1.2: Maps and Geography

Tools for reading maps

Numerous lab exercises in this class rely on a somewhat in-depth geography of planet Earth (primarily continents, countries, major cities, and spatial orientation). Rather than having you memorize a bunch of states/cities, this portion of the lab will simply introduce you to the numerous tools/techniques/rules for how Geography is used in this course. You will be allowed to use any/all of these tools on any assignment/quiz in this course, so the key for this lab is to get comfortable with how to use them.

First Tool: Spatial Orientation

Have you ever wondered what direction West/East/North/South is relative to where you were at? You can often use landmarks/geographical features (such as the surrounding hills) as a reference point; for example, in Silicon Valley, the hills that have lots of tall trees/forest are to the west of the city, while the hills that have lots of brown grass (may be green in winter) are to the east of the city. You can then quickly determine which direction is North and which is South.

For this class, you won't have to do that. You just need to follow one simple rule: for any map you see in this class, north will be on the top, south will be on the bottom, west will be on the left, and east will be on the right. Depending on the map projection used, there may be a very slight deviation from this, but not enough to make a real difference (and it will be mentioned in the textbook when that deviation occurs). This orientation is shown in Figure \(\PageIndex{1}\).

Figure \(\PageIndex{1}\): Cardinal Points on all maps in this class. North at the top, south at the bottom, east on the right, and west on the left. (Public Domain; Alicia Mullens)

Second Tool: Continent and Country Maps

You'll often see questions asking which continent a particular weather/climate feature is located in. You can always refer to Figure \(\PageIndex{2}\) for quick reference.

Figure \(\PageIndex{2}\): Map of all of the Continents. (CC0 1.0; Atharva Kurhe via Wikimedia Commons).

We need to examine the world as a whole to better understand Climate Change. The good news is that, while the class's geographical scope is global, the content won’t be any more difficult or rigorous than a typical Meteorology lab. It’s just that we need to look at the globe to understand global warming.

Third Tool: Averages and Anomalies Maps

Climate is the description of the average conditions of the atmosphere for a given region (such as temperature and precipitation)… what would be considered normal. Because of this, a key indicator of changes in a location’s climate is the presence of anomalies. Usually, when discussing global warming, someone will say, “It’s warmer than it used to be!” Such a statement would be valid if a location has been experiencing abnormally warm conditions for a prolonged period. To determine whether a location has become warmer, we need two main pieces of information: the location's average temperature and how much warmer it is now. That second piece of information is called an anomaly – a deviation from the average. We will examine various averages and anomaly maps in this course, but just to get you acclimated to them, let’s examine a few now:

Figure \(\PageIndex{3}\): Global average annual precipitation map. (CC BY 4.0; S. Berghald via Wikimedia Commons). Alternative description of image.

Figure \(\PageIndex{4}\): Global precipitation anomalies map for March of 2022. (Public Domain; NOAA Climate.gov). Alternative description of image.

Figure \(\PageIndex{3}\) displays the average precipitation for locations all over the world for the 30-year period ending in 2020, while Figure \(\PageIndex{4}\) displays the differences from average in precipitation amounts for March of 2022. Note that averages are taken over a long period of time while anomalies are determined for a short period of time. We’ll actually cover the difference between Weather and Climate in Investigation 1, but an anomaly is determined by comparing the condition of the atmosphere at a given time, it’s “weather,” to the average condition over a long period of time, of the “climate”. Also note that, while this book will strive to keep map projections as consistent as possible, there will be some variation because information is drawn from a large number of sources. But the rule shared earlier in this section will always apply: North at the top, South at the bottom, West on the left, East on the right, regardless of projection.

The last thing to note before we work with these maps is the color shading. Any map with color shading will include a legend explaining the colors. For Figure \(\PageIndex{3}\), the legend is somewhat blurry, but the driest locations are shaded in red (on the left of the legend) while the wettest locations are shaded in blue (on the right of the legend). For figure 1.2.4, below-average precipitation (negative anomalies) are located on the left of the legend in increasing shades of brown, while above-average precipitation (positive anomalies) are located on the right of the legend in increasing shades of green.

During the investigations in this book, you will be presented with similar maps/images that show weather/climate data from around the world. You need to be able to interpret these maps based on the information shown. Some questions will then be asked to check your understanding of the data presented. Based on Figures \(\PageIndex{3}\) and Figure \(\PageIndex{4}\), let's answer the following questions.

1. On average, the driest locations on Earth are located in which areas?
   1. Eastern North America and the northern portion of South America
   2. Central Asia and sub-Saharan Africa
   3. Western South America and Northern Africa
   4. Australia and North Asia
2. Meanwhile, the wettest locations on Earth are located in which areas?
   1. Western North America and sub-Saharan Africa
   2. Northern South America and the maritime East Asia regions
   3. Northern Africa and Western North America
   4. Middle East and Arabian Peninsula

The previous two questions were based on averages. Now, let’s examine the anomalies.

3. In March of 2022, locations that were significantly drier than average include:
   1. The Middle East and Arabian Peninsula
   2. China and Southeast Asia
   3. The Eastern United States and Northern Brazil
   4. Western Australia
4. Meanwhile, locations that were significantly wetter than average include:
   1. The entire United States and Australia
   2. India and Northern Africa
   3. The Equatorial Pacific (West of South America)
   4. Most of China and Southeast Asia
5. Finally, let’s focus on the USA. The Precipitation Anomalies across the United States show:
   1. Drier than average conditions across the entire United States
   2. Wetter-than-average conditions across the entire United States
   3. Drier than average in the West and average to slightly wetter than average across the Eastern United States
   4. Wetter than average in the West and Drier than average in the East.

We'll come back to averages and anomalies later in this investigation. While the information may seem trivial, it's good to get comfortable interpreting such maps.