Atmospheric Humidity and Water Phases

Atmospheric Sciences - Chapter 4 to 7

Chapter 4.1: Atmospheric Humidity (LO1)

• Earth's hydraulic cycle includes evaporation, condensation, precipitation, and transpiration.
• Water circulation is constant because 70% of the Earth's surface is ocean.
• Evaporation transforms liquid into gas by using the sun's energy.
• Condensation is the process of water vapor turning back into liquid or ice, forming clouds.
• Precipitation occurs when cloud particles grow and fall to the ground as liquid or solid water.
• The hydraulic cycle describes the movement and exchange of water among Earth, atmosphere, and oceans.
• Evaporation and transpiration from continental areas account for 15% of water evaporated annually into oceans, while 85% evaporates from the oceans.

Chapter 4.2: The Many Phases of Water (LO2)

• Water has three states: gas (water vapor), liquid (water), and solid (ice).
• In gas form, water vapor molecules move freely. Higher temperatures speed up molecule movement.
• In liquid form, water molecules continuously bump into each other. Lower temperatures slow molecule movement.
• In solid form (ice), water molecules arrange into hexagonal crystals.
• Sublimation is when ice transforms directly into water vapor (gas) without becoming liquid.
• Deposition occurs when water vapor molecules attach to an ice crystal, becoming part of the ice crystal
• Water vapor becomes visible as cloud droplets and ice crystals. This is called a change of state or phase change.

Chapter 4.3: Evaporation, Condensation, and Saturation (LO3,LO4)

• In the liquid-to-vapor state, water molecules break from liquid surfaces and enter the air, called evaporation.
• In the vapor-to-liquid state, water molecules return to liquid surfaces, called condensation.
• Saturated air has balanced evaporation and condensation rates, meaning it has maximum water vapor for the existing temperature and pressure.
• Under saturated conditions, the loss of liquid or vapor molecules results from every evaporating molecule which must condense.
• Removing the cover of liquid allows vapor molecules to blows into the air, creating difference with the amount of molecules needed for saturation and allows evaporation.
• Water, oxygen, and nitrogen molecules colliding changes their speed and direction, but not the air temperature .
• Water vapor condenses on condensation nuclei (dust, smoke, salt) in chilly/cold air or they will bounce off in warmer air.
• Billions of water vapor molecules condensing on nuclei form cloud droplets, which is more likely as air cools.
• More water vapor can exist in warmer as opposed to cooler air.

Chapter 4.4(a-e): Humidity (LO5,LO6)

• Humidity generally describes the air's water vapor content.
• Absolute humidity measures the mass of water vapor per volume of air or otherwise known as the water vapor density and is measured as mass of water vapor/volume of air.
• Specific humidity is the mass of water vapor relative to the total mass of air in a parcel and is measured as mass of water vapor/total mass of air..
• Mixing ratio measures the mass of water vapor relative to the mass of dry air in the given volume
• Actual vapor pressure is the pressure exerted by water vapor molecules in a volume of air
• Saturation vapor pressure is the maximum amount of water vapor needed to keep equilibrium with pure water or ice surface, or the maximum amount of water vapor the air can hold with the temperature and pressure.
• Relative humidity measures the amount of water vapor in air compared to the amount needed for saturation expressed via: water vapor content/water vapor capacity or via actual vapor pressure/saturation vapor pressure X 100 percent.
• Supersaturation is when the air contains more water vapor than needed for saturation on a flat pure water or ice surface and relative humidity is greater than 100%.
• Dew-point temperature is the temperature air must cool to reach saturation.
• Frost point is the temperature at which air becomes saturated with respect to ice
• Temperature and relative humidity are oppositely correlated throughout the day
• Lower dew point temperatures on clear nights means lower expected minimum temperatures due to less water vapor.

Chapter 4.5 (a-c): Assessment and Impacts of Humidity (LO7,LO8,LO9,LO10)

• High relative humidities are found in tropics and near poles, with average relative humidity being near 30 degrees latitude.
• The Pacific air is much cooler than the Gulf air, and westerly winds cools the air with the temperature of the water. Resulting in lower dew point temperatures over the Pacific.
• Air moving inland increases temperature, but maintains the same dew point. Results in high relative humidity in the southeastern states.
• Saturated air cools to 21°C (70F), producing a dew-point temperature in the air to 21°C, where vapor and saturation pressure equals to 25 millibars.
• Heated air with -15°C dew points and air temperature drops relative humidity to 8 percent. Results in rapid moisture evaporation stresses/harms plants, animals, and humans requiring an increase in increase in relative humidity to fix.
• Less cooling means less evaporation and is usually felt warmer with lower humidity and equal temperatures.
• Wet-bulb temperature is the lowest achievable by evaporating water into the air.
• Heat Index (HI) combines air temperature and relative humidity to determine apparent temperature - how hot it feels.
• Apparent temperature combines air temperature and relative humidity for determine how hot a person feels.
• A Psychrometer is an instrument with two thermometers to measures measures water vapor content in the air.

