Environmental lapse rate Essay Example

Environmental lapse rate Essay Example Environmental lapse rate Paper Environmental lapse rate Paper The temperature measured at the ground is 15. Assuming that the air parcel moves adiabatically through the atmosphere, what will be its temperature at each pressure level up to and including 500 hap? Assume ground level is equivalent to 1000 hap) (4 marks). Height (hap)Temperature 500 -35 600 -25 700 -15 800 -5 900 5 1000 15 If the parcel is then forced down to a height of 3000 m, what will its temperature be? (2 marks). If a parcel is then forced down a height of mm, its temperature will be -1 ICC as mm is papa. This is due to the fact that the atmospheric pressure at mm is papa. Temperature decreases along the DALE because the air parcel expands. This is due to fact that pressure decreases within the atmosphere. Re-calculate parts (1) and (2) but this time assume that air parcel is saturated (6 marks). Height (hap) Temperature 500 -15 600 -9 700 -3 800 3 900 9 If the saturated air parcel is now forced down a height of mm, its imperative will be -ICC as mm is equal to papa Environmental Stability Exercise C (Total 10 marks) The following temperature soundings are obtained: Height (hap) Tenderheartednesss air parcel (Co/mm/papa) Unsaturated air parcel (001000m/ 1 Poppa) 1000 34 34 34 800 12 22 14 700 2164 600 -2 10 -6 500 -12 4-16 300 -25 -8 -36 -30 -14 -46 The stability of the atmosphere with the saturated air mass is unstable as the air mass is warmer than the environment. However if the parcel of air were to be saturated from ground level, it would rise in the atmosphere and decrease in temperature at the SAL R. But this parcel of air would carry on ascending in the atmosphere, making it stable. The unsaturated air mass is conditionally unstable, as it will rise to about at papa/mm the parcel of air becomes saturated as it has become cooler than the environmental temperature surrounding it. It will then continue to decreasing in temperature at the saturated adiabatic lapse rate (SAL R) of around ICC / mm, as it descends making it unstable Dew points, relative humidity and cloud formation Exercise D (Total = 22 marks) Plot a graph of mixing ratio vs.. Temperature and use this to help answer the questions in this section (6 marks). The graph may be plotted either in Excel or on regular graph paper. See attached If the temperature and the dew point of a parcel of air at the ground are DDCD and DDCD respectively what will the height of condensation be? (6 marks). Height of Condensation 125 (Ta-Tad) = 125 (23-13) = 125 x 10 Height of Condensation= mm Calculate the relative humidity of this parcel of air at the ground (8 marks). What happens if the dew point and temperature at the ground are equal? (2 marks). Relative Humidity (RE)= (Actual Vapor Density) (Saturation Vapor Density) x 100 ICC = 28. 1 numb ICC = 14. Numb = 14. 979 28. 104 = 0. 53298 0. 53298X100= 53. 289% marks). If the dew point and the ground level temperature were to be equal the surrounding air parcel would be saturated (completely), as the relative humidity would be at its maximum. Exercise E (Total = 12 marks) Explain clearly the nature and possible behavior of an air parcel rising from the ground, with a dew point of 1 co and the following environmental temperature profile. See table Height (m) Temperature0cTemperature of air parcel (Co) Dew point Co 28 28 10 1000 15 188 2000 9-2 6 3000 -3 -8 2 -10 4-8 15 -14 -14 Assuming that the air parcel and the environmental temperature at ground level are equal. The air parcel rises adiabatically losing ICC per mm and the dew point decreases by ICC every mm. The air parcel remains unsaturated or dry at mm and then after mm it becomes saturated. Therefore the height of condensation lies within the altitudes of mm-mm. This can be calculated relatively easy using this equation: Height of condensation 125 (Ta Tad) Inputting my figures = 125 (28- 10) = 125 x 18 = mm After saturation of the air parcel, the temperature of the air parcel will crease at the saturated adiabatic lapse rate (SALE), which is around 6001000m. When the temperature of the air parcel is warmer than the environmental temperature as it is from mm mm the atmosphere is unstable. When the parcel reaches mm, it becomes stable because the air parcel is colder than the environmental temperature, in that case the air parcel stops rising. Therefore the atmosphere is conditionally unstable. Exercise F (Total = 14 marks) A mass of air with a ground temperature of ICC and a dew point of -ICC is forced to ascend a 3000 m mountain. If the environmental temperature at 000 m is Describe the changes in air mass and dew point temperatures you might expect to observe. (8 marks). I have drawn a diagram of the changes in air mass and dew point temperatures you might expect to observe below When air is forced down a mountain, it is an example of forced convection. The air mass and dew point values change as the air mass rises and falls. According to thermodynamics, as air rises, it looses heat energy, as pressure is lost because of the air mass expanding in size. The temperature decreases by 10 and the dew point temperature decreases by ICC. At the top of the mountain, the air parcel saturates at mm. The air parcel is cooler than the environmental temperature, which means that the air parcel will begin to fall down the slope at the Dry Adiabatic Lapse Rate (DALE). At each altitude the air parcel temperature decreases by 1 co and the dew point rises by ICC. As pressure is being increased when the air parcel is decreasing temperature increases. There has been a 1 net increase in air mass temperature from 1 ICC to ICC; same with the dew point temperature as there has been a ICC decrease from -ICC. We can calculate height of condensation takes place at with this simple equation 125X22 -mm Therefore we can at about the altitude of mm clouds start forming as the air parcel starts becoming saturated. Calculate the relative humidity of the air masses before and after ascent. (4 marks). Relative Humidity = Virtue XIII% Mart Before ascent Air temperature= 18 Mixing ratio-? egg/Keg 2. 8 Relative humidity O After descent Mixing ratio= egg/keg Mixing ratio-? 