Taking representative Tamarix chinensis forest in the national-level special protection zone for ocean ecology of Changyi city in Shandong province of China as the objective, this research studied how to use remote sensing technology to evaluate natural eco-environment and analyze spatiotemporal variation. In the process of constructing the index system of ecological environment effect evaluation based on RSEI (Remote Sensing Ecological Index) model, AOD (Aerosol Optical Depth), Salinity, Greenness, Wetness, Heat and Dryness, which can represent the ecological environment of the reserve, were selected as the corresponding indexes. In order to accurately obtain the value of the RSEI of the study area and to retain the information of the original indexes to the greatest extent, the SPCA (spatial principal components analysis) method was applied in this research. Finally, the RSEI was applied to evaluate the ecological and environmental effects and to analyze the spatial characteristics and spatiotemporal evolution of the study area. The results not only provide scientific evidence and technical guidance for the protection, transformation and management of the Tamarix chinensis forest in the protection zone but also push the development of the universal model of the ecological environment quality with a remote sensing evaluation index system at a regional scale.

Seabed liquefaction and sediment resuspension under wave loading are key issues in marine engineering, but are usually regarded as independent processes (instead of coexisting and interacting processes). Here, we analyzed random wave-induced seabed liquefaction and its impact on sediment resuspension using flume experiments. Results show that in a nonliquefaction scenario, excess pore pressure in the seabed oscillates with wave fluctuations, but pressure accumulation is low, while a consistent upward pressure gradient promotes sediment suspension. Wave-induced shear stress was the key driver of sediment resuspension in a nonliquefaction scenario. In the liquefied state, waves with different amplitudes differently responded to excess pore pressure; small-amplitude waves accumulated pressure, while large-amplitude waves dissipated it. Liquefied soil formed mud waves, creating elliptical motion along with random waves. Seabed liquefaction accelerated sediment resuspension in the following ways: reducing soil critical shear stress; forming seepage channels inside the seabed; forming mud waves, resulting in increased turbulent kinetic energy; dissipating excess pore pressure and releasing porewater, expelling fine-grained sediment from the liquefied soil. Our study reveals the variation in excess pore pressure in silty seabed under random waves and its effect on sediment resuspension, which is significant for understanding soil liquefaction and sediment movement of silt.

The last deglaciation is a transition from the cold glacial period to the warm Holocene, when Northern Hemisphere summer insolation began to increase, accompanied by global warming and obvious rises of sea level and atmospheric CO 2 (Denton et al., 2010;Lambeck et al., 2014;Shakun et al., 2012). However, a series of abrupt cooling events, such as the Heinrich stadial 1 (H1, 17.5-14.7 ka) and the Younger Dryas event (YD, 12.9-11.6 ka), disrupted the warming trend in the high northern latitude region (e.g., Denton et al., 2010). The East Asian summer monsoon (EASM) region also shows these rapid climate events during the last deglaciation, thus providing an insight into the sensitivity of climate system perturbations and the prediction of monsoon development under global warming scenarios (e.g., An et al., 2015;P. X. Wang et al., 2017).To date, EASM variations during the last deglaciation have been extensively explored using various climatic archives and models. Previous research has generally confirmed a direct teleconnection between the EASM and the North Atlantic climate anomalies through ocean-atmosphere interactions (e.g.,

A prevailing view for abrupt millennial-scale climate fluctuations during the last deglaciation in the Northern Hemisphere is tightly linked to changes in the Atlantic meridional overturning circulation (AMOC) (McManus et al., 2004). Evidence suggests that perturbations in the North Pacific can also have a significant impact on regional and global climate fluctuations by altering the poleward transport of heat and moisture (Praetorius