Meteorology Unit Test Flashcards

Daily Tides

Sun and moon pull on Earth, and as Earth spins for 24 hours a day, in different areas, it causes high and low tides twice a day everywhere on our planet

Why are high/low tides 50 minutes later each day?

High and low tides are 50-60 minutes later each day because the moon revolves around the Earth in the same direction that the Earth rotates around its axis. So, it takes the Earth an extra 50 minutes to “catch up” to the moon. When a specific location on the Earth aligns with the Moon's gravitational pull (creating a high tide), it takes slightly longer than a 24-hour rotation for that location to be back in the same alignment again, resulting in the 50-minute delay

Neap tides

At the 1st and 3rd quarter moon phases, the sun, moon, and Earth will be at right angles. This causes both objects to somewhat negate each other’s effects and create less drastic differences in daily high & low tides.

Spring tides

When the sun, moon and Earth are aligned at its new and full moon stages, both objects almost “work together,” creating more drastic differences in daily high & low tides.

Relationship between latitude, solar heating, and global wind patterns

The Earth’s spherical shape results in solar radiation being distributed unevenly. At the equator, solar radiation strikes directly at that point, resulting in higher temperatures. Warm air near the equator rises which creates low-pressure zones while cooler air, which is more dense, sinks at higher latitudes. This forms high pressure zones. These pressure zones set the course for global wind patterns, since winds will try to always move from high to low pressure zones.  However, as these winds move from the poles to the equator, they are deflected by the coriolis effect of Earth’s spin, causing them to move in certain directions (to the right in the Northern Hemisphere, to the left in the Southern Hemisphere). 

Coriolis Effect

• This is created due to the rotation of the planet on its axis, deflecting air. Essentially, the Coriolis Effect is how the planet spins and Earth rotating on its axis, in which latitudes causing bigger and slower moving fluids deflect them to the right in the Northern hemisphere and left in the Southern Hemisphere.

• NORTHERN: Winds rotate clockwise around high pressure, counterclockwise around low pressure

• SOUTHERN: Winds rotate counterclockwise around high pressure, and clockwise around low pressure

Global winds

Three causes of global ocean current patterns

Winds, tides, and differences in water density.

Winds and global ocean currents

Surface currents are primarily as a result of global wind systems. This is known as the transfer of energy from the atmosphere to the hydrosphere. Wind currents can push the highest layer of water around the Earth, creating top currents.  They guide the global conveyor belt, and they can pick up moisture from warmer waters to power storms & other major meteorological events. Additionally, the Coriolis Effect causes moving water to deflect, affecting the direction that ocean currents move. 

Differences in water density

Temperature and salinity changes can impact the density of water, related to thermohaline circulation.  Low temperatures & high salinity levels lead to higher water density, as high temperatures and low salinity levels lead to low water density.  Denser water will sink, moving underwater in a process called Downwelling and creating deep sea currents, which power the global conveyor belt.  Then, that water may rise again through Upwelling.

Tides

Tides can help move water up and down along coastlines, spreading sediments and other materials around & generally causing water to move in smaller currents.  They aren’t necessarily super important, but they are a main factor responsible for the movement of sea currents. They drive regional water movement.

Thermohaline circulation

Warm, less dense water rises, and cold, dense water sinks. This is due to the density of the water. As the seawater gets saltier, its density increases, and it starts to sink. Surface water is pulled in to replace the sinking water, which in turn eventually becomes cold and salty enough to sink. The most dense waters are found at the poles due to ice taking in all the water and leaving salt out.  Less dense waters are found near the equator due to higher temperatures there, as warmer water is less dense, though the evaporation can still fuel this process through leaving salt out.

How warm/cold currents impact climate

These two processes move temperature, salt, and other things through the oceans, keeping things balanced. Since water moves from high to low pressure, and colder waters are denser & under higher pressure, falling, and warmer waters are less dense & under less pressure, rising, this change causes waters to move from the poles to the equator and back, powering currents at the surface and in the deep ocean.  Most of this is due to convection, and it also helps global conditions to stay balanced by spreading temperatures around the world & balancing them, helping the whole world be habitable. Warm currents create temperate or warm climates, whereas cold currents create colder climates.

Air masses

Two components of air masses: Temperature and Humidity

Temp:

• T: Tropical: Warm (often low latitudes)

• P: Polar: Cold (high latitudes)

Humidity:

• C: continental: Dry air masses originating over land

• M: maritime: Moist air masses forming over oceans

• A: arctic air: Very cold & dry air masses

Cold front

The front edge of a moving mass of cold air that pushes underneath the warmer air mass like a plow. Moves quickly, causes a drop in temperature, thunderstorms, and heavy rain. After thunderstorms, it is followed by cooler, drier air. Has cumulus/cumulonimbus clouds.

