Exam 1 Flashcards
What is Dalton’s Law of partial pressure?
The total pressure inside the parcel is equal to the sum of the pressures of the individual gases.
What is the temperature, in F, for freezing and boiling water?
Freezing: 32 F
Boiling 212 F
What is the temperature, in C, for freezing and boiling water?
Freezing: 0 C
Boiling: 100 C
What is the temperature, in K, for freezing and boiling water?
Freezing: 273.15 K
Boiling: 373.15 K
What is the conversion of C to F?
4/5(C)+32
OR
1.8(C)+32
What is the conversion of F to C?
(F-32)/1.8
What is the conversion of C to K?
C+273.15
What is specific heat?
The amount of energy required to raise one gram of a substance by 1 degree C
What is latent heat?
The energy involved in the change of state
What is sensible heat?
Heat you can feel
Which processes release latent heat into the atmosphere?
Condensation and freezing
Which processes take away heat from the atmosphere?
Evaporation and melting
What is Kirchoff’s Law?
When objects (like gases in the atmosphere) selectively absorb and emit radiation (selective absorbers). They allow solar radiation in, but trap longwaves
What is the Stefan Boltzmann Law?
Describes energy emitted based on its temperature. Hotter bodies emit more energy than colder bodies
What is Wien’s Law?
Details the wavelength of PEAK emission of a body based on its temperature. Different from Stefan Boltzmann by focusing only on peak wavelength emission, not the overall energy. Earth’s max emission is 10 micrometers. The Sun’s max emission is 0.5 micrometers. Hotter bodies will have shorter wavelengths of max emission
What is the difference between shortwave and longwave radiation?
Shortwaves have more energy. Longwaves have less energy
What are components of the electromagnetic spectrum?
They travel at the “speed of light” as a wavelength.
What is ultraviolet radiation?
Shortwave radiation. Comes from the sun
What is visible light?
Part of the electromagnetic spectrum that we can see
What is an atmospheric window?
Exists between 8-13 micrometers where very little IR radiation is absorbed by the atmosphere. Allows for some of Earth’s emitted radiation to escape directly to space
What is infrared/ terrestrial radiation?
Radiation that is radiating from the Earth
How do clouds alter energy received at the surface during the day and night?
Clouds are poor absorbers of solar radiation and reflect solar radiation. Therefore, if it is cloudy during the day, the temperatures are cooler. If it is cloudy during the night, the temperatures are warmer.
What is Rayleigh scattering?
Reflects shorter wavelengths (ex: UV). Reflects off gases in the atmosphere. Scatters in all directions
What is Mie scattering?
Reflects all wavelengths equally. Scatters forward primarily. Reflects off of aresols.
Why is the sky blue?
Incoming solar radiation gets scattered by gas molecules in the atmosphere (nitrogen, oxygen, etc). Because Rayleigh scattering prefers shorter wavelengths (purple and blue), these will be scattered disproportionately.
Why are there red sunsets?
Because the sun is at the horizon, solar radiation has a longer path to travel to get to the Earth. Shorter wavelengths will deplete as the radiation makes its way to Earth, and what will be left are longwaves (red and orange).
What are selective absorbers?
Objects such as gases in the atmosphere that selectively absorb and emit radiation “Kirchoff’s Law”
What role do selective absorbers play in the greenhouse effect?
The atmosphere selectively absorbs infrared radiation from the Earth’s surface but acts as a window and transmits shortwave radiation
What is albedo?
The percent of reflected solar radiation (outgoing solar/ incoming solar)
What has high albedo and what has low albedo?
High: Fresh snow, clouds, venus, ice
Low: Forest, dry (plowed) field, grassy field
What are the main processes of the hydrologic cycle?
Evaporation, condensation, precipitation
What are the phases of water?
Solid, liquid, gas
What are names given to water phase changes?
Evaporation, condensation, melting, freezing, sublimation, deposition
What is absolute humidity?
