Seminar: Matic Šavli: Data assimilation of Doppler wind lidar observations in NWP models

Sreda, 24. februar 2016, ob 13:00
Predavalnica F3, 1. nadstropje, FMF, Jadranska 19, Ljubljana

V okviru internega seminarja na katedri za meteorologijo nam bo predaval naš mladi sodelavec Matic Šavli. Seminar je odprt za vse obiskovalce, potekal pa bo v angleškem jeziku.

Povzetek:

The lack of direct wind observations is one of the top missing links in the Global Observation System (GOS). Majority of currently available wind measurements are based on indirect retrievals meaning that winds are estimated from movements of water vapor and cloud structures in the troposphere. Direct wind profiles are available from radio-sondes and partly from aircrafts. As the Numerical Weather Prediction (NWP) is an initial value problem, new wind observing systems and their assimilation is one of the top priorities.
Since 1990s there are efforts to build space-borne wind lidars. Due to technical constraints this is still a challenge, but the technology has now advanced to the level where a trade-off between quantity and quality of such observations is such that their implementation is possible.
In the seminar an overview of various studies regarding the assimilation of wind profiles from satellite with a lidar will be given. The focus is on the ADM-Aeolus mission by ESA but several other proposals of a more general Doppler wind lidar (DWL) observations will be discussed. A majority of such studies confirms the positive impact of DWL observations in global models, primarily in areas where existing wind observations are sparse.
A lack of dominant wind-temperature coupling (i.e. geostrophical balance) is the main challenge in the assimilation of mesoscale processes. Thus higher resolution Limited Area Models (LAM)s should also profit from additional wind profile observations. A status of the Mesoscale wind profile assimilation ESA-PECS project will be discussed including some challenging aspects.