Page 197 - 《高原气象》2025年第5期

5 期 徐新妍等：川西北生态示范区及周边地区极端气温指数时空变化分布特征 1315

Characteristics of Temporal and Spatial Distribution of Extreme

Temperature Indices in the Ecological Demonstration Area and
Surrounding Areas of Northwest Sichuan province

1
2
XU Xinyan ， YUAN Shujie ， LIU Zhihan ， SU Lixin ， GAO Zongting 3， 4
3， 4
1
（1. School of Atmospheric Sciences， Chengdu University of Information Technology， Chengdu 610225， China；
2. School of Atmospheric Sciences， Nanjing University， Nanjing 210093， Jiangsu， China；
3. Institute of Meteorological Sciences of Jilin Province， Changchun 130062， Jilin， China；
4. Jilin Provincial Key Laboratory of Changbai Mountain Meteorology & Climate Change， Changchun 130062， Jilin， China）
Abstract： Using the day-by-day average temperature， maximum temperature， and minimum temperature data
from a total of 70 ground-based conventional observatories in the Northwest Sichuan Ecological Demonstration
Area as well as its peripheral areas from 1961 to 2022， and adopting the climatic propensity rate， EOF（Empiri‐
cal Orthogonal Function） analysis method， and Morlet complex wavelet method， we analyzed the temporal and
spatial change characteristics of the extreme temperature indices in the Northwest Sichuan and its peripheral ar‐
eas， and the results show that： （1） The extreme temperature warm indices and extreme value indices in the study
area show an increasing trend， the extreme temperature cold indices show a decreasing trend， and the DTR（Diur‐
nal Temperature Range） change is not obvious； the warm and cold indices have similar magnitude of change，
the rate of change of the night indices is greater than that of the day indices， and the climate change of the ex‐
treme temperature indices of the neighboring areas is more significant compared to that of Northwest Sichuan.
（2） Extreme temperature indices in Northwest Sichuan have 2~3 main cycles in 2~30 years； neighboring areas
have 2~3 main cycles in 2~20 years. Most of the indices in Northwest Sichuan have a sudden change of cycle
around 2000， and the frequency of alternation between short and medium cycles is increasing. The cycles of FD0
（Frost Days）， TN10P（Cold Nights）， TX10P（Cold Days）， and CSDI（Cold Spell Duration） in the neighboring
regions changed abruptly around 1990， and the frequency of short- and medium-cycle alternation decreased； the
cycle changes of the extreme temperature indices in Northwest Sichuan have lagged compared with those in the
neighboring regions.（3） TNx（Max TN）， TXx（Max TX）， and TR20 （Tropical Nights ） show an increasing
trend in the northern part of the study area； TXn（Min TX） shows an increasing trend in the eastern part of NW
Sichuan as well as in the neighboring areas； ID0（Ice Days） and TN10P decrease over the whole area； FD0 de‐
creases in NW Sichuan and increases in the neighboring areas； TNn（Min TN）， TN90P（Warm Nights）， and
DTR decrease in NW Sichuan and increase in the neighboring areas； CSDI and SU25（Summer Days） increase in
the east and decrease in the west， and WSDI（Warm Spell Duration） is the opposite. CSDI and SU25 increased in
the east and decreased in the west in the study area， while WSDI was the opposite.（4） In the study area， the ex‐
treme temperature cold indices mainly show a decreasing trend， the extreme value indices change less， and the
rest of the indices mainly show an increasing trend； the overall warming trend is shown， and the indices change
in the study area respond well to the global warming， with the peripheral areas showing more significant changes.
Key words： Northwest Sichuan Ecological Demonstration Area； extreme temperature indices； spatial and tem‐
poral change characteristics； wavelet analysis； EOF analysis