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Abstract. The monthly standardized precipitation evapotranspiration index (SPEI) can be used to monitor and assess drought characteristics with 1-month or longer drought duration. Based on data from 1961 to 2018 at 427 meteorological stations across mainland China, we developed a daily SPEI dataset to overcome the shortcoming of the coarse temporal scale of monthly SPEI. Our dataset not only can be used to identify the start and end dates of drought events, but also can be used to investigate the meteorological, agricultural, hydrological, and socioeconomic droughts with a different timescales. In the present study, the SPEI data with 3-month (about 90 d) timescale were taken as a demonstration example to analyze spatial distribution and temporal changes in drought conditions for mainland China. The SPEI data with a 3-month (about 90 d) timescale showed no obvious intensifying trends in terms of severity, duration, and frequency of drought events from 1961 to 2018. Our drought dataset serves as a unique resource with daily resolution to a variety of research communities including meteorology, geography, and natural hazard studies. The daily SPEI dataset developed is free, open, and publicly available from this study. The dataset with daily SPEI is publicly available via the figshare portal (Wang et al., 2020c), with https://doi.org/10.6084/m9.figshare.12568280.Highlights. A multi-scale daily SPEI dataset was developed across mainland China from 1961 to 2018. The daily SPEI dataset can be used to identify the start and end days of the drought event. The developed daily SPEI dataset in this study is free, open, and publicly available.

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Rolling element bearing fault diagnostics has been a topic of intensive research.As the rolling element bearings are a critical component of rotating machinery, failure of these components results in the breakdown of the mechanical structure in which they operate. The correct detection of incipient faults on the bearings can reduce the production cost by allowing maintenance engineers to schedule a replacement at the most convenient time. Envelope analysis is a widespread method in bearing diagnostics, where the frequency band that carries the fault information is detected and amplitude demodulated to obtain the envelope, whose spectrum reveals the repetition frequencies of the particular fault. It is often used along with Fast Kurtogram, which selects this band based on the kurtosis level. However, this methodology shows difficulty in selecting the correct band on complex signals. Signals contaminated with Electro-Magnetic Interference (EMI) are one such example where Envelope Analysis based on the Fast Kurtogram (FK) often fails to diagnose bearing faults. EMI is often present in mechanisms whose motor is controlled by a Variable-Frequency Drive (VFD), and shows a behaviour similar to that of bearing faults, and thus increases the

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This paper proposes a flow-path network (FPN) model to simulate complex surface flow based on a drainage-constrained triangulated irregular network (TIN). The TIN was constructed using critical points and drainage lines extracted from a digital terrain surface. Runoff generated on the surface was simplified as 'water volumes' at constrained random points that were then used as the starting points of flow paths (i.e. flow source points). The flow-path for each 'water volume' was constructed by tracing the direction of flow from the flow source point over the TIN surface to the stream system and then to the outlet of the watershed. The FPN was represented by a set of topologically defined one-dimensional line segments and nodes. Hydrologic variables, such as flow velocity and volume, were computed and integrated into the FPN to support dynamic surface flow simulation. A hypothetical rainfall event simulation on a hilly landscape showed that the FPN model was able to simulate the dynamics of surface flow over time. A real-world catchment test demonstrated that flow rates predicted by the FPN model agreed well with field observations. Overall, the FPN model proposed in this study provides a vector-based modeling framework for simulating surface flow dynamics. Further studies are required to enhance the simulations of individual hydrologic processes such as flow generation and overland and channel flows, which were much simplified in this study.