Mass of water vapor per volume of air. Measured in g/m3= volume. Not commonly used because if volume changes, then absolute humidity changes.
What is specific humidity?
Mass of water vapor/ mass of (all) air.
What is mixing ratio?
Mass of water vapor/ mass of DRY AIR (no water vapor)
What is relative humidity?
(Actual water vapor/ saturation water vapor) x 100%
RH is changed by either change of vapor content or change in saturation. Change in saturation includes a temp change. A decrease in temperature causes an increase in relatively humidity (inverse relationship)
What are 3 ways to calculate RH?
1) RH = (vapor pressure/ saturation vapor pressure) x 100%
2) RH = (mixing ratio/ saturation mixing ratio) x 100%
3) RH =(specific humidity/ saturation specific humidity) x 100%
What is saturation?
When evaporation and condensation are equal. “For each molecule that evaporates, one condenses”
What is dew point?
The temperature at which saturation occurs.
o High dew point = high humidity
o Low dew point = low humidity
What is the relationship between RH, dew point, and saturation?
Relative humidity indicates how close it is to saturation. Dew point indicates the amount of water vapor needed to reach saturation.
How does both indoor and outdoor RH and dew point impact human comfort?
Due to an increase in temperature in a heated home (in the winter) there is a decrease in relative humidity (becomes drier), causing more evaporation from body, plants, etc.
High RH causes less evaporation cooling. High dew point can cause the air to become saturated faster
What is the difference between dew, frozen dew, and frost?
Dew: forms on objects near the surface when they cool to dew point (more likely on clear nights due to increased radiative cooling)
Frozen dew: vapor that first condenses into dew, then freezes
Frost: forms through deposition (vapor –> solid) when dew point is below 0°C. Low energy process
What is condensation nuclei, and why are they important?
Particles (solids) suspended in the air around which water condenses or freezes (hydrophobic/hygroscopic). They are necessary for cloud growth.
What are the main types of fog, and how are they formed?
** Make sure to look at diagrams of these processes**
Radiation: Most common for US and Ohio. Clear night, lots of radiational cooling. Ground is warm from the day and radiates it out, cooling the surface. If cooled enough, it will reach the dew point making the air saturated.
Advection: air moving horizontally from a water source to a land source (warm, humid air moves over a cold surface and chill to dew point). Doesn’t have to be water –> land, but it often is
Upslope: Wind hits topographic barrier and is forced upwards (ex: mountain). As wind increases in height, it always cools. Fog forms upslope. Wind doesn’t want to be pushed upward, but a breeze might force it.
Evaporation/ Mixing Fog: Warm surface provides enough moisture to saturate a dry (RH < 100%) air parcel; short lived. Examples: Steam fog and breath in winter
What is the formula for the weighted average of mixing fog?
[Weight 1(value 1)] + [Weight 2(value 2)]/ (Weight 1 + Weight 2)
What are the characteristics of clouds?
Height (of Ohio specifically): Low (<2000m/ greater than fist. Abundance of liquid water), mid (2000-7000m/ size of thumb. “Alto”), high (>5000m/ size of thumbnail. “cirro”), vertical (extend through all levels of atmosphere
Appearance: shape, density, color
What are the different forms of clouds?
Cirrus: thin, wispy clouds of ice
Stratus: layered clouds, flat appearance, not much vertical development
Cumulus: clouds with vertical development, puffy “cauliflower” or “picture cloud” appearance, more vertical than horizontal
Nimbus: rain/ precipitation (storm) clouds, tinted clouds: grey, black, even green, darker because of a lot of water in them
What are the different names of clouds?
Cirrostratus, Cirrocumulus, Cirrus
Altostratus, Altocumulus
Stratus, Cumulus
Cumulonimbus, Nimbostratus, Stratocumulus
What cloud is the most common around the world?
Stratocumulus
What are some unusual clouds, and what do they indicate with current weather?
