Weather and Climate Study

What is humidity

A measurement of the amount of water in the air

What is absolute humidity

Absolute humidity is the density of the water vapor (How much water vapor is in 1m³ of air)

What is specific humidity

The mass of the water vapor vs the total mass of the air

What is the saturation specific humidity

The maximum amount of water vapor that can be in a certain volume of air at a given temperature

What is the relative humidity

It is the amount of water vapor in the air vs how much there could be

What is the pattern of humidity vs temperature

As temperature increases, humidity typically decreases

What is Dalton’s Law as related to vapor pressures

The individual vapor pressures added together make up the total vapor pressure in a certain amount of air

What is saturation vapor pressure

The maximum vapor pressure that can exist at a certain temperature

What is the dew point

The temperature at which the air will become saturated, it is always equal to or lower than the temperature never higher

What are the seasonal humidity patterns

The colder seasons are a lot more humid than the warmer seasons

What is a diabatic process

A process that adds or removes energy directly changing the heat of an object

What is an adiabatic process

A process that will cool the air or heat it without adding or removing energy to the air

What is an air parcel?

It is a theoretical amount of air that is used to demonstrate how air behaves in the atmosphere

What is the Dry adiabatic lapse rate

The constant rate at which air cools as it ascends into the atmosphere

What is the environmental lapse rate

The actual rate at which air cools as it ascends

What is the lifting condensation level

This is the altitude at which the air parcel is cooled to the dewpoint and becomes saturated following the saturated adiabatic lapse rate

What are the 4 methods to lifting air? and are they adiabatic or diabatic?

Oreographic lifting: When air is forced upwards by terrain and cools and condenses, one side will get a lot of clouds but on the opposite side the air will warm and become unsaturated, creating a rain shadow making the other side have very little rain. This is adiabatic

Frontal lifting: This occurs when fronts collide and the warm front is forced into the air and condensed forming stratiform clouds (Only on a warm front). A cold front is when a cold front is the aggressor, and a warm front is when a warm front is the aggressor. This is adiabatic cooling

Convergence: This occurs when an area of low pressure has winds from high pressure areas converging at the low pressure area, and when these winds from different directions collide they lift themselves up and condense creating clouds, this is adiabatic

Localized convective lifting: Different surface temperatures cause different air temps and the higher temps are lifted creating updrafts, this is a diabatic process

What is the measure of how stable an atmosphere is

it’s tendancy to resist vertical movement

If there is a larger lapse rate what is the air said to be?

Statistically unstable

Is the SALR constant?

No it depends on the temperature of the air parcel, the higher the temp, the lower the lapse rate

At what point in the ascent of air does the lapse rate decrease

The moist ascent since moist air cools slower than dry air

When the air is stable what is the relationship between the DALR and the ELR

The relationship will be that the DALR is greater than the ELR

What is the relationship between the SALR, DALR, and ELR when the air is absolutley unstable

The ELR will be greater than the SALR and the DALR

What is the relationship between the SALR, DALR, and the ELR when the air is conditionally unstable

SALR<ELR<DALR

Do all clouds form percipitation, and why?

No, this is due to the size and slow fall rates of some clouds which makes it so the droplets cannot get big enough to fall

What needs to happen to a cloud droplet for it to become percipitation?

The droplets need to collide with other droplets very quickly and have a fast growth rate

What are the forces that act on cloud droplets that determine if they can fall

Gravity, which pulls the droplet down, drag, which keeps the droplet in the air, and the updrafts, which the droplet needs to grow to very large sizes to be able to reach a velocity high enough to overcome

What is supersaturation?

This is when the RH exceeds 100% typically by 1% and this helps form very big droplets

What are the 3 ways droplets can grow

• Growth by condensation

This occurs when the air cools and saturates at a certain altitude, and this can produce clouds but typically is a method that is too weak to produce percipitation

• Growth by warm clouds

In these types of clouds, they are warmer than 0C, this makes it so there are big updrafts that bring the water molecules up causing them to collide with other droplets, these other droplets either get pushed away or stick to the collector drop causing it to grow and fall as percipitation

• Growth by cool and cold clouds

Cool clouds are clouds that are very big like towering cumulonimbus and have parts at the bottom which are not freezing but are freezing at a certain point and up

Cold clouds are entierly freezing clouds

In these clouds, the freezing parts have supercooled droplets which are freezing but they dont freeze due to no condensation neuclei, this makes it so when they collide with an ice crystal they will stick to it and freeze creating snow, or sleet

This is called the Bugeron Process

What is Riming

When supercooled droplets collide with ice crystals

What is Aggregation

When ice crystals join together at the tips where water molecules will stick

What is a drought and what is it caused by

• Drought = long-term lack of precipitation

• Caused by persistent high-pressure systems

  • Block clouds + rain

What are the types of energy in the atmosphere and how do they power the winds which drives all the weather?

