Effect of snow-covered ground albedo on the accuracy of air temperature measurements

open8Solar radiation is one of the main factors which introduce significant deviations between thermometers reading and true air temperature value. Techniques to protect the sensors from direct radiative influence have been adopted almost since the beginning of meteorological observations. Reflected radiation from a snow-covered surface can also cause extra warming to thermometers hosted in solar shields, which are not always optimised to protect the sensors from this further radiative heat transfer. This phenomenon can cause errors in near-surface temperature measurements results, with a relevant impact on the quality of data records and series. This study experimentally evaluates the effect of reflected radiation from a snow-covered surface on the accuracy of air temperature measurements. The investigation is based on the evaluation of temperature differences between pairs of identical instruments, positioned above ground covered by natural vegetation, with one instrument in snow-free conditions and the other above a snow-covered surface, at the same time and at the same site. The work involved a representative number of sensors and shields, in terms of different typologies, technologies and engineering solutions, from different manufacturers. A mountain site with acceptable field conditions, offering long-lasting snow presence to maximise data availability, was selected to perform the experiment. Quantities of influence, such as relative humidity, wind speed and direction and solar radiation (global and reflected), were constantly measured. The main findings of this work show that none of the involved instruments were immune to the extra heating due to the snow-reflected radiation. Excluding nighttimes and days of high wind or low incident radiation, the differences among sensors positioned above natural soil and identical ones exposed to snow albedo ranged up to more than 3 ∘C. Solar screens with forced ventilation showed a partially reduced effect compared to most of the naturally ventilated ones. A full data analysis is reported here, together with complete results and uncertainties.openhttps://doi.org/10.5281/zenodo.5126973Musacchio, Chiara; Coppa, Graziano; Begeš, Gaber; Hofstätter-Mohler, Christina; Massano, Laura; Nigrelli, Guido; Sanna, Francesca; Merlone, AndreaMusacchio, Chiara; Coppa, Graziano; Begeš, Gaber; Hofstätter-Mohler, Christina; Massano, Laura; Nigrelli, Guido; Sanna, Francesca; Merlone, Andre

Attitudes toward westbound refugees in the East German press

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67107/2/10.1177_002200277001400303.pd

Nuclear Clusters as a Probe for Expansion Flow in Heavy Ion Reactions at 10-15AGeV

A phase space coalescence description based on the Wigner-function method for cluster formation in relativistic nucleus-nucleus collisions is presented. The momentum distributions of nuclear clusters d,t and He are predicted for central Au(11.6AGeV)Au and Si(14.6AGeV)Si reactions in the framework of the RQMD transport approach. Transverse expansion leads to a strong shoulder-arm shape and different inverse slope parameters in the transverse spectra of nuclear clusters deviating markedly from thermal distributions. A clear ``bounce-off'' event shape is seen: the averaged transverse flow velocities in the reaction plane are for clusters larger than for protons. The cluster yields --particularly at low $p_t$ at midrapidities-- and the in-plane (anti)flow of clusters and pions change if suitably strong baryon potential interactions are included. This allows to study the transient pressure at high density via the event shape analysis of nucleons, nucleon clusters and other hadrons.Comment: 38 pages, 9 figures, LaTeX type, eps used, subm. to Phys. Rev.

Active Suppression Induced by Repetitive Self-Epitopes Protects against EAE Development

10.1371/journal.pone.0064888PLoS ONE85e6488