Physical Geography Exam 2 Notes: Hydro + Atmo + Biosphere

Waves

undulations of water

• transmitted from particle to particle

• carrying energy from one place to another

• caused by friction between wind & ocean surface

Tides

daily oscillations in sea level

• caused by gravitational pull of moon & sun

Spring tide

maximum tidal range

Straightening

A coastal erosion in which waves bend around headland and wear it down

Beach Drift

A coastal erosion which is a movement of particles along the beach

Longshore current

A Coastal erosion movement in which the current is/moves parallel to the beach

Barrier formations

long, narrow dispositional features

• usually sand, offshore and parallel to coast

• act as a barrier to storm energy

• shift position in response to wave action & longshore current

Delta

river meeting an ocean

• either river, wave or tide dominated

• If channel backfills w sed → can super-elevated relative to its banks + avulse (jump banks and flow somewhere more downhill)

Rio Grivalja, Mexico Delta

smoothness of the coastline — wave-Dom Delta

Ganges Brahmaputra Delta

if tide goes up → water pushes up to the rivers

if tide goes down → water pushes down toward ocean

THUS, tidal-Dom Delta

Mississippi Delta

River primarily controls sedimentary dispensary

THUS, river-Dom Delta

Relative sea level =

Eustatic + Isostatic + Tectonics + Local effects

Tectonics

Lifts land (dec. relative sea lvl) or sink land (inc relative sea lvl)

Isostatic (ice sheet)

ice mass depresses land below, displaces nearby land UPWARD creating forebulge

Isostatic (Glacial Isostatic Adjustment)

land once beneath ice sheet rebounds, forebulge collapses as land goes DOWN

Eustatic

process that describes changes in the mass of water in the oceans.

• Sea-level rise for this due to melting of ice sheets and glaciers; increased runoff from lakes, rivers, and groundwater; and increased oceanic precipitation

The equilibrium line altitude (ELA)

elevation where snow accumulation = snow melt

• we reconstruct ELA in the past through moraines

unconstrained glaciers

ice sheets, ice caps and ice streams

Constrained glaciers

ice fields, valley glaciers, transection glaciers (interconnected valley glaciers), piedmont glaciers, cirque and niche glaciers

a glacier ____ when a huge mass of ice breaks off at the front of the glacier

calves

_____ due to their relatively fast flow and an extensional (stretching) flow at their lower end

crevasses

near-vertical __ ____ where calving happens

ice cliff

Abrasion

Scraping of rocks on the glacier bed

Quarrying

Plucking blocks from the glacier bed

Subglacial channel

Rivers under glaciers

Glaciers tend to

widen valley bases & oversteepen their sides → u-shaped valley

Cold-based glaciers on bedrock

very slow movement

Warm-based glaciers on bedrock

relatively slow movement

Warm-based glaciers on sediment

lubrication from melting ice makes it move faster

Lateral moraines

forms on the end of flowing ice

Terminal moraines

mark the farthest extent of the glacier

short wavelength energy

can pass through human bodies and Earth

• hotter objects radiate energy at this wavelength

Long-wavelength energy

can be sensed as heart (like thermal infrared) or used to bounce off solid objects for locating (like radar)

Isolation

Earth’s axial tilt is why the tropics are where they are

Milankovitch Cycles

Earth’s position relative to the sun varies on long timescales

• In the past 2 million years, the pattern of continental ice sheet growth and decay has gone from a 41,000 year cycle to a 100,000 year cycle

Albedo

proportion of shortwave radiant energy scattered upward by a surface

Atmospheric CO2 is a product of

global wind patterns, patterns in ecosystem productivity, and anthropogenic sources (agriculture and fossil fuel burning)

Temperature inversion

usually air temp decreases w/ elevation, but in an inversion, it increases

• ex: On clear, calm nights, the ground radiates energy back out
  to space and the ground cools, cooling the air above it and
  trapping the cold near the ground

Community

formed by interactions among populations of living organisms at a particular time

Habitat

type of enviornment in which an organism lives

Niche

function of an organism w/in a community

Components of the ecosystem

Abiotic (nonliving) and biotic (living)

Proxies

something that can be used to represent the value of something in a calculation

• preserved in archives like sediments & ice cores

Biological proxies

plants and animals that tolerate specific climate conditions

Physical proxies

textural or sedimentological indicators of climate condition

Chemical proxies

the presence, quantity or composition of chemicals that are controlled by climate-dependent reactions

