Phd Position in atmospheric Physical Chemistry
The laboratory for Atmophere, Environment, and Space Observation (LATMOS,
Laboratoire Atmosphères, Milieux, Observations Spatiales) and The French
Aerospace Lab (ONERA) seeks applicants for a phd position in atmospheric
Physical Chemistry.
Subject
Airborne infrared sounder can be used as a sensor to monitor military
target using a limb line of sight. However, false alarm could occur, and
the corresponding rate must be as low as possible. This explains
importance to identify and characterize the potential causes of false
alarm. In this way it is then possible to identify and eliminate them
during their detection.
Transient luminous events (TLEs) were observed in the high atmosphere for
the first time in 1990. Such phenomena could induce a false alarm. TLEs
occur most of the time over thunderstorm clouds and they persist less than
a second. Depending on their shape and their duration TLEs are called
Sprites, Blue Jets, Elves, luminous halos and gigantic jets. The
associated energized electrons excite, ionize or dissociate the major
constituents of the Earth's atmosphere. Atomic or molecular species
excited in electronic or vibrational states can induce various chains of
chemical reactions and local enhancements of the concentrations of O_3 ,
NOx (i.e. NO+NO_2 ), NO^+ , and OH.
Energy deposition following a TLE event produces molecules in
vibrationally excited levels. The local thermodynamic equilibrium is
perturbed and it is then necessary to consider the population of each
vibrational energy level individually in order to simulate the accurate
radiative transfer of hot bands. This case is called Non Local
Thermodynamic Equilibrium (NLTE).
The aims of this thesis will be to quantify the impact of TLEs on the
chemical and vibrational atmospheric composition in order to deduce its
effect on the atmospheric background radiance. For this, the successful
applicant will develop a vibrational kinetic model. Then, he/she will
couple this model with a full atmospheric chemical box model. It will
allow predicting the disturbance of vibrational temperatures and of
chemical concentrations by TLE discharges (blue jets, sprites).
The resulting work will allow modeling the infrared signature of TLEs.
This radiation will be calculated on an altitude range corresponding to
the studied TLEs, and then propagated to a limb viewing instrument at a
distance of a few kilometers and an altitude of 10-15 km for an aircraft,
20-40 km for a stratospheric balloon.
The thesis will take place in close cooperation between the French
aerospace lab ONERA/MPSO (modélisation physique de la scène optronique)
and LATMOS (Laboratoire Atmosphère Milieux Observations Spatiales).
Requirements
Dynamic and motivated student with M.Sc./Diploma and with skills in at
least one of the following fields:
- Atmospheric Physic or chemistry,
- Radiative transfer,
- Molecular spectroscopy,
- Atmospheric remote sensing.
Lab languages are French and English. It is expected that the candidate
will also col-laborate with external institutes.
Application
For further information or sent your application please contact
[log in to unmask] <mailto:[log in to unmask]> and
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Application (in English or in French) must include the following:
* A cover letter
* Curriculum vitae
* Diplomas – all relevant certifications
* Other information for consideration, e.g. list of publications (if
any), letters of recommendation
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Laboratoire Inter-universitaire des Systèmes Atmosphériques
http://www.lisa.u-pec.fr/
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