Abstract

Evaluation and projection of temperature extremes over China are carried out with 8 model datasets from CMIP5. Compared with the NCEP reanalysis data, multi-model weighted ensemble is capable of reproducing the 8 temperature extreme indices and 20-year return values of annual maximum/minimum temperatures. The time correlation coefficients of all the 8 indices between multi-model ensemble and the reanalysis can reach a significance level of 0.10. The spatial correlation coefficient of 20-year return level of annual maximum/minimum temperatures is greater than 0.98. Under the RCP4.5 scenario, more extreme warm events and less cold events are expected over China in multi-model ensemble. By the middle of the 21st century, the heat wave duration index will be multiplied 2.6 times. At the end of the 21st century, the cold wave duration index will decrease 71%, and the 20-year return value will increase 4°C in parts of China for the maximum/minimum temperatures. Yao, Y., Y. Luo, J.-B. Huang, 2012: Evaluation and projection of temperature extremes over China based on CMIP5 model. Adv. Clim. Change Res., 3 (4), doi: 10.3724/SP.J.1248.2012.00179.

Abstract

There is an increasing interest in using new lighting technologies such as light emitting diode (LED), induction, and plasma light sources in roadway lighting. The most commonly claimed benefits of the new lighting systems include increased reliability, improved efficiency, and reduced maintenance costs. While Indiana Department of Transportation (INDOT) is also getting a lot of interest from vendors pushing the new light sources for roadway lighting applications, none of these new lighting technologies has been used in the state highway systems by INDOT. Before adopting the new lighting technologies, INDOT would like to determine if the new lighting technologies meet required light output and if they are cost effective. Moreover, it is necessary for INDOT to establish standardized guidelines for evaluating the new lighting systems prior to the formal adoption. This study first conducted literature reviews on the new lighting technologies. Surveys were also conducted to identify the perceptions of state highway agencies and local cities towards the new lighting technologies including LED, induction, and plasma, and their experiences in use of these new lighting technologies. Various luminaires, including high pressure sodium (HPS), LED, plasma, and induction luminaires from different manufacturers were installed and evaluated for both conventional and high mast lightings at a test site over a period of 12 months. Illuminance measurements were made to determine the light levels and illuminance uniformities produced by those LED, plasma and induction luminaires with the existing lighting infrastructures. Comparisons were also made between the light performances produced by different luminaires. Electric currents were measured to determine the energy consumptions by different luminaires. Life cycle cost analysis was also conducted to determine if the new lighting sources are cost-effective compared to the corresponding HPS lighting sources and assess the possible return or payback periods for the LED, plasma, and induction luminaires evaluated in this study. Illuminance measurements were also made for two urban street lightings to map the light performances of LED and plasma luminaires with different lighting layouts. Main findings and recommendations were made to assist INDOT Traffic Engineering in upgrading the lighting policies and developing technical specifications for adopting the new lighting technologies.