Meteorological Characteristics Analyses of a Continuous Polluted Weather Process in Chengdu

An analysis of the circulation situation and the evolution of ground meteorological elements during a heavy polluted weather process in Chengdu in January 2013 is performed by using the meteorological observational data and NCEP/NCAR 1o×1o reanalysis data. It is found that: (1) The continuous polluted weather process occurred under the static stability weather background of the control of weak high-pressure ridge and geopotential height fields are extremely high,and locating in the degraded cold high pressure fields or uniform pressure fields and wind fields is weak on surface. (2) the surface meteorological characteristics of the serious polluted weather process are: the surface cold high pressure gradually degenerates,surface temperature becomes higher,sea level pressure decreases,The relative humidity increases to about 80%,no precipitation or weak precipitation,visibility decreases to even below 10 km,ground wind speed weakens. (3) the low-level meteorological characteristics of weak wind,weak vertical wind,and the existence of inversion on the ground and 700hPa altitude make the pollutants hard to spreading in the vertical direction,and make the pollution further aggravating.