Mechanism of The Summer Rainfall Variation in Transitional Climate Zone in East Asia From the Perspective of Moisture Supply During 1979-2010 Based On The Lagrangian Method

Transitional Climate Zone (TCZ) over East Asia, characterized by semi-arid climate, is ecologically fragile environment with limited water resources, making atmospheric moisture supply being the key influential factor. This study investigates the moisture sources of summer (JJA) rainfall in the TCZ over East Asia during 1979-2010 with the Lagrangian particle dispersion model. Seven moisture source regions and associated contribution are quantified: Eurasia continent to northwest of the TCZ (EC, 18.01%), central-eastern China (CEC, 17.14%), western Pacific Ocean (WPO, 7.46%), South China Sea and Indonesia (SCSI, 3.56%), Bay of Bengal (BOB, 2.55%), Arabian Sea (AS, 2.13%) and local evaporation (TCZ, 19.96%). The moisture contribution from ocean (16.06%) is less than those from the continent (55.11%), due to the great loss en-route. In particular, the local evaporation not only contributes the most moisture among 7 selected source regions, but also has the greatest influence in summer precipitation variability in TCZ. Furthermore, westerlies precipitation and monsoon precipitation are discriminated according to the dominant system of water vapor source regions. It is found that summer monsoon contributes most of water vapor (33.2%) to summer rainfall in TCZ, while only 18.01% comes from the mid-latitude westerlies dominant area. Finally, further analysis of dry and wet years shows that summer monsoon system also takes more responsibility for a drier or wetter summer in TCZ from the perspective of moisture supply, followed by local evaporation and mid-latitude westerlies.

Flexible IoT Gas Sensor Node for Automated Life Science Environments Using Stationary and Mobile Robots

In recent years the degree of automation in life science laboratories increased considerably by introducing stationary and mobile robots. This trend requires intensified considerations of the occupational safety for cooperating humans, since the robots operate with low volatile compounds that partially emit hazardous vapors, which especially do arise if accidents or leakages occur. For the fast detection of such or similar situations a modular IoT-sensor node was developed. The sensor node consists of four hardware layers, which can be configured individually regarding basic functionality and measured parameters for varying application focuses. In this paper the sensor node is equipped with two gas sensors (BME688, SGP30) for a continuous TVOC measurement. In investigations under controlled laboratory conditions the general sensors’ behavior regarding different VOCs and varying installation conditions are performed. In practical investigations the sensor node’s integration into simple laboratory applications using stationary and mobile robots is shown and examined. The investigation results show that the selected sensors are suitable for the early detection of solvent vapors in life science laboratories. The sensor response and thus the system’s applicability depends on the used compounds, the distance between sensor node and vapor source as well as the speed of the automation systems.

Zn diffusion technology for InP-InGaAs avalanche photodiodes

This paper presents a study of Zn diffusion process into InP and InGaAs/InP epitaxial heterostructures grown by molecular beam epitaxy. It was found that both diffusion systems: a resistively heated quartz reactor with a solid-state Zn vapor source placed inside and hydrogen or nitrogen as the carrier gas and MOCVD reactor with hydrogen as the carrier gas allow achieving similar dopant concentration above 2*10e18 cm-3. The depth of the diffusion front in the InP layer is located from 2 to 3.5 μm depending on the temperature and time of the diffusion process. The diffusion of Zn into InP through the intermediate InGaAs layer provides better surface quality comparing with direct zinc diffusion into InP surface.

The Significance of Hydrogen and Oxygen Stable Isotopes in the Water Vapor Source in Dingxi Area

Deuterium excess and stable oxygen isotopes in precipitation have been widely applied to trace the source of water vapor. In this study, hydrogen and oxygen isotope analyses of samples were collected on seven sampling stations in Dingxi area from April 2019 to April 2020. The seasonal variation of hydrogen and oxygen stable isotopes as well as the d-excess indicate that the source of water vapor in Dingxi area is mostly from a single source. However, there are different sources of water vapor in the summer. Meanwhile, water vapor sources were analyzed using the Lagrange algorithm, indicating two different principal water vapor sources for precipitation in the area: some locally recycled water vapor in summer and autumn, and most water vapor from the westerly belt. Further studies using the PSCF and CWT analysis methods show that the locally recycled water vapor contributes more to its precipitation in the northwest of Dingxi area.

Holocene hydroclimate changes in continental Croatia recorded in speleothem δ13C and δ18O from Nova Grgosova Cave

