Aerology, deriving from the Greek words aer (air) and -logia (study), was the historical discipline dedicated to the systematic investigation of the atmosphere. This field sought to understand the physical and chemical properties of the air surrounding the Earth. While the term is rarely used today, its methods and findings laid the foundational groundwork for modern atmospheric science and meteorology.
Aerology Defined: The Study of the Upper Air
Aerology was historically defined as the branch of meteorology focusing specifically on the “free atmosphere,” meaning the air above the surface boundary layer. Unlike general meteorology, which concentrated on near-surface weather, aerology sought to describe and understand the conditions of the total vertical extent of the air column. This specialized focus became prominent during the late 19th and early 20th centuries, as scientists realized the crucial role of the upper atmosphere in driving weather.
The primary objective was to map the vertical structure of the atmosphere, particularly in the upper troposphere and the lower stratosphere. Scientists were interested in how parameters like air temperature, atmospheric pressure, humidity, and wind speed changed with altitude. This study of vertical structure was considered a separate discipline because collecting data at high altitudes was logistically challenging and required specialized techniques.
Aerological research provided the first comprehensive view of the atmosphere’s layered architecture. The use of early instruments led directly to the discovery of the stratosphere in 1902, which fundamentally changed the understanding of atmospheric dynamics. This work established the importance of three-dimensional analysis for weather prediction, treating the atmosphere as a vertically integrated system.
The Tools and Techniques of Early Aerology
The data for aerology was gathered using innovative methods before the widespread availability of aircraft and satellite technology. One of the earliest methods involved using kites flown on long tethers to carry recording devices like barometers and thermometers. These instruments measured conditions up to a few kilometers above the surface.
A significant advancement came with sounding balloons, typically filled with hydrogen. These balloons carried small instrument packages called meteorographs, which mechanically recorded temperature, pressure, and humidity changes during ascent. After the balloon burst, the package parachuted back to Earth and had to be retrieved to analyze the data.
By the 1930s, the radiosonde revolutionized data collection by incorporating a small radio transmitter. Attached to a balloon, the radiosonde measured atmospheric variables and transmitted the data in real-time back to a ground station. When tracked by radio equipment to calculate wind speed and direction, the observation was called a rawinsonde observation, providing a complete vertical profile.
The Modern Successor: Aerology’s Role in Atmospheric Science
The term aerology began to fade from common scientific usage, absorbed by the broader fields of Meteorology and Atmospheric Science. This transition accelerated after World War II, which saw immense investment in atmospheric research. The fundamental goal of aerology—understanding vertical atmospheric structure—remains central to modern science, but the methods are now far more sophisticated.
Modern Data Collection
Advanced technology now fulfills the mission once carried out by balloons and kites. Satellite remote sensing provides continuous, global measurements of temperature, moisture, and wind. Ground-based radar and high-altitude research aircraft offer detailed observations of atmospheric processes. Sophisticated computer models process vast data to simulate vertical dynamics, greatly enhancing forecasting capabilities.
While “aerology” is mostly historical, the rigorous data collection practices it championed established the foundation for modern weather forecasting and climate science. The global network of radiosonde stations established in the 1930s still operates, providing the routine, high-resolution vertical profiles essential for initializing global weather models. The core scientific pursuit of aerology has been integrated into the larger discipline of atmospheric science.