Low-Level Convergence Lines over Northeastern Australia. Part I: The North Australian Cloud Line

Goler, Robert; Reeder, Michael J.; Smith, Roger K.; Richter, Harald; Arnup, Sarah; Keenan, Tom; May, Peter; Hacker, Jorg
November 2006
Monthly Weather Review;Nov2006, Vol. 134 Issue 11, p3092
Academic Journal
Observations of dry-season north Australian cloud lines (NACLs) that form in the Gulf of Carpentaria region of northern Australia and the sea-breeze circulations that initiate them are described. The observations were made during the 2002 Gulf Lines Experiment (GLEX) and include measurements made by an instrumented research aircraft. The observations are compared with numerical simulations made from a two-dimensional cloud-scale model. Particular emphasis is placed on the interaction between the east coast and west coast sea breezes near the west coast of Cape York Peninsula. The sea breezes are highly asymmetric due to the low-level easterly synoptic flow over the peninsula. The west coast sea breeze is well defined with a sharp leading edge since the opposing flow limits its inland penetration, keeping it close to its source of cold air. In contrast, the east coast sea breeze is poorly defined since it is aided by the easterly flow and becomes highly modified by daytime convective mixing as it crosses over the peninsula. Both the observations and the numerical model show that, in the early morning hours, the mature NACL forms at the leading edge of a gravity current. The numerical model simulations show that this gravity current arises as a westward-moving land breeze from Cape York Peninsula. Convergence at the leading edge of this land breeze is accompanied by ascent, which when strong enough produces cloud. Observations show that the decay of the NACL is associated with a decline in the low-level convergence and a weakening of the ascent.


Related Articles

  • Daytime Local Circulations and Their Interactions in the Seoul Metropolitan Area. Ryu, Young-Hee; Baik, Jong-Jin // Journal of Applied Meteorology & Climatology;Apr2013, Vol. 52 Issue 4, p784 

    Daytime local circulations and their interactions in the Seoul, South Korea, metropolitan area are investigated using a high-resolution mesoscale model. It is found that the urban-breeze circulation interacts strongly with other local circulations, such as sea-breeze, cross-valley, and...

  • Observation of Sea Breeze Front and its Induced Convection over Chennai in Southern Peninsular India Using Doppler Weather Radar. Suresh, R. // Pure & Applied Geophysics;Aug2007, Vol. 164 Issue 8/9, p1511 

    Sea breeze, the onshore wind over a coastal belt during daytime, is a welcoming weather phenomenon as it modulates the weather condition by moderating the scorching temperature and acts as a favourable mechanism to trigger convection and induce precipitation over coastal and interior locations....

  • Simulating the influence of the South Atlantic dipole on the South Atlantic convergence zone during neutral ENSO. Bombardi, Rodrigo; Carvalho, Leila; Jones, Charles // Theoretical & Applied Climatology;Oct2014, Vol. 118 Issue 1/2, p251 

    The South Atlantic Convergence Zone (SACZ) is an intrinsic characteristic of the South American Summer Monsoon. In a recent study, we verified that the main mode of coupled variability over the South Atlantic (South Atlantic Dipole (SAD)) plays a role in modulating the position of extratropical...

  • Roles of the Atmospheric Heat Sources in Maintaining the Subtropical Convergence Zones: An... Kodama, Yasu-Masa // Journal of the Atmospheric Sciences;12/1/99, Vol. 56 Issue 23, p4032 

    Uses an aqua-planet general circulation model (GCM) to study diabatic heating contributions in tropical monsoons and the subtropical convergence zones (STCZ) that maintain the STCZ. Role of the tropical monsoons in forming the STCZ; Influence of the strong heating in the STCZ to atmospheric...

  • Observational and Numerical Study on the Influence of Large-Scale Flow Direction and Coastline Shape on Sea-Breeze Evolution. Gilliam, Robert C.; Raman, Sethu; Niyogi, Dev Dutta S. // Boundary-Layer Meteorology;May2004, Vol. 111 Issue 2, p275 

    In this study radar, surface observations and numerical simulations are used to examine the inland penetration and intensity of the sea breeze during various large-scale flow regimes along the curved coastline of the Carolinas, U.S.A. The results clearly indicate that the flow direction relative...

  • Dynamical analysis of sea-breeze hodograph rotation in Sardinia. Moisseeva, N.; Steyn, D. G. // Atmospheric Chemistry & Physics;2014, Vol. 14 Issue 24, p13471 

    This study investigates the diurnal evolution of sea-breeze (SB) rotation over an island at the middle latitudes. Earlier research on sea breezes in Sardinia shows that the onshore winds around various coasts of the island exhibit both the theoretically predicted clockwise rotation as well as...

  • Convective Initiation ahead of the Sea-Breeze Front. Fovell, Robert G. // Monthly Weather Review;Jan2005, Vol. 133 Issue 1, p264 

    In earlier work, a three-dimensional cloud model was used to simulate the interaction between the sea-breeze front (SBF) and front-parallel horizontal convective rolls (HCRs), resulting in the SBF systematically encountering roll updrafts and downdrafts as it progressed inland. Interestingly,...

  • Climatological characteristics of frontogenesis and related circulations over East China in June and July. Hou, Jun; Guan, Zhaoyong // Acta Meteorologica Sinica;Apr2013, Vol. 27 Issue 2, p144 

    Based on daily precipitation data from 212 stations in East China and NCEP/NCAR daily global final analysis data in June and July from 2000 to 2010, the climatological characteristics of frontogenesis and related circulations have been analyzed. The results demonstrate that frontogenesis...

  • The Annual Cycle of East African Precipitation. Yang, Wenchang; Seager, Richard; Cane, Mark A.; Lyon, Bradfield // Journal of Climate;Mar2015, Vol. 28 Issue 6, p2385 

    East African precipitation is characterized by a dry annual mean climatology compared to other deep tropical land areas and a bimodal annual cycle with the major rainy season during March-May (MAM; often called the 'long rains') and the second during October-December (OND; often called the...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics