lab assignment josh sra 7570104

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GEOG 1F91 – Fall 2023 LAB 4 - 1 Micro-Meteorological Variations in Weather Elements TEXT REFERENCES : Chapter 4 – Global Energy System Chapter 5 – Global Temperature Patterns Chapter 7 – Atmospheric Moisture and Precipitation OBJECTIVE Previous Lab exercises have investigated some of the factors controlling atmospheric temperature and moisture conditions and their interactions at the Earth’s surface. This exercise provides a hands-on opportunity to observe the additional effects of topography, shade and wind, as well as the nature of the surface, on several meteorological parameters. A demonstration of how the measurements are made will occur at the start of the lab, followed by the collection of field data. NOTE: You’ll be spending some time outdoors for this lab so please dress accordingly! WHY IS THIS IMPORTANT? In previous labs, in lecture, and in the textbook, the discussion is usually focused on large-scale general patterns that are supposed to be found in the natural environment. Our own experiences, however, may be slightly different. While waiting for the bus on a cold winter morning, we know it feels warmer standing in the sun than in the shade, or inside the bus shelter rather than outside in the wind. We also know that this distinction is lost on cloudy or windless days. The local weather report may state the same temperature for the entire Niagara Peninsula although the wine industry, for example, promotes Niagara wines in terms of, “a unique microclimate”. So how much of a local effect is there? How much do variations on the micro scale actually affect the weather we feel? This lab examines this very phenomenon and also gives you an appreciation for the various methods of data collection that can be employed to answer these questions. INTRODUCTION So far in the labs we have considered both the spatial and temporal variations in the factors that may control the meteorological conditions we experience at the surface. Lab #1 demonstrated that the nature of the surface exerts a control over the net radiation available at the surface. For example, a dark, opaque surface, such as a freshly paved parking lot absorbs a great deal of radiation, resulting in a high surface temperature. Conversely, a lighter coloured surface with a higher albedo can have a much cooler surface temperature under otherwise identical conditions. Whether the surface is water, allowing the penetration of sunlight, or land, where the effects of insolation are concentrated at the surface may also have a large influence on the meteorological conditions at the surface. This surface temperature, in turn acts as a control on the relative humidity. (See Strahler_Figure_6.6.pdf posted on Brightspace). Lab #2 suggests the resulting temperature variations from place to place may initiate convective air flow, thus mixing the air and therefore blurring the temperature differences we would expect to feel.

GEOG 1F91 – Fall 2023 LAB 4 - 2 Micro-Meteorological Variations in Weather Elements One would therefore expect different conditions between areas fully exposed to the wind and those sheltered from the wind. The natural environment is, therefore, much less consistent than we may have considered so far. Lab #3 suggests even wet surfaces experiencing evaporation may behave differently from otherwise identical dry surfaces, particularly if one considers the absorption or release of latent heat. In addition to changes in the nature of the surface affecting the amount of net radiation on that surface, within very short distances one can also expect to find variations due to atmospheric obstructions (e.g., shade). These changes can vary in time, ranging from short-lived events, such as the passing of an isolated cloud temporarily blocking some of the sunlight, to longer events, such as the continual shading of an area by vegetation or a building. Of course, shading of this nature is time dependent as the direction of shading is controlled by the location of the sun in the sky during the day. The intensity of solar radiation actually reaching the surface of the Earth at any moment can also vary a great deal, depending on factors including the season (i.e., spring, summer, fall or winter), and the time of day (i.e., morning, afternoon or night). The greater the angle with which the sun’s rays strike the surface, the more spread out the energy is over a larger surface area, thus reducing its intensity. This, of course, controls the overall pattern of global temperatures. The tropics, which receive the most intense insolation, are warmer, and the polar regions, which receive the most indirect insolation, are cooler. Although the sun can only be directly overhead in the tropics on a global scale, local topography can result in slopes facing the sun and receiving much more insolation than slopes facing away from the sun (Figure 4.1). As was the case when considering shading, this effect can change throughout the day as the sun moves across the sky. Figure 4.1: The Effect of Slope Angle on Sunlight Intensity on the Ground (From: McKnight, T.L and D. Hess (2000) Physical Geography: A Landscape Appreciation. 6 th Ed. Prentice Hall.)

