Formation Cause Analysis of a Heavy Fog in the Middle East of Henan Province in 2012
Abstract：Using the observational data of meteorological stations and NCEP 1°×1° reanalysis data, a large range of heavy fog process which occurred on January 10, 2012 in the Middle East of Henan prov-ince was analyzed, in order to reveal its formation cause. The results are as follows. 1 ) The circulation background conditions contained straight upper circulation, weak northerly airstream before the high pres-sure ridge on middle and lower level, uniform pressure field and weak cold air activities on ground. 2) On T-lnp figure, the various unstable index, status curve and stratification curve showed the whole atmos-phere above the heavy fog area was in a stable stratification state, t (from 925 hPa to ground )≥ 2℃ , and the wet layer (t-td≤4 ℃) top height was more than 1000 hPa (above altitude 250 m). 3) The warm advection injection in the boundary layer was conducive to the inversion establishment and the fog strengthening and maintaining; the zero advection zone between the cold and warm advection could better distinguish the fog area and non-fog area. 4) In the field of T639 forecasting, the fog area occurred on the followings: temperature inversion zone near surface, ground wind speed ≤ 3 m/s area, and ground relative humidity over 90% area which covered with weak rise near ground. Numerical forecast can be used to forecast regional heavy fog.
Keywords：heavy fogtemperature inversionwarm advectionpredictability
Publication Date：2012-08-07
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：6( 27-32 )