[1] The Syabru-Bensi hot springs are located at the Main Central Thrust (MCT) zone in central Nepal. High carbon dioxide and radon exhalation fluxes (reaching 19 kg m À2 d À1and 5 Bq m À2 s À1, respectively) are associated with these hot springs, making this site a promising case to study the relationship between self-potential and fluids (gas and water) exhalation along a fault zone. A high-resolution self-potential map, covering an area of 100 m by 150 m that surrounds the main gas and water discharge spots, exhibits a dipolar self-potential anomaly with a negative peak reaching À180 mV at the main gas discharge spot. The positive lobe of the anomaly reaching 120 mV is located along the terraces above the main gas and water discharge spots. Several electrical resistivity tomograms were performed in this area. The resistivity tomogram crossing the degassing area shows a dipping resistive channel interpreted as a fracture zone channeling the gas and the hot water. We propose a numerical finite difference model to simulate the flow pattern in this area with the constraints imposed by the electrical resistivity tomograms, the self-potential data, the position of the gas vents, and hot water discharge area. This study provides insights on the generation of electrical currents associated with geothermal circulation in a geodynamically active area, a necessary prerequisite to study, using self-potentials, a possible modulation of the geothermal circulation by tectonic activity.

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Nepal has approximately 1000 operational brick kilns, which contribute significantly to ambient air pollution. They also account for 1.81% of the total bricks produced in the South Asian region. Little is known about their emissions, which are consequently not represented in regional/global emission inventories. This study compared emissions from seven brick kilns. Four were Fixed Chimney Bull’s Trench Kilns (FCBTKs) and three were Induced-Draught Zigzag Kilns (IDZKs). The concentrations of carbon dioxide (CO2), sulfur dioxide (SO2), black carbon (BC), and particulate matter (PM) with a diameter less than 2.5 µm (PM2.5) were measured. The respective emission factors (EFs) were estimated using the carbon mass balance method. The average fuel-based EF for CO2, SO2, PM2.5, and BC were estimated as 1633 ± 134, 22 ± 22, 3.8 ± 2.6 and 0.6 ± 0.2 g per kg, respectively, for all FCBTKs. Those for IDZKs were 1981 ± 232, 24 ± 22, 3.1 ± 1, and 0.4 ± 0.2 g per kg, respectively. Overall, the study found that converting the technology from straight-line kilns to zigzag kilns can reduce PM2.5 emissions by ~20% and BC emissions by ~30%, based on emission factor estimates of per kilogram of fuel. While considering per kilogram of fired brick, emission reductions were approximately 40% for PM2.5 and 55% for BC, but this definitely depends on proper stacking and firing procedures.

This study utilized the Weather Research and Forecasting (WRF) model version 3.5.1 to evaluate the impact of urbanization on summertime precipitation in Osaka, Japan. The evaluation was conducted by comparing the WRF simulations with the present land use and no-urban land use (replacing “Urban” with “Paddy”) for August from 2006 to 2010. The urbanization increased mean air temperature by 2.1°C in urban areas because of increased sensible heat flux and decreased mean humidity by 0.8 g kg−1because of decreased latent heat flux. In addition, the urbanization increased duration of the southwesterly sea breeze. The urbanization increased precipitation in urban areas and decreased in the surrounding areas. The mean precipitation in urban areas was increased by 20 mm month−1(27% of the total amount without the synoptic-scale precipitation). The precipitation increase was generally due to the enhancement of the formation and development of convective clouds by the increase in sensible heat flux during afternoon and evening time periods. The urbanization in Osaka changes spatial and temporal distribution patterns of precipitation and evaporation, and consequently it substantially affects the water cycle in and around the urban areas of Osaka.

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