Lab 11_Atmospheric Circulation

METO 1010 Online Lab 11. Atmospheric Circulation Instructions: 1) Type your answers in this Microsoft Word file and save your completed lab on your computer. Do not modify the format of the file. 2) Upload your lab on CANVAS by the due date. To upload the file, go to the course homepage and click on “assignments”. Click on the assignment that you want to submit, and on “submit assignment”. In the “file upload” box, click on “choose file” and select the appropriate file. Finally, click on “submit assignment”. Only .doc, .docx, and .pdf files are accepted. 3) In questions that require calculations, you are not required to show every step of your work, but the more detailed your answers are the more likely you are to receive partial credit for wrong answers. 4) Proper units and terminology are always necessary. 1) Refer to the figure on the last page. In the figure, the area inside the circle represents the Earth’s surface. The region outside the circle represents a cross-sectional view of the lower atmosphere. Print out the page and draw sketches to show the global pressure zones, the surface wind zones, and the general circulation of the lower atmosphere (you can also draw on the figure directly in Microsoft Word, if you prefer). The Earth is rotating (so the Coriolis force should be in evidence). However, you are to assume a uniform Earth surface, such as entirely covered with water, so that there are no land and water contrasts. Essentially, you have to reproduce the figure on the slides that show the general circulation of the atmosphere. Follow these directions carefully. When you are done, take a picture of your completed figure and insert it below. a) Inside the circle, draw in the idealized global pattern of surface wind zones, using a series of arrows to show both the direction and the deflection (caused by the Coriolis force) of the wind. (1 point) b) To the right of the circle, label each of the pressure zones and each of the wind zones. These names must be written in precise alignment with the latitudes of the pressure and wind zones on your diagram. (1 point) c) Just outside the circle on the left side (cross-sectional view of the troposphere), draw a cross- sectional view of the three-cell model of the general circulation of the lower atmosphere. Use a series of short arrows that will show where the air is rising and descending, and the direction of the wind flow aloft and parallel to the surface. Do this on the left side of the diagram from the 1

North Pole to the South Pole. Label the three cells with their correct names (i.e., Hadley cell from 0 to 30° N and S, Ferrell cell from 30 to 60°N and S, Polar cell from 60 to 90°N and S). (1 point) 2) a) Go to the following website https://earth.nullschool.net/#current/wind/surface/level/orthographic=-55.21,15.31,325 . You will see a real time animation of surface winds for the whole Earth. Take a screenshot of the 2

There is a relationship between the two. both the screenshot and the actual animation have moving cyclones. But the direction of the movement is different for them. For the screenshot, the direction of the movement is different depending on the direction of the winds. For the actual animation one, the movement is both from west to east only for the inner cycle to be anticlockwise. 3) Go to the following website http://weather.rap.ucar.edu/ . Click on “upper air”, and on “300 mb” on the second raw (i.e., including contours). You will see a 300 mb map with colors indicating wind speeds in knots. This is an isobaric map, so the lines indicate elevations [in decameters (dm); 1 dm=10 m] at which the pressure is 300 mb. A pressure of 300 mb is found at ~30,000 ft (~9000 m) of elevation, which is the elevation at which you find the jet stream. In the map, the jet stream is in the area where you find the highest wind speeds. Each station has a symbol for wind direction and speed, temperature (in °C; on the upper left), difference between temperature and dew point (in °C; on the lower left), and elevation of the 300 mb surface in dm (on the upper right). Save the image in your computer and insert it below. (1 point) a) Where is the jet stream located with respect to your location? To the north or to the south? (1 point) to the south b) What is the wind speed (in knots) in the part of the jet stream that is closest to your location? (1 point) 40 kts c) Convert the wind speed into mi/hr. (1 point) 46.03 mi/hr 4) Summarize the weather and oceanographic patterns associated with normal, El Niño, and La Niña conditions by filling out the table below. Words in parentheses in each column indicate choices. (4.5 points) 4

Western Equatorial Pacific Eastern Equatorial Pacific Condition s Surface Water Temperature (Warm, Cool, or Cold) Atmospheri c Pressure (High, Low, or Very Low) Rainfall (Heavy Rain, Dry, or Drought) Surface Water Temperature (Warm, Cool, or Cold) Atmospheri c Pressure (Very High, High, or Low) Rainfall (Heavy Rain, Dry, or Drought) Normal Warm Low Wet Cool High Dry El Niño Cold Very High Drought Warm Low Heavy Rain La Niña Warm Very Low Heavy Rain Cold Very High Drought 5) Go to the website of the Earth System Research Lab at the following address https://www.esrl.noaa.gov/psd/enso/enso.current.html . This website documents the current state of the Tropical Pacific. Scroll down to "Maps of Sea Surface Temperatures (SST)" and select the "Latest Sea Surface Temperature Monthly Anomaly." Save the image in your computer and 5

c) Based on your answers in parts a and b, do you expect precipitation in the eastern equatorial Pacific to be higher than average, lower than average, or just average? (1 point) Lower than average d) Based on your answer in part a, do you expect upwelling in the eastern equatorial Pacific to be stronger than average, weaker than average, or just average? (1 point) Stronger than average 7 Polar Cell

8 Hadley Cell Ferrel Cell Polar High Polar Easterlies Westerlies Westerlies SE Trade Wind NE Trade Wind Polar Easterlies Equator Subpolar tropical High Pressure Subpolar Low Pressure