Chapter 5.1: The Formation of Dew and Frost (LO1)

• Objects near Earth's surface radiate infrared radiation rapidly which cools ground and other surrounding surface as contact occurs.
• Dew condenses as temperature falls below the surface air's point.
• Frozen dew is liquid dew transformed into tiny ice beads upon contact.
• Clear and calm nights are more prone to dew, as opposed to on cloudy and windy nights.
• Visible white frost is formed on cold clear mornings when the dew-point temperature is at or below freezing as water vapor can change directly to ice in this air to ice transition.
• Frost is ice produced by deposition with noticeable treelike branching, occurring when air temp falls below the frost point.

Chapter 5.2: Condensation Nuclei (LO2)

• On standard day air volumes container between 1000 and 150000 particles.
• Condensation nuclei is the general name for tiny particles on whose surfaces water vapor begins to condense.
• Aitken nuclei are small and less than 0.2 mm in radius, large one are within 0.2 and 1mm, and giant have radii larger than 1mm..
• Aitken Nuclei have radii of less than .1um
• Large nuclei has ranging particle sizes .1 - 1um
• Giant nuclei have radii exceeding 1um
• Large and giant nuclei are most often used to produces clouds that usually have a size between 100 and 1000 per cubic centimenter.
• Dust, volcanoes, factory smoke, forest fires, ocean spray, and phytoplankton emissions contribute to these particles.
• Condensation nuclei suspended in the air can occur for multiple days and is abundent due its light, so it decrease in country air, industrial cities, "cleaner" air over ocean.
• Hygroscopic describes water vapor condensing at surfaces below 100 percent humidity , with dried potato chips and salt attracted to water.
• Hydrophobic resists condensation even with 100 percent humidity, like coco powder and wax which are "water-repelling.

Chapter 5.3: Haze (LO3)

• Haze is dry, wet, or salt particles dispersed in atmosphere, which is visible cumulatively with diminished visibility.
• Small particles are in small, dry haze particles of around .1 mm
• Visiting haze locations are possible to notice afternoon objects better with not changed particles due to the relative humidity remaining under where active hygroscopic nuclei are at.
• Dry haze partitions disperse while permitting others to enter the air.
• If night temperatures cools with increased relative humidity close to 75%, condensation starts to develop on active nuclei to generate vapor haze. Size increase on articles permit scattering of light.
• High relative humidities during cooler mornings permits haze to scatter much source for light, making it impossible to detect distant objects.
• Wet haze appears dull gray and is observed with high sea relative humidity over oceans, while seawater appears across horizon.

Chapter 5.4: Fog (LO4)

• Fog is a cloud with its base where the Earth's surface is
• When relative humidity enters close to 100 percent, haze particles may grows and begin to condense when the water becomes visible.
• The reduced visibility during less then 1 km and saturated air permits cloud of floating water droplets in near ground locations.
• City smog is thick and polluted with air
• The acidification that occurs creates combines pollutants containing sulfur and nitrogen oxides, acid fog can occur.
• Acid fog forms when drops mix sulfur pollutants that produce acid water, which measure with < 5 pH measure.
• Fog droplets settle close 5 cm /each second
• Fog forms via cooling with dew saturation. Evaporation and mixing occurs when water enters and mixes.

Chapter 5.4a: Radiation Fog

• Conduction and radiation are how temperature is reduced to be near fog. Temperature reduced from Earth is called radiation cooling
• Radiation fog is mostly seen over land when reduces radiation with low point air, resulting in floor and valley cloud.
• Radiant usually visible because moisture is within direct levels, making temperature lower to not radiate as much
• This fog occurs often close sunrise with low breeze.

Chapter 5.4b: Advection Fog

• Advection fog is made from warm, most air close to a cold surface beneath the air.
• Advection fog does not occur without air movement because temperatures have to continue, to drop when needed.
• Advection fog is created on headlands where air blends and ascends.
• Winds can carry fog above warmer grounds, fog usually is gone and causes cloud barrier.

Chapter 5.4c: Upslope Fog

• Upslope Fog is formed from air moisture that is stable and climbing an elevated mountain.
• Upslope forms from the east side of Rockies with a kilometer land barrier.
• Fog generates due to saturation form of air.

