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朱辉清， 2006. 微气象、 地形区域输电线路覆冰厚度设计研究［J］. sion lines in micro-meteorological and topographical regions［J］.
湖 北 电 力 ， 30（增 刊）： 13-15. DOI： 10. 19308/j. hep. 2006. Hubei Electric Power， 30（Supplement）： 13-15. DOI： 10. 19308/
s2. 006. Zhu H Q， 2006. Design on icing thickness of transmis‐ j. hep. 2006. s2. 006.

Analysis of Synoptic Scale Systems for Different Types

of Power Grid Icing in Yunnan

HOU Ruiqin， TAN Guirong， XU Rongrong
（State Key Laboratory of Climate System Prediction and Risk Management/Key Laboratory of Meteorological Disaster，
Ministry of Education/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters，
Nanjing University of Information Science and Technology， Nanjing 210044， Jiangsu， China）

Abstract： The eastern and northeastern regions of Yunnan province are severe ice-coating areas. This study con‐
ducts a diagnostic analysis of a one-week ice-coating event in Zhaotong of Yunnan province during December
2023， utilizing manual observations， power grid sensor data， and ERA5 reanalysis data. The results indicate that
the ice-coating area is predominantly located on the northern windward slope of the plateau， with the maximum
ice thickness observed at elevations between 1500 and 2000 meters. The types of ice-coating are complex and var‐
ied， closely related to the timing of cold air influence. Specifically， the high-temperature and high-humidity type
（GG type， t>0 ℃， RH≥75%） occurs during the initial stage of cold air influence. When the cold and warm air
masses confront each other and a stationary front is maintained， the low-temperature and high-humidity type
（DG type， t≤0 ℃， RH≥75%） occurs most frequently. As the cold air influence near its end， the low-temperature
and low-humidity type （DD type， t≤0 ℃， RH<75%） becomes dominated. The high-temperature and low-humid‐
ity type（GD type， t>0 ℃， RH<75%）is the least frequent. During the ice formation period， the 500 hPa level is
characterized by westerly airflow or short-wave troughs. At the 700 hPa level， southwesterly winds are ob‐
served， occasionally reaching the intensity of southwesterly jets， which transport abundant moisture. At 700
hPa， a wind shear line sometimes forms， coinciding with the surface stationary front， providing favorable dy‐
namic uplift conditions for precipitation during icing events. The GG and DG types of icing occur under condi‐
tions of abundant moisture and strong uplift. Both of them are mixed icing associated with freezing rain （driz‐
zle）， sleet， snow or fog. In contrast， the DD and GD types occur during the late stage of cold air retreat， charac‐
terized by weaker humidity and dynamic conditions. The DD type may be associated with freezing fog and driz‐
zle under the influence of surface radiative cooling at night. In contrast， the formation of GD type is more likely
related to fog or weak precipitation induced by local surface thermal or micro-terrain uplift.
Key words： cryogenic freezing； ice-coating； synoptic system； Yunnan