Fast radiative cooling of polycyclic aromatic hydrocarbon (PAH) was studied by probing the time evolution of the internal energy distribution of hot molecular ensembles in the ms range. Anthracene cations (C14H10) prepared in an electron cyclotron resonance ion source were stored in an electrostatic storage ring, the Mini-Ring [1]. The experiment showed that in the first milliseconds, the time ...

Satellite measurements and numerical forecast model reanalysis data are used to compute an updated estimate of the cloud radiative effect on the global multi-annual mean radiative energy budget of the atmosphere and surface. The cloud radiative cooling effect through reflection of short wave radiation dominates over the long wave heating effect, resulting in a net cooling of the climate system ...

The contraction processes of metal-free molecular clouds of starlike mass (or cloud cores) are investigated. We calculate radiative transfer of the H2 lines and examine quasi-static contraction with radiative cooling. Comparing two time-scales, the free-fall time tff and the time-scale of quasi-static contraction tqsc (∼ tcool, the cooling time) of these cores, we find that the ratio of the two...

Recent cloud-resolving numerical modeling results suggest that radiative forcing causes accelerated rates of tropical cyclogenesis and early intensification. Furthermore, observational studies of tropical cyclones have found that oscillations of the cloud canopy areal extent often occur that are clearly related to the solar diurnal cycle. A theory is put forward to explain these findings. The p...

Daytime radiative cooling has attracted extensive research interest due to its potential impact for energy sustainability. To achieve subambient during the daytime, a white surface that strongly scatters incident solar light is normally desired. However, in many practical applications (e.g., roofing materials and car coatings), colored surfaces are more popular. Because of this, there strong de...

Clouds forming during the summer monsoon over the Indian subcontinent affect its evolution through their radiative impact as well as the release of latent heat. While the latter is previously studied to some extent, comparatively little is known about the radiative impact of different cloud types and the vertical structure of their radiative heating/cooling effects. Therefore, the main aim of t...

The gas temperature in the cores of many clusters of galaxies drops inward by about a factor of three or more within the central 100 kpc radius. The radiative cooling time drops over the same region from 5 or more Gyr down to about 10 8 yr. Although it would seem that cooling has taken place, XMM and Chandra spectra show no evidence for strong mass cooling rates of gas below 1–2 keV. Chandra im...

We study steady, homogeneous and subsonic cooling flows in poor clusters of galaxies in light of the recent proposal that radiative cooling of the intracluster gas can explain the observations of the ‘entropy floor’ and other related X-ray observations. We study a family of cooling flow solutions parameterized by the mass flux rate, and then determine the resulting entropy and the X-ray luminos...

Passive radiative cooling has recently received renewed interest because of its unprecedented capabilities in terrestrial objects below ambient air temperature without external energy consumption and greenhouse gas emission. This technology been demonstrated as promising replacements/complements conventional compressed air-based active systems, which can significantly impact the global landscap...