A Study On The Cyclical Characteristics Of International Food Price Fluctuations

China is a large country of grain production and consumption. The qualities of production and consumption in China are very large. In recent years, international grain prices (short for IGP) fluctuate fiercely because of grain demand and supply factors. Especially in2008, the IGP rises into a highest peak; IGP has aroused widespread concern in the community. Grain is the lifeline of the national economy, and also is the basic necessities of human life. The price of grain is a price foundation in national economy; it's up to the weight in CPI above1/3. With China's economic development and the accelerated process of industrialization, the demand for grain imports and the degree of dependence on foreign trade are increasing. At the same time, the grain problem becomes another important concern in China, in addition to energy and finance. It also relates the entire country's economic operation. Study on the cyclical characteristics of fluctuation of international grain price, find suitable ways to protect the reference of IGP to domestic grain price (short for CGP), has significant meanings to hold economic system steady and improve the people's livelihood.The most important part of this paper is the study of cyclical characteristics of fluctuation of IGP. So, in this paper we use spectrum analysis replaces the analysis of time series to change the time series to frequency series. The method of spectrum analysis is better than time series analysis, because it can change the series into frequency, and then we can compare which cycle is the most important one for comparing the spectral density. The result of spectrum analysis shows that the series of IGPCYC has a main cycle about16.5years and a minor cycle about7.5and3.5years. So we can use the B-P filter to filter the unused cycles to get the fluctuation trend of IGP. We can find that in2014the IGP will reduce slightly, in the long term, the IGP will reduce and in middle and short term, it will rise up.In chapter4, we use theoretical analysis to decide the main factors affecting the fluctuation of IGP. We classify the factors in supply and demand. We focus on these factors:world population change, the development of global economy, the development of bioenergy, the change of the dollar exchange rate, the change of climate, the world grain cultivated area, the world grain stocks, the change of energy prices and the cost of grain production. In empirical part, we choose the world grain cultivated area(GL), the dollar's broad trade-weighted index(USDIB), the emissions of CO2in the world(CO2), the ending stock quantity of grain in the world(GS), and the international oil prices to average(COA) as the main indexes. Use VAR model to study the long-run co integration relationships between these factors to IGP. The results show that GL, GS has a negative impulse to IGP; COA, CO2, USDIB has a positive impulse to IGP. Variance decomposition result shows that GS and CO2have the greater explanation to IGP, USDIB and COA have a small explanation to IGP, GL has a little explanation to IGP.In chapter5, we first analyze the transmission mechanism of IGP to our national economy. Then use cross spectrum analysis to study the relationships of IGP and CGP. The main indexes we use are cross amplitude spectrum, coherence spectrum, and phase spectrum. The results show that the fluctuation cycle of IGP is short for CGP. Most numbers of phase spectrum are above zero, which means the fluctuation of IGP can change the fluctuation of CGP. In the cycle of16.67years, the fluctuation cycle of IGP short for1.74years to CGP. In the cycle of7.14years, the fluctuation cycle of IGP short for1.48years to CGP. In the cycle of3.33years, the fluctuation cycle of IGP short for4.6months.Finally, according to the empirical analysis results, we give advices mainly on:Proposed to stabilize domestic food production, domestic supply and demand balance advocated; strengthen market monitoring food consumption, stable living standards; stabilize the prices of agricultural and industrial production levels, suggestions to improve the employment situation in terms of investment in the downstream industry.