Lightning detection: From ground to sky

How the study of lightning went from earthbound to a bird’s eye view

June 20, 2023

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Lightning may be stunning, but it is also a deadly, destructive force. Meteorologists have studied lightning for centuries, working out its behavior and developing ways to detect lightning strikes. Tools and techniques for lightning detection have come a long way since Benjamin Franklin tested his lightning rod, shifting our view of this powerful severe weather from the ground to the sky.

Lightning in North Dakota: July 5, 2014. (Image credit: Jeremy Bower)

Observation

In the early 1700s, lightning detection was solely observational. We relied on seeing lightning and waiting for the thunderclap to determine how far away it was, which is roughly accurate and still practiced by many people.

A drawing of a Dutch telescope in use in the 17th century. A nobleman stands atop a hill with the telescope to his right eye. On the left side of the painting, there is a town of stone buildings. — A Dutch telescope in use in the 17th century. Engraved by Adriaen van de Venne. (Image credit: Public Domain)

Franklin’s Lightning Rod

In the mid-18th century, Benjamin Franklin invented the lightning rod. Franklin began experimenting with electricity in 1745 which led him to the idea. The pointed rod was made of conductive material, such as aluminum or copper, and placed on top of a building with a wire running down to another rod stuck in the ground, which would conduct a lightning bolt’s electricity safely away from the building and into the ground. He theorized about the concept long before he ever flew his famous kite, saying, "The electrical fire would, I think, be drawn out of a cloud silently, before it could come near enough to strike."

Illustration showing the parts of a lightning rod, by Giuseppe Toaldo. A lightning rod sits atop a tower, with a line running down the side of the tower and across the ground to a buried rod, which disperses the electrical charge from the lightning bolt. — Illustration showing the parts of a lightning rod, by Giuseppe Toaldo. (Image credit: Public Domain)

Popov's Lightning Detector

Alexander Stepanovich Popov devised a lightning detector based on an early radio wave receiver in the late 1800s. It detected lightning by sensing its electromagnetic pulses using a coherer receiver that had been invented by Édouard Branly in 1890. A coherer consists of a tube containing two closely spaced electrodes. Between the electrodes are iron filings that stick together, establishing a path through which an electrical current can flow. In 1895, Popov’s device was installed at the meteorological observatory of the Institute of Forestry in St. Petersburg. His lightning detector was also adapted to transmit electrical signals in morse code.

A black and white photo of Popov’s coherer receiver, which he used to detect lightning. — Popov’s coherer receiver, which he used to detect lightning. (Image credit: Public Domain)

Time-of-arrival Geolocation Techniques

Time-of-arrival (TOA) geolocation techniques were developed in the 1930s and 1940s to aid in ship navigation. In the late 1950s, meteorologists began using these same techniques to locate lightning. The TOA method used the delay in arrival time at multiple lightning detection stations to determine where the lightning was and when it would arrive in the area of concern.

A photo of two field notebooks, a pencil, and glasses sitting on a vintage map. — Two field notebooks, a pencil, and glasses sit on a vintage map. (Image credit: Dariusz Sankowski, Pixabay)

Lightning Mapping Array Systems

In the late 20th century, Lightning Mapping Array (LMA) systems were developed. These are a network of stations consisting of antennas, GPS receivers, and processing systems that detect lightning and estimate the location and travel speed of the lightning bolt based on the time it takes the frequency signal radiated by the discharge to arrive at the various antenna stations in the array.

A photo of one of the sensors in the NOAA National Severe Storms Laboratory's portable Lightning Mapping Array (LMA). The sensor consists of an aerial with a solar panel in front of it. — One of the sensors in the NOAA National Severe Storms Laboratory’s portable Lightning Mapping Array (LMA). (Image credit: Public Domain)

Lightning Prediction?

Although you may hear the term “lightning prediction,” lightning strikes can not truly be predicted. What can be predicted are electrostatic events. However, not all of these lead to lightning, so lightning “prediction” is not especially reliable. Observations and technology are bringing people closer to accurate predictions. NOAA’s ProbSevere LightningCast offsite link model uses visible, near-infrared, and long-wave infrared channels aboard the GOES Advanced Baseline Imager (ABI) to predict the probability of lightning in the next 60 minutes.

Satellites

Satellites have allowed us to detect and map lightning storms like never before – from space. NOAA Geostationary Operational Environmental Satellites (GOES-R) are equipped with an instrument called the Geostationary Lightning Mapper (GLM), the first optical lightning detector on a satellite in geostationary orbit. NOAA began using the GLM in March 2017. In July 2018, the National Weather Service started including its data in the determination of operational weather forecasts.

Prior to the Geostationary Lightning Mapper, the NASA Tropical Rainfall Measuring Mission (TRMM) low earth orbit satellite had the Lightning Imaging Sensor (LIS) onboard, which operated similarly. NASA’s spare LIS is now on the International Space Station. On April 29, 2020, NOAA’s Geostationary Lightning Mapper captured the longest lightning flash on record, which covered a distance of 477 miles.

An Integrated Approach

Currently, NOAA uses both Lightning Mapping Array systems and satellite imagery to detect and locate ground lightning and in-cloud lightning in three dimensions, as well as time. These collected methods of observation keep us safer than ever from lightning strikes.

The Geostationary Lightning Mapper (GLM) instrument, onboard NOAA’s GOES-18 satellite, is now providing striking lightning observations of the Western Hemisphere. (Image credit: NOAA Satellites)
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A photo of the Oklahoma Lightning Mapping Array (OKLMA) site north of Chickasha, OK. There is a VHF antenna on the right that sands signals to a small plastic building on the left, which houses electronics that process those signals. — Oklahoma Lightning Mapping Array (OKLMA) site north of Chickasha, OK. (Image credit: NOAA)
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