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Why temperature of air parcel increase during the wet adiabatic lapse ratev?
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How does temperature change as you tavel up?
The air at the ground is at a higher pressure than air higher up; this is because the air at the ground is compressed by the weight of all the air above it. Air weighs quite a lot: A square column of air one meter across weighs ten tonnes! The air pressure decreases steadily as you go up, since there's less air pressing down from above, until you reach zero pressure, which is outer space.If you've ever opened a container of compressed gas, like a bottle of carbon dioxide or nitrogen, you'll notice that the air coming out of it is very cold. (Even a bottle of soda does this a little; it's the cold that makes it "steam" briefly when opened.) Reducing the pressure makes most gases colder.In what follows, I'll talk a lot about "air parcels". You should imagine a "chunk" of air, identical to the air around it, but identified by drawing an imaginary boundary around it, or by marking each of the molecules in it with a little tattoo.Now, the air in the lower atmosphere (the "troposphere") is constantly mixed by convection, which results from sunlight heating the ground. So air parcels are being constantly lifted from the ground to high altitude and back again. As a chunk of air rises, its pressure decreases, and so its temperature drops. Descending parcels are warmed as they're compressed. This is what makes the air cooler higher up: the process is called adiabatic expansion/compression.But why do gases cool when they're compressed? I'll give a verbal and a mathematical explanation. Imagine a parcel rising from the ground high into the atmosphere without gaining any net energy. As it rises, it is gaining gravitational potential energy. This energy must come from somewhere: the only source of energy is the internal thermal energy of the molecules in the parcel -- the energy in the shaking and jiggling of the molecules. If the molecules shake and jiggle less, it means they must have a lower temperature.The mathemtical explanation: you may have heard of the ideal gas law:PV = nRT (1) which says that gas pressure (P) times volume (V) is proportional to the temperature (T). (n is the number of moles of gas molecules in the parcel, and R is a fundamental constant; both remain the same in this problem). So we see that when P goes down (on top of the mountain), T also goes down. But wait! The volume V of the gas goes up at the same time, which would increase the temperature! Which of P and V wins?To find the answer, we need the "adiabatic expansion" equation, which says that if no energy is gained or lost by an air parcel,P Vgamma = constant = P0 V0gamma (2) where P0 is the pressure and V0 is the volume before we expanded or compressed the gas. Putting equation 1 into equation 2, we can eliminate the volume V:P/P0 = (V/V0)(-gamma) V = V0 (P/P0)(-1/gamma) PV = P V0(P/P0)(-1/gamma) (n R) P(1-1/gamma) = ----- P0(-1/gamma) T V0 Since n, R, P0, and V0 are all constants, this is an equation relating pressure P to temperature T for a parcel. As long as (1-1/gamma) > 0, T will decrease whenever P decreases (as we go up in the atmosphere). gamma = 1.4 for air, giving (1-1/gamma) = .28 > 0. Therefore, the atmosphere gets colder as you go up and pressure decreases.Why does the ideal gas law hold? Where does the adiabatic expansion law come from? Why is gamma = 1.4 for air? These are much harder questions, dealt with in college thermodynamics courses, and beyond the scope of this question.
Why does it hurt to hold a heavy parcel by the spring?
it hurts to hold a heavy parcel by the string because you are holding a small surface area meaning that the force is more recognisable and the pain is a lot more intense because of the small surface area the pain is more concentrated.
Describe three situations when you have to estimate the weight of something?
Guessing the weight of ingreadients in a cake (the scales wont work), guessing your own weight and esimating the weight of a parcel
Why does it hurt to hold a heavy parcel by the string?
When pressure increases area decreases and vice versal. It hurts to hold a parcel with string as it's handle because ,you are holding the weight on a small area therefore the pressure increases .(pressure is directly proportional to force and inversely proportional to area)
What are the 4 cooling methods for clouds?
Condensation or Deposition of WaterClouds form when the water vapor condenses into small particles. The particles in clouds can either be liquid or solids. Liquid particles suspended in the atmosphere are referred to as cloud droplets and the solid particles are often called ice crystals. The potential for cloud formation (and precipitation) depends on the amount of water vapor in the atmosphere. As a parcel of air rises, the moisture it contains cools and condenses out onto small particles of dust called cloud condensation nuclei until a cloud forms.As a volume of unsaturated air cools, its relative humidity increases. If sufficiently cooled, the relative humidity becomes 100%, the temperature equals the dew point. Here's a fun hands-on activity (applet) to help you explore the relationship between temperature, dew point temperature and relative humidity.Lifting of AirLifting, also referred to as adiabatic cooling, is the most common method of humidification of air to form clouds. As air rises it expands because pressure decreases with altitude. Kinetic energy is converted to potential energy and the parcel temperature decreases, and the relative humidity increases.The two main large scale lifting processes that result in cloud formation are convection and advection of air. Convection refers to air rising vertically in the atmosphere due to heating. Advection is the horizontal transfer of air that usually results in warmer air being forced up over cooler air. Both advection and convection results in the formation of clouds.The method of vertical lifting (orographic, convective, convergence, or frontal) and the stability of the atmosphere determines the type of cloud. Cumulus clouds tend to form in unstable atmospheres. Layered cloudsform in more stable environments in which large layers of air are slowly lifted.Cloud's RoleClouds play a crucial role in our global climate. Clouds reflect shortwave solar energy back into space and tend to cool the earth. On the other hand, clouds absorb longwave terrestrial radiation and warm the planet. Satellites are helping scientists study this important dynamic.