Chapter 5.4d: Evaporation (Mixing) Fog

• Moist winds from mouth that mixes with saturated air creates evaporation fog that can result in mist.
• This form of fog is usually called steam fog (produces moist when air mixes wet air, while warmer drops enter cold fog.

Chapter 5.5: Foggy Weather

• Fog is relevant with coastal sides because current moves near the American Alps.
• Fog permits produce development by shading light below Celsius by keeping light below freezing by keeping current temp at 7 degrees

Chapter 5.6 a-e: Clouds (LO5,LO6, LO7,LO8)

• A cloud is a mixture of water and frozen ice floating that are characterized within ten core clouds

• Stratus ("layer), Cumulus ("heap), Cirrus(" curl of hair), Nimbus ("violent rain").

• High clouds are at 20,00 - 60,00 ft, which are the same kind of word for words listed ( cirrus/stratus/cumulus (low clouds are < 65,00 which also a type of word/definition and cumulus (vertical)) Satellites

• Mid/High Altitude (cirrostratus / sun high), is within a cooler point compared to warmer/low air clouds that can be determined

• Mid /Low Altitude ( alto is in dim sun light, broken when sky breaks.

Chapter 5.6b: Cloud Identification – High +Middle

• Middle and high altitudes form above at around 16,000 ft .
• The thin sheets ( cirrus are the most common by the winds)
• The smalls but less seen is by rolling, ripples near the skies ( cirrocumulus cloud )
• The high "sheets" that cover the sky is halos is known is cirrostratus clouds near moon. All of theses highs could potential rain near the 12 - 24 hours. (high altitudes) Altocumulus:

Chapter 5.6b: Cloud Identification – Low + Vertical

• Lows are around 6500 ft which mainly contain ice and water
• Nimbostratus is wet looking with some precipitations with distances reaching 10,000 ft.
• Stratocumulus is lower, chunky and has light breaking around with sunlight

Chapter 5.6c: Some Unusual Clouds

• Lenticulars: clouds shape in lens are formed after "waves"
• Banner clouds: is banner like from an area mountain
• Cap cloud /pileus resemble the sky cap when rains or build and are attached but is smooth
• Mammatus is form below sky bag from "clouds".
• Contrail is light that made during air flights

Chapter 5.6c: Some Unusual Clouds cont.

• Nacreous is unusual cloud ( soft and peal around 30 km in Earth
• Noctilucent cloud waves a the 60 - 90 km pole
• Star shines brightly for both in higher air.

Chapter 5.6d: Cloud Observations – Determining Sky Conditions

• Clear , 1/8-2-8 (clouds are present), 3/ 8 to 3/8 (partly) 4.8 to 7 /8 broken (mostly), 8/8-over cast Infrared measures send from cloud level above

Chapter 5.6e: Satellite Observations

• Cloud platforms are essential because +70% water are where cloud is
• Geostationary runs earth for 36,000km
• Polar closely runs earth in revolutions

Chapter 6.1: Atmospheric Stability (LO1)

• Stable balance by opposing moves and returning to starting position
• An unstable volume and favors "both"

Chapter 6.2: Determining Stability (LO2, LO3)

• Stable, moves back to area and "heavier" area is
• Unstable will stay when reaches point to remain that

Chapter 6.2a: A Stable Atmosphere

• Env is a decrease with the elevation that can use a radiosonde
• Absolutely : is an air when low the the moisture rate

Chapter 6.2b: An Unstable Atmosphere

• Air when high, the environment permits a low heat, constant "stable air", resulting in temp instability

Chapter 6.2c: A Conditionally Unstable Atmosphere

• Depending, is stable when saturate, unstably permits, but saturation occurs when unstability happens.

Chapter 6.2d: Causes of Instability and Causes

• Weather turns high due temp drops
• Warm causes, day high with sun, high winds can lead to unstably conditions

Chapter 6.3a: Convection and Clouds (LO4,LO5, LO6)

• Motions that occur can be from edges with air
• Clouds shade with upward surface leading to a side with fragments from sides.
• Clouds depend by with air and surface conditions with humidity
• Cumulus clouds are due single motion and by 100 percent mixing

Chapter 6.3a: Convection and Clouds (LO4,LO5, LO6) cont.

• Higher air with warmer atmosphere (level of motion) which cloud forms.

Chapter 6.3b: Topography and Clouds

• Moving air permits lifting by a topographic to lead to clouds
• Orographic is a barrier lifted from air form the lift from a cloud.
• Mountains generate that produce colling by making air to cloud through mountains.
• The side that does receives clouds more on winds. This side is also known as a "shadow" .
• Unsaturated increase in dry air + 2 degree = where level occurs from saturation.
• Descending side increase warmer/ compress by with potential