ERTH303N Part 3

Wall cloud

area of rotating clouds that extends downward beneath the updraft area of the mesocyclone

Funnel cloud

Rapidly spinning vortex that can emerge from the base of the wall cloud to form a tornado

EF scale (fujita)

Intensity of a tornado by the damage caused and a proxy for estimating wind speeds

Doppler radar

a specialized radar system that uses the Doppler effect (change in frequency) to measure the velocity, direction, and speed of objects like precipitation

Limitation: can only see ~ 200 miles from coast

Multiple vortex tornado

tornadoes that contain several smaller intense whirls called suction vortices that orbit the center of the larger tornado circulation.

Tornado alignment

from SW to NE because they develop just ahead of a cold front

Hurricane

tropical cyclonic storm having sustained minimum winds of 119 km/h (74 mph). form between 5-20° N/S latitude and need very warm ocean temperatures (>= 80 ° F).

Do not form near equator due to zero Coriolis force

Tropical systems (initiated by easterly waves)

– Thunderstorms

– Tropical squall lines/clusters

– Tropical depressions, storms, and hurricanes

Easterly waves

large migratory wavelike (east-west) disturbance in the trade winds

Tropical disturbance

organized mass of thunderstorms often with a very slight cyclonic wind circulation (< 23 mph)

Tropical depression

more organized cyclonic circulation (23 – 38 mph)

Tropical storm

sustained winds 39 – 73 mph; during this phase a name is given

Eye

circular area of relatively light winds, low pressure, and fair weather at the center of the hurricane

Eye wall

doughnut-shaped area of intense winds, thunderstorms, and precipitation surrounding the eye

Spiral rain bands

curved bands of clouds and precipitation that spiral inward towards the center of the hurricane

Hurricane cross section

image

Trade wind inversion (inhibits hurricanes)

forms in association with subsidence that occurs in regions associated with subtropical high; inhibits the development of strong thunderstorms

Hurricane decay

• Movement over cooler water

• Movement over land—storm loses its source of warm, moist air

• Strong upper level winds— can tear hurricanes apart

Saffir-simpson scale

ranks the intensity of hurricanes based on a scale from 1 – 5 (i.e.—5 categories)

Storm surge

abnormal rise of water generated by a storm over and above the predicted astronomical tides. product of cyclonic winds

Data buoys

Only means of continuous direct measurement of surface conditions over ocean areas

Galveston hurricane

• Landfall on 9/8/1900

• Category 4 (145 mph winds)

• Deadliest in U.S. history (8000 killed)

• Storm surge > 15 ft; city on 8.7 ft above sea level at the time

Hurricane andrew

• One of the costliest in U.S. history

• Category 5 (175 mph winds)

Hurricane Katrina (far from worst case)

• Costliest in U.S. history

• 1.2 Million evacuated

• > 1,800 deaths

• Category 5 at peak but hit as a Category 3

• Storm surge breached levees in New Orleans, submerging 80% of the city

Hurricane Sandy

deadliest and most destructive hurricane of the 2012 Atlantic hurricane season, as well as the second-costliest hurricane in United States history. Cat 3 at peak

Labor day hurricane

strongest winds probably exceeded 200 miles per hour

intensification of winds happened over a mere 36 hours

AMO

during warm phase: more hurricanes

during cool phase: less hurricanes

climate change means warmer waters and more hurricanes

Climate normal

30‐year average of a weather/climate variable (e.g.—temperature). Also includes degree days, probabilities, standard deviations, etc

Climate weirding

belief that climate change causes or will cause various weather‐related extremes to become more intense

Basic elements of W&C

– Temperature – Humidity – Type/amount of cloudiness – Air pressure – Type/amount of precipitation – Wind speed/direction

Tectonic scale climate change

climate change over intervals of millions of years

Orbital scale climate change

climate change over intervals of tens of thousands to hundreds of thousands of years

Millennial oscillation scale climate change

fluctuations in climate lasting thousands of years

Proxy data

tree rings, ice cores, ash beds, palynology, and corals—used by scientists to reconstruct past climates and environmental conditions

Eccentricity

refers the shape of Earth’s orbit around the sun (i.e.—how much the orbit is squashed)

every 100,000 yrs

Obliquity

change in axial tilt of Earth with respect to its orbital plane

every ~41,000 yrs

Precession

wobbling of Earth’s axis, like a spinning top that is winding down

every 20,000 yrs

Milankovitch

Eccentricity, obliquity, and precession control ice ages

Fossilized pollen (palynology)

analyze pollen in dated lake sediment layers to produced records of past vegetation change

Last glacial maximum

118 – 21 kya. Ended by ~10 kya

time of glacial lake MSO

Medieval warm

increased solar radiation, reduced volcanic activity, and shifting ocean circulation patterns brought warmer temps

700‐1200 A.D

Little ice age

~1200 ‐1800 A.D. Varied regionally. Glaciers grow in Europe (1000 m lower than in 1850s)

Sunspot cycle

11-year cycle of solar activity driven by the sun’s magnetic field, where sunspot numbers rise to a "solar maximum" (high activity) and fall to a "solar minimum" (low activity)

Year without a summer

Tambora in 1815, together with an eruption from an unknown volcano in 1809, produced the “Year Without a Summer” (1816)

GCM garbage in-out

large-scale, low-resolution biases in GCMs propagate into regional models, rendering downscaling ineffective if the driving data is flawed. Subgrid-scale variability—physical processes smaller than grid cells (e.g., clouds, terrain)—causes significant uncertainty and requires parameterization

Global dimming

reduction in radiation at Earth's surface. Varies by location. Probably due in part to increased aerosol reflectance

Torrid, temperate, frigid zone

torrid near equator, warm, humid

temperate at middle latitude, cooler, not freezing

frigid at poles, icy climate

Koppen climate

Shows mean and monthly precip/temp. Simple, allows for nested, detailed data classes. Shows vegetation patterns

doesn’t include wind, extremes, intensity, insolation, cloud cover, causes

Thornwaite climate

depends on potential evapotranspiration. Useful for agriculture

Climograph

plots mean monthly temp in continuous line. Mean monthly precip is bars at bottom

GCM (global climate model)

Grid cells over globe. Garbage in, garbage out model. All processes are lumped into one cell

Regional modelling

examines smaller areas in more detail

2023 climate graph

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IPCC

The IPCC is a scientific body under the auspices of the United Nations (UN). It reviews and assesses the most recent scientific information produced worldwide relevant to the understanding of climate change. It does not conduct any research nor does it monitor climate related data or parameters

6 assessment reports

in 1990, 1995, 2001, 2007, 2014, and 2021-23

Representative concentration pathways (RCP)

four main scenarios of total radiative forcing that occurs by 2100

Representative emission pathways (REP)

trajectories of emissions of GHGs, aerosols, land-use, etc., that are more nuanced

downburst, microburst, macroburst

down: localized downdraft with straight-line concentrated bursts of wind (evaporative cooling)

microburst: downburst with a diameter < 4 km for 2-5 min

macroburst: downburst with a diameter < 4 km