Research And Application Of Drought Monitoring Based On Multi-resource Data In Chongqing

In China, one of the most frequencies meteorological disasters is drought, and when its duration last in a long term, the influence would extend in large areas, it has a great influence on national economy, especially on agricultural production. Chongq-ing is located in eastern part of Sichuan Basin, and is the transition zone of the Tibet-an plateau and the middle and lower reaches of the Yangtze River. However, regionl and periodic droughts often occur in Chongqing due to the complicated topography, with uneven spatial distribution of temporal and rainfall resources. It leads to a great loss on agricultural production and limit the improvement of national livings. Chong-qing is called mountain city and foggy city because of the conditions of complexity in topography and climate, therefore, it is difficult to monitoring the drought. In this the-sis, take into consideration of the characteristics in Chongqing, the remote sensing da-ta, meteorological sites data, and drought monitoring model have been utilized to mo-nitor the drought in summer and winter in Chongqing, and then assess the severity of the drought, coping with drought relief measures, and the drought relief measures are suggested. It is of great importance in reducing the loss caused by drought.On the basis of collection of literature about drought monitoring at home and ab-road, and then comparison of those materials and summarized the remote sensing and meteorological drought monitoring model characteristics, taking Chongqing as an ex-ample to study the monitoring results in southwest mountainous, hilly, complex terr-ain condition in China. The vegetation water supply index is used, which is based on MODIS remote sensing data, because it has a better effect in high vegetation coverage areas, contrast the drought monitoring effect based on NDVI and EVI, and the serio-us drought occurred in 2006 in Chongqing is chosen to study. combination of temper-ature, precipitation, relative humidity data during the drought trend, evolution law, verify its relationship between the drought, and study the distribution and the evolu-tion process of the drought; Based on the historical meteorological sites data to study the history of drought according to the MCI( modify comprehensive meteorological drought index) drought index, and to explore the relationship between the meteorological factors and the frequency of individual drought and its spatial distribu-tion. Taking the 2010 winter and spring drought as an example to study the entire pro-cess of changes in drought. The results show that MCI index in winter has good drou-ght monitoring effect; Using the nearly 50 years meteorological sites data, considering the factors such as longitude and latitude, altitude, rainfall, study the seasonal drought frequency and its spatiotemporal distribution disciplines. The main conclusions are summarized as follows:1. There is a good results when using soil moisture data to verify the vegetation water supply index, this shows that the good practicability of vegetation water supply index in Chongqing. The serious drought trend in 2006 roughly can be divided into five stages: drought outcrop- droughts occur- drought increased- drought severe – the remission, during the whole drought period, in addition to the southeast of Youya-ng county, Xiushan county, northeast minority area, there were serious drought in oth-er regions of Chongqing.2. Based on the vegetation water supply index method, using the MODIS remote sensing data including NDVI and EVI, LST, combined with the data of soil moisture, the EVI data has been used to observe the change tread because which has better effe-ct of drought monitoring, take the drought in 2006 for example, droughts in different levels in whole city and the change regulation of each level drought, and the evolution process of the drought has been study, combination the precipitation, temperature, rel-ative humidity, show that vegetation water supply index and meteorological factor not only has good correlation, but also has a strong correlation with the response in time and space.3. On the basis of MCI drought index, and combining with the historical meteoro-logical sites data, study the drought occurrence regularity. It shows that the annual dr-ought was 1.42 times in Chongqing. Spatial distribution of droughts is that northeast and west are the high frequency of drought area, southeastern, northern and Qijiang county are low frequency from the historical meteorological data. According to the method, the annual average number of drought of each site are 2.0, 1.8, 1.2, 1.2, 2.2 times, respectively. Study the laws of droughts in space and time, from the 1960 s to the first decade of 21 th century, monitor the winter and spring drought in 2010 using the MCI index, the results show that the winter drought were more serious than sprin-g, from the December of 2009 to February of 2010 were the worst drought period, in addition to the small area of northeast of Chongqing, other areas were affected by serious drought.4. Based on the meteorological sites data, with regression analysis method,Consi-deration the factors such as longitude and latitude, altitude, rainfall, to calculate the appropriate frequency equation for each kind of drought, to obtain the accuracy data of drought spatial distribution, analysis the regular of droughts and space distribution characteristics. The results show that the frequency of seasonal drought have bigger differences in spatial distribution in Chongqing, and major drought of a year called Fuhan occurs in the late summer, which period is from late July to august.