Spatial-temporal drought characteristics in the Pearl River basin in the
last 60 years based on the MCI of Penman-Monteith
Abstract
The Pearl River Basin is prone to drought, and it is of great practical
significance to use the comprehensive meteorological drought index to
accurately assess its spatial and temporal variability. Based on the
daily MCI values of 75 meteorological stations in the Pearl River Basin
from 1961 to 2020, the spatial and temporal evolution characteristics of
drought days, drought station ratio, drought impact range, and
cumulative drought intensity are analyzed by using Kriging spatial
interpolation, linear trend analysis, Mann-Kendall mutation test and
empirical orthogonal function (EOF). The results show that the
distribution of drought days generally shows a decreasing trend from the
middle of the basin to the east and west, and areawide and local
droughts are prone to occur. Drought days are highest in winter,
followed by spring and autumn, and lowest in summer. Spatially, the
distribution is more west than east in spring and winter, less west than
east in autumn, and very few drought days in summer throughout the
basin. The cumulative drought intensity is close to the same trend as
the drought impact, showing a positive correlation. The first mode of
cumulative drought intensity’s EOF expansion reflects consistent
basin-wide drought variation, while the second mode reflects the spatial
distribution characteristics of the inverse phase variation in the
western and eastern parts of the basin.