GEOG 1F91 – Fall 2023 LAB 4 - 3 Micro-Meteorological Variations in Weather Elements EXERCISE We will concentrate our efforts on measuring the following parameters: - Air temperature - Relative humidity - Net radiation - Light intensity - Ground surface temperature - Wind speed and direction - Slope angle ( NOTE: record SOUTH facing slopes as POSITIVE angles, and NORTH facing slopes as NEGATIVE angles). Measurements will be made along a transect across the hill located between B and C Blocks of the Mackenzie Chown Complex. The orientation of this hill provides both south facing and north facing slopes to facilitate the study of the effect of topography on insolation at the surface (see Fig. 4.1 above). The transect will continue under the bridge between B and C Blocks to facilitate the study of the effects of shade, which should also be noted. Both the hill and the buildings can affect the wind experienced along the transect. Measurements will be at 5 m intervals along the transect, which starts on the concrete sidewalk. Figure 4.2 – Transect location between B and C blocks of the Mackenzie Chown complex (Provided by Brock University Map, Data & GIS Library, 2016 . Copyright, 2013 - The Regional Municipality of Niagara, Area Municipalities and their suppliers have donated this orthoimagery for use under license by Brock University.) Mackenzie Chown Complex - B Block Transect Location Mackenzie Chown Complex - C Block

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GEOG 1F91 – Fall 2023 LAB 4 - 4 Micro-Meteorological Variations in Weather Elements To facilitate an assessment of seasonal variations in these parameters, a data set from May 2001 is included on Brightspace (as an Excel spreadsheet: SpringTransect.xls ). PROCEDURE AND QUESTIONS Before beginning the data collection portion of the lab, write down what you think you will find along the transect. Since, as human beings, we are most sensitive to differences in air temperature, this hypothesis must specifically address any changes in air temperature you expect to experience along the transect during your time in the field. If we assume the air temperature to be the result of the net radiation received at the surface (as the atmosphere is heated from below, via conduction), and that the net radiation depends on factors such as sun or shade, the albedo and the surface temperature (remembering the net radiation equation from Lab #1), how do you expect the air temperature to vary along the length of the transect? For example, do you expect the temperature to be relatively constant, or do you expect it to be different, depending upon location along the transect (i.e., in the sun or the shade, on a north facing or south facing slope, etc.). Base this hypothesis on the conditions you observe just before the data collection begins, and what you think will happen based on your own experiences. Your hand written Hypothesis Statement MUST be submitted to your lab instructor BEFORE any data is collected. That means before the outdoor measurements begin in order to receive the grades allocated to this portion of the lab. Be sure to retain a copy for yourself for use when writing up the results. As you’ll need to compare your hypothesis with the actual results for your write up, be sure to make a separate record of your hypothesis before you leave. A paper copy of the Hypothesis Statement will be provided to you in class from your lab instructor. QUESTION 1 - After acquiring the complete data set (your lab section’s net radiation, light intensity, and relative humidity data is posted to Brightspace (available on Brightspace under CONTENTS -> Lab Assignment Information -> Lab 4 -> Class Data folder), complete the typed Data Sheet , and save the file as a PDF or Word file. Do NOT upload a copy of your hand written field notes, or marks will be deducted. Your Data Sheet must be typed, saved, and uploaded as a PDF or Word file! (8 marks) Plot the following separate line (not scatterplot) graphs (using Microsoft Excel, or hand-drawn on graph paper): QUESTION 2 - Slope angle (on the y-axis) against distance along the transect (on the x-axis) QUESTION 3 - Net radiation against distance QUESTION 4 - Light intensity against distance QUESTION 5 - Surface temperature against distance QUESTION 6 - Air temperature against distance QUESTION 7 - Relative humidity against distance

