Probing quark gluon plasma with jets

We study multiple scatterings of jets on constituents of quark gluon plasma and introduce energy--energy correlations to quantify their effects. The effects from a longitudinally expanding plasma on medium as well as high energy jets are found to be significant at both RHIC and LHC energies. Because jets escape from the plasma long before the completion of mixed phase, these effects are free from complications of final state hadronic interactions and decays. These suggest that jets can be used to probe the plasma that might be created in future high energy heavy ion collisions.Comment: 15 pages, 6 figures in 5 ps files included, McGill/94-1

Analysis trends of ultraviolet B fluxes in the continental US with USDA and TOMS data

Many environmental factors, such as stratospheric ozone, aerosols, and clouds, may affect ultraviolet (UV) irradiance. The aim of this study was to investigate the possible association between ultraviolet B (UVB) radiation and total cloud amount, ozone, and aerosols simultaneously, leading to the assessment of possible impacts of climate change on UVB flux variations in the Continental United States (US). Findings indicate that in the past 22 years, while ozone decreased and aerosols increased across the US, the UVB decrease in the northern states was consistent with the increase in aerosols and total cloud amount. Climate change impact resulting in higher total cloud amount in the northern states might result in lower UVB in the future. © Copyright 2013 SPIE

Evapotranspiration analysis based on topography algorithm in the Yellow River Delta

A remote sensing regional evapotranspiration (ET) model was built on the basis of topography correction (slope, aspect and elevation), herein. A variety of satellite data which have visible, near-infrared and thermal infrared remote sensing data can be used by this improved model. Combined with conventional ground meteorological information, it can estimate regional distribution of ET under different climate and terrain conditions, expanding the scope of application. Taking into account the terrain factors, we modified the algorithm of SEBAL model. Results showed that, the modified inversion method of evapotranspiration can better reflect actual evapotranspiration condition. Evapotranspiration changes were consistent with land use types. This research indicates that application of medium or high resolution satellite data to calculate regional ET under undulating landform should consider the impact of terrain. It improves the accuracy of ET estimates and has important reference value for the work of the regional water balance and regional agricultural climate research. © Copyright 2013 SPIE

Concomitant flow and space variations of evapotranspiration due to changes in LUCC under seawater intrusion in a coastal region

This paper provides a coherent pattern identification analysis of coastal land use and land cover (LULC) under the impact of seawater intrusion. This study analysis applied the 4-, 3-, and 2-band false color composite Landsat satellite data to characterize the LULC in the study area. The evapotranspiration (ET) and heat fluxes were estimated by using the SEBAL model with two-time phase thermal infrared band images and regional surface parameters. Our findings are as follows: 1) Due to its distance from the sea, the vegetation index gradually increases as the level of land use gradually increased. 2) The different influences of seawater intrusion in the study area resulted in significantly different influences of land surface parameters (LST, Gn, MSAVI, and Uindex) on ET. There are a variety of types of relational patterns between parameters (LST, Gn, MSAVI and Uindex) and ET (positive, negative, and no relationship). 3) Seawater intrusion significantly affected the spatial pattern of LUCC, which evidently affected the spatial distribution of ET. The spatial distribution pattern and change characteristics of ET were formed by double driving forces of seawater intrusion and LUCC under the background effects of regional climate. © Copyright 2013 SPIE