Studying Topography, Orographic Rainfall, and Ecosystems (STORE)

Transcription

1 Studying Topography, Orographic Rainfall, and Ecosystems (STORE) Introduction Basic Lesson 2: Using ArcGIS Explorer to Analyze the Connection between Topography and Rainfall This lesson introduces Geographical Information Systems (GIS) to the students. Students create their own map, learn to read the data contained in the map and use basic GIS functions. GIS in this lesson is essential to understanding the relationship between topography and rainfall. Future lessons in STORE will build upon the scientific and GIS understanding that the students take away from this lesson. This lesson focuses on the California Study Area (see Figure 1 below). The meteorology GIS data used in this lesson comes from data distributed by the National Oceanic and Atmospheric Administration (NOAA) National Climatic Data Center (NCDC). NCDC has the largest archive of national and global quality controlled weather data. NCDC distributes weather data collected by surface meteorological instruments operated by the National Weather Service and other government agencies. Many of these stations are located at airports and other public facilities. As an example, the San Jose and Modesto weather stations are located at San Jose International and Modesto City County Airports, respectively and the Sonora weather station is located at a U.S. Forest Service Ranger Station. Figure 1. California Study Area. 1

2 Objective To introduce and teach the basics of GIS to the students. To challenge students to see rainfall patterns over mountains and valleys. Lesson Duration 1 class period, 45 to 55 minutes Requirements ArcGIS Explorer software Downloaded and unzipped ArcGIS Explorer files for STORE GIS-intensive lessons folder. Note this folder contains map layers, add-ins and function cards. 2

3 Part 1 - Create a map of the California Study Area in ArcGIS Explorer 1. Open ArcGIS Explorer. If prompted for Kml File Association choose Do not associate KML with ArcGIS Explorer. Screen will open and look similar to 2D view of world below. 3

4 2. If ArcGIS Explorer opens in 3D view click the 2D/3D button to switch to 2D view. 3. Click on the Add Content button and from drop down list choose Shapefiles. 4. Add National Climatic Data Center (NCDC) Weather Stations for California study area by navigating to the California folder within the ArcGIS Explorer files for STORE 4

5 GIS intensive lessons. Select the ca weather stations.shp shapefile. Click Open at the lower right. 5

6 5. The view will automatically zoom to the California weather stations data extent. You will see five weather stations. If you don t see five stations, move your cursor to the lower left of the map and use the slider to zoom out slightly. You can also zoom in and out using your mouse. 6. Change the basemap to show cities, roads, and topography. Click on the Basemap button and from drop down list choose World Topography. 7. Your map will look similar to the image below. You may want to explore how different base maps look. Return to the World Topography basemap before proceeding. 6

7 8. Change the symbology of the California weather stations to a sphere. It will be easier to select the exact weather station location by clicking on the center of the sphere rather than the tip of the balloon pointer. From the Contents on the left hand side choose ca weather stations shapefile (point). 7

8 9. Under the Appearance tab scroll down and choose a red sphere. This will mark each weather station with a red sphere. 10. Your map will look similar to the image below. You may want to explore how different symbols look. Be sure to return to the red sphere symbology before proceeding. 8

9 11. Save your map. Click the ArcGIS Explorer icon at the top left, choose Save As, and then choose ArcGIS Explorer Map. 12. Navigate to the California folder and name your map CA Study Area Map.nmf. Click Save. 9

10 Part 2 - Learn how to read the map layers tabular data in ArcGIS Explorer 1. Select ca weather stations on the left hand Contents panel on the left hand side of your ArcGIS Explorer Desktop window. 2. Click on any one of the weather stations to view tabular information about that station. Note: You must click on the red dot and on the name of the weather stations on the map (to the right of the Contents panel) to view tabular information. Tabular information will appear in a pop-up window and includes the following information: LONGITUDE (in decimal degrees) LATITUDE (in decimal degrees) STATION (station name) ELEVATION (in meters above sea level) ANN_TEMP_F (annual mean temperature F) ANN_TEMP_C (annual mean temperature C) JAN_TEMP_F (January mean monthly temperature F) JAN_TEMP_C (January mean monthly temperature C) JUL_TEMP_F (July mean monthly temperature F) JUL_TEMP_C (July mean monthly temperature C) ANN_PRECIP (annual mean precipitation in inches) JAN_PRECIP (January mean precipitation in inches) JUL_PRECIP (July mean precipitation in inches) ANN_SNOW (annual mean snowfall in inches) 3. Below is a view of a pop-up window displaying the tabular information for the Mount Madonna weather station. Your map will appear as below. 10