When the environmental lapse rate is less than the dry adiabatic rate a parcel of air will be?
Then the air is called "stable" because a parcel of air from the surface lifted upward will drop in temperature at the dry adiabatic lapse rate. If the environmental lapse rate is less, then the lifted air will be cooler and more dense than the surrounding air, and thus stop moving upward through the atmosphere.
What is wet-bulb temperature?
Wet bulb temperature is the temperature that you get when you put a wet sock over a standard thermometer and blow air over it. It's a customary approximation for the adiabatic saturation temperature, the temperature that the air would reach if you evaporated water into it until it was saturated without exchanging heat with the surroundings.The wet-bulb temperature is the temperature a parcel of air would have if it were cooled to saturation (100% relative humidity) by the evaporation of water into it, with the latent heat being supplied by the parcel.
How does the moist adiabatic lapse rate compare with the dry-adiabatic lapse rate?
environmental lapse rate involves the actual temperature of the atmosphere at various heights. adiabatic cooling is the cooling of air caused when air is not allowed to expand or compress.
What is adiabatic?
Adiabaticity is the quality of being adiabatic, having no heat transfer.
What is the name of cooling for a rising air parcel?
This is usually adiabatic cooling. Adiabatic refers to a process that does not exchange heat with the air around it. Air that is adiabatically cooled is cooled only because the decreasing pressure with height forces it to cool.
What is an adiabatic lapse rate?
An adiabiatic lapse rate is the rate of the decrease of temperature with height of a parcel of dry air lifted upward through the atmosphere with no addition or deletion of heat.
What is saturated adiabatic rate?
The Saturated adiabatic lapse rate is :All air has a moisture content and when a parcel of air heated by its surroundings starts to rise at the dry adiabatic lapse rate it rises until its temperature reaches that of the dew point where its vapour content starts to condense out as tiny liquid water droplets and normally forms the base of a cloud. As this 'heated' parcel of air is still warmer than the environmental lapse rate (circa 1C/1000ft) latent heat is being released as it still continues to rise but now at a reduced rate - it is this reduced rate @1.5C/1000ft that is known as the saturated adiabatic lapse rate. It will cease rising when the environmental temperatures level out and this forms or terminates resulting as the top of the cloud. Meteorologists and pilots use this environmental lapse rate and known dew point temperature to work out the base and tops of cloud for regional and airport forecasts.
What is saturated adiabatic lapse rate?
The Saturated adiabatic lapse rate is :All air has a moisture content and when a parcel of air heated by its surroundings starts to rise at the dry adiabatic lapse rate it rises until its temperature reaches that of the dew point where its vapour content starts to condense out as tiny liquid water droplets and normally forms the base of a cloud. As this 'heated' parcel of air is still warmer than the environmental lapse rate (circa 1C/1000ft) latent heat is being released as it still continues to rise but now at a reduced rate - it is this reduced rate @1.5C/1000ft that is known as the saturated adiabatic lapse rate. It will cease rising when the environmental temperatures level out and this forms or terminates resulting as the top of the cloud. Meteorologists and pilots use this environmental lapse rate and known dew point temperature to work out the base and tops of cloud for regional and airport forecasts.
The lapse rate for moist air is lower than for dry air because?
- Moist air has water vapor in it. - As a moist air parcel rises, the water vapor will condense (latent heat of condensation) - latent heat is released, meaning a temperature increase occurs within that air parcel, effectively dampening its lapse rate. Thus, the latent heat of condensation is working to decrease the lapse rate because sensible heat is being released in the process; its called the Moist Adiabatic Rate (MAR) In contrast, the Dry Adiabatic Rate (DAR) considered for Dry air (no water vapor) does not involve condensation, and thus no latent heat is released; meaning the lapse rate is unaffected.
Why potential temperature increases with height?
No, if you are referring to height above sea level, then it is the opposite way around. Approximately, for every 100m above sea level you go, the temperature drops around 0.7-1 degree celcius.
What is a parcel in relation meteorology?
A parcel refers to a parcel of air that is used to conceptualize certain processes in the atmosphere. It is useful to use a discrete unit like a "parcel" of air when learning certain processes, such as adiabatic processes when air rises and sinks. The is because you want to know how some unit of unadulterated air will behave when you raise or lower it in the atmosphere and change the pressure applied to it, for example, whereas air in the "environment" is free to mix, which complicates things.
Why you want to promote?
in atmosphere when an air PARCEL rises then it's temperature is comapred with temperature of the surrounding air.if the temperature of air parcel is less than surrounding air then that means air parcel is denser than surrounding. In this situtaion it's tendancy in such situation is to return to it's original position. (STABLE CONDITION OF ATMOSPHER)but if parcel's temperature is higher than surrounding air then that means it is lighter that surrounding air. In this situation it's tendacy is to rise up and up. (INSTABLE CONDITION OF ATMOSPHERE).This will continue until parcel finds same temperature as that of the surrounding (Temperature of surrounding and air parcel is the same).It becomes stable at that positionHuman being are like that air parcel.Humans will continue it's journey for promotion until he finds a position satisfying his conditons...........