We present the first stable isotope (δ13C and δ18O) speleothem record from continental Croatia retrieved from two coeval stalagmites from Nova Grgosova Cave. U-Th dates constrain the stalagmite growth history from 10 ka to the present, revealing coeval growth between 7.8 and 5.6 ka. We interpret δ18O as an autumn/winter hydrological proxy related to changes of vapor source, precipitation amount, and/or seasonal rainfall distribution, while δ13C predominantly responds to spring/summer vegetation status and soil microbial activity. We identify several centennial to millennial-scale hydroclimate oscillations during this period that result from multiple forcing factors. Along with amount and source effect, it appears that some centennial variations were governed also by seasonal moisture balance. From 9.2 to 8.8 ka BP, the local environmental setting was characterized by enhanced vegetation activity, while during the 8.2 ka event the main feature was a change in precipitation seasonality. The most prominent change, identified in both δ13C records, is a sudden decline of vegetation and soil biological activity around 7.4 ka, indicating a precipitation decrease at a time of maximum plant growth in spring and summer and likely also reduced precipitation in autumn and winter. Although small in magnitude in these speleothems, a peak in δ18O and δ13C values at 4.3–4.1 ka suggests that both summer and winter conditions were substantially drier during the 4.2 ka event, in accordance with increased Mediterranean aridity and consistent with other global climate changes reported at this time. Compared to the present North Atlantic Oscillation (NAO) influence, we assume that millennial Holocene NAO-like variations were persistent through the Holocene via their effect on modifying local/regional air temperature, vapor origin, and inter- and intrannual precipitation distribution. Anthropogenic deforestation, which was the first major human impact on the environment during the Neolithic agricultural revolution, is excluded as a leading factor in δ13C variability since the first sedentary settlements were established further to the east in more arable locations along river valleys. However, the impact of intensive mining around the cave site during the last millennium is evident, with substantial deforestation driving an increase in δ13C.

Isotopic and Hydrochemical Study of Groundwater in an Area Between the Lesser Zab and Tigris River, Northern Iraq

Stable isotopes (2H, 18O) in the water cycle can carry all the information about the movement of water molecules, their ratio different from one place to another in rainfall. Stable isotopes are the function of evaporation, relative humidity, temperature and different longitude, latitude and altitude. On this base. A total of 28 water sample (20 samples were analyzed for major ions and 8 samples for stable isotopes) were collected for two periods to study the origin and the type of groundwater in the area between Lesser Zab and the Tigris river The Results indicated that groundwater samples in the study area are brackish saline water and excessively mineralized water. The average groundwater was classified as Mg-Na-Calcium: Cl-Sulfate for two periods. The groundwater samples represent earth alkali with privilege sulfate and chloride according to the piper diagram. The mean values of 18H and 2O in the groundwater sample are -27.7 and -4.9, respectively for the dry period, and -29.8 and -5.2, respectively, for the wet period. The d-excess varies significantly depending on the humidity and temperature at the vapor source. Isotopic analysis of 2H -18O for groundwater in the study area shows that the origin of groundwater in the study area is of meteoric origin from global source and rain from a local source. The downward shifting of the regression line on the 2H-18O diagram indicates that the samples have undergone evaporation events.

δ2H and δ18O in Precipitation and Water Vapor Disentangle Seasonal Wind Directions on the Loess Plateau

In many areas of the Loess Plateau, groundwater is too deep to extract, making meteoric water (snow and rain) the only viable water resource. Here we traced the rainwater and water vapor sources using the δ2H and δ18O signature of precipitation in the northern mountainous region of Yuzhong on the Loess Plateau. The local meteoric water line in 2016 and 2017 was defined as δ2H = 6.8 (±0.3)∙δ18O + 4.4 (±2.0) and δ2H = 7.1 (±0.2)∙δ18O + 1.5 (±1.6), respectively. The temperature and precipitation amount are considered to be the main factor controlling the δ2H and δ18O variation of precipitation, and consequently, relationships were first explored between δ18O and local surface air temperature and precipitation amount by linear regression analysis. The temperature effect was significant in the wet seasons but was irrelevant in the dry seasons on daily and seasonal scales. The amount effect was significant in the wet seasons on a daily scale but irrelevant in the dry seasons. However, based on the data of the Global Network of Isotopes in Precipitation (GNIP) (1985–1987, 1996–1999) of Lanzhou weather station, the amount effects were absent at seasonal scales and were not useful to discriminate either wetter or drier seasons or even wetter or drier decades. Over the whole year, the resulting air mass trajectories were consistent with the main sources of water vapor were from the Atlantic Ocean via westerlies and from the Arctic region, with 46%, 64%, and 40% of water vapor coming from the westerlies, and 54%, 36%, and 60% water vapor from the north in spring, autumn and winter, respectively. In the summer, however, the southeast monsoon (21%) was also an important water vapor source in the Loess Plateau. Concluding, using the δ2H and δ18O signatures of precipitation water, we disentangled and quantified the seasonal wind directions that are important for the prediction of water resources for local and regional land use.

Effects of Plasma and Evaporated Atoms on the Spatial Distribution of Coating Film Thickness for Electron Beam-Induced Material Evaporation

This paper investigates the spatial distributions of electron beam-evaporated atoms and electron beam-induced plasma in the coating process. The materials evaporated by electron beams first form vapour and then a little of plasma is generated in the vapour. The spatial distributions of electron beam-induced atoms and plasma play an important role on the coating uniformity of composition and thickness. The radial distribution of coating deposition thickness of electron beam-evaporated atoms predicted by this study agrees with the available experimental data. The predicted distribution of ion density in the electron beam-induced plasma agrees with the available measured data. The results reveal that the normalized coating thicknesses at the divergence angle of 6 and 14 degrees of vapor source, respectively, are 0.8 and 0.2 of these at divergence angle of 0 degree of vapor source for titanium and aluminum evaporated separately. The similar tendency for the decreasing coating thickness with the radial distance is also obtained for the co-evaporation of aluminum, titanium, and copper. High rotation rate of substrate of vapor source leads to the small deposition rate. Most ions in the electron beam-induced plasma are attracted by electrons of the electon beam and are located at the neighbourhood of the beam region. Therefore, the ion and ion-attracted electron densities rapidly decrease with the increasing radial distance from the electron beam.