Warm front

The front edge of advancing warm air mass that replaces colder air with warmer air. Slow, warm, makes clouds, fog, some storms, light rain with drizzle, multi-layered clouds, sometimes clear. Stratus, Nimbostratus and sometimes cirrus to indicate it advancing on a retreating cold front

Wind Facts

Winds move from high to low pressure and are named for the direction they come from, and measured by an anemometer. On a synoptic plot wind direction is shown by an arrow pointing where the wind is coming from and the speed is indicated by lines. Winds are strongest when their isobars are close together meaning they have a steep pressure gradient (a greater pressure difference between high and low pressure), and this creates quicker movements (greater wind speeds) from high to low pressure zones. So, winds are strongest when the pressure difference is greatest.

Winds and pressure relationships (HSALRTCC)

In high pressure systems air sinks, moves away from the system, and moves clockwise in the Northern Hemisphere. This leads to cooler, clearer skies, and sunny weather.

In low pressure systems air rises, air moves towards the system, and moves counterclockwise (Northern Hemisphere), which can lead to warmer clouds, storms and precipitation. 

Air pressure facts

• Is measured with a barometer and shown in the top right of a synoptic plot. On weather maps isobars connect areas with equal air pressure. As altitude increases, air pressure decreases because there is less air above.

• Take the pressure given, remove the 10 or 9 at the beginning, and remove the decimal point that is present.

Clouds

• Can indicate fronts approaching, cumulonimbus =severe storm

• Need condensation nuclei (dust or particulates) for water vapor to attach to

Naming:

• Cumulus=heap, pile 

  Nimbo=rain

  Stratus=layer

  Alto=mid

  Cirrus=high

10 Cloud Types

• Cumulus

• Stratus

• Stratocumulus

• Cirrus

• cirrocumulus

• Cumulonimbus

• Cirrostratus

• altocumulus

• altostratus

• nimbostratus

Absolute humidity

Is the mass of water vapor contained in a given volume of air at a certain temperature,

Relative humidity

Relative humidity is the ratio of water vapor content in the air to the maximum amount that it could hold at that same temperature.

Dew point

Dew point is the atmospheric temperature that dew can form at or below (when water vapor condenses). The atmospheric temperature varies based on air pressure and the humidity of the location. One hundred percent humidity will occur if the certain temperature is reached.

If the difference between temperature and dew point are closer….

the relative humidity is higher since water is more able to condense

Atmospheric Concentration

78.08% nitrogen, 20.95% oxygen, 0.93% argon, 0.04% other gases

Original Atmosphere

• Mainly hydrogen and helium. After comets struck the earth and condensed water vapor in the air to make the oceans, these gases escaped into space

• Outgassing from volcanoes released more complex gases & compounds, like sulfurs, methane, ammonia, carbon dioxide. These later broke down into simpler molecules

• Simple organisms developed, like cyanobacteria. They took CO2 and turned it into oxygen through photosynthesis

• About 2 billion years ago, the amount of oxygen spiked and has stayed about the same. (Cambrian Explosion)

• The ozone layer formed due to an accumulation of oxygen in the atmosphere.

Troposphere

• Is the layer closest to the surface of Earth, up to 12 km

• Nearly all life and weather occur in this layer.

• The air is denser than in other layers, and thins as you rise. (High to low air pressure). In this layer, as you move up, temperature DECREASES.

• Warmed via convection

Stratosphere

• 12 to 50 km

• The temperature in this layer becomes WARMER as you increase altitude.

• The air is thinner (low air pressure) and drier than in the previous layer.

• Contains the Ozone layer

Mesosphere

• 50-80 km

• Coldest layer

• Meteoroids usually burn up in this layer, creating shooting stars.

• It is a pretty thin layer

Thermosphere

• 80 to 700 km

• Temperatures are very high, more than 2000 degrees F. Hard to measure, however, because it is actually quite cold as air is very spaced out

• This is where space begins.

Exosphere

• Above 700 km

• Is the outermost layer of Earth’s atmosphere but there is no exact dividing line between this layer and space.

