer is thicker, a second outer halo can form

Recognize in photos: sun dog, halo, corona, and glory

sun dog: ok I got this teehee, also a kind of halo

halo: sun dogs or sun pillars, pillars is when bright light appears to be above or below a setting or rising sun

corona: looks like colorful circle around sun or moon, with a second ring around that

glory: looks same as corona, except it happens around an observer’s shadow on a cloud, usually seen from an airplace

What process that we saw applied to light also happens to sound waves and

accounts for acoustic shadows? What does “heat lightning” have to do with this?

Refraction

An acoustic shadow is what causes heat lightening, when no thunder is heard, even though the area is relatively close to the source of the sound

Over what time interval does NOAA compute climate norms?

thirty years

what does the word anthropogenic mean?

human caused

What is a forcing?

something external to the climate system that influences the state of climate

ex: burning of fossil fuels

Do climate models invoking only natural processes explain global climate trends in the second half of the last century?

No

What is meant by the term proxy in climate science?

it refers to a preserved natural archive that indirectly records past environmental conditions, providing clues about past climate states

ex: tree rings, pollen, air bubbles, isotopes, marine sediments, fossil records, geologic evidence like glacial deposits

Do ecosystems consist only of living organisms?

no, the living organisms are within the non-living substances they depend on

Climate impact of volcanic eruptions

changes the global radiative equilibrium, leading to global cooling or global warming

Which hemisphere (north or south) has more land and had more glacial ice in the Ice Age

Northern Hemisphere

General idea of the Milankovitch cycle

cyclical changes in Earth’s orbit and axial tilt, which influence the amount of soalr radiation received by the planet. played a significant factor in long-term climate fluctuations like ice ages and interglacial periods

Three elements of the Milankovitch cycle, basic understanding of each (don’t

need to know periods)

Tilt of Earth’s rotational axis, precession of Earth’s axis which is wobble of the Earth’s axis of rotation and compared to a spinning top slowing down, eccentricity of Earth’s orbit around the Sun which is nearly circular, Earth has a slightly elongated ellipse

Positive and negative feedback: general concept, recognize examples as positive or negative, be familiar with highlighted climatological examples

Positive feedback loop: self-reinforcing, amplifies initial process, ex.: dam failure, ice-albedo, permafrost-melting

Negative feedback loop: self-defeating, stabilizes, ex.: homeostatic thermoregulation, radiative heat loss, algal growth

Significance of the Younger Dryas event

it shows the extreme sensitivity of the Earth’s climate system to perturbations

what happened is glacial meltwater shifted to the north atlantic and fresh water shut down thermohaline circulation, cooling was followed by rapid warming

Why don’t we focus on the most abundant greenhouse gas when we talk about human impacts on climate?

water vapor is most abundant, but it is not directly influenced by humans

Have atmospheric CO2 levels been as high as they are today at any other time in the last 400,000 years?

no

What are hindcasts, and why are they important?

Hindcasts refers to using boundary conditions derived from proxy climate date sources to simulate climates from the geologic past

They allow climate scientists to determine skill, a measure of how much greater accuracy of a prediction is compared to the accuracy of some typically simple prediction

Adaptation vs. mitigation

aww I loved sustainable environment…

adaptation: process of adjustment to actual or expected climate change and its effects

mitigation: making changes to limit or prevent climate change, ex.: emissions reduction, possible ghg removal

Two causes of rising sea level

melting of glaciers and increased sea temperature - thermal expansion

Island country highlighted as most threatened by sea level rise (what kind of

island makes it so?)

The Maldives - these islands are on atolls

Why are ice shelves of particular concern with regard to future sea level change

when one disintegrates, the dam breaks and the ice sheet surges into the ocean causing sudden rise in sea level

Several detrimental impacts of climate change

sea level rise, arctic sea-ice loss, heatwaves, wildfires, drought, changes to agricultural production

Will agriculture be impacted negatively everywhere by climate change?

no, not everywhere - some high-latitude or temperate regions may see increased yields due to longer growing seasons and increased carbon concentrations, but they will still have to deal with more extreme weather events

Mistaking weather for climate

remember that individual events can almost never be directly attributed to climate change, however, increased frequency of events may

Where is most of the energy of global warming ending up (reading quiz question)

the oceans