Open AccessShort vertical-wavelength gravity wave activities in the upper troposphere lower stratosphere observed with global navigation satellite system radio occultation under different QBO phases
Author(s) -
Firas Rasyad,
Tri Wahyu Hadi,
Noersomadi
Publication year - 2021
Publication title -
iop conference series. earth and environmental science
Language(s) - English
Resource type - Journals
eISSN - 1755-1307
pISSN - 1755-1315
DOI - 10.1088/1755-1315/893/1/012007
Subject(s) - stratosphere , radio occultation , troposphere , quasi biennial oscillation , atmospheric sciences , tropopause , occultation , gravity wave , wavelength , environmental science , microwave limb sounder , gravitational wave , climatology , physics , geology , ionosphere , astrophysics , geophysics , optoelectronics
Gravity Waves (GWs) are believed to play important role in the generation of the driving force of the stratospheric Quasi-Biennial Oscillation (QBO). Deep convection in the equatorial region can generate large amount of GW with short vertical wavelength (λ z <1 km) but studies of these wave activities in the upper troposphere lower stratosphere (UTLS) region are still limited. Recent advances in Global Navigation Satellite System (GNSS) Radio Occultation (RO) retrieval techniques have made it possible to derive global temperature profile with vertical resolution of less than 1 km. In this research, activities of GW with λ z from 0.5 to 3.5 km in the UTLS region of 20-27 km heights are identified by calculating the GW potential energy ( E p ). Correlation between GW activities and QBO phases is examined using 50 hPa zonal wind as the QBO index. The results show that during both easterly and westerly QBO phases, the GW E p value increases gradually with time and reaches its peak in the transition periods. This pattern is seen in E p with all vertical wavelengths between 0.5-3.5 km but the percentage value of E p for λ z <1 km is higher during the transition from westerly to easterly QBO. The GW E p values exhibit downward propagation with the QBO phase but there are also discernible upward propagations of GW activities below 24 km height and intersect those two bring large changes in QBO phases. Additionally, higher percentage of E p with λ z <1 km is also found to be associated with El Niño events.