Abstract: The Beijing-Tianjin region, economically developed and densely populated, is highly vulnerable to drought events, which poses a challenge to its socio-economic development and water security. This paper presents a method for identifying droughts using a three-dimensional approach that considers longitude, latitude, and time, and an application of the Standardized Vegetation Index (SVCI) to detection of the drought events in this region. We quantify the events based on duration, area share, and intensity, and examine their frequencies and return periods using the Copula function. The results show the drought events identified using SVCI align with those recorded in literature, indicating the results of this study are reliable. In the study region, totally 48 drought events occurred from 1982 to 2020, with 34 lasting three months or longer. Compared to its two-dimensional version, the three-dimensional Copula function is more effective in fitting the joint distributions of drought variables in the region, considering more factors for better fitting.

Key words: drought event, three-dimensional identification, copula, return period, Beijing-Tianjin region, remote sensing