Three-Dimensional Constituent Transport Models and the Study of Interannual Variability

Three-dimensional numerical simulations of canonical statistically steady, statistically planar turbulent flames have been used in an attempt to produce distributed burning in lean methane and hydrogen flames. Dilatation across the flame means that extremely large Karlovitz numbers are required; even at the extreme levels of turbulence studied (up to a Karlovitz number of 8767) distributed burning was only achieved in the hydrogen case. In this case, turbulence was found to broaden the reaction zone visually by around an order of magnitude, and thermodiffusive effects (typically present for lean hydrogen flames) were not observed. In the preheat zone, the species compositions differ considerably from those of one-dimensional flames based a number of different transport models (mixture averaged, unity Lewis number and a turbulent eddy viscosity model). The behaviour is a characteristic of turbulence dominating non-unity Lewis number species transport, and the distinct limit is again attributed to dilatation and its effect on the turbulence. Peak local reaction rates are found to be lower in the distributed case than in the lower Karlovitz cases but higher than in the laminar flame, which is attributed to effects that arise from the modified fuel-temperature distribution that results from turbulent mixing dominating low Lewis number thermodiffusive effects. Finally, approaches to achieve distributed burning at realisable conditions are discussed; factors that increase the likelihood of realising distributed burning are higher pressure, lower equivalence ratio, higher Lewis number and lower reactant temperature.

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Influence of the Monsoon Trough on Westward-Propagating Tropical Waves over the Western North Pacific. Part I: Observations

Journal of Climate ◽

10.1175/jcli-d-14-00806.1 ◽

2015 ◽

Vol 28 (18) ◽

pp. 7108-7127 ◽

Cited By ~ 21

Author(s):

Liang Wu ◽

Zhiping Wen ◽

Renguang Wu

Keyword(s):

Interannual Variability ◽

North Pacific ◽

Western North Pacific ◽

Three Dimensional ◽

Marked Change ◽

Monsoon Trough ◽

Dimensional Structure ◽

Tropical Depression ◽

Tropical Waves ◽

East West

Abstract The present study investigates the possible linkage between the monsoon trough and the interannual variability of the activity of westward-propagating tropical waves (WTW) over the western North Pacific (WNP) during July–November for the period 1979–2007. It is shown that the interannual variability of WTW activity is closely related to the location of the monsoon trough. During the years when the enhanced (weakened) monsoon trough extends eastward (retreats westward), the lower-tropospheric WTW activity is above (below) normal within the southeastern quadrant of the WNP. Furthermore, this study evaluates different wave structures and dynamics of two types of WTWs, equatorial Rossby (ER) waves and mixed Rossby–gravity (MRG)–tropical depression (TD)-type waves, in strong monsoon trough (S-MT) and weak monsoon trough (W-MT) years over the WNP. There is a significant change in the three-dimensional structure as those waves propagate westward to the east of the monsoon trough. For the TD–MRG waves, an apparent transition from MRG waves to off-equatorial TD disturbances is identified in the region of the monsoon trough. For the ER waves, their amplitudes have a faster growth, but their structures and propagation characters have no marked change. Differences in the location of the monsoon trough may lead to an east–west contrast in the WTWs. In a companion study (Part II), diagnostics of energetics and numerical experiments are conducted to explain the observed results in the present study.

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Estimation of spatially varying parameters in three-dimensional cohesive sediment transport models by assimilating remote sensing data

Journal of Marine Science and Technology ◽

10.1007/s00773-017-0477-3 ◽

2017 ◽

Vol 23 (2) ◽

pp. 319-332 ◽

Cited By ~ 5

Author(s):

Jicai Zhang ◽

Dongdong Chu ◽

Daosheng Wang ◽

Anzhou Cao ◽

Xianqing Lv ◽

...

Keyword(s):

Remote Sensing ◽

Sediment Transport ◽

Three Dimensional ◽

Remote Sensing Data ◽

Cohesive Sediment ◽

Transport Models ◽

Varying Parameters ◽

Sensing Data ◽

Cohesive Sediment Transport ◽

Spatially Varying

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Review of effective emissions modeling and computation

Geoscientific Model Development ◽

10.5194/gmd-4-643-2011 ◽

2011 ◽

Vol 4 (3) ◽

pp. 643-667 ◽

Cited By ~ 25

Author(s):

R. Paoli ◽

D. Cariolle ◽

R. Sausen

Keyword(s):

Large Scale ◽

Three Dimensional ◽

Reaction Rates ◽

Transport Models ◽

Global Circulation ◽

Global Circulation Models ◽

Emissions Modeling ◽

Exhaust Plumes ◽

Physical And Chemical ◽

Scale Grid

Abstract. An important issue in the evaluation of the environmental impact of emissions from concentrated sources such as transport modes, is to understand how processes occurring at the scales of exhaust plumes can influence the physical and chemical state of the atmosphere at regional and global scales. Indeed, three-dimensional global circulation models or chemistry transport models generally assume that emissions are instantaneously diluted into large-scale grid boxes, which may lead, for example, to overpredict the efficiency of NOx to produce ozone. In recent times, various methods have been developed to incorporate parameterizations of plume processes into global models that are based e.g. on correcting the original emission indexes or on introducing "subgrid" reaction rates in the models. This paper provides a review of the techniques proposed so far in the literature to account for local conversion of emissions in the plume, as well as the implementation of these techniques into atmospheric codes.

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Solving Three-Dimensional Transport Models with Synchronous and Asynchronous Iterative Algorithms in a Grid Computing Environment

19th IEEE International Parallel and Distributed Processing Symposium ◽

10.1109/ipdps.2005.405 ◽

2005 ◽

Cited By ~ 1

Author(s):

J.M. Bahi ◽

R. Couturier ◽

M. Salomon

Keyword(s):

Grid Computing ◽

Three Dimensional ◽

Iterative Algorithms ◽

Computing Environment ◽

Transport Models

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Subtropical trace gas profiles determined by ground-based FTIR spectroscopy at Izaña (28° N, 16° W): Five-year record, error analysis, and comparison with 3-D CTMs

Atmospheric Chemistry and Physics ◽

10.5194/acp-5-153-2005 ◽

2005 ◽

Vol 5 (1) ◽

pp. 153-167 ◽

Cited By ~ 49

Author(s):

M. Schneider ◽

T. Blumenstock ◽

M. P. Chipperfield ◽

F. Hase ◽

W. Kouker ◽

...

Keyword(s):

Error Analysis ◽

Three Dimensional ◽

Trace Gas ◽

Transport Models ◽

Solar Absorption ◽

Annual Cycles ◽

Mixing Ratios ◽

Chemical Transport Models ◽

Tenerife Island ◽

The Vertical Distribution

Abstract. Within the framework of the NDSC (Network for the Detection of Stratospheric Change) ground-based FTIR solar absorption spectra have been routinely recorded at Izaña Observatory (28° N, 16° W) on Tenerife Island since March 1999. By analyzing the shape of the absorption lines, and their different temperature sensitivities, the vertical distribution of the absorbers can be retrieved. Unique time series of subtropical profiles of O3, HCl, HF, N2O, and CH4 are presented. The effects of both dynamical and chemical annually varying trace gas cycles can be seen in the retrieved profiles. These include enhanced upwelling and photochemistry in summer and a more disturbed atmosphere in winter, which are typical of the subtropical stratosphere. A detailed error analysis has been performed for each profile. The output from two different three-dimensional (3-D) chemical transport models (CTMs), which are forced by ECMWF analyses, are compared to the measured profiles. Both models agree well with the measurements in tracking abrupt variations in the atmospheric structure, e.g. due to tropical streamers, in particular for the lower stratosphere. Simulated and measured profiles also reflect similar dynamical and chemical annual cycles. However, the differences between their mixing ratios clearly exceed the error bars estimated for the measured profiles. Possible reasons for this are discussed.

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