Turbulence Parameterization in a Deep Convection Model

1982 ◽  
pp. 395-409
Author(s):  
J. L. Redelsperger ◽  
G. Sommeria
Keyword(s):  
Deep Convection ◽  
Turbulence Parameterization ◽  
Convection Model

Geochemistry of syntectonic, crustal fluid regimes along the Lithoprobe Southern Canadian Cordillera Transect

1995 ◽  
Vol 32 (10) ◽  
pp. 1699-1719 ◽  
Author(s):  
Bruce E. Nesbitt ◽  
Karlis Muehlenbachs
Keyword(s):  
Deep Convection ◽  
Canadian Cordillera ◽  
Depth Of Penetration ◽  
Crustal Fluid ◽  
Quartz Veins ◽  
Economic Significance ◽  
Rock Types ◽  
Brittle Ductile Transition ◽  
Fluid Convection ◽  
Convection Model

In conjunction with the Lithoprobe southern Canadian Cordillera program, an extensive examination of geochemical indicators of origins, movement, chemical evolution, and economic significance of paleocrustal fluids was conducted. The study area covers approximately 360 000 km2from the Canadian Rockies to Vancouver Island. Research incorporated petrological, mineralogical, fluid-inclusion, δ18O, δD, δ13C, and Rb/Sr studies of samples of quartz ± carbonate veins and other rock types. The results of the study document a variety of pre-, syn-, and postorogenic, crustal fluid events. In the Rockies, a major pre-Laramide hydrothermal event was identified, which was comprised of a west to east migration of warm, saline brines. This was followed by a major circulation of meteoric water in the Rockies during Laramide uplift. In the southern Omineca extensional zone, convecting surface fluids penetrated to the brittle–ductile transition at 350–450 °C and locally into the underlying more ductile rocks. A principal conclusion of the study is that most quartz ± carbonate veins in metamorphic rocks in the southern Canadian Cordillera precipitated from deeply converted surface fluids. This conclusion supports a surface fluid convection model for the genesis of mesothermal Au–quartz veins, common in greenschist-facies rocks worldwide. The combination of our geochemical results with the results of other Lithoprobe studies indicates that widespread and deep convection of surface fluids in rocks undergoing active metamorphism is a commonplace phenomena in extensional settings, while in compressional-thrust settings the depth of penetration of surface fluids is more limited.

scholarly journals Convection: the likely source of the medium-scale gravity waves observed in the OH airglow layer near Brasilia, Brazil, during the SpreadFEx campaign

2009 ◽  
Vol 27 (1) ◽  
pp. 231-259 ◽  
Author(s):  
S. L. Vadas ◽  
M. J. Taylor ◽  
P.-D. Pautet ◽  
P. A. Stamus ◽  
D. C. Fritts ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Deep Convection ◽  
The Other ◽  
Medium Scale ◽  
Trace Model ◽  
Spread F ◽  
Convection Model ◽  
Ray Trace ◽  
Convective Plume ◽  
Vertical Scales

Abstract. Six medium-scale gravity waves (GWs) with horizontal wavelengths of λH=60–160 km were detected on four nights by Taylor et al. (2009) in the OH airglow layer near Brasilia, at 15° S, 47° W, during the Spread F Experiment (SpreadFEx) in Brazil in 2005. We reverse and forward ray trace these GWs to the tropopause and into the thermosphere using a ray trace model which includes thermospheric dissipation. We identify the convective plumes, convective clusters, and convective regions which may have generated these GWs. We find that deep convection is the highly likely source of four of these GWs. We pinpoint the specific deep convective plumes which likely excited two of these GWs on the nights of 30 September and 1 October. On these nights, the source location/time uncertainties were small and deep convection was sporadic near the modeled source locations. We locate the regions containing deep convective plumes and clusters which likely excited the other two GWs. The last 2 GWs were probably also excited from deep convection; however, they must have been ducted ~500–700 km if so. Two of the GWs were likely downwards-propagating initially (after which they reflected upwards from the Earth's surface), while one of the GWs was likely upwards-propagating initially from the convective plume/cluster. We also estimate the amplitudes and vertical scales of these waves at the tropopause, and compare their scales with those from a simple, linear convection model. Finally, we calculate each GW's dissipation altitude, location, and amplitude. We find that the dissipation altitude depends sensitively on the winds at and above the OH layer. We also find that several of these GWs may have penetrated to high enough altitudes to potentially seed equatorial spread F (ESF) if located somewhat farther from the magnetic equator.

