Use of Regional Covariance in Data Assimilation Method to Improve the Estimation Accuracy of a Three Dimensional Contaminant Transport Model

2011 ◽  
Author(s):  
Shoou-Yuh Chang ◽  
Sikdar Latif
Keyword(s):  
Data Assimilation ◽  
Contaminant Transport ◽  
Transport Model ◽  
Three Dimensional ◽  
Estimation Accuracy

scholarly journals Generalizing Source Geometry of Site Contamination by Simulating and Analyzing Analytical Solution of Three-Dimensional Solute Transport Model

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Xingwei Wang ◽  
Jiajun Chen ◽  
Hao Wang ◽  
Jianfei Liu
Keyword(s):  
Solute Transport ◽  
Contaminant Transport ◽  
Transport Model ◽  
Three Dimensional ◽  
Fate And Transport ◽  
Source Area ◽  
Equation Model ◽  
Plume Migration ◽  
Advective Diffusion ◽  
Source Geometry

Due to the uneven distribution of pollutions and blur edge of pollutant area, there will exist uncertainty of source term shape in advective-diffusion equation model of contaminant transport. How to generalize those irregular source terms and deal with those uncertainties is very critical but rarely studied in previous research. In this study, the fate and transport of contaminant from rectangular and elliptic source geometry were simulated based on a three-dimensional analytical solute transport model, and the source geometry generalization guideline was developed by comparing the migration of contaminant. The result indicated that the variation of source area size had no effect on pollution plume migration when the plume migrated as far as five times of source side length. The migration of pollution plume became slower with the increase of aquifer thickness. The contaminant concentration was decreasing with scale factor rising, and the differences among various scale factors became smaller with the distance to field increasing.

Assessment of the quality of the ozone measurements from the Odin/SMR instrument using data assimilation

2007 ◽  
Vol 85 (11) ◽  
pp. 1209-1223 ◽  
Author(s):  
S Massart ◽  
A Piacentini ◽  
D Cariolle ◽  
L El Amraoui ◽  
N Semane
Keyword(s):  
Data Assimilation ◽  
Transport Model ◽  
Three Dimensional ◽  
The Other ◽  
Measuring Instruments ◽  
Atmospheric Measurements ◽  
Data Set ◽  
Ozone Data ◽  
Using Data

Space-based remote-sensing instruments providing atmospheric measurements have different time and space resolutions, and coverage. This makes the direct comparison of the measurements very difficult. Data assimilation has proven to be a far more powerful tool than simple interpolation techniques to create three-dimensional analyzed fields for a given data set. In this paper, we describe how the assimilation of ozone data from the Odin/SMR instrument can be used to assess its precisions and biases against other ozone-measuring instruments. To assess the quality of Odin/SMR ozone retrievals by MOLIERE-5 against ozonesondes, Envisat/MIPAS, Earth Probe/TOMS, and UARS/HALOE data, we use a three-dimensional variational assimilation scheme applied to the Météo-France MOCAGE chemistry transport model. The MOCAGE-PALM assimilation system has been already used by Météo-France and CERFACS to analyse the Envisat/MIPAS data for the ASSET intercomparison exercise. We have further developed and calibrated the configuration of this system to better account for the Odin/SMR ozone profiles. The upgraded system is used to assimilate the Odin/SMR ozone during the August 2003 – November 2003 period and intercomparisons are made with the other ozone measuring techniques. The Odin/SMR analysis and the other ozone data sets are in good agreement at mid and high latitudes, while in the lower tropical stratosphere, we found a positive bias of the Odin/SMR, Envisat/MIPAS, and Earth Probe/TOMS data compared to measurements from UARS/HALOE and ozonesondes. The precision of Odin/SMR ozone retrievals in terms of standard deviation is about 20% in the tropics, below 10% at high southern latitudes, and below 5% at high northern latitudes. PACS No.: 82.33.Tb

scholarly journals Accelerating Contaminant Transport Simulation in MT3DMS Using JASMIN-Based Parallel Computing

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1480
Author(s):  
Xingwei Liu ◽  
Qiulan Zhang ◽  
Tangpei Cheng
Keyword(s):  
Contaminant Transport ◽  
Large Scale ◽  
Transport Model ◽  
Parallel Implementation ◽  
Domain Decomposition Method ◽  
Three Dimensional ