ترغب بنشر مسار تعليمي؟ اضغط هنا

Atmospheric instability as a loss of a metastable equilibrium

44   0   0.0 ( 0 )
 نشر من قبل Yuri Kornyushin
 تاريخ النشر 2012
  مجال البحث فيزياء
والبحث باللغة English
 تأليف Yuri Kornyushin




اسأل ChatGPT حول البحث

General thermodynamic theory of metastable states is used in this short note to try to understand better atmospheric instabilities. It is shown that not only cooling of a cloud can lead to rain, but heating also, especially when there are charged water drops in a cloud (in this case we have rain with lightning). The influence of the global warming on weather is discussed.

قيم البحث

اقرأ أيضاً

The stability properties of intermediate-order climate models are investigated by computing their Lyapunov exponents (LEs). The two models considered are PUMA (Portable University Model of the Atmosphere), a primitive-equation simple general circulat ion model, and MAOOAM (Modular Arbitrary-Order Ocean-Atmosphere Model), a quasi-geostrophic coupled ocean-atmosphere model on a beta-plane. We wish to investigate the effect of the different levels of filtering on the instabilities and dynamics of the atmospheric flows. Moreover, we assess the impact of the oceanic coupling, the dissipation scheme and the resolution on the spectra of LEs. The PUMA Lyapunov spectrum is computed for two different values of the meridional temperature gradient defining the Newtonian forcing. The increase of the gradient gives rise to a higher baroclinicity and stronger instabilities, corresponding to a larger dimension of the unstable manifold and a larger first LE. The convergence rate of the rate functional for the large deviation law of the finite-time Lyapunov exponents (FTLEs) is fast for all exponents, which can be interpreted as resulting from the absence of a clear-cut atmospheric time-scale separation in such a model. The MAOOAM spectra show that the dominant atmospheric instability is correctly represented even at low resolutions. However, the dynamics of the central manifold, which is mostly associated to the ocean dynamics, is not fully resolved because of its associated long time scales, even at intermediate orders. This paper highlights the need to investigate the natural variability of the atmosphere-ocean coupled dynamics by associating rate of growth and decay of perturbations to the physical modes described using the formalism of the covariant Lyapunov vectors and to consider long integrations in order to disentangle the dynamical processes occurring at all time scales.
We investigate a chain of spinless fermions with nearest-neighbour interactions that are subject to a local loss process. We determine the time evolution of the system using matrix product state methods. We find that at intermediate times a metastabl e state is formed, which has very different properties than usual equilibrium states. In particular, in a region around the loss, the filling is reduced, while Friedel oscillations with a period corresponding to the original filling continue to exist. The associated momentum distribution is emptied at all momenta by the loss process and the Fermi edge remains approximately at its original value. Even in the presence of strong interactions, where a redistribution by the scattering is naively expected, such a regime can exist over a long time-scale. Additionally, we point out the existence a system.
We present a combined experimental and theoretical study on the radiative lifetime of CO in the $a^3Pi_{1,2}, v=0$ state. CO molecules in a beam are prepared in selected rotational levels of this metastable state, Stark-decelerated and electrostatica lly trapped. From the phosphorescence decay in the trap, the radiative lifetime is measured to be $2.63pm0.03$ ms for the $a^3Pi_1, v=0, J=1$ level. From spin-orbit coupling between the $a^3Pi$ and the $A^1Pi$ state a 20% longer radiative lifetime of 3.16 ms is calculated for this level. It is concluded that coupling to other $^1Pi$ states contributes to the observed phosphorescence rate of metastable CO.
We identified and computed the horizontal wavelengths of atmospheric gravity waves in clouds using a visible camera installed on a window of the Columbus module of the International Space Station (ISS) and controlled by a Raspberry Pi computer. The e xperiment was designed in the context of the Astro Pi challenge, a project run by ESA in collaboration with the Raspberry Pi Foundation, where students are allowed the opportunity to write a code to be executed at the ISS. A code was developed to maximize the probability of capturing images of clouds while the ISS is orbiting the Earth. Several constraints had to be fulfilled such as the experiment duration limit (3 hours) and the maximum data size (3 gigabytes). After receiving the data from the ISS, small-scale gravity waves were observed in different regions in the northern hemisphere with horizontal wavelengths in the range of 1.0 to 4.7 km.
We report on the Stark deceleration and electrostatic trapping of $^{14}$NH ($a ^1Delta$) radicals. In the trap, the molecules are excited on the spin-forbidden $A ^3Pi leftarrow a ^1Delta$ transition and detected via their subsequent fluorescence to the $X ^3Sigma^-$ ground state. The 1/e trapping time is 1.4 $pm$ 0.1 s, from which a lower limit of 2.7 s for the radiative lifetime of the $a ^1Delta, v=0,J=2$ state is deduced. The spectral profile of the molecules in the trapping field is measured to probe their spatial distribution. Electrostatic trapping of metastable NH followed by optical pumping of the trapped molecules to the electronic ground state is an important step towards accumulation of these radicals in a magnetic trap.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا