Seasonal Prediction of Extreme High-Temperature Days in Southwestern China Based on the Physical Precursors

Extreme high temperatures frequently occur in southwestern China, significantly impacting the local ecological system and economic development. However, accurate prediction of extreme high-temperature days (EHDs) in this region is still an unresolved challenge. Based on the spatiotemporal characteri...

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Bibliographic Details
Published in:Advances in atmospheric sciences 2023-07, Vol.40 (7), p.1212-1224
Main Authors: Zhou, Zhiyi, Li, Juan, Chen, Haishan, Zhu, Zhiwei
Format: Article
Language:English
Subjects:
Anomalies
Atmospheric Sciences
Correlation coefficient
Correlation coefficients
Drought
Dynamic height
Earth and Environmental Science
Earth Sciences
Economic development
Empirical models
Extreme heat
Extreme high temperatures
Geophysics/Geodesy
Geopotential
Geopotential height
Height anomalies
High temperature
Hydrologic drought
Hydrology
Lower bounds
Meteorology
Original Paper
Physics
Precursors
Predictions
Sea surface
Snow accumulation
Snow depth
Temperature
Thermodynamic fields
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Summary:Extreme high temperatures frequently occur in southwestern China, significantly impacting the local ecological system and economic development. However, accurate prediction of extreme high-temperature days (EHDs) in this region is still an unresolved challenge. Based on the spatiotemporal characteristics of EHDs over China, a domain-averaged EHD index over southwestern China (SWC-EHDs) during April–May is defined. The simultaneous dynamic and thermodynamic fields associated with the increased SWC-EHDs are a local upper-level anticyclonic (high-pressure) anomaly and wavy geopotential height anomaly patterns over Eurasia. In tracing the origins of the lower boundary anomalies, two physically meaningful precursors are detected for SWC-EHDs. They are the tripolar SST change tendency from December–January to February–March in the northern Atlantic and the February–March mean snow depth in central Asia. Using these two selected predictors, a physics-based empirical model prediction was applied to the training period of 1961–2005 to obtain a skillful prediction of the EHDs index, attaining a correlation coefficient of 0.76 in the independent prediction period (2006–19), suggesting that 58% of the total SWC-EHDs variability is predictable. This study provides an estimate for the lower bound of the seasonal predictability of EHDs as well as for the hydrological drought over southwestern China.
ISSN:0256-1530
1861-9533
DOI:10.1007/s00376-022-2075-5