Observation in meteorology

meteorology measuring devices

In order to know the meteorological situation of all parts of the world, observing our planet is essential. Thanks to many observation instruments we can know and even predict the meteorological conditions of almost every corner of the planet earth.

In order to know the state of the meteorology, measurements are made in thousands of meteorological stations located not only on land, but also on the sea, at different heights of the atmosphere and even on satellites from outer space. How do the devices that observe our planet and its meteorological conditions work? How important are they in terms of weather forecasting?

Observation in meteorology

observation is necessary in meteorology

The measuring devices of the different meteorological variables such as pressure, winds, humidity, rainfall, temperatures, etc. They are located in fixed positions throughout the entire planet. They are located both in places on the mainland, such as plains, mountains, valleys, cities, as well as along the routes traced by ships and airplanes, taking advantage of the fact that they all have meteorological instruments on board.

The use that can be made of the information provided by all these observation sources is very varied: from the mere temporal record in specific stations, to the elaboration of meteorological predictions. In any case, meteorological centers centralize information by area, process it, control its quality, and distribute it to users who may need it to study the atmosphere.

When a communication is made to the public about the result of the meteorological observation, it is called a meteorological report. Thus, the newscast is called «the part«. The result of the meteorological observation can be shown both verbally and with representations. Normally, a map of the area to be observed is used and the meteorological variables that have been observed and their evolution are represented on it.

With the set of meteorological variables studied, models can be built to help in their prediction. For it, are based on patterns of operation and behavior of these meteorological variables to environmental conditions and how they can evolve over time is analyzed. Weather forecasting is very necessary in everyday life to be able to know what the weather will be after the next few days and to be able to act according to the weather.

Weather forecasting models use the data obtained after so many years of records to be able to formulate the characteristics that make up the climate of a region. As you know, weather is not the same as weather. Meteorology refers the state of meteorological variables at a certain time. However, the climate is the set of these variables throughout the years. For example, a climate is polar, when variables such as temperature, precipitation in the form of snow, winds, etc. They form a cold climate, in which low temperatures below zero degrees predominate.

Meteorological observation apparatus

weather stations measure variables

Of course, the basis of all meteorological observations lies in the meteorological instruments that are used to take the measurements. This table summarizes some of the most commonly used instruments:

A meteorological station usually has several of these instruments, even if it is very complete. For the measurements of the meteorological variables to be carried out correctly, they must be carried out according to the criteria established by the World Meteorological Organization. These criteria are based on the correct location, orientation and environmental conditions that may affect the measuring devices and alter the results obtained.

In order for the data to be rigorous, the enclosure of a meteorological station must have a sentry box, a kind of white wooden cage located 1.5 m from the ground, inside which the thermometers, the hygrometer and the evaporimeter are located. In addition, in many cases, the stations have a weather tower. Measuring devices such as thermometers, anemometers and wind vanes are located on it, which inform us about the meteorological conditions at different heights.

Observation meteorological satellites

meteorological satellites used to observe the weather

As mentioned before and without a doubt, observation satellites are the most complex, but the ones that give good results. The position that satellites occupy, in orbit around the Earth, allows them to have a privileged vision, much wider and more comprehensive than that of any device located on the earth's surface.

Satellites receive electromagnetic radiation emitted and reflected by the Earth. The first comes from itself and the second comes from the Sun, but is reflected on the earth's surface and in the atmosphere before reaching the satellite. The satellites capture certain frequencies of this radiation, of different intensity depending on the atmospheric conditions, to later process the data and elaborate the images that will be received at the ground stations, where they will be interpreted.

Meteorological satellites can be classified according to the orbit on which they are located and according to their types:

Geostationary satellites

geostationary satellites are fixed

These satellites rotate at the same time that the Earth does, so they only visualize a fixed point located on the Earth's equator. Typically, these satellites are located at very great distances from Earth (about 40.000 km).

The advantages offered by these satellites are that, being so far away, their field of view is very wide, as large as the entire face of the planet. In addition, they also provide information in a continuous way about a specific area that you want to observe and allow the meteorological evolution in that area.

Polar satellites

the polar satellites are closer

The polar satellites are those that orbit much closer than the previous ones (between 100 and 200 km high) so they offer us a closer view of our planet. The downside is that, although it offers us images with higher resolution and clearer, they are able to observe less space.

A meteorological satellite has the appropriate instrumentation to capture information about various properties of planet Earth, but mainly it captures visible and infrared electromagnetic radiation. From this information two types of satellite images are produced, which are called the spectrum band to which they correspond. If the images received are placed one after the other, viewed as a sequence, we will be able to appreciate the movements of the clouds, just as the weather man shows us on television every day.

Types of observations

Depending on the information collected by the two types of meteorological satellites, we can make observation maps with the two types of images that the satellites collect: First, there are the images that are visible in the visible and, second, those that are in the infrared.

Visible images (VIS)

images of the visible are only during the day

The visible images constitute an image very similar to the one we would perceive if we were located on the satellite, since, as our eyes would do, the satellite captures the solar radiation after reflecting on the clouds, the land or the sea, depending on the zone.

The brightness of the image depends on three factors: the intensity of the solar radiation, the angle of elevation of the sun and the reflectivity of the observed body. The average reflectivity (or albedo) of the Earth-Atmosphere system is 30%, but, as we saw in the previous chapter, snow and some clouds are capable of reflecting a large amount of light, so that in a visible satellite image they would appear brighter than, for example, the sea.

Although clouds are generally good reflectors, their albedo depends on the thickness and nature of the particles that make them up. A cirrus, for example, being a thin cloud formed by ice crystals, barely reflects solar radiation, so it is difficult to see it in a visible image (they are almost transparent).

Infrared (IR) imaging

infrared images measure the heat emitted by bodies

The intensity of infrared radiation emitted by a body is directly related to its temperature. Thus, a high and cold cloud, such as a cirrus, will appear very bright in such an image. The desert at noon, if there are no clouds above it, will appear as a very dark area in the image, due to its high temperature. Infrared images can be enhanced in color depending on the emission temperature of the area, thus facilitating the identification of very cold areas, usually corresponding to highly developed cloud tops.

Infrared images make it difficult to distinguish low clouds and fogsSince their temperature is similar to that of the surface where they are, they could be confused with it.

Infrared images are used especially at night, since there is no light for the satellites that capture visible images to capture. You have to think that whether it is day or night, bodies emit heat and, depending on their temperature, they will be whiter or darker. For this reason, the two types of observation are used to better contrast the information and complete it to the maximum.

With this information, you will already know more about meteorology and the importance of its observation for the creation of models that help in the prediction of the weather.


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  1.   Old man said

    No, the newscast is not called the part because it gives meteorological information (which no one colloquially calls the part, but the weather).
    The newscast is called the part, and less and less frequently, for having inherited from the national radio of Spain the custom and routine of giving it, of giving the official war report, of the notorious 1936/1939 civil war, which it was broadcast daily from Generalissimo Franco's headquarters.
    "Shut up, they are going to give the report!" It was the wake-up call that after the usual announcing clarinet gave whoever had more authority in the house, so that the silence would allow listening to the all-important war news.
    The war passed, the television arrived (1956), the custom remained, very true, of calling the news "the part"
    In the old days of Mariano Medina, no one said he was "the man of the part", but the man of the time.