Constructing suitable meteorological drought indicators is an important foundation for drought monitoring and drought evaluation services. Based on the daily average temperature and precipitation of 155 national meteorological stations in Sichuan Province from 1997 to 2021, as well as the crop area data of each county (city or district), the modified meteorological drought composite index (MCI_m) is formed by improving the seasonal adjustment coefficient of the meteorological drought composite index (MCI). The regional drought process identification method was revised according to annual drought disaster area and annual effective irrigation area and 51 regional drought processes in Sichuan Province were identified in the past years. The temporal and spatial distribution characteristics of regional drought processes in Sichuan Province were analyzed by using empirical orthogonal function (EOF), rotated empirical orthogonal function (REOF) and Morlet wavelet analysis. The results show that the evolution results of the durative day, average intensity, average impact area and comprehensive intensity index of the regional drought processes in Sichuan Province decrease initially, followed by increase, but then again decrease. The average annual cumulative days of regional drought process in the basin area were more than those in the mountains area around the basin, and those in the mountains area around the basin were more than those in western Sichuan Plateau and Panxi area. The spatial pattern of annual accumulated MCI_m anomaly decomposed by EOF was consistent in Sichuan Province and was also opposite in the northern and southern parts of Sichuan. Sichuan Province can be divided into six drought climatic areas. The annual cumulative MCI_m periodic change from 2009 to 2015 was more obvious than that from 2001 to 2008 in each area. The identified regional drought processes according to improved regional drought process identification method are in good agreement with the drought disaster situation and could better reflect the actual situation of drought in Sichuan Province more accurately.

Based on the daily observation data at 6 national meteorological stations and 135 regional meteorological stations in southeastern Hubei Province and digital elevation model (DEM) data with 30 m spatial resolution, nine suitability indexes were selected by comprehensively considering the meteorological and geographic factors affecting the growth and development, yield and quality of loquat in southeastern Hubei Province, including annual average temperature, annual minimum temperature, active accumulative temperature greater than or equal to 10.0 ℃, days with daily minimum temperature less than or equal to -3.0 ℃ and daily average temperature greater than or equal to 25.0 ℃ in May, annual precipitation, precipitation from August to October, slope direction and slope, etc. And on this basis that the refined ecological suitability division of loquat planting in southeastern Hubei Province was studied under the operation environment of ArcGIS by using analytic hierarchy process and comprehensive ecological suitability method. The results show that the main factors affecting ecological suitability of loquat planting in southeastern Hubei Province are annual minimum temperature and days with daily minimum temperature less than or equal to -3.0 ℃ on the whole. The whole region is divided into ecological unsuitable zone, sub-suitable zone, suitable zone and the most suitable zone. Among them, the areas along the river and lake in the northwest are the most suitable zone, in which can be planted early-maturing varieties of loquat. The areas with elevation from 100 m to 250 m are suitable zone in the central and the southeast of Hubei Province, in which is suitable to plant medium-maturing varieties of loquat, and the hillside with elevation from 251 m to 450 m are sub-suitable zone, in which can be developed late and medium maturing varieties of loquats with good nutrition and function, while the mountainous areas with elevation more than 450 m are unsuitable zone. Elementarily proved, the production practice of loquat in large-scale planting area of southeastern Hubei Province is in good agreement with zoning results. The zoning results can provide reference for the rational layout of loquat planting in southeastern Hubei Province.

The typical fog and haze episode in the Sichuan basin from December 16, 2014 to January 27, 2015 was selected according to the method of determination of fog and haze days at a single station and the regional fog and haze process. Based on air quality index (AQI), mass concentration of pollutant, meteorological element characteristics and atmospheric circulation, the characteristics and mechanism of the generation, evolution and transformation of this continuous fog and haze weather were studied. The results are as follows: (1) The fog and  haze process was characterized by strong intensity, long duration and wide range. (2) Both mass concentration of pollutant and AQI were highly consistent with the fog and haze weather process, and the main pollutant in this fog and haze process was PM2.5, followed by PM10. (3) It can be seen from the process of formation, evolution and transition of a longlasting severe fog and haze episode that there were stages of pollutant accumulation with different intensities, reaching the peak value and rapidly weakening. Therefore, the intensity of fog and haze weather process was closely related to weather situation and vertical structure of boundary layer. The average temperature was 1.24 ℃ higher than the normal years, the rainfall was 34.77% lower than the same period, relative humidity was 2.67% lower than the same period, sunshine hours was 10.33 hours more than the same period, and wind speed was close to or slight higher than that of the normal years. The stable atmospheric circulation feature provided favorable environmental field for fog and hazy weather and heavy air pollution. Strong temperature inversion layer, sinking motion in the boundary layer and convergence in weak wind fields on the ground prevented water and pollutants from diffusing to the upper air.