The Douglas scale is used to describe wave height and sea conditions . You've probably heard it a thousand times on the weather news, where they refer to sea conditions as swell, moderate swell, rough seas, etc. All these terms describe the state of the sea at that moment, depending on the wind and its intensity. It's primarily used to describe wave behavior in the following days.
In this article, we'll tell you all about the characteristics, meaning, and importance of the Douglas scale in meteorology.
Origin of the Douglas scale
This nomenclature, used to describe wave height and sea conditions, was created by the English admiral Henry Percy Douglas. This scale was established in 1917 and was used by the British Royal Navy's meteorological service. At that time, it was a scale with two codes: one to estimate the current sea state and another to describe the height of the waves as affected by the wind.
There is no doubt that it is one of the most widely used scales throughout the history of meteorology. Until today it is still used to describe the waves and the state of the sea in the coming days. It is mainly used in television weather reports that are very useful for fishing boats and commercial vessels.
The Douglas scale's success lies in its great simplicity and highly descriptive way of explaining maritime conditions at any given time. These characteristics have ensured its longevity, allowing any maritime professional or sailing enthusiast to sell weather reports.
To understand the Douglas scale, we must know the relative height of the waves. This height is reflected in the first code of the scale. It signifies the significant wave height. This first code refers to the wave height that an experienced observer could perceive with the naked eye from a given starting point. This starting point does not necessarily have to be the shoreline. It is equivalent to the average height of the highest third of the waves.
State of the sea on the Spanish coasts
This scale is used to determine sea conditions off our coasts and in maritime directions. This information is obtained from the deep-water buoy network, located far offshore at great depths. They are typically positioned at a depth of around 200 meters, ensuring their measurements are not affected by local effects that might cause changes due to the open sea.
The entire coastal buoy network is distributed in the vicinity of port facilities. These buoys are anchored at a depth of approximately 100 meters. The vast majority of these buoy measurements are influenced by the coastal profile and the effects of the seabed. Therefore, the information collected by this type of tracking is representative only under local conditions.
As we might expect, sea conditions are closely linked to wind strength. Wind intensity was tabulated on the Beaufort scale , which allows for a better understanding of the Douglas scale and its importance in meteorology . This scale was numbered from 0 to 12, using adjectives commonly found in nautical jargon . You have probably heard some of these terms related to the Beaufort scale, which we will list below:
- Calm
- Ventolin
- Lazy, Lazy
- Bonancible, Fresh
- cool
- Duro
- Very hard
- Temporary
- Storm
- Hurricane
Wave height of the Douglas scale
The first code on the Douglas scale is significant wave height. Let's analyze these values:
- Grade 0: no waves. The state of the sea can be seen that the surface is smooth like a mirror. There are no waves
- Grade 1: curly sea. The sea begins to alter in some parts. The waves are up to 10 inches in size.
- Grade 2: marejadilla. Shorter but well marked waves are formed here. They begin to break into small ridges with foam that is not very white but rather glassy in appearance. The waves can reach a size of 50 centimeters.
- Grade 3: storm surge. It is one in which the state of the sea can be seen how long balls are formed with well-characterized white foam ridges. It is here where the sea wind is quite defined and is easily distinguished from the background sea that may exist. When the waves break there is a murmur that quickly fades. The waves reach a size of 1.25 meters.
- Grade 4: strong swell. Longer tails form with ridges of foam all over. The sea breaks in a constant murmur. Here the waves can reach a size of 2.5 meters.
- Grade 5: thick. Very high waves begin to form with areas of white foam covering a large area. When the waves break, they produce a dull noise like throwing things. Here the waves reach a maximum size of 4 meters.
- Grade 6: very thick. The sea is completely upset and the white foam forms to break the crests of the waves and begin to arrange in bands in the direction of the wind. Here the waves reach a maximum size of 6 meters.
- Grade 7: wooded. Here the height and length of the waves and their crests increases notably. The foam is arranged in narrow bands in the direction of the wind. Here the waves reach a maximum size of 9 meters.
- Grade 8: mountainous. Here are high waves. Large areas become covered with foam in the direction of the wind. Here the waves can reach a maximum size of 14 meters.
- Grade 9: huge. The waves get so high that sometimes the boats can disappear from view at your breasts. The sea becomes covered with white foam arranged in bands in the direction of the wind. Here the waves reach sizes greater than 14 meters.
I hope that with this information you can learn more about climbing Douglas.