High road-surface temperature due to heat waves can lead to dangerous driving conditions such as tire blowouts and deformation induced by thermal stress on the roads. In this study, a Mobile Observation Vehicle dataset, with high spatial and temporal resolutions for the heat-wave episode that occurred on 16-17 August 2018, is used to understand environmental characteristics on urban road-surface and air temperatures in Seoul. This study demonstrates that the magnitude of urban road-surface temperature is dependent on the differences in incoming solar radiation due to screening of high-rise buildings in the Gangnam area, and is associated with the topographical features in the Gangbuk area. The road-surface temperature in the section of darker-colored asphalts was higher than that of lighter-colored asphalts, with a mean difference of 6.8°C, and both surface and air temperatures on the iron plate were highest, with means of 51.7°C and 35.1°C, respectively. In addition, during the water-sprinkling period, road-surface temperature was cooled by about 8.7°C (19%) compared with that in the period without water-sprinkling, but there was no significant change in air temperature. The current results could be practically used to improve roadsurface temperature prediction models for civil engineers or road managers.

The northwestern part of the East/Japan Sea (EJS) is a region with large sea surface temperature (SST) variability and is known as a hotspot of marine heatwaves (MHW) stress for marine environments that peaked in boreal winter (January-February-March). This could have profound impacts on the marine ecosystems over the EJS. Here, we used a set of high-resolution satellite and reanalysis products to systematically analyze the spatiotemporal SST variations and examine their linkage to a large-scale mode of climate variability, such as the Arctic Oscillation (AO). The results show that AO-related wind forcing modulates the SST variability over the EJS via the oceanic dynamic adjustment processes. In particular, the abnormally warm SSTs in the northwestern part of the EJS are driven by the anomalous anticyclonic eddy-like circulation and Ekman downwelling during a positive AO phase. This physical linkage between a positive AO and the abnormally warm SST could be conducive to MHW occurrences in the EJS as in the extremely positive AO event during the winter of 2020. These results have implications that the MHW occurrences in the EJS could be amplified by natural climate variability along with long-term SST warming.

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In this study, we used an intensive observation dataset of a mobile observation vehicle (MOVE) to investigate the characteristics of thermal environments and diurnal variations of road surface temperature (RST) and air temperature, particularly at the urban street level, during the 2019 Building Block 3-dimensional urban Meteorological Experiment (BBMEX) campaign in Seoul. For the purpose of comparing characteristics of RST and air temperature with different surrounding thermal environments, we divided the road into four sections (S1: Open Section, S2: High-Rise Buildings, S3: Low-Rise Buildings, S4: Street Trees). This study demonstrates that the greater sky view factors (SVFs) are generally coincident with the greater RSTs, with a significance at the 5% level. The diurnal variations indicated that the time lag between observed maximum air temperature and RST has about one hour, which is attributable to an increase air temperatures above artificial pavement through heat convection with some latency. The diurnal temperature ranges (DTRs) of RST in S2 and S4 were relatively smaller than those of S1 and S3, with differences ranging from 2.9 °C to 4.5 °C. The current results will assist planners and decision makers in determining policy priorities with regard to urban street design and planning.

Ejector is an equipment devised for making use of the low pressure occurring from the fast fluid injection and it is a transportation equipment which can obtain vacuum using the kinetic energy of the fluid. This ejector system is, nowadays, widely used for construction machinery, heavy equipments, the cooling and ventilation of electronic devices and for the various fluid transportation and pumps.In this study, it is attempted to perform a numerical analysis and an experiment to find out the characteristics of fluid quantity, velocity and the pressure distribution of the induction pipe by changing the length and the radius ratio of the nozzle of ejector .From the results, it is investigated that the distributions of velocity and pressure of induction pipe attached are changing with the length and the radius ratio of the nozzle. In addition, it is shown that for the small and large ejector, the efficiency is the maximum when the length of the nozzle arrived to the neck of the ejector, however, if it is installed at below or above the neck the efficiency is rather decreased . † †