TITLE:
Analysis of Spatiotemporal Drought Distribution Characteristics in Dali Prefecture Based on the CI Index
AUTHORS:
Haocui Zi, Wujun Xi
KEYWORDS:
Dali Prefecture, Composite Index of Meteorological Drought (CI), Drought Days, Drought Frequency, Spatial Distribution
JOURNAL NAME:
Journal of Geoscience and Environment Protection,
Vol.13 No.11,
November
12,
2025
ABSTRACT: Drought is one of the primary meteorological disasters affecting Dali Prefecture. This study employs the Integrated Meteorological Drought Index (IMDI) to systematically analyze the spatiotemporal evolution characteristics of meteorological drought in Dali Prefecture from 2002 to 2023. Using linear trend analysis, spatial interpolation, and meteorological statistical methods, the key findings are as follows: interannual drought frequency fluctuated between 5.3% and 34.2%, with a mean of 24.3%; the 2019 extreme drought event showed significant correlation with concurrent Indian Ocean sea surface temperature anomalies; spatially, drought frequency exhibited a north-high-south-low pattern, ranging from 23.1% in the south to 29.8% in the north, with northern counties (e.g., Jianchuan, Heqing) recording the maximum frequency (29.8%) resulting from the föhn effect on the leeward slope of the Nushan Mountains and high agricultural water consumption; annual drought duration increased significantly at 1.9 days/decade; seasonally, droughts intensified in spring (+0.62 days/decade) and winter (+1.5 days/decade) but weakened in summer (−0.8 days/decade) and autumn (−0.4 days/decade), a pattern potentially linked to East Asian monsoon weakening causing reduced winter-spring moisture transport; for drought severity, light drought dominated (annual mean: 42.5 days, 58% of total drought days) followed by progressively shorter durations of moderate, severe, and extreme drought, while combined severe/extreme drought duration increased at 0.7 days/decade, consistent with regional warming and increased evapotranspiration. This study elucidates the spatiotemporal drought patterns and climatic drivers in Dali Prefecture, providing a scientific basis for drought resilience planning and optimized water resource allocation in this plateau marginal region.