Working With Major US Storm Data
Explore how to clean, analyze, and visualize major US storm data using Python. Understand tropical cyclone characteristics, storm categories, and the evolution of data collection methods to interpret historical storm records effectively.
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What is a storm?
Hurricanes—or more precisely, tropical cyclones—are tropical because they form over oceans within tropical regions. The term tropics refers to the area of the earth’s surface that falls within 23 degrees (or so) of the equator, to both its north and south. The storms are called cyclones, as shown in the following figure because the movement of their winds is cyclical (clockwise in the Southern Hemisphere and counterclockwise in the Northern Hemisphere).
Cyclones are fed by evaporated ocean water and leave torrential and often violent thunderstorms in their wake — especially after driving over habited land areas. In broad terms, a storm producing sustained winds of between 34 and 63 knots (or between 39 and 72 miles per hour) is considered a tropical storm. Storms with winds above 64 knots (73 mph) are hurricanes (or typhoons in the Western Pacific or North Indian oceans). Categories between one and five are used to measure hurricanes, where category five hurricanes are the most violent and dangerous.
Where does major storm data come from?
Reliable and broadly consistent historical storm data has existed for the past century and a half, at least in the US. But properly understanding the context of that data will require some knowledge of how those observations were made over the years.
Until the 1940s, most observations were made by the crews of ocean-going ships. But ship crews can only observe and report what they see, and what they see will be determined by where they go. Before the opening of the Panama Canal in 1914, ships traveling between Europe and the Pacific ocean would follow a route around the southern tip of South America that largely missed US coastal areas. As a result, likely, a significant percentage of weather events were simply missed.
Similarly, the advent of aircraft surveillance in the 1940s would have allowed scientists to catch more events that would have earlier been missed. The use of weather satellites from the 1960s on has allowed us to see just about all ocean activity.
These changes, and their impact on storm data, are neatly summarized on this website from the US government National Oceanic and Atmospheric Administration (NOAA) site, based on a data analysis study performed for the Geophysical Fluid Dynamics Laboratory (GFDL).
Question: What is tropics?