Producers

organisms capable of using CO2 as sole source of carbon (C)

Net photosynthesis

photosynthetic gain – respiration loss

Net primary productivity

net photosynthesis for whole plant community

2 types of Nutrient cycling

Gaseous (partly in atmosphere) & sedimentary (in lithosphere)

Oxygen cycle

first time the atmosphere had free oxygen - The Great Oxygenation Event (The GOE)

Banded iron formation (BIFs)

economically important iron ores that record early ocean oxygenation

Nitrogen cycle

Nitrogen fixation: chemical process by which NO2 is converted to NO3 (ammonia)

Nitrogen needs to be fixed to be made into amino acids, protein and nay nitrogen-containing organic compound

Carbon cycle

silicate (granite) weathering → C sink (removes carbon from the atmosphere)

Carbonate rocks getting cooked in the lithosphere → C source to the atmosphere

Wind is determined by

Pressure Gradients

• out of a high and into a low, thats the way the wind likes to blow”

El Nino

• trade winds blow east to west

• warm air (low pressure) in the west & cold air in the east (high pressure)

• heat from pacific ocean center

• each event is different, sometimes reverses and lasts for months

Coriolis Effect

horizontal wind motion

• Earth’s rotation means that winds are deflected to the right in the northern hemisphere and to the left in the southern hemisphere

• explains why hurricanes have crossed the equator

Hadley cells

Coriolis effect + differential heating of Earth’s surface = planet-wide wind circulation systems

• Winds are named for the direction from which they come (so 30-60 degrees winds are called the Westerlies)

• Europeans exploit this during triangular trade

The Intertropical Convergence Zone (ITCZ)

Convergence of the trade winds, band of low pressure between the n and s hemisphere Hardley cells. area of low pressure causes heavy rain when it is over an area and drought when it moves elsewhere

• position shifts w the seasons as sun hits north v south of the equator at diff times of the year

• responsible for wet & dry seasons in the tropics

Humidity

Warm air can hold more moisture than dry air

• air cooling → saturation-specific humidity decreases

• more cooling → SSH = specific humidity

  • aka air is at max saturation (most possible water vapor)

• more cooling → condensation

  • temp at which saturation occurs is the dew point temp (Temp at which condensation/dew forms)

Specific Humidity

the mass of water vapor in air over the mass of total air (the actual amount of water in a given volume of air

Saturation-specific humidity (aka maximum specific humidity)

the maximum quantity of moisture that a given volume of air can contain at any time

• Dependent on air temperature

Relative humidity formula

𝑠𝑝𝑒𝑐𝑖𝑓𝑖𝑐 ℎ𝑢𝑚𝑖𝑑𝑖𝑡𝑦 × 100
𝑠𝑎𝑡𝑢𝑟𝑎𝑡𝑖𝑜𝑛 𝑠𝑝𝑒𝑐𝑖𝑓𝑖𝑐 ℎ𝑢𝑚𝑖𝑑𝑖𝑡𝑦

Stability

tendency of air parcel to stay in same place determined by difference in temperature of parcel & surrounding air

as air rises → hits lower air pressure → expands & cools

as air sinks → hits higher air pressure → contracts & heats

inc temp = dec density = air parcel rises

dec temp = inc density = air parcel sinks

Adiabatic rate

rate that air cools by expansion or heats by contraction

• T change that occurs w/o heat exchange between surrounding environment & air parcel

  
  

• Moist Adiabatic Rate (MAR)

  • rate for moist air (i.e., > 100% relative humidity)

  • avg MAR = 6C°/1000m

• Dry Adiabatic Rate (DAR)

  • rate for dry air (i.e., < 100% relative humidity)

  • avg DAR = 10C°/1000m

    
    

Lifting condensation level

altitude at which condensation begins (i.e., clouds form), switch from DAR to
MAR

When air parcels rise + condense

[Environmental] lapse rate =
rate that T dec with inc altitude
- still air (outside balloon)

Adiabatic = rate that T of
moving air parcel dec with inc
altitude
- moving air (inside balloon)

Unstable

Environmental lapse rate > adiabatic rates
(surrounding air cools more quickly with altitude than air parcel → air parcel will continue to rise)