The sustainable development of the marine economic system to accurately grasp the dynamic evolution characteristics and main driving factors of the vulnerability of the marine economic system so as to effectively identify the problems in the operation of the marine economy is extremely important. Based on the establishment of a three-level assessment index system for the vulnerability of the marine economic system, the vulnerability of the marine economic system of Jiangsu Province in 2008-2016 was evaluated by using the comprehensive index model and the catastrophe progression model, and the results were compared based on the unified evaluation criteria. The main influencing factors were analyzed by principal component analysis and Pearson correlation analysis. It's found that 2014, 2015 and 2012 are in a general state, 2009 and 2010 are in a poor state, and the vulnerability state from 2008 to 2011 is lower than that in 2012. The overall volatility is small indicating a stable system. Among them, the scale of marine industry and profit and loss of marine resources are the main components of marine economic system vulnerability having the highest correlation with the vulnerability of marine economic system. This study enriches the theoretical method and empirical research on the vulnerability of the marine economic system and has practical significance in allowing for timely targeted control measures to affect the vulnerability of the marine economic system.

This paper aimed to construct an improved economic value estimation model (EVIW model) to assess the economic value of water, which plays an important role in the sustainable development of crop planting and irrigation design, especially in arid areas lacking water resources. Firstly, the current EVIW model was based upon improvements and adjustments to the cost-benefit analysis models of previous researchers. Then, to elaborate the whole process of estimation, an empirical study based on the data of Yanqi Basin was conducted. Subsequently, in order to verify the accuracy of the EVIW model, the economic value of irrigation water in this study area was estimated for a second time using the benefit sharing coefficient method. It was concluded that the estimated results of the current EVIW model are in good agreement with those of the traditional benefit sharing coefficient model. The estimation results of the economic value of irrigation water were found to be highly acceptable in terms of accuracy and scientific rigor.

This paper aims to estimate the economic value of agricultural water use in Arizona based on an improved economic value estimation model (EVIW model). In this research, EVIW method is optimized for the economic value estimation of agricultural water use from the perspective of crops. Crop Price per unit for crop production, crop yield per acre and irrigation area are used to calculate gross profit. Crop variable costs per acre (labor costs, chemical costs, machinery fuel and repair costs, etc.) and corresponding irrigation areas are used to calculate variable costs. Gross revenues and variable costs are used to calculate the net returns generated by irrigation water. Arizona agricultural water use for crops are estimated based on meteorological data and Cropland Data Layers. Finally, economic values of agricultural water are determined by the net returns of irrigated crops and agricultural water use. The results show that the economic values of agricultural water are positive and negative with great variations. The models applied in the research bring forward practical conclusions for further water allocations, transfer, and policies.

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