3/31/24, 11 : 17 PM Lightning in the Peaks: Northern Arizona Climate and Lightning Strikes: GPH 112: Intro to Phys Geography Lab (2024 Spring) Page 1 of 7 https://canvas.asu.edu/courses/178831/quizzes/1343074 ? module_item_id=12797102 Lightning in the Peaks: Northern Arizona Climate and Lightning Strikes Due Feb 14 at 11:59pm Points 5 Questions 3 Available after Jan 21 at 12am Time Limit None Instructions For the following questions, investigate the monthly changes in lightning strike, temperature, dew point, and precipitation data for Flagstaff, Arizona. Remember, dew point simply is the temperature that the air would have to cool to in order for moisture in the air to condense into water droplets (forming dew or clouds). Humidity on the other hand is the ratio of moisture in the air compared to how much it can hold. This is dependent on temperature, so we'll stick with dew point as it easier to see a seasonal shift. In essence, the higher the dew point, the more moisture that exists within the atmosphere - however, dew point cannot exceed air temperature and is dependent on air temperature. Colder air simply cannot hold as much moisture, so there is less available to condense and form clouds (think of polar deserts like Antarctica!). When you hear of dry heat, that often is associated with warm, dry air, meaning a large difference between temperature and dew point. When that begins to change, and dew point increases, it feels humid and uncomfortable, and you are more likely to have rain and storms. Changes in dew point are one of the driving features for the change in precipitation and lightning strikes across the southwestern United States during the summer, as the North American Monsoon becomes more prominent. Monthly climate data for Flagstaff, Arizona can be found below. Monthly Air Temperature Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec C 1.7 2.8 4.4 7.2 11.6 18.3 19.4 16.6 15.0 10.0 3.9 0.6 F 35.1 37.0 39.9 45.0 52.9 64.9 66.9 61.9 59.0 50.0 39.0 33.1 Monthly Dew Point Temperature Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec C -9.4 -5.0 -6.1 -5.6 -3.9 -3.9 10.6 11.1 10.0 2.8 -5.6 -3.9 F 15.0 23.0 21.0 22.0 25.0 25.0 51.0 52.0 50.0 37.0 22.0 25.0 Monthly Precipitation o o o o

3/31/24, 11 : 17 PM Lightning in the Peaks: Northern Arizona Climate and Lightning Strikes: GPH 112: Intro to Phys Geography Lab (2024 Spring) Page 2 of 7 https://canvas.asu.edu/courses/178831/quizzes/1343074 ? module_item_id=12797102 Attempt History Attempt Time Score LATEST Attempt 1 2 minutes 5 out of 5 Score for this quiz: 5 out of 5 Submitted Feb 14 at 8:02pm This attempt took 2 minutes.  Question 1 2 / 2 pts Answer 1: .06% Correct! Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec mm 50.0 54.0 50.0 34.0 35.0 12.0 121.0 132.0 67.0 35.0 33.0 45.0 in 2.0 2.1 2.0 1.3 1.4 0.5 4.8 5.2 2.6 1.4 1.3 1.8 Study Area Lightning Strikes Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Count 0 0 10 25 25 10 3200 3500 500 10 0 0 First, let's understand why we are using lightning strikes in August, and not in May or June. It has to do with the change of moisture in the atmosphere, brought by the North American Monsoon. To prove this, answer the following questions using the data table above: Monthly Percentage = ((Sum of May, June OR July, August) / Total Precipitation)*100 Calculate the percentage of annual precipitation that falls in May and June: 7.8% Calculate the percentage of annual precipitation that falls in July and August: [ Select ] Which month of the year had the greatest difference between temperature and dew point: [ Select ] Which two months had the highest number of lightning strikes: [ Select ] Recall your knowledge from the lecture on the North American Monsoon. Why does the precipitation and lightning strike count change so dramatically throughout the summer? [ Select ]