2. G/keg Relative humidity= 100 18 . 46% . Before ascent the humidity of the air mass was 21. 5% and after descent the humidity of the air mass was 18. 46% 3. How would the behavior of the air mass change (if at all) if the mountain as only 2000 m high and the environmental temperature at that height was -7 co? (2 marks) If the mountain were only mm, the temperature of the dew point would decrease by -ICC as we have seen beforehand and so would become saturated. With the environmental temperature at -7 Co the air parcel would be warmer than that of the surroundings and consequently the air parcel will carry on growing and expanding in size, dropping in pressure and losing heat at the saturated adiabatic lapse rate. Deprograms and stability Exercise G (Total = 18 marks) Values of the environmental air temperature are obtained at each of the eights given below. The dew point temperature (Tad) at the surface is 1 ICC. Plot a deprogram to show the trajectory of an air parcel or air mass rising from the surface. Explain, by reference to the deprogram how the parcel would behave and, hence, describe the stability of the atmosphere. Annotate the deprogram to indicate clearly the presence of any condensation levels or changes in air parcel/mass behavior. See diphtheria attached Height (hap) Height (m) Dew point (Co) Temperature (Co) 1000 010 15 900 1000 88 800 2000 23 700 3000 -4 -8 600 4000 -10 -6 500 5000 -16 -15 The dew point rises adiabatically losing heat. At mm or papa saturation of the air parcel occurs as the dew point and the air parcel are at the same temperatures. To calculate the height Of condensation we can use this simple equation Height of condensation = 125 (Ta Tad) = 125(15-10) -mm On my Deprogram attached, I have shown a dew point (red line) which come together with the dry adiabatic line (green line). This illustrates the fact that when the saturated air parcel stopped ascending. When the air is saturated the air parcel stops ascending. The dew point will continue to cool down at he saturated adiabatic lapse rate of around ICC per mm. From this I illustrated the saturated adiabatic line (SALE) (black line). The Environmental Lapse Rate (LEER) is shown in green on the deprogram, and lies to the right of the SALE. This means that the atmosphere is stable, which means thats the air parcel will continue to rise. Exercise H (Total = 100 marks). You should be aiming to write about 500 words As you will have seen during these exercises, air behaves in a certain way when it is forced to rise over a topographic barrier. Describe one example of such a topographically induced airflow from somewhere in the oral, indicating clearly how geography and atmospheric conditions influence the creation and behavior of the wind. Illustrate your discussion with diagrams as appropriate, and make sure that you provide clear references for the information you give (note that Wisped is not an acceptable source Of information). The meaning of a topographic barrier is an obstruction within the land e. G. Mountain ranges that change wind and rainfall pattern within the mountainous area. An example of such a topographically induced airflow is the Serbia Nevada mountain range. The Sierra Nevada is located in the west f the United States running along the east of California. It extends north about implies from the Mojave Desert to the Northern Californian Cascade Range. The Sierra Nevada varies in width and is about miles wide at Lake Tahoe and miles wide towards the south of the mountain range. Its remarkable skyline and extraordinary landscapes makes it one of North Americas premiere views. Biologically, it is the home to the worlds most ancient trees, the sequoia. In previous history, the focus Of the gold rush and now is the home to 3 national parks, 20 special wilderness areas and 2 cantonal monuments. Topographic barriers such as mountains and hills force normal winds within the area up and over their slopes which are about 4421 m high at the highest peak. As an air parcel rises, it cools as the higher it goes within the atmosphere, the more pressure is lost and therefore heat is lost as there is energy being transferred in order for the air parcel to expand. Cooler air is capable of holding less water vapor than warmer air. As the air parcel cools it reaches its maximum saturation point, this water vapor is forced to condense, depositing rain or snow on windward slopes. When air is met by a mountain, it is elevated up and over the mountain, cooling as it rises. If the air cools to its saturation point, the water vapor condenses and a cloud forms. When these air parcels form large enough droplets; precipitation will form. Westerly Wind coming in from the Pacific Ocean carrying water vapor is trapped by the Sierra Nevada and is forced up an uphill slope where Otherwise the air would have passed unscathed. This air is then forced back down causing a phenomenon called the Sierra Nevada wind rotors. These wind rotors are periodic changes of atmospheric pressure, temperature and altitude in a current of air caused by vertical displacement e. G. A topographical barrier such as the Sierra Nevada. The result of these wind rotors is as mild as strong winds or windstorms. The strength of the wind rotor is dependent upon wind speed coming in, ground temperature, wind patterns and water vapor. With that said, the formations of these wind rotors are unpredictable. As air up a mountain is cooler due to the environmental lapse rate (air cools around 6. ICC every mm an air parcel rises up. This creates a distinct monochromatic around the mountain range. The lower zone of the mountain angel is dry and cooler whereas the top has cold and severe conditions. This is indicated by the flora existing in these parts. The positioning of uphill slopes in relation to the sun has an influence on the climate. South-facing slopes are sunnier and support entirely different ecological communities than north-facing slopes. The south side of a mountain may experience spring conditions weeks or even months ahead of its north side. Where year-round snow or glaciers exist, they are supported by the shade provided by north- and west-facing slopes.