ESTIMASI KETINGGIAN PLANETARY BOUNDARY LAYER INDONESIA MENGGUNAKAN DATA ECMWF REANALYSIS ERA-INTERM

Abstract

Planetary Boundary Layer (PBL) is part of the troposphere, directly influenced by Earth's surface and play a major role on climate, weather, and air quality. Due to complexity and variation over time, PBL become more difficult to observe from space. A fundamental approach to identify PBL is by determining the height. PBL heights are computed by using seven gradient-based methods of relative humidity (RH), virtual temperature (Tv), potential temperature (Ɵ), potential virtual temperature (Ɵv), specific humidity (q), atmospheric refractivity (N) and wind speed (V) are derived from 0 0 0 0 0 0 ECMWF Reanalysis Era Interim data for six months at 10 N–10 S, 90 W –150 E with a spatial resolution of 2.5 x 2.5 . Some methods showed identical results of PBL height estimation over certain time and place. Ɵv and V methods consistently give higher PBL heights, whereas q and N methods yields significantly lower heights. High monthly and daily variations are generally found in the entire land, whereas ocean regions are relatively constant. Several sources of both parametric and structural uncertainty of PBL height values are estimated statistically using the Student's t test, F test, Kormogorov Sminorv test, Pearson's linear correlation test and nonparametric Spearman rank correlation test. We Found any statistically significant differences between seven gradient methods. The average different in mean PBL height are several hundreds to thousands for most methods are compared. PBLheights in Indonesia using the gradient method of RH is about 2000 m - 4000m during the day and at night were at below 2500 m .