3/31/24, 11 : 17 PM Lightning in the Peaks: Northern Arizona Climate and Lightning Strikes: GPH 112: Intro to Phys Geography Lab (2024 Spring) Page 4 of 7 https://canvas.asu.edu/courses/178831/quizzes/1343074 ? module_item_id=12797102 The greatest clusters of lightning occurs primarily on the middle-slopes on cool north and west facing sides of the peaks and hills. Correct! The greatest clusters of lightning occurs primarily on the middle-slopes on warm south and east facing sides of the peaks and hills. The greatest clusters of lightning occurs primarily along the high ridgeline and mountain tops of the San Francisco Peaks. The greatest clusters of lightning occurs primarily in the low, flat regions near Flagstaff and west of the San Francisco peaks. You should have seen the slopes, especially over Shultz Pass and the eastern slopes of the San Francisco Peaks (in the image below), absolutely covered in lightning strikes, while the cooler mountain slopes on the western and north side were much quieter.  Question 3 Fast travel to the eastern edge of Flagstaff at these coordinates: 35.2191 N , -111.5863 W. Change the geovisualization layer to display air temperature. Use the helicopter fast travel mode to go from your current location to 35.4023N, -111.7008 W, a transect taking you up and over the San Francisco Peaks to the northwest. While you travel, closely look at the lightning strike distribution. What lightning strike pattern do you observe while moving up and over the San Francisco Peaks in this transect? HINT: You can see where lightning strikes are happening by observing the small circles on the ground. Those are where lightning will randomly strike, and if you waited (or flew) and watched, would see this clustering.

3/31/24, 11 : 17 PM Lightning in the Peaks: Northern Arizona Climate and Lightning Strikes: GPH 112: Intro to Phys Geography Lab (2024 Spring) Page 5 of 7 https://canvas.asu.edu/courses/178831/quizzes/1343074 ? module_item_id=12797102 2 / 2 pts Of course, lightning strikes in other places as well, not just in one area. Often though, the first thunderstorms of the day will begin over the higher terrain around Flagstaff, and more generally over the higher terrain across Arizona. You might be familiar with radar on a weather app. It's a bunch of colors meaning rain is nearby or heading your way. We're going to take a look at a radar loop in northern Arizona to help us begin to understand the distribution of lightning we see within the lightning game. But first, we need to briefly look at what radar is and how to interpret it. Radar dishes send out a pulse of energy that bounces off objects in the air like dust, rain, hail, or even bats and bugs. The data collected by this return signal can tell us the size, speed, and direction of the objects the radar pulse bounces off of. You are likely most familiar with radar reflectivity, or the strength of the return signal related to size of the features. This value is in dBZ or decibels. A value of 20 dBZ is typically the point at which light rain begins. A value around 40-45 dBZ indicates heavy rain. The values of 60 to 65 dBZ is about the level where 1" (2.5 cm) diameter hail can occur. You can see the scale an an image of a strong thunderstorm with heavy rain and possible hail in the picture to the right. Radar can get a little bit more complicated due to how it is measured, and you can even start to discern features within a storm system, like rotation or debris lofted by tornadoes. But that's beyond this 100 level class, if you are interested in learning more how to interpret radar, ASU has meteorology courses that dive a bit deeper. In the meantime, if you want to learn to interpret the greater details of radar yourself, check out this National Weather Service website: https://www.weather.gov/jetstream/doppler_intro (https://www.weather.gov/jetstream/doppler_intro) Below is a 2 hour base reflectivity loop centered over northern Arizona. You can see Flagstaff located just below the middle of the map, and the San Francisco Peaks north of the city. Interstate 40 cuts through the lower third of the map from west to east and Interstate 17 extends south of Flagstaff towards Phoenix. If you look closely, you can see some major feature labels like Flagstaff, the San Francisco Peaks, Upper Lake Mary, and Sitgreaves Mountain.

3/31/24, 11 : 17 PM Lightning in the Peaks: Northern Arizona Climate and Lightning Strikes: GPH 112: Intro to Phys Geography Lab (2024 Spring) Page 7 of 7 https://canvas.asu.edu/courses/178831/quizzes/1343074 ? module_item_id=12797102 Quiz Score: 5 out of 5