Oceanography

• Global Winds create Global Currents at the surface, these currents move heat around the planet

• Deep Sea Currents- thermohaline are density driven: colder=denser, saltier=denser

Hurricanes

• Can produce tornadoes

• Names include tropical cyclones, typhoons, hurricanes

• One of most powerful and damaging of all storms

• Measured based on wind speed (quantitative) and then damage

• Larger, last longer

• Energy from warm ocean waters (80 F) and warm air

• Form in summer/fall

• Form near equator

• Easy to predict

• Categorized on Saffir-Simpson Scale from 1-5

Tornadoes

• Can’t produce hurricanes

• Measured based on qualitative data to estimate wind speed

• Smaller, shorter duration

• Less damaging due to size

• Other names include twisters and waterspouts

• From the energy of supercells, form in areas with these

• Form in cumulonimbus/thunderstorm clouds, usually on land

• Spring/summer, but can happen anytime

• Hard to predict, as they are covered by clouds

• Enhanced Fujita Scale, 0-5

Both hurricanes and tornadoes

• Produce strong winds

• Are ultimately driven by the convection process

• Both are low pressure systems that are deflected counterclockwise due to the Coriolis Effect

• Both are considered severe weather, both may cause severe damage

Day (sea breeze)

Sea breeze is cooler, land breeze is warmer, as water has higher heat capacity and sun is heating land. As land is heated, hot air rises becoming less dense creating low pressure. Air over sea keeps high pressure. Breeze moves towards land due to pressures.

Night (land breeze)

Sea breeze is warmer, land breeze is cooler as it is not being heated. At night the land cools rapidly (land temp. changes more quickly than water), and direction changes as sea air is warmer. Land breeze pressure becomes higher, and sea breeze becomes lower. Breeze from land moves towards water.

Monsoon

• Seasonal change in the direction of prevailing winds in the region, lasting 3 to 4 months with transition, affecting India and east Asia.

• Winter monsoons: cold, high pressure on land, and dry, and airflow is towards water. Summer: warm and low pressure in the summer, as the inland plateau heats and becomes very warm, winds are attracted to land.

• Shifting regional pressures influences air masses which can bring dry weather or precipitation. Air masses include mT, cT, and cP.

Climate factors

LE POT VP

Latitude and climate

• Different latitudes receive amounts of solar radiation as well as experiencing general regional pressure conditions

• Equator receives the most solar radiation because they are closer and radiation hits at a perpendicular angle. The climate of these places is much higher, with low pressure.

• The poles that are high latitude experience no radiation and a colder climate.

• Latitude may also impact rainfall based on regional pressures, as the equator will have a lot because of L, whereas poles will be dry because of H.

Elevation

The temperature of the atmosphere drops 3 F every 1000 feet in elevation

Proximity to water

Bodies of water have a moderating effect on climate, because water has a high specific heat capacity, it takes more heat to change the temperature of a body of water. So, areas close to bodies of water will have relatively mild winters and cool summers

Ocean currents

Transport warm water and precipitation from the equator and cold water from the poels back to the tropics. Ocean currents regulate global climate, counteracting the uneven distribution of solar radiation reaching the Earth’s surface. Without currents, temperatures would be extreme and less habitable.

Topography

Mountainous areas tend to have more extreme weather because it acts as a barrier to air movements, moisture, and rain clouds. One side of the mountain may be dry (rain shadow) while the other is full of vegetation.

Vegetation

Influences both the albedo and the amount of water vapor and carbon dioxide in the air. Most plants and forest soils have very low albedo (.03 to .20) and absorb a lot of energy, reducing heat.

Prevailing winds

Bring air from one type of climate to another. Warm winds that travel over water collect moisture as they travel, and the water vapor in the air will condense as it moves into colder climates, causing temperate coastal areas to receive heavy rainfall.

Rain shadow

As air is pushed up the slope of a mountain, it cools the air, creating condensation and producing clouds. However, mountains act as physical barriers & prevent the passage of rain over themselves. The side of the mountain that the rain is coming from will be the wetter side, and have much more vegetation than the dry barren side, that the rain can’t cross over to. After the dry air advances and dissipates, it may dry out an area.

Weather vs climate

Weather

• Daily changes in temperature, pressure, humidity, cloud cover, air pressure, storms, and other factors

• Being more local and in a shorter span of time. 

Climate

• Is the changes in weather patterns overtime, such as the sea level rise over the past years over a large area

• Based on overall measurements and trends in a specific area from years of measuring, essentially the average of weather in an area

Albedo

Albedo is the ratio of what the Earth reflects and absorbs, so a higher albedo means the earth is more reflective (rather than absorbing it), which would cool the climate and temperature. This is measured with decimals from 0 to 1, with 0 being not reflective at all and 1 being very reflective. Lower albedo means absorbing heat, whereas a higher albedo indicates reflecting more heat.

Albedo and temperature

A low albedo does not always indicate a hot area, such as with forests. It simply means an area absorbs a lot of sunlight. However, a low albedo often indicates a warmer area & a high albedo often indicates a cooler area.