Studies on the short-term planetary wave activity in the MLT region over Southern hemisphere using super DARN HF radar.

• Main Author: Ngwane, Ntlakanipho.
• Other Authors: Sivakumar, Venkataraman., Mthembu, Sibusiso Hector.
• Format: Thesis
• Language: English
• Published: 2023
• Subjects: Chemical composition; Super Dual Auroral Radar Network; semi-diurnal tide; Antarctic; SANAE; Antarc*
• Online Access: https://researchspace.ukzn.ac.za/handle/10413/22464

Master’s Degree. University of KwaZulu-Natal, Durban. The atmospheric vertical pressure profile, chemical composition and temperature distribution, together, define a set of conditions governing the manifestation of atmospheric dynamics. Observations and extensive research shows that lower atmospheric layers play host to the formation of forced atmospheric waves such as atmospheric planetary waves and solar tides. These waves serve as transportation modes for energy budgets and ascend to upper atmospheric layers where they induce significant meteorological processes. Planetary waves, tides and gravity waves often dissipate energy in the mesosphere lower-thermosphere (MLT) region. This dissertation presents a study of the planetary wave variability in the MLT region using the South African National Antarctic Expedition High Frequency (SANAE HF) radar data, a component of the Super Dual Auroral Radar Network (SuperDARN). The focus is on short term planetary waves with periods ranging from 2 to 6 days. This planetary wave variability in the MLT is investigated during the occurrence of minor sudden stratospheric warming (SSW) events. The study also investigates the assertion that there is a non-linear interaction between planetary waves and atmospheric tides. The mesospheric wind data considered stretched from year 1998 to year 2008. The criterion towards a conclusive investigation of short term planetary waves included determining years within the said interval (1998 to 2008) with minor SSW events. The 11 year long temperature data from the NCEP/NCAR reanalysis project was used for this. The study managed to show the previously stated finding that mesospheric wind reversal occurs a week prior the stratospheric wind reversal linked with the warming. Years 2002, 2003 and 2007 were shown to host minor SSW events. In year 2002, minor SSW events occurred in days 235, 243 and day 255. In year 2003, the minor SSW event occurred in day 280. The minor SSW for year 2007 occurred in day 263. This meant that the planetary ...