• Atmosphere powered by:

  • Potential Energy (PE) → stored (e.g., lifted air)

  • Kinetic Energy (KE) → motion (wind)

• Continuous conversion keeps air moving

What is George Hadley’s single cell model?

It is a model that shows heating and rising of air at the equator which goes to the poles and cools and sinks back down which then travels back down to the equator.

This made winds that would flow from the poles to the equator which would also be deflected by Corrilis force, which makes the winds flow from east to west

This helped to develop an idea of how the general circulation works but was not that helpful

What are the 3 cells in the 3 cell model?

Hadley cell: This is the cell closest to the equator where air will rise at 0 and sink at 30 and the surface winds flow from the 30 to the equator causing easterly trade winds

Ferrel Cell: This is a weird cell driven by eddies which are distruptions of the normal flow and it flows like this, at 30 the air sinks and flows poleward until 60 which the air is driven up by the polar cell. This makes it flow different and produces the westerlies

The polar cell: It is the weakest cell that flows from 60 to 90 which is the poles. This air sinks at the poles and rises with the ferrel cell. The boundary at the polar and ferrel cells form a frontal zone called the polar front and is a place where a lot of storms take place

What are thermally direct and indirect cells

Thermally direct cells: These are cells that are driven by thermal action meaning air sinks at cold places and rises at warm places which makes the thermal energy convert to kinetic energy

Thermally indirect cells: These are cells that are driven by eddies and thermal cells like the ferrel cell where it flows opposite of the thermal cycle

What does the three cell model help to explain

It can explain the surface winds well but not really winds aloft

What are the doldrums and horse latitudes?

Doldrums are located at the Inter-Tropical Convergence Zone where warm air rises, and the horse latitudes are located at 30 degrees latitude or at the mid-latitudes where air sinks. Since the air is moving vertically in both it minimizes horizontal air movement making minimal wind and precipitation, causing deserts and conditions that are bad for sailing

What are Semi-permenant pressure cells

These are persistant high and low pressure cells that change with the seasons and do not move much. Examples include:

Alieutian low between alaska and russia

icelandic low at iceland

tibetan low near india

These lows are strongest during the summer and the tibetan one near india helps produce the monsoon there

Siberian High near West Russia and Siberia

Hawian high near hawaii

Bermuda-Azorez high between america and europe

These are strongest during the winter

Where do desserts form?

They like to form in places with little clouds such as places where air sinks like the midlattitudes, rainshadows, polar desserts, and costal places

What are jet streams?

These are small narrow streams at high altitudes in the westerlies that have very high wind speeds. This is caused by places of pressure differences and circle at the collision places of the cells like the polar jet stream and the mid lattitude jet stream

What are Rosby waves

These are waves that interfere with the smooth flow of the jet streams. These waves start out small due to temp. differences, the corrilis force, and eddies, which break the flow then the waves increase in amplitude forming troughs and ridges and they can even cuttof parts of the jet stream forming cyclones

These can cause storms, heat waves, and cold outbreaks

How does the winter affect Rosby waves

In the winter these temp. differences are way greater. This makes it so that the jet streams move even faster and while there are less troughs and ridges, they are larger and more intense

What are atmoshperic rivers

They are low altitude wind patterns that bring warm moist air towards the poles and create lots of rain

What is the ocean cirrculation and why does it matter?

Colder water lower in the oceans flows towards the surface and warmer water flows down to replace the colder water, this creates ocean currents which help regulate costal temperatures and ditruibute nutrient rich water equally

What is the Ekman Spiral?

A: A pattern where ocean currents change direction and slow with depth due to wind, Coriolis effect, and friction.

What is Ekman transport?

The net movement of water 90° to the wind (right in Northern Hemisphere).

How do winds drive ocean gyres?

Trade winds push water west at low latitudes, westerlies push water east at mid-latitudes, and Ekman transport plus Coriolis create circular gyres.

What are monsoons

Seasonal reversals of winds, this is due to the land cooling faster than the sea in the winter but heating faster than the sea in the summer, this causes droughts and floods based on the wind patterns

Droughts are associated with the winter and floods are associated with the summer

What causes local winds? What are some examples?

Small-scale temperature and pressure differences. An example can be sea breezes during the day and land breezes at night

What is an air mass