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Projecte llegit

Títol: Numerical simulation of the atmospheric features in the observation of Majorca Island from the Catalonia central coast.

Estudiants que han llegit aquest projecte:

Director/a: MAZÓN BUESO, JORDI

Departament: FIS

Títol: Numerical simulation of the atmospheric features in the observation of Majorca Island from the Catalonia central coast.

Data inici oferta: 17-03-2020     Data finalització oferta: 17-11-2020


Estudis d'assignació del projecte:
    GR ENG SIST AEROESP
Tipus: Individual
 
Lloc de realització: EETAC
 
Segon director/a (UPC): PINO GONZÁLEZ, DAVID
 
Paraules clau:
WRF simulation, air transparency, Majorca, observation, mirage.
 
Descripció del contingut i pla d'activitats:
The observation of the Balearic Islands from the central coast of Catalonia is a well known and not uncommon phenomenon since many decades ago. However, numerical simulation to find out weather features has not been done.
Based on studies from other regions of the planet, the phenomenon of observing the island of Mallorca could be explained by well-defined and unusual atmospheric conditions in the Mediterranean region between Catalonia and the Balearic Islands, which lead to the formation of a upper mirage, also known as Fata Morgana. Some times the propagation of light rays through the atmosphere becomes complex with the formation of organized atmospheric structures, which cover a wide range of length and time scales that induce temporal space variability in the refraction of light, which can distort the trajectories of rays and make this observation possible.
It should be take in consideration that this phenomenon is more typical of cold climates, with a transparent atmosphere and without the presence of rainfall. The sea surface temperature of the Mediterranean between Catalonia and the Balearic Islands is characterized by a high values, providing water vapour and saline aerosols to the air, which reduces the transparency of the air.

The goal of this project is to find out and describe the physics behind the observations of Mallorca from Catalonia and vice versa. It is the first time that this phenomenon is studied by using numerical simulation, with the Weather Research and Forecasting (WRF) mesoscale model. After a compilation and statistical analysis of the observations of the island from the Fabra Observatory, where for many years there has been a monitoring of these observations, several episodes of observation between Catalonia and the Balearic Islands will be simulated, with the aim of understanding the causes that make up this phenomenon.
The project is close related with the air transparency and the visibility, and so over the landing, descent and takking off aircraft's operations.
 
Overview (resum en anglès):
From the Fabra Observatory located in Barcelona, located at 413 m above sea level, it is possible to frequently observe the mountains of the island of Mallorca despite the 190 km that separate the two locations.

In the present work, we analyze the relevance of the different meteorological variables that facilitate the sightings of Mallorca. The goal is to determine if the atmospheric transparency is the only influential factor in the sightings or if also a refraction of the rays of light. This is a common phenomenon over the sea, where the temperature difference between the surface of the water and the air above can lead to a thermal inversion, thus creating a gradient of the refractive index that will cause the refraction of light rays according to Snell's law.

In our study we will use data from observations made from January 30, 2010 to December 25, 2019, which will allow us to perform statistics on the frequency of light (type I), regular (type II) or excellent observations (type III).

From all these observations, we will select the days 24, 25, 26 and 27 January 2019. For these days a WRF mesoscale numerical simulations is performed.The output of the model is used to calculate the trajectory of the light rays by means of the Eikonal¿s equation.

Therefore, the main objective of this project is to demonstrate, by analyzing the trajectory of light rays, whether in the sightings between Mallorca and Catalonia there is an optical phenomenon and determine which are the meteorological variables that affect the transparency of the air, and therefore the quality of the observations.

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