lecture 5 Flashcards
what does the coriolis effect help us with?
- Helps us understand why we see the directs/ patterns of air movement
Describes how air, water, or another object moves over a rotating surface
what level does the coriolis effect occur at
Surface level - what we feel at sea level, not atmospheric level
why does coriolis effect have an impact?
- Earths diameter - greater at the equator than the poles
- Earth is rotating faster at equator bc of diameter than the poles
how does coriolis impact air and water at equator
Air/water at the equator (moving toward poles) has higher radial velocity than region into which it is moving and accelerates eastward
ow does coriolis impact air and water at poles
- Air/water at poles (moving towards equator) has less radial velocity than where it is headed and deflected westward
how does coriolis impact winds from poles to equator
- Air deflects/ descends once it hits 30 degree latitude
○ As it goes down it goes from the pole where air is moving slowly, to the equator where it is moving faster - that’s why we see deflection
Average surface windflow patterns?
- Low in jan, high in july
○ Reflects the amount of solar heat- Relatively consistent averages
how is ocean structured? what results in thermocline
- Relatively stable vertical layers (limited mixing)
- Sun heats ocean from the top - results in Thermocline
- Sharp temp gradient between warm surface water and cooler intermediate waters
describe halocline
- Halocline
○ Salinity gradient b/w less saline surface water and more saline intermediate water
○ It starts low and gets higher as you get deeper
○ Liquid water is denser
○ Water with more salt is heavier
Arctic waters can have higher salt bc of the ice
what do thermocline + halocline cause?
- Thermocline + halocline = pycnocline (gradient in water density)
○ Cold water = higher density
○ More saline water = higher density
Layering more pronounced in tropical waters
why is water mixing important?
- Deep layers
○ Mix slowly with surface water thousands of years)
○ Critical in element cycling, productivity, climate
○ Long-term sinks for C and sources of nutrients- ocean productivity
Nutrients build up at the bottom of the ocean bc of dead matter falling + decomp
describe upwelling
- Where nutrient rich deep water moves rapidly to the surface
- Support high levels of 1 and 2 degree productivity (think fertilizer)
- Location of many of the world’s fisheries
what does ocean circulation play a role in?
- Ocean circulation plays a critical role in earth’s climate system
High heat capacity moderates land temperatures
○ Ex. Ocean can keep areas in canada warm (despite the cold) bc of the depth and the heat capacity
○ Chances the habitat
Accounts for 40% of poleward heat transport
what drives surface currents? patterns similar to? deflected at?
- Surface currents- driven by surface winds
○ Patterns similar to those of prevailing winds
Deflected 20-40 degrees relative to the wind - coriolis effect
landform impacts on climate?
- Spatial distribution of land, water, and mountains modify the general latitudinal climate trends
- Ocean moderation of costal land temperatures
how do mountains impact climate
○ Climate changes with elevation
○ Multiple biomes found on single mountains
○ Exposure aspect and slope
Rain shadows
* Range created by the mountains - change in aspect (light exposure) created by mountains
describe rainshadows
- Areas of low precipitation on the leeward side of a mountain (down wind)
- Air has to go over mountains to move - results in the air cooling
- As it loses moisture, air becomes warmer on the other side
○ Higher precip. On the side of the mountain where the air is rising
why can we find diversity on mountains?
Can find lots of diversity on mountains bc of this gradient/ range of habitats for organisms to use within a smaller area
- Vegetative effects on climate? what is albedo
- Abiotic and biotic factors impact the climate
- Albedo- reflection of light on surfaced based on color
○ Vegetation reflects more light than bare ground
as plants grow and change the reflectivity of the surface, it changes the climate
- Albedo- reflection of light on surfaced based on color
what is the primary force responsible for temporal variation
- Primary force responsible for the temporal variation in earths climate is changes in solar radiation
what scales does variation in climate occur at?
- Variation in climate occurs at a range of temporal scales:
○ Long term changes: variations in earths orbit - responsible for the ice ages
○ Interannual change: e.g. El Nino
○ Short term change: seasonal and diurnal cycles
○ Now seeing human induced changes on a long term scale - climate change
describe long term changes to climate
ng term changes:
○ Mainly due to predictable changes in eath’s orbit
○ Milankovitch cycles
what are Milankovitch cycles? describe each
§ Eccentricity changes (change in orbit shape/width) - cyclic interaction stemming from earth’s interactions with other planets (not just the sun)
§ Changes in obliquity ( tilt)
§ Changes in axial precession (wobble) 26,000 yr cycle - if humans are changing the distribution of ice, then the process of wobble is impacted
q
what do milankovitch cycles impact
Interactions among these 3 cycles produces cycles of solar input that correlate with glacial cycles
○ Separate out naturally occurring effects from changes due to human interactions with the environment
