Atmospheric Science Notes PDF

In the air Cryogenic: production or behavior of materials at very low temperatures ​ Ex) Nitrogen gas and oxygen gas will condense into liquid ​ ​ Nitrogen gas: -183 ​ ​ Oxygen gas: -196 Gases Oxygen gas: 19% of the atmosphere Nitrogen gas: 80% of the atmosphere Carbon...

In the air Cryogenic: production or behavior of materials at very low temperatures ​ Ex) Nitrogen gas and oxygen gas will condense into liquid ​ ​ Nitrogen gas: -183 ​ ​ Oxygen gas: -196 Gases Oxygen gas: 19% of the atmosphere Nitrogen gas: 80% of the atmosphere Carbon dioxide gas: trace amounts but is a greenhouse gas, product of combustion, required by the plants for photosynthesis Water vapor: trace amounts but responsible for precipitation Ozone: trace amounts but absorbs UV radiation. (can be destroyed by chemical pollutants such as CFCs) Methan: very potent greenhouse gas The advantages of the Kelvin scale: Kelvin scale is an absolute scale, which means that 0K is the absolute zero. What would be the difference at the atomic scale with C and K? 273.15 more than Celsius scale. What causes gas pressure? Gas pressure is caused by the continuous collisions of gas molecules with the walls of their container. What is happening on the atomic scale? fast-moving gas molecules exert force on the container walls each time they collide, and the collective effect of these collisions results in measurable pressure. Electromagnetic spectrum Why does water boil at just 68C on the top of mount Everest? Water boils when its vapor pressure (the pressure from water molecules escaping as gas) matches the surrounding air pressure. Therefore, the reason why water boil at just 68C on the top of mount everest is because the atmospheric pressure is much lower at high altitudes, which means that there’s less pressure holding the water molecules in, they can escape into gas form at just 68°C, so water boils at a lower temperature. Explain the can crush demonstration. Why was water in the can boiled before placing it ​ ​ in the ice water? Why did the can get crushed when it was plunged into the ice water? As the water is heated and boiled, steam displaces the air in the container above the water. And when the can was put into the cold water, Since the air pressure outside the can is stronger than that inside the can, it causes the can to collapse. Variables ​ Proportional relationship (a relationship between two variables where when one variable changes, increases, or decreases the other will change at a constant rate): =Pressure v Temperature in degrees Kelvin As temperature in Kelvin increases, pressure increases proportionally, assuming volume is constant.  In Kelvin, temperature is an absolute scale, meaning it starts from absolute zero (0 K). When temperature increases, the gas molecules move faster and hit the container walls harder, increasing pressure. If you double the temperature in Kelvin, the pressure also doubles (if volume is constant). ​ Inversely proportional relationship (occurs when one value increases and the other decreases): =Pressure v Volume As volume decreases, pressure increases, and vice versa When you decrease the volume, gas molecules have less space to move, so they collide with the container walls more often, increasing pressure. If you double the volume, the pressure is cut in half. ​ Linear relationship (a statistical term used to describe a straight-line relationship between two variables): =Pressure v Temperature in degrees Celsius Since temperature in Celsius is not an absolute scale, the relationship is linear but not directly proportional (it does not pass through the origin). The problem with Celsius is that it does not start at absolute zero (it starts at -273.15°C). So, while increasing temperature increases pressure, it’s not strictly proportional because the scale shifts. The relationship is linear but not proportional. How does typical sea breeze created? 1.​ During the day, the land heats up faster than the ocean because land absorbs and radiates heat more quickly. 2.​ The warm air over the land rises, creating a low-pressure area. 3.​ The cooler, denser air over the ocean moves in to replace the rising warm air, creating a breeze from the sea to the land. 4.​ Higher up in the atmosphere, the warm air cools down and sinks over the ocean, completing a circulation pattern. What causes wind? Warm air above land expands and rises, and heavier, cooler air rushes in to take its place, creating wind. What causes typhoons? Air is rushing in towards a low pressure area UV radiations ​ More melanin: more protection from sun’s rays ​ UV-B and UV-C are the most dangerous ​ main defense is Ozone (O3) in the atmosphere ​ CFC are gases (chloroflurocarbons) that destroy Ozone (O3). They were used in air conditioners. ​Visible radiation: Visible radiation is the light  (colors) we see. When it hits non-transparent solids or liquids it is absorbed and it heats them up. ​ Infrared radiation: We can see it but we can feel it as heat ​ Greenhouse effect:The returned infrared radiation warms the atmosphere near the Earth's surface, which is called the greenhouse effect. Humidity ( the amount of water vapor in the air.) ​ Absolute humidity: measured by the amount of water vapor in the air in grams of water per kg of air Temperature °C Max Absolute Humidity g water / kg air 0 2 10 7 20 15 25 20 30 30 ​ Relative humidity (percentage) ○​ Relative humidity of air = Absolute Humidity in the air x 100 ​ ​ ​ Max absolute humidity For example if on a 25 °C day the absolute humidity was actually 10 g water / kg air Then the percentage humidity is 10 x 100 = 50 % ​ ​ ​ ​ 20 Wind The pathway of the wind from the ocean: Where evaporation occurs: Where most precipitation occurs: On the mountain Where least precipitation occurs: On the leeward side of the mountain (the side away from the ocean), because the air has already lost most of its moisture, creating a dry area known as a rain shadow What would make the air move up in altitude? ​ A physical landform such as a hill or mountain will cause the air to rise up to flow over it. ​ A mass of denser cold air comes in from the side and below pushing the warmer more humid air upwards Why is Sahara desert with very low precipitation? Off the west coast of the Sahara is a cold water ocean current. So the air above this cold water can not carry much water, then it blows over the land and heats up. So no precipitation. Another reason for an area to get low precipitation is if it is in a “rain shadow” of a mountain range. Temperature Explain why tropical regions are hotter than temperature regions: Nearer the equator the sun’s rays are hitting straight on, rather than hitting at an angle. The two main ways heat is distributed from tropical regions to temperate regions. ​ wind currents, which move warm air from the tropics toward the poles, ​ ocean currents, which transport warm water from the equator to cooler regions How cold front causes precipitation as a cold front comes in and drives under the mass of warm air, the warmer and moist air will be forced upwards. As the warm air is pushed higher, the moisture it carries condenses and falls as rain. Why the East Coast of Australia is Wet While the West Coast is Dry The East Coast of Australia is influenced by the warm East Australian Current, which brings warm, moist air from the ocean. This moisture rises, cools, and condenses, leading to high rainfall. The West Coast is affected by the cold West Australian Current, which brings cool, dry air, reducing evaporation and leading to low rainfall.