Abstract
The radio acoustic sounding system (RASS) with the equatorial atmosphere radar (EAR) at Koto Tabang, Indonesia was adapted to test the effects of the acoustic source location and acoustic frequency range on the continuous measurement of height profiles of temperature in the tropical troposphere. We installed the acoustic transmitting system by using six high-power horn speakers and four subwoofers. We developed a three-dimensional ray-tracing method of acoustic waves to predict the shape of acoustic wavefronts, accounting for the effects of the background winds on acoustic wave propagation. Then, we selected the appropriate antenna beam directions for EAR that satisfy the Bragg condition between the radar and acoustic wave propagation vectors. We carried out eight campaign observations in 2016, testing the performance of EAR–RASS. We found that the location and acoustic frequency range affected the RASS echoes. We also tested the compensation method of the background wind velocity with EAR to obtain the true sound speed. We intensively analyzed the RASS results from August 29 to September 3, 2016, when radiosondes were launched 12 times from the EAR site. We successfully retrieved the temperature profiles from RASS from 2 to 6–14 km with time and height resolutions of about 10 min and 150 m, respectively. Some temperature profiles were obtained up to about the tropopause at 17 km, although the observation period was short. During the RASS campaign, we detected a few interesting events regarding temperature variations as well as large perturbations in the three components of wind velocity.
Highlights
The behavior of atmospheric disturbances in the tropics was studied by using various observation techniques, such as radiosonde, weather radar, wind profiling radar (WPR), lidars, and satellite images
We focused on radio acoustic sounding system (RASS) in this study, which is a combination of a high-power sound transmitter and WPR for observations of time and height variations in temperature in the tropical troposphere
Temperature variations observed with equatorial atmosphere radar (EAR)–RASS in August–September 2016 We focus on the EAR–RASS results during campaign (7) from 08:56 local time in Indonesia (LT) on August 29 to 06:18 LT on September 3
Summary
The behavior of atmospheric disturbances in the tropics was studied by using various observation techniques, such as radiosonde, weather radar, wind profiling radar (WPR), lidars, and satellite images. Mesoscale numerical weather prediction (NWP) models were adopted to investigate dynamical characteristics during the events of intense cumulonimbus convection, land–sea circulation, and diurnal variations of convective activities (e.g., Emanuel 1987; Frank and Cohen 1987; Welsh et al 1999; Zhang and Fritsch 1988). Ground-based remote sensing techniques are useful for studying tropical convection. Given these conditions, equatorial atmosphere radar (EAR) was constructed in 2001 in Koto Tabang, West Sumatra under intensive collaboration between Japan and Indonesia (Fukao et al 2003). EAR is equipped with an active phased array antenna and can measure three components of wind velocity
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
