WEAX 201 Module 3 Study Guide

WEAX 201 Module 3 Study Guide Latent heat When water changes phase, it transfers _________which play an important role in energy exchange between the ocean and atmosphere and in convective weather development. 60% Water in gas form (water vapor) is the most abundant atmospheric greenhouse gas and accounts for _____of the atmospheric greenhouse effect. Evaporation Water vapor enters the atmosphere via _______ and transpiration by plants over land. Clouds Once in the atmosphere, water vapor can condense into liquid, or deposit to ice, to form ________. Precipitation Water leaves the atmosphere via ________. Water _____exists in all three phases in the earth's atmosphere: liquid water, ice, and water vapor. Condensation Water molecules leave the water surface via evaporation, and attach to the surface via ________. Exceeds When evaporation _______condensation, the air over the water surface is unsaturated. Equals When evaporation _______condensation, the air over a water surface is saturated. Expanding or contracting The parcel's pressure always adjusts to that of the environment by___________. Unsaturated Air not at its maximum capacity for water vapor is _______ atmospheric conditions allow for water molecules to remain as a vapor. Saturated Air at its maximum capacity for water vapor is ________ atmospheric conditions do not allow water to remain in vapor form, and water molecules start to condense into liquid. Temperature Air's capacity for water vapor is highly ______ dependent. Increases As air temperature ________, water vapor molecules move faster, and are more likely to stay in vapor form and less likely to condense to liquid. Cooled Saturation (and thus condensation) becomes more likely as air is _______. Warm, cold _____ air has a greater capacity for water vapor than ______ air. More Warm air can contain ______ water vapor molecules without becoming saturated, compared to cold air. Humidity A general term for some description or measurement of the amount of water vapor in the air. Absolute humidity Measures the density (mass/volume) of water vapor in an air parcel. Constant If the amount of water vapor in a parcel remains constant with no change in volume, absolute humidity would remain ______. Rises or descends With no change in water vapor content, absolute humidity will change as the parcel volume changes, i.e. as it_______. Vapor pressure (e) The partial pressure exerted by the water vapor molecules within an air parcel. Increases, increases At a given air pressure, as the percentage of water vapor molecules in an air parcel ________, the amount of pressure exerted by the vapor (vapor pressure) _____. Saturation vapor pressure (es) The pressure that water vapor molecules woudl exert if the air were saturated with water vapor at a given temperature. Maximum Saturation vapor pressure is a measure of the air's _______ capacity for water vapor, or the saturation limit of air. True As temperature increases, air's capacity for water vapor increases = saturation vapor pressure increases. Higher _____saturation vapor pressure means the air has a greater capacity for water vapor. Relative humidity The ratio of the actual amount of vapor in the air to its capacity for water. Percentage Relative humidity is the ratio of the actual vapor pressure to the saturation vapor pressure expressed as a _____. Changes Relative humidity will change if water vapor content, or the capacity for water vapor ______. Dew Point Temperature (Td) The temperature to which a parcel of air (at a constant pressure and water vapor content) would have to be cooled in order to reach saturation. High dew point temperature High water vapor content Low dew point temperature Low water vapor content Increase Evaporation of water into the air (i.e. during the heat of the day) will _______ the dew point temperature. Decrease Condensation of water out of the air (i.e. as air cools overnight) will ________ dew point temperature. Advection _____of moist/dry air into a region will increase/decrease the dew point temperature. Dew point depression The difference temperature and dew point temperature (T-Td), called the _______, is an indicator of how high or low the relative humidity is. Increases and relative humidity decreases As air temperature increases during the day, air's capacity for water vapor increases, taking it farther from saturation = (T-Td) ___________ Decreases relative humidity increases As air temperature decreases in the evening/overnight, the air's capacity for water vapor decreases taking it closer to saturation = (T-Td) ______. Temperature much greater than dew point temperature Dew point depression is large Air is far from being saturated Relative humidity is low Temperature close to dew point temperature Dew point depression is small Air is closer to being saturated Relative humidity is high Temperature = dew point temperature Dew point depression is = 0 Air is saturated Relative humidity = 100% Greater than or equal to Temperature is always ______ to dew point temperature Condensation nuclei In the atmosphere, due to the effects of _______, condensation takes place (clouds, fog, or haze observed) when (T-Td) 3-5 degrees. Wind direction The humidity of a region depends on ________, proximity to the ocean, and ocean temperature. Less dense At a given temperature, humid air is ___ than drier air. Less water vapor If we know that City A has a lower surface dew point temperature than City B, we can conclude that City A contains ____ near the surface than City B. Higher capacity for water vapor If we know that City A has a higher temperature than City B, we can conclude that City A contains _____ the surface than City B. The difference between air temperature and dew point temperature is higher in the desert southwest. In the summer, the Gulf Coast state have a higher realtive humidity than the desert southwest. This is because: Formation of dew and frost