Temporal and spatial variations in the sub-daily precipitation structure over the Qinghai-Tibet Plateau (QTP).

Precipitation is a vital component of the global atmospheric and hydrological cycles and influencing the distribution of water resources. Even subtle changes in precipitation can significantly impact ecosystems, energy cycles, agricultural production, and food security. Therefore, understanding the changes in the precipitation structure under climate change is essential. The Qinghai-Tibet Plateau (QTP) is a region sensitive to global climate change and profoundly impacts the atmospheric water cycle in Asia and even globally, rendering it a hot topic in climate change research in recent years. Few studies have examined on the sub-daily scale precipitation structure over the QTP. In this paper, the characteristics of sub-daily precipitation on the QTP were systematically investigated from multiple perspectives, including the concentration index, skewness (the third standardized moment of a distribution), and kurtosis (the fourth standardized moment of a distribution). The results indicated that the frequency of moderate-intensity nighttime precipitation on the QTP generally increased, and the analysis of both the concentration index and kurtosis (skewness) suggested that extreme precipitation was more frequent in the southwestern foothills of the QTP. Furthermore, potential high-risk areas for natural disasters were identified on the QTP, and found that the southeastern part of the plateau constituted a potential hotspot area for flood disasters. Given the complexity of climate change, a comprehensive analysis of the spatiotemporal characteristics of diurnal and nighttime precipitation changes on the QTP could help reveal the regularity of precipitation changes. This has significant implications for forecasting, warning, disaster preparedness, and mitigation efforts on the QTP.

Intelligent monitoring of water quality based on image analytics.

Owing to the limitations of the spatial arrangement of monitoring stations and time acquisition of satellite remote sensing images, the water quality monitoring of rivers, especially small- and medium-sized rivers, cannot be satisfied in terms of time and space continuity. In this study, we propose a standardization method for the camera images derived at different locations on different time considering the influences of light, shadows, reflections, ripples, leaves and so on. After this algorithm is established, an estimation algorithm based on the comprehensive appearance of water body is proposed, which has the potential of realising real-time, mobile, and continuous monitoring of water quality with low costs. The test results showed that the accuracy of the model was quite high compared to the results of the hydrological monitoring stations. Compared with the single-point detection of water quality monitoring stations, this method has advantages in terms of dynamic detection and small- andmedium-sized water body detection, which can serve as a supplement to traditional detection.

Zoning of precipitation regimes on the Qinghai-Tibet Plateau and its surrounding areas responded by the vegetation distribution.

Compared with other factors influencing vegetation patterns, such as light and temperature, precipitation has relatively large variability, especially on the Qinghai-Tibet Plateau (QTP), where the natural environment is extremely fragile and sensitive. However, the impact of precipitation regimes, rather than precipitation amount, on vegetation has seldom been revealed. This study characterised the precipitation regimes by both the amount and temporal distribution of precipitation and zoned the QTP as different precipitation regimes accordingly. The response of vegetation to such precipitation regimes was then investigated. The results indicate that the vegetation patterns are quite consistent with zoning, that is, there is a certain type or a few dominant types of vegetation in each sub-region divided by the precipitation regimes. The areas where the precipitation became more uniform within a year were concentrated in grassland and bare land, which benefits the restoration and improvement of the ecological environment of the plateau. The increase in precipitation variability in the south-eastern part of the plateau may lead to natural disasters such as floods and mudslides. This study provides a novel perspective to understand the distribution of vegetation patterns.