Transcript One
Water in the Atmosphere Monroe Chapter 24, Sections 1 and 2 and 3 479 - 493 Water can exist in any of three different forms. 1. Water vapor 2. Water liquid 3. Water solid It takes energy, however, to move between them. Humidity is the amount of H2O that is in air. Absolute humidity is how many grams of water are in the air. Humidity is the amount of H2O that is in air. Specific humidity is how many grams of water are in the air. Relative humidity is how much H2O is in the air, compared to how much it CAN hold. Humidity is the amount of H2O that is in air. Absolute humidity is how many grams of water are in the air. Relative humidity is how much H2O is in the air, compared to how much it CAN hold. If it has 20 grams of H2O, and it CAN hold 40 grams of H2O, then the relative humidity is 50%. Humidity is the amount of H2O that is in air. Absolute humidity is how many grams of water are in the air. Relative humidity is how much H2O is in the air, compared to how much it CAN hold. If it has 20 grams of H2O, and it CAN hold 40 grams of H2O, then the relative humidity is 50%. If it can hold 30 grams of H2O, and it can only hold 30 grams of H2O, then the relative humidity is 100%, and the air is saturated. When the temperature falls, and the air is saturated, the DEW POINT has been reached. Above freezing, you have water on your windshield Below freezing, you have frost on your windshield A psychrometer is used to determine relative humidity. When air rises, it expands and cools. When air rises, it expands and cools. This is called ADIABATIC COOLING. Pure dry air will cool about 1ºC for each 100 meters you rise. Most air is moist, and will cool about .75ºC for each 100 meters. When air rises, it expands and cools. This is called ADIABATIC COOLING. Pure dry air will cool about 1ºC for each 100 meters you rise. Most air is moist, and will cool about .75ºC for each 100 meters. This building in Dubai is now the tallest in the world. It is about 800 meters tall, so it will be about 8ºC cooler at the top… or about 15ºF. When air rises, and cools to its dew point, water will collect around CONDENSATION NUCLEI. When air rises, and cools to its dew point, water will collect around CONDENSATION NUCLEI. This is called the condensation level, and this is why clouds are flat on the bottom. When air rises, and cools to its dew point, water will collect around CONDENSATION NUCLEI. This is called the condensation level, and this is why clouds are flat on the bottom. Air can be cooled in one of three ways. 1. Forceful lifting, like when air is pushed over a mountain. It is pushed up and is cooled because it expands. When air rises, and cools to its dew point, water will collect around CONDENSATION NUCLEI. This is called the condensation level, and this is why clouds are flat on the bottom. Air can be cooled in one of three ways. 1. Forceful lifting, like when air is pushed over a mountain. It is pushed up and is cooled because it expands. 2. Temperature changes, like when different temperature of air mixes, and one goes up (and the other goes down). When air rises, and cools to its dew point, water will collect around CONDENSATION NUCLEI. This is called the condensation level, and this is why clouds are flat on the bottom. Air can be cooled in one of three ways. 1. Forceful lifting, like when air is pushed over a mountain. It is pushed up and is cooled because it expands. 2. Temperature changes, like when different temperature of air mixes, and one goes up (and the other goes down). 3. Advective cooling, like when air blows across a cold body of water, such as a great lake. Fog is just a cloud on the ground. Radiation fog, is just when the layer of air next to the ground is cooled below its dew point. This is the kind we see around here a lot, and it is often in patches. Fog is just a cloud on the ground. Radiation fog, is just when the layer of air next to the ground is cooled below its dew point. This is the kind we see around here a lot, and it is often in patches. Advection fog, is when warm air moves across a cold surface. Often happens on water. Fog is just a cloud on the ground. Radiation fog, is just when the layer of air next to the ground is cooled below its dew point. This is the kind we see around here a lot, and it is often in patches. Advection fog, is when warm air moves across a cold surface. Often happens on water. Steam fog, is when cool air moves over warm water. Upslope fog, is when air is pushed up a mountainside, falls below its dew point, and forms a cloud, or in this case fog. Precipitation is ANY moisture that falls to the ground. It can be a liquid or a solid. Precipitation is ANY moisture that falls to the ground. It can be a liquid or a solid. RAIN is liquid precipitation. Raindrops are between .5mm and 5mm in diameter. If they are smaller than that, it is drizzle, if it is larger than that, they will break apart and be smaller again. Precipitation is ANY moisture that falls to the ground. It can be a liquid or a solid. RAIN is liquid precipitation. Raindrops are between .5mm and 5mm in diameter. DRIZZLE is liquid precipitation that is smaller than .5 mm in diameter. It usually results in small amount of moisture on the ground. Precipitation is ANY moisture that falls to the ground. It can be a liquid or a solid. RAIN is liquid precipitation. Raindrops are between .5mm and 5mm in diameter. DRIZZLE is liquid precipitation that is smaller than .5 mm in diameter. SLEET is the name for raindrops that have frozen when they get near the ground. Precipitation is ANY moisture that falls to the ground. It can be a liquid or a solid. RAIN is liquid precipitation. Raindrops are between .5mm and 5mm in diameter. DRIZZLE is liquid precipitation that is smaller than .5 mm in diameter. SLEET is the name for raindrops that have frozen when they get near the ground. GLAZE ice is the name for the effect when rain freezes on a surface that is really cold, even when the air is not. Another name for this is “black ice”. Precipitation is ANY moisture that falls to the ground. It can be a liquid or a solid. RAIN is liquid precipitation. Raindrops are between .5mm and 5mm in diameter. DRIZZLE is liquid precipitation that is smaller than .5 mm in diameter. SLEET is the name for raindrops that have frozen when they get near the ground. GLAZE ice is the name for the effect when rain freezes on a surface that is really cold, even when the air is not. HAIL is a name for lumps of ice that fall from the sky. Precipitation is caused by COALESCENCE of moisture. Precipitation is caused by COALESCENCE of moisture. Precipitation is caused by COALESCENCE of moisture. Precipitation is caused by COALESCENCE of moisture. Precipitation is caused by COALESCENCE of moisture. Precipitation is caused by COALESCENCE of moisture.