Remote Sensing-Based Dynamic Monitoring of Immovable Cultural Relics, from Environmental Factors to the Protected Cultural Site: A Case Study of the Shunji Bridge

This paper explores the ability of remote sensing techniques to monitor immovable cultural relics on multiple scales. The Shunji Bridge, a destroyed cultural relic, located in the Jinjiang River Basin, Fujian Province, China, was studied in terms of the environmental factors at the macroscale and the protected cultural site at the microscale. At the macroscale, moderate spatial resolution images of the Jinjiang River Basin were processed in the Google Earth Engine (GEE) platform to extract environmental factors, such as land cover and vegetation cover. At the microscale, Google Earth time series images were used to extract attribute information to reflect the spatial and temporal changes in the Shunji Bridge before, during and after its destruction. Quantitative assessment of the Shunji Bridge was performed to assess the degree of the impacts that different factors had on the immovable cultural relic. Spatial analysis methods were applied to trace back to the source of the bridge destruction and to track the situation after the bridge was destroyed. The causes of the destruction of the bridge are revealed at both the macro- and microscales. This study provides technical support for the natural disaster risk assessment of immovable cultural relics. The findings of this research can provide suggestions for the protection of immovable cultural relics.

Response of Hydrological Drought to Meteorological Drought under the Influence of Large Reservoir

Based on monthly streamflow and precipitation data from 1960 to 2010 in the Jinjiang River Basin of China, Standardized Precipitation Index (SPI) and Standardized Streamflow Index (SSI) were used to represent meteorological and hydrological drought, respectively. The response of hydrological drought to meteorological drought under the influence of Shanmei reservoir was investigated. The results indicate that SPI and SSI have a decreasing trend during recent several decades. Monthly scales of SSI series have a significant decreasing trend from November to the following February and a significant increasing trend from May to July at Shilong hydrological station. There are three significant periodic variations with a cycle of 6-7 years, 11-12 years, and 20-21 years for annual scales of SSI series. SPI series have the same periodic variations before the 1980s, but they have not been synchronous with SSI since the 1980s at Shilong due to influences of Shanmei reservoir, especially at the periodic variations of 20-21 years. The variation of the lag time of hydrological drought in response to meteorological drought is significant at the seasonal scale. The lag time of hydrological drought to meteorological drought extends one month on average in spring, summer, and autumn but about three months in winter.

Sediment Transport in the Quanzhou Bay

Observations on 6 ship moorings during the spring and neap tides show that the suspended sediment concentration (SSC) changed according to the variation of the local tidal forcings under the normal weather conditions. During the neap tide, the measured concentration of suspended sediment is comparable to that of Jinjiang River, the only external sediment source in the course of observations; while during the spring tide, the observed SSC is one order higher than that of Jinjiang, meaning that relative to the riverine impact, the tidal current is more probably responsible for the sharp variation of SSC between the spring and neap cycle.