Scud: when there’s heavy ppt and the air saturates sub cloud levels near the ground. Forms an almost broken status cloud. Not really exciting weather-wise, but can show where flow is and find rotation.
Mammatus: Like utters. Little downdrafts pushing down from the anvil cloud. Strong vertical motions, often has hail. Calm
Lenticular: UFO-shaped. Mountain winds that oscillate on the side of a mountain that sheer off the top of a cloud and create a lens-look.
Nacreous: Mostly non-liquid. Forms in stratosphere. High altitudes.
Noctilucent: Mostly non-liquid. Coldest regions of the atmosphere.
What is the concept of parcel theory?
That small pockets of air (parcels) risk and sink moving independently of the environment.
Expansion: cooling, lower pressure
Contraction: warming, higher pressure
What are adiabatic processes?
Process in which temperature changes but no heat (energy differences) is added for removed from the substance. It’s important for cloud formation.
What is the dry adiabatic and saturated lapse rate?
Dry Adiabatic Lapse Rate (DALR): 10°C/ 1000m or 10°C/ 10m (CONSTANT)
Saturated Adiabatic Lapse Rate (SALR): 6/5°C/ 1000m (NOT CONSTANT)
Why is the saturated adiabatic rate less than the dry adiabatic lapse rate?
As saturated air cools, the capacity to hold water vapor decreases
What is the environmental lapse rate (ELR)?
The observed temperature profile of the atmosphere on any given day vertical temp change of atmosphere.
What are the differences between absolutely stable, conditionally unstable, and absolutely unstable?
Absolutely Stable: ELR < SALR (3-5 C° <5-6 C°). If forced to rise, will form stratus clouds by spreading horizontally. Usually near surface cool air formed by either radiational cooling at night or advection. DOES NOT WANT TO RISE!
Conditionally Unstable: ELR is between DALR and SALR (5-10°C). DALR > ELR > SALR. ELR averages at 6.5°C/km. Amount of instability is determined by where saturation occurs. If dry –> stable. If saturated –> unstable
Absolutely Unstable: Need cool air aloft (cold air advection, radiational cooling in clouds/ air) and warming of surface (insolation, warm air advection, air over a warm surface). Or mixing and lifting, but cool air aloft and warming are most common.
If ELR is more vertical it’s more stable. If it’s leaning left more it’s more unstable.
What happens to a layer of air as it rises or sinks?
As an air parcel rises, it cools and expands. As it sinks, it compresses and warms. If the air parcel doesn’t cool drastically, or it warms, as it rises in the atmosphere, the atmosphere is stable. If the air parcel cools drastically as it rises, it is unstable.
What is convective instability?
A layer where the bottom is saturated and the top is unsaturated is forced upwards making the unsaturated portion cool at the DALR rapidly and the saturated portion cool at the SALR slower. This makes the top much colder than the bottom faster, leading to absolute instability.
What are the four main sources of lift in the atmosphere?
Convection: warm air rises/ vertical motions
Orographic: forced to rise topography
Frontal: warm and cold fronts; dry lines (density or humidity)
Convergence: air coming together
—- (air) –>,,,,,,,,, <– (air) —-
What is the Lifted Condensation Level and the Level of Free Convection?
LCL: Where saturation first occurs; uniform level; reason why cloud bases are flat
Level of Free Convection: Point where air parcel temp > environmental temp
What is entrainment? How does it affect cloud growth/ development?
The mixing of environmental air into a pre-existing air
current or cloud so that it becomes part of the current or cloud. When the air is really dry around the cloud, cloud droplets evaporate quickly. Entrainment then puts cooler air into the cloud alongside the evaporation cloud droplets. If the cooling reaches the DALR, the air stops rising and cloud development halts (even if the lapse rate may indicate a conditionally unstable atmosphere).
What is the rain shadow effect?
Where precipitation is less on the leeward side of a mountain
What is meant by an atmospheric trigger mechanism?
Something that causes the development of clouds and instability.
