Table 1.
Data sources and processing of socioeconomic and environmental factors in this study.
| Variables/Description | Data Processing | The Source of Data |
|---|---|---|
| Population size | Summing the population (persons) for each grid based on the 2010 population density data | Data Center of Resources and Environmental Science, Chinese Academy of Sciences (RESDC, www.resdc.cn) |
| Land urbanization level (LUL) | Calculating the area ratio of urbanized land to the grid based on the 2010 data of land use and coverage change | |
| Economic conditions | Summing the gross domestic product (GDP) values (RMB) for each grid based on the 2010 GDP data | |
| Road density | Calculating the ratio of total length of relatively low-level (town and/or district) roads to the grid (km·per·km2) based on the road network data | |
| ☯ Annual mean temperature (AMT) | Annual mean values of temperature (June–November in 2014) in each grid | China Meteorological Data Service Center (CMDC, http://data.cma.cn/) |
| ☯ Annual mean precipitation (AMP) | Annual mean values of precipitation (June–November in 2014) in each grid | |
| ☯ Annual mean relative humidity (AMH) | Annual mean values of relative humidity (June–November in 2014) in each grid | |
| Vegetation index | Annual mean values of normalized difference of vegetation index (NDVI) (June–November in 2014) in each grid | https://ladsweb.nascom.nasa.gov/data |
☯ Annual mean values of climatic conditions and vegetation index in June–November were calculated in each grid because the 2014 DF cases were mainly reported in these months.