GEOG 1F91 – Fall 2023 LAB 4 - 5 Micro-Meteorological Variations in Weather Elements Save each graph ( e.g. copy/paste from Excel; screen capture from Excel; cropped photos of hand-drawn graphs ) into a separate document from your Student Handout answer file. Save your graphs document as a PDF or Word file with an appropriate file name and upload to Brightspace . Do NOT upload the Excel files, or marks will be deducted. (18 marks: 6 plots x 3 marks each) QUESTION 8 - Describe the change in light intensity measured along the length of the transect. By comparing the appropriate plots, comment on the strength of the relationship between slope angle and light intensity. Was this relationship as strong as you expected, considering the effect noted in Figure 4.1 (above)? If not, what other factors likely played a role in affecting this? (4 marks) As the length of the transect increases the light intensity has a downwards slope until the transect reaches 40 which is under the building and where very little light intensity reaches due to minimal sunlight. As you go past the building the light intensity begins to increase once again. When increasing the angle of incidence of a light beam, the intensity of the reflected light ray is also increased. This relationship was not expected by me because I did not take into account the sunlight not reaching past the building. QUESTION 9 - Describe how the measured values of net radiation change along the transect as the character of the surface (e.g., pavement vs. grass), the surface temperature and the lighting conditions change. How important were each of these factors in controlling the intensity of net radiation? Is this what you expected after what you discovered in Lab #1? (4 marks) As the transect increases the net radiation has a downwards slope until it reaches 0 where there is minimal sunlight where it starts increasing. The pavement that appears directly above the sun has a higher net radiation due to it being able to absorb energy making the surface temperature hot despite it being cloudy. As you move onto the grass the surface temperature becomes cooler. Once you move away from the sun the surface temperatures for both grass and pavement decrease. All of these factors are important when determining net radiation because if there’s a deficit in one it may cause a decrease in net radiation and the opposite would happen with an increase of sunlight and surface temperature. Yes this is what I expected QUESTION 10 - Compare air temperature and relative humidity. Did they show the inverse relationship as depicted in Figure 6.6 (see Strahler Fig. 6.6.pdf posted on Brightspace) ? Explain why, or why not. Remember to discuss the relationship between temperature and absolute humidity. (4 marks) Air temperature and relative humidity did not show the inverse relationship depicted in the graph because the relative humidity is greater than the temperature. The air will have a HIGHER relative humidity if the air is cooler, and a LOWER relative humidity if the air is warmer .

GEOG 1F91 – Fall 2023 LAB 4 - 6 Micro-Meteorological Variations in Weather Elements QUESTION 11 - Compare ground surface temperature and air temperature. How strong was the relationship between these two parameters? Was this relationship as strong as you would expect, given the troposphere is heated from below via conduction? (4 marks) Air and surface temperature are similar as they’re both trending in a similar direction and intersect (have the same temperature) at the 45-meter mark. Yes, they have a strong relationship because when surface Atmospheric variations directly alter soil conditions through changes in temperature. QUESTION 12 - Compare the two sets of data – the one you gathered during the lab and the one provided on Brightspace in the Lab 4 folder ( GEOG 1F91 - Lab 4 – Spring Transect.xls ). Given that the transect is in the same location in both cases, describe the differences you note in the data as a result of the obvious seasonal difference (i.e., autumn versus early summer). (4 marks) QUESTION 13 - Was your initial hypothesis validated by the data your lab group collected? Did you see the changes you predicted? Comment on why, or why not, these initial expectations were accurate. Be sure to restate your hypothesis, as part of your discussion. (4 marks) Yes, my initial hypothesis was correct, the temperature was hotter as you moved away from the building. When you move closer to the building it gets colder because there’s minimal sunlight hitting below the building. I initially predicted it would be warmer from 1-2-6 and it would be colder 3-4-5

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GEOG 1F91 – Fall 2023 LAB 4 - 7 Micro-Meteorological Variations in Weather Elements HYPOTHESIS STATEMENT This MUST be submitted to your Lab Leader BEFORE the outdoor measurements begin in order to receive the grades allocated to this portion of the lab. Be sure to retain a copy for yourself for use when writing up the results. Due Date Lab Assignment #4 “Micro-Meteorological Variations in Weather Elements” is due by 11:59 pm the night before the regular two (2) week time period closes. Make sure to complete and submit your assignment by its due date. All submissions through Brightspace are time-stamped. Late assignments will not be marked (i.e. receive a mark of zero). Your online submission for this lab assignment should include the following files: 1) Data Collection Table – typed [ not hand-written ] (PDF or Word file format) 2) Graphs Document – containing your six (6) graphs (PDF or Word file format) 3) Lab Questions Answer Sheet - completed (PDF or Word file format)

lab assignment josh sra 7570104

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