Vous êtes ici : Accueil / Agenda / 9/11/2018: Séminaire de Tristan L'Ecuyer

9/11/2018: Séminaire de Tristan L'Ecuyer

A Quest to Fill a Startling Gap in Observing the Polar Climate. Tristan L'Ecuyer ( Department of Atmospheric and Oceanic Sciences, University of Wisconsin, Madison)
Quand ? Le 09/11/2018,
de 11:30 à 12:30
Où ? Salle de réunion du LMD/Jussieu (T45-55, 3e étage)
S'adresser à
Téléphone 0144272799
Ajouter un événement au calendrier vCal
iCal

While the underlying theory behind polar feedback mechanisms has been known for a long time, current climate models still struggle to capture observed rates of sea ice decline and ice sheet mass. This may be explained, at least in part, by a historical lack of observational constraints the roles clouds and snowfall play in modulating polar processes. Satellite observations collected in the last decade have shed new light on these processes and are revealing that atmospheric reanalyses and global climate models exhibit significant biases in several key energy and water fluxes that influence ice-sheet dynamics and, ultimately, project onto global sea level rise. Reconstructions of polar energy balance from these modern satellite observations also reveal a troubling gap in our ability to observe key properties of the polar environment. Far-infrared radiation (that occurring at wavelengths longer than 15 microns) makes up 60% of the thermal emission from the Arctic and nearly half of Earth’s emission, globally. Remarkably, however, while far-infrared spectra have been collected from every planet in the solar system, Earth’s far-infrared emission spectrum has never been systematically documented. These measurements could offer powerful new insights into the key processes at work in the rapidly changing Arctic. This presentation will also describe a new satellite mission concept aimed at addressing this critical observational gap. The Polar Radiant Energy in the Far-InfaRed Experiment (PREFIRE) utilizes two CubeSats in asynchronous orbits to systematically document the spectral variation of thermal emission across the mid- and far-infrared (5 – 45 microns) throughout the Arctic. We anticipate that PREFIRE measurements will reveal changes in the full spectrum of Arctic radiant energy associated with processes that operate on scales ranging from sub-daily to seasonal. By distinguishing the unique spectral fingerprints of changes in temperature, water vapor, clouds, and surface melt processes, PREFIRE will help untangle the complex time-varying errors in model physics responsible for the large spread in simulations of the Arctic energy budget.


 

« Janvier 2019 »
Janvier
DiLuMaMeJeVeSa
12345
6789101112
13141516171819
20212223242526
2728293031
Événements à venir
21/01/2019 Séminaire Pierre GENTINE au LMD - Ecole Polytechnique 21/01/2019 10:00 - 11:00 — Slle de réunion "Marie-Claire Lanceau" du LMD/X
21/2/2019: Séminaire de Martin Singh 21/02/2019 10:30 - 12:30 — Salle de réunion du LMD/Jussieu (T45-55, 3e étage)
25/2-1/3/2019: UCP2019 25/02/2019 - 01/03/2019 — Harnack-Haus, Berlin
15-19/7/2019: Convection Parametrization: progress and challenges workshop 15/07/2019 - 19/07/2019 — MetOffice, Exeter
Tous les événements à venir…