An Improved Gridded Bathymetric Dataset and Tidal Model for the Maldives Archipelago

A large tidal model of the St. Lawrence River covering the region from Montreal to lie du Bic is connected directly to a mini computer for data acquisition and control of the tidal boundary. Some of the more important concepts for the design and operation of a computer based system for this application are described. Details of an adaptive feedback controller for diurnal tides are given. A 16 mm film (N.R.C.-Division of Mechanical Engineering, film no. HYP 620, same title) describes the instrumentation and operation of the model. A report (N.R.C.-Division of Mechanical Engineering, Report No. MH-110, same title) provides further details of this system.

Download Full-text

Climatology of migrating and non-migrating tides observed by three meteor radars in the southern equatorial region

10.5194/acp-2021-33 ◽

2021 ◽

Author(s):

Jianyuan Wang ◽

Wen Yi ◽

Jianfei Wu ◽

Tingdi Chen ◽

Xianghui Xue ◽

...

Keyword(s):

Harmonic Analysis ◽

Northern Hemisphere ◽

Climate Model ◽

Equatorial Region ◽

Stratospheric Sudden Warming ◽

Tidal Model ◽

Community Climate Model ◽

Zonal Wavenumber ◽

Climatic Features ◽

Community Climate

Abstract. We present a study of migrating and non-migrating tidal winds observed simultaneously by three meteor radars situated in the southern equatorial region. The radars are located at Cariri (7.4° S, 36.5° W), Brazil, Kototabang (0.2° S, 100.3° E), Indonesia and Darwin (12.3° S, 130.8° E), Australia. Harmonic analysis was used to obtain amplitudes and phases for diurnal and semidiurnal solar migrating and non-migrating tides between 80 and 100 km altitude during the period 2005 to 2008. They include the important tidal components of diurnal westward-propagating zonal wavenumber 1 (DW1), diurnal eastward-propagating zonal wavenumber 3 (DE3), semidiurnal westward-propagating zonal wavenumber 2 (SW2), and semidiurnal eastward-propagating zonal wavenumber 2 (SE2). In addition, we also present a climatology of these wind tides and analyze the reliability of the fitting through the reference to Whole Atmosphere Community Climate Model (WACCM) winds. The analysis suggests that the migrating tides could be well fitted by the three different radars, but the non-migrating tides might be overestimated. The results based on observations were also compared with the Climatological Tidal Model of the Thermosphere (CTMT). In general, climatic features between observations and model migrating tides were satisfactory in both wind components. However, the features of the DW1, DE3 and SW2 amplitudes in both wind components were slightly different from the results of the CTMT models. This result is probably because tides could be enhanced by the 2006 northern hemisphere stratospheric sudden warming (NH-SSW) event.

Download Full-text