Desertification has become a major threat to the global ecological environment, and the desertification monitoring is crucial for desertification prevention and control. Based on the Suomi/NPP (National Polar-orbiting Partnership) remote sensing data and the observation data of 8 meteorological stations during the vegetation growing season (from May to September) from 2014 to 2021 in the Qaidam Basin, the desertification difference index (DDI) was calculated by using NDVI-Albedo (Normalized Difference Vegetation Index-Albedo) feature space. Moreover, the natural discontinuity method, Sen+M-K trend analysis method, correlation analysis method, accuracy error matrix and transfer matrix analysis were also used to explore the spatial and temporal dynamic evolution of land desertification and the influence of meteorological factors to desertification in the Qaidam Basin from 2014 to 2020 during the vegetation growing season. The results are as follows: (1) The NDVI-Albedo feature space performs a high applicability in the Qaidam Basin (R² greater than or equal to 0.65), with an overall classification accuracy of 79.38% and a Kappa coefficient of 0.62. (2) From 2014 to 2021, the degree of land desertification in the eastern and southern Qaidam Basin is lower than that in the western and central Qaidam Basin. Furthermore, DDI shows a significantly increase in some areas, especially in southern and eastern region with the increase rate of DDI over 0.01a^-1. The total area of desertification land in the Qaidam Basin shows a decreasing trend with a rate of -1 173 km²·a^-1. Additionally, a transforming characteristic occurs between different degrees desertification land that severe desertification lands transferred to mild desertification land. (3) Correlation analysis shows that precipitation and average relative humidity are significantly positively correlated with DDI (P<0.01), and correlation coefficients are 0.91 and 0.86, respectively, indicating that the water is the dominant factor affecting desertification in the Qaidam Basin.

 Based on monthly dust data from 9 automatic weather stations in the Qaidam Basin from 1961 to 2019, the dust index was calculated, and the spatiotemporal variation characteristics and the main influence factors of dust intensity were analyzed. The results are as follows: (1) In recent 59 years, the intensity of dust showed a significant decrease trend with a deceleration of 2.05 a-1 in the Qaidam Basin. The annual variation of dust intensity showed a single peak distribution with the strongest in the 1970s. The mutation of dust index occurred in 1990 in the Qaidam Basin. The monthly average dust index also showed a single peak distribution to some extent, with the peak in April in spring and the valley in December in winter. (2) The dust intensity in the Qaidam Basin was high in the abdomen and low in the periphery as a whole, in recent 59 years, except for Lenghu, the dust intensity of other areas showed a significant weakening trend. The weakening rates of Nuomuhong and Golmud were faster and the weakening rate of dust intensity in spring was the fastest. (3) In recent 59 years, the annual average temperature increased, precipitation increased, wind speed decreased, windy days decreased in the Qaidam Basin, which was important reasons for the weakening of dust intensity.

Based on the conventional observation data from ground weather stations, disaster situation and cloud images in the Qinghai Plateau from 2005 to 2016, the disastrous convective weathers were selected and classified. And on this basis the temporal and spatial distribution characteristics of disastrous convection with different types and their relationship with topography were analyzed. The results are as follows: (1) The disastrous convection in the Qinghai Plateau mainly included thunderstorm, short-time heavy precipitation, hail and mixed type during 2005-2016, and they distributed mostly in the east of the Qinghai Plateau. (2) Topography played a key role in the location, frequency and intensity of disastrous convection. Thunderstorms mostly occurred in mountainous areas, the short-time heavy precipitation and hail mainly occurred in windward slopes, river valleys and open lowlands. The predominant disastrous convections were the mixed type and hail in agricultural area of eastern Qinghai, the mixed in pastoral area of southern Qinghai and the short-time heavy precipitation in Qinghai Lake, Qilian Mountains and Qaidam Basin, respectively. (3) The disastrous convection over the Qinghai Plateau decreased in a fluctuating tendency during 2005-2016. The days and frequencies of disastrous convection were more from 2005 to 2010 (the earlier stage), and they decreased significantly from 2011 to 2016 (the later stage), while the annual variations characteristics of disastrous convection with different types were slightly different. The days of hail and thunderstorm were larger in the early stage and decreased significantly in the later stage. The change trend of mixed type and short-time heavy precipitation days wasn’t obvious, but the annual fluctuant range of the former was larger than that of the latter. (4) Disastrous convection mainly occurred from May to September in the Qinghai Plateau, and the monthly days and frequencies of disastrous convection with different types showed a typical single peak distribution. The peak of hail and mixed type days and frequencies was in August and that of thunderstorm days and frequencies was in June, while the peak of short-time heavy precipitation days and frequencies was in August and July, respectively. (5) Disastrous convection concentrated from 13:00 pm to 01:00 am in the next day, the hail and mixed types dominated at the peak stage (16:00-20:00), while the short-time heavy precipitation dominated in the nighttime.