Simulation of equatorial and high-latitude jets on Jupiter in a deep convection model

Nature ◽  
2005 ◽  
Vol 438 (7065) ◽  
pp. 193-196 ◽  
Author(s):  
Moritz Heimpel ◽  
Jonathan Aurnou ◽  
Johannes Wicht
Keyword(s):  
High Latitude ◽  
Deep Convection ◽  
Convection Model

A MICRO-CONVECTION MODEL FOR THERMAL CONDUCTIVITY OF NANOFLUIDS

Equipment ◽  
2006 ◽  
Author(s):  
H. E. Patel ◽  
K. B. Anoop ◽  
T. Sundararajan ◽  
S. K. Das
Keyword(s):  
Thermal Conductivity ◽  
Convection Model

Late Quaternary palaeo-oceanography of the Denmark Strait overflow pathway, South-East Greenland margin

1998 ◽  
Vol 180 ◽  
pp. 163-167
Author(s):  
Antoon Kuijpers ◽  
Jørn Bo Jensen ◽  
Simon R . Troelstra ◽  
And shipboard scientific party of RV Professor Logachev and RV Dana
Keyword(s):  
North Atlantic ◽  
Deep Water ◽  
Deep Convection ◽  
Conveyor Belt ◽  
Water Masses ◽  
Labrador Sea ◽  
Greenland Sea ◽  
The North ◽  
Denmark Strait ◽  
The North Atlantic

Direct interaction between the atmosphere and the deep ocean basins takes place today only in the Southern Ocean near the Antarctic continent and in the northern extremity of the North Atlantic Ocean, notably in the Norwegian–Greenland Sea and Labrador Sea. Cooling and evaporation cause surface waters in the latter region to become dense and sink. At depth, further mixing occurs with Arctic water masses from adjacent polar shelves. Export of these water masses from the Norwegian–Greenland Sea (Norwegian Sea Overflow Water) to the North Atlantic basin occurs via two major gateways, the Denmark Strait system and the Faeroe– Shetland Channel and Faeroe Bank Channel system (e.g. Dickson et al. 1990; Fig.1). Deep convection in the Labrador Sea produces intermediate waters (Labrador Sea Water), which spreads across the North Atlantic. Deep waters thus formed in the North Atlantic (North Atlantic Deep Water) constitute an essential component of a global ‘conveyor’ belt extending from the North Atlantic via the Southern and Indian Oceans to the Pacific. Water masses return as a (warm) surface water flow. In the North Atlantic this is the Gulf Stream and the relatively warm and saline North Atlantic Current. Numerous palaeo-oceanographic studies have indicated that climatic changes in the North Atlantic region are closely related to changes in surface circulation and in the production of North Atlantic Deep Water. Abrupt shut-down of the ocean-overturning and subsequently of the conveyor belt is believed to represent a potential explanation for rapid climate deterioration at high latitudes, such as those that caused the Quaternary ice ages. Here it should be noted, that significant changes in deep convection in Greenland waters have also recently occurred. While in the Greenland Sea deep water formation over the last decade has drastically decreased, a strong increase of deep convection has simultaneously been observed in the Labrador Sea (Sy et al. 1997).

Les tempêtes de fin d'hiver 2020

2020 ◽  
pp. 089
Author(s):  
Michael Kreitz
Keyword(s):  
Conceptual Models ◽  
Deep Convection

La fin de l'hiver 2019-2020 est marquée par la succession de tempêtes. Les zones de vents forts répondent à des schémas conceptuels très différent : jet de basses couches, jet en air froid, sting jet, forte instabilité et tempête de pente aval. The end of winter 2019-2020 is characterised by successive windstorms. The areas of severe winds correspond to various conceptual models: warm jet, cold jet, sting jet, deep convection and downslope windstorm.

scholarly journals Subseasonal Forecasts of the Northern Queensland Floods of February 2019: Causes and Forecast Evaluation

Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 758
Author(s):  
Wayne Yuan-Huai Tsai ◽  
Mong-Ming Lu ◽  
Chung-Hsiung Sui ◽  
Yin-Min Cho
Keyword(s):  
Large Scale ◽  
Deep Convection ◽  
Austral Summer ◽  
Rainfall Event ◽  
Monsoon Depression ◽  
Forecast Skill ◽  
Sea Surface ◽  
Central Pacific ◽  
Percentile Rank ◽  
Extended Range

During the austral summer 2018/19, devastating floods occurred over northeast Australia that killed approximately 625,000 head of cattle and inundated over 3000 homes in Townsville. In this paper, the disastrous event was identified as a record-breaking subseasonal peak rainfall event (SPRE). The SPRE was mainly induced by an anomalously strong monsoon depression that was modulated by the convective phases of an MJO and an equatorial Rossby (ER) wave. The ER wave originated from an active equatorial deep convection associated with the El Niño warm sea surface temperatures near the dateline over the central Pacific. Based on the S2S Project Database, we analyzed the extended-range forecast skill of the SPRE from two different perspectives, the monsoon depression represented by an 850-hPa wind shear index and the 15-day accumulated precipitation characterized by the percentile rank (PR) and the ratio to the three-month seasonal (DJF) totals. The results of four S2S models of this study suggest that the monsoon depression can maintain the same level of skill as the short-range (3 days) forecast up to 8–10 days. For precipitation parameters, the conclusions are similar to the monsoon depression. For the 2019 northern Queensland SPRE, the model forecast was, in general, worse than the expectation derived from the hindcast analysis. The clear modulation of the ER wave that enhanced the SPRE monsoon depression circulation and precipitation is suspected as the main cause for the lower forecast skill. The analysis procedure proposed in this study can be applied to analyze the SPREs and their associated large-scale drivers in other regions.

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