An Analysis Of Planetary Boundary Layer Height Based On Multiple Datasets

The global planetary boundary layer height(PBLH)plays an important role in air quality diagnosis and weather/hydrometerology forecast.By using 45-year(1973-2017)of Integrated Global Radiosonde Archive(IGRA)data,13-year(2006-2018)of Constellation Observing System for Meteorology Ionosphere and Climate(COSMIC)data and 39-year(1979-2017)of European Center for Medium-Range Weather Forecasts(ECMWF)Reanalysis Interim(ERAInterim)data,PBLH has been estimated.The PBLH is determined by the bulk Richardson number(BRN)method for IGRA radiosonde data and verified by the parcel method and the potential temperature gradient method.In general,the BRN method could represent the height of the convective boundary layer(BL)and neutral residual layer cases,but have a relatively large uncertainty in the stable BL cases.For the COSMIC data set,the wavelet covariance method is used to estimate PBLH.The results show that the height of the boundary layer estimated by the COSMIC is much higher than that of the IGRA.According to the analysis of spatial distribution characteristics of PBLH based on the multiple data sets,we found that the seasonal spatial distribution of the IGRA is consistent with that of the ERA-Interim reanalysis data no matter at 0000 or 1200 UTC.The value of PBLH in the Equatorial low latitude area is larger than that in the middle high latitude area.By comparing the diurnal variation of PBLH between COSMIC and IGRA in the same latitude,the results show that both of them have diurnal variation,but the diurnal variation from IGRA is more obvious.For ERA-Interim,we found that diurnal change of PBLH has obvious meridional change with time,and the maximum value of PBLH will appears at 1500 UTC.The diurnal and seasonal variation of PBLH over land and oceans are quite different.For stations over land,PBLH shows an apparent diurnal cycle and seasonal variations,with a distinct maximum around 1500 LT and higher values in summer.As compared with land,the PBLH diurnal cycles over oceans are quite mild and the PBLHs are much lower,along with little seasonal changes.The seasonal variations in the median PBLH diurnal cycle are positively correlated with the near-surface temperature and negatively correlated with the near-surface relative humidity.In addition,there is no significant trend in the nighttime PBLH for almost all the studied latitudes over both 2 surface characteristics,while the daytime PBLH exhibits a statistically significant increasing trend at most hours between 1200 and 1800 LT over both land and ocean at most latitudes.