Research progress on the agriculture drought disaster risk and its research theoretical framework

Drought disaster risk occurrence frequency is one of most high, and its affection is most severe in the worldwide, which is more serious in China and had threatened our food security. With the climate change, drought disaster had serious impacts on agricultural production and increasing risks of agricultural disasters. Therefore, the agricultural drought risk characteristics and management problem are particularly important under climate warming conditions. Drought disaster risk was effected by the spatial and temporal pattern of drought risk hazard factors such as the frequency and intensity of precipitation, environmental vulnerability, sensitivity and exposure. These three factors are both independent and connected each other. In view of this, based on the crops drought threshold and the risk mechanism, firstly, we analyzed the drought disaster risk research progress domestic and overseas in recent, which can provide information to the future studies. Secondly, the agriculture drought risk assessment must be established based on detailed agricultural drought dynamic monitoring and assessment methods, and the main technological process included building the assessed database using the meteorological observation data, drought disaster data, integration of data and remote sensing, a long sequence of yield and climate and drought disaster loss data (including agricultural drought of drought induced areas, drought -occurred areas and no harvest areas), based on remote sensing inversion, field investigation, mathematical statistics and so on, comparing the adaptability of the drought monitoring index, identifying the drought disaster hazard index. Thirdly, based on the long term drought disaster and production data, selecting the occurring drought samples in the crop growth period and calculating reduction rate, building the relationship between production and drought disaster index, based on the reduction rate to quantify the hazard index critical value and grading, quantify the contribution degree of the drought in different growth period to production, confirming the different agriculture drought intensity threshold values and its classifications. And then, based on the theory of coupled risk simulation, combined the drought disaster hazard factor, environmental vulnerability, sensitivity and exposure theory to build the agriculture key growth period disaster risk assessment models. Based on the built models, the different grades drought threshold values, the drought risk development characteristics and drought regional difference can be identified. Lastly, revealed the contribution of key physical factor to risk and it physical mechanism to happen. These can provide some information on the agriculture key growth period drought risk physical mechanism and improving risk management levels.