Low pressures and anticyclones refer to the different pressures in the atmosphere. Atmospheric pressure is measured in millibars (mbar). A millibar is equal to one thousandth of a bar., and one bar is equivalent to one atmosphere (atm). Understanding what a millibar means is essential, since the difference in millibars in a region generates depressions and anticyclones. It is also interesting to highlight the differences between anticyclones and depressions in relation to other phenomena such as atmospheric rivers.
Anticyclones and depressions are easily identifiable on a map due to the isobars, which are lines that connect points of equal pressure. If the pressure is higher than normal, i.e., 1024 mb or more, we are talking about an anticyclone. On the contrary, if the pressure is low, about 996 millibars, we refer to it as a storm. This has a significant impact on the weather associated with each type of pressure, as well as on the difference between weather and climate.
The Anticyclone
Normally, the anticyclone is considered as a phenomenon associated with stable time, which includes clear, sunny skies. Its pressure is approximately from 1016 millibars or moreDuring an anticyclone, the air is more stable than the surrounding air, descending from the atmosphere to the surface in a process called "subsidence." This phenomenon limits the formation of precipitation, creating ideal conditions for outdoor activities. For more information on the different types of anticyclones, you can consult the anticyclone and its characteristicsAs well as Azores anticyclone.
The sinking of air varies according to the hemisphere. In the Northern Hemisphere, the air descends in a clockwise vortex, while in the Southern Hemisphere, it does so counterclockwise. This results in clear skies and stable weather conditions, with higher temperatures during the summer. However, during the winter, even though the skies remain clear, it can also generate thermal inversions and fog, especially in urban areas, where pollution can concentrate. To better understand the climate, it is useful to consult a weather map.
Storm
The storm, in contrast to the anticyclone, is related to unstable timeThis includes cloudy skies, precipitation, and occasionally snowfall. Its atmospheric pressure is less than 1016 millibars, which makes it a low-pressure area. Knowing this information helps people prepare for potential storms, such as those that may bring storms like Gloria and also in situations such as analysis of storm Bert.
The air in a low pressure system rises, rotating in the opposite direction to the anticyclone. In the Northern Hemisphere, the rotation occurs counterclockwise. These types of unstable air masses often generate intense winds and a decrease in temperature in both summer and winter, due to the entry of clouds that block the sun's rays. During this type of phenomenon, it is common for dark clouds and storm conditions.
The interaction of cold and warm air during the formation of a storm usually generates abrupt climate changes, which can result in meteorological phenomena such as storms. In fact, storms can be responsible for heavy rains and winds that can cause damage in various regions. In this sense, the prevention of natural disasters It is essential to protect the population, especially in the event of events such as the Atlantic storm related to hurricanes.
The Coriolis Effect
It is important to mention the Coriolis effect, which plays a crucial role in the behavior of depressions and anticyclones. The Earth's rotation causes air moving toward low-pressure areas to not follow a straight path, but to deflect. In the Northern Hemisphere, this means the air deflects to the right, while in the Southern Hemisphere it deflects to the left. To better understand this phenomenon, you can consult an article on how a cyclone forms.
This wind deflection, caused by the Coriolis effect, contributes to the formation of high and low pressure systems. The Coriolis force also affects wind direction and speed, creating complex weather patterns that are fundamental to meteorology. This is especially relevant when analyzing the Impact of artificial intelligence on weather forecasting.
Types of Anticyclones
Anticyclones are not a homogeneous phenomenon; there are several types, classified according to their location and the conditions they generate:
- Siberian Anticyclone: It originates in Eurasia for much of the year and is characterized by being a mass of dry, cold air.
- Subtropical Anticyclone: It includes the Azores and Pacific regions, producing warm, dry climates. You can read more about the latter in the .
- Dynamic Anticyclone: It generates a hot, dry and sunny climate.
- North Atlantic Anticyclone: Its location is usually in the middle of the Cantabrian Sea, providing dry winters and displacing cyclones.
- South Pacific Anticyclone: It occurs when air masses from the south to the north collect moisture and transport it to the coasts, forming low clouds with high humidity content.
Types of Storms
Storms are also diverse and are classified according to their formation:
- Thermal Depressions: They are generated when the air temperature is significantly higher than its surroundings, causing hot air to rise and generate heavy rains.
- Dynamic Storms: They arise due to the rise of air masses towards the tropopause, where the pressures of the cold air masses displace the warm air.
Knowledge about these phenomena can prevent adverse situations and thus make daily life easier. For example, you can learn to prepare for changing conditions by consulting a how a storm forms.
Both anticyclones and depressions have a significant impact on daily life, affecting everything from the planning outdoor activities even navigation patterns at sea. Understanding these phenomena is crucial for predicting the weather and making informed decisions.
For example, an anticyclone may be a good forecast for an outdoor event, while the arrival of a storm may mean that plans need to be reconsidered. Furthermore, low-pressure systems are responsible for most severe thunderstorms, meaning that increased preparation may be necessary at these times. This is evident in situations like the analysis of storm Fabien.
Understanding the differences between anticyclones and depressions is essential for making informed decisions based on the weather. Whether planning activities with family and friends or sailing, recognizing these areas of atmospheric pressure will allow you to better anticipate changes in the weather and the conditions that may arise.
The study of these meteorological phenomena not only helps us prepare for the weather to come, but also gives us insight into the global behavior of the climate and its constant evolution.
