EULAG (Eulerian/semi-Lagrangian numerical model for fluids) is an established computational model for simulating thermo-fluid flows across a wide range of scales and physical scenarios. It is noteworthy for its non-oscillatory semi-implicit integration algorithms, robust elliptic solver, and generalized coordinate formulation enabling grid adaptivity technology. Here we summarize the mathematical and numerical model design and illustrate its capabilities with examples of simulations of high Reynolds number flows throughout a range of scales and problems, from canonical decaying turbulence in a triply-periodic box through breaking of internal gravity waves in the Earth's atmosphere, to turbulent solar convection.
room 17 budynku przy Pasteura 7, at 14:30

dr Francisco P.J. Valero (SIO/Univ. of California, San Diego, La Jolla, CA 92093)
The L-1 and L-2 Earth-Sun Lagrange points mark positions where the gravitational pull of the Earth and Sun precisely equals the centripetal force required to rotate with the Earth about the Sun with the same orbital period as the Earth. Therefore, a satellite maintained at or near one of these Lagrange points would keep the same relative position to the Sun and the Earth and be able to observe most points on the planet as the Earth rotates during the day. L-1 and L-2 are of particular interest because a satellite at either location can easily be maintained near the Sun-Earth line and views, respectively, the entire daytime hemisphere or the entire nighttime hemisphere. Synoptic, high temporal-resolution observations would be obtained as every point on the planet transits from sunrise to sunset (L-1) or from sunset to sunrise (L-2). A pair of deep-space observatories, one at L-1 and one at L-2, could simultaneously observe almost the entire Earth's surface and atmosphere. Such unique attributes are incorporated in the Deep Space Climate Observatory (DSCOVR) that will systematically observe climate drivers (radiation, aerosols, ozone, clouds, water vapor) from L-1 in a way not possible with other satellites. The combination of Solar Lagrange Points (SLPs), LEO, and GEO satellites would certainly provide a powerful observational tool as well as enriched data sets for Earth sciences. Such synergism is greatly enhanced when one considers the potential of utilizing LEO, GEO, and SLPs satellites as an integrated observational system. For example, a satellite at L-1 will view the Earth plus the Moon while simultaneously having in its field of view (at one time or another) all Earth-orbiting satellites. This view offers the opportunity to use the Moon as a calibration reference that can in turn be shared with all other Earth observation satellites. In other words, the deep-space observatory can become an important link between LEO and GEO satellites while at the same time providing the data necessary to build an integrated Earth observational system. Such synergism would certainly help advance Earth sciences and greatly enhance the return for the nation's investment in space. A synergistic, integrated system composed of LEO, GEO, and SLPs platforms is likely the way of the future.
room 17 budynku przy Pasteura 7, at 13:15

dr inż. Bogdan H. Chojnicki (Katedra Agrometeorologii, Akademia Rolnicza im. Augusta Cieszkowskiego w Poznaniu)
dr inż. Bogdan H. Chojnicki, dr inż. Marek Urbaniak, prof. dr hab. Janusz Olejnik Obserwowane obecnie zmiany globalne wywołane wzrostem aktywności człowieka na Ziemi dotyczą również chemizmu atmosfery. Ludzkość staje m.in. przed faktem gwałtownego wzrostu stężenia dwutlenku węgla (CO2) w atmosferze. Obawy związane ze globalnym ociepleniem klimatu wynikających między innymi z oddziaływania atmosferycznego CO2 znalazły swój wyraz w protokole z Kyoto przyjętym w 1997 roku. Od tego czasu pomiary wielkości wymiany dwutlenku węgla między powierzchnią ziemi a atmosferą znacznie zyskały na znaczeniu. Obserwacje wielkości wymiany CO2 (Fc) mogą być realizowane przy pomocy różnych technik, jednak ostatnimi czasy popularność zyskuje metoda kowariancji wirów (eddy covariance - EC). Polega ona na pomiarach fluktuacji stężenia CO2 oraz pionowej składowej prędkości wiatru. W Europie ustanowiona została sieć kilkudziesięciu stacji pomiarowych monitorujących Fc w ramach zintegrowanego projektu badawczego CARBOEUROPE IP. Stacja pomiarowa w Rzecinie stanowi element tej sieci a pomiary Fc wykonywane są nad powierzchnią torfowiska w Rzecinie (70 km na północny zachód od Poznania) od końca 2003 roku. Celem proponowanego seminarium jest opis budowy, działania systemu pomiarowego oraz analiza wyników pomiarów w Rzecinie w latach 2004-2006.
room 17 budynku przy Pasteura 7, at 13:15

dr hab. Wojciech Grabowski (NCAR, Boulder, Colorado, USA)
Cloud-resolving modeling, also known as cumulus ensemble modeling or cloud-system-resolving modeling, refers to an approach where cloud dynamics and microphysics are explicitly represented, in contrast to the situation where they are parameterized as in climate and weather prediction models. Cloud-resolving models are nonhydrostatic small-scale models, and when applied to deep convection they use horizontal gridlengths in the range of 1 to 3 km (thus are really convection-permitting, not cloud-resolving). In this lecture, I will briefly review the design of such models, present some examples of their applications, and review progress in their application to the climate research through the super-parameterization approach and global cloud-resolving modeling.