11 4. To view more than one weather station table data at a time, refer to the Pinning Popups function card. 5. Close the popup window by clicking on the x in the right top hand corner of the pop-up window after you have finished viewing weather station tabular data. This is how you close all pop-up windows. Question 1: Compare values among the stations. Which station recorded the most annual precipitation? How does elevation at this weather station compare with the elevation of the other weather stations? According to your answers to the above questions, do precipitation and elevation appear to be closely aligned? 11

12 Part 3 - Modify the functionality of ArcGIS Explorer and create a terrain profile 1. To create a terrain profile along the path of the California weather stations you will need to install an Add-In. If the Add-Ins tab is not visible at the top click the ArcGIS Explorer icon at the top left, choose ArcGIS Explorer Options at the bottom. 2. An ArcGIS Explorer Options window will display. Within the ArcGIS Explorer Options window select Resources on the left and then to the right of Manage Add-Ins click on the Add-Ins button. 12

13 3. You may see a window pop up that indicates new add-ins have been detected. If so, choose Restart Now. 4. An ArcGIS Explorer Add-ins window will display. If new add-ins have not been detected the screen below will appear. If add-ins have previously been installed, they will appear under Add-in Files: within this window. Click on the Add button in the upper 13

14 left hand corner of the window. 14

15 5. Navigate to the folder named Add-ins within the ArcGIS Explorer files for STORE GIS intensive lessons folder, select TerrainProfile900, and then click Open at the lower right. You will be prompted to restart ArcGIS Explorer. Click Restart Now. 6. If you had to restart ArcGIS Explorer, the CA Study Area Map.nmf will re-open. Create a terrain profile based on the locations of the California weather stations. Under the Add-Ins tab at the top select Profile. 15

16 7. Click on the center of each red sphere that denotes a weather observation station starting from west moving in an easterly direction. Double click on the last station. 8. A terrain profile will be generated and the terrain profile path will be added to the left hand Contents. A terrain profile is a vertical two-dimensional view that mimics what you would see from the ground if you were looking at a vertical slice of land with all of its changes in elevation. You can dismiss the terrain profile plot by clicking on the small x in the upper right hand corner ot the terrain profile window. You can recall the terrain profile anytime by right clicking on terrain profile under the left hand Contents panel and choosing Show Popup. 9. Save your map. Click the ArcGIS Explorer icon at the top left and choose Save. 16

17 Part 4 - Visualize variations in precipitation corresponding to changes in elevation (Orographic Rainfall) 1. Click on the Add Content button and from drop down list choose ArcGIS Layers. Hint: Add files to your map by clicking on the Add Content button and selecting from the type of data file to add listed in the drop down list (as shown in screen short of Part 1 of this lesson). 2. Navigate to the California folder. Add the National Climatic Data Center (NCDC) ca average annual precipitation.lpk layer package. Click Open at the lower right. The view will automatically zoom to average annual precipitation for the California study area and will look similar to the view below. You can drag the terrain profile window and adjust the map view to accommodate both on your screen. 17

18 3. Click on Manage Layers at the top right of your screen. 4. The Manage Layers dialog box will pop up. 5. Select the ca average annual precipitation layer and make sure it is highlighted. Click on the Move Down button. Move the ca average annual precipitation layer below the 18

19 ca weather stations layer as shown below. After you re done, close the box. 6. Right click ca average annual precipitation layer listed under the maps Content panel. Scroll down and click on the Show Legend. 7. You can move the Legend window below the Contents panel and adjust the size of the window. Below is an example of what your screen will look like. 19

20 Question 2: Look closely at your results from Part 2 and Figure 2 (below). As you move your eye along the terrain path, what pattern do you see in precipitation in relation to elevation? Based on your understanding of orographic rainfall (first introduced in Basic Lesson 1), provide a simple explanation as to why this pattern occurs. 20

21 Figure 2. Average annual precipitation overlain on a topographic relief map for the California Study Area. The darker blue areas overlain on land represent greater average annual precipitation. 8. Once you have answered Question 2, close the terrain profile pop-up window. Additional Information The Hydrologic Cycle at This link shows how climate zones in the US are very closely related with elevation. Mountainous areas have colder/wetter climates than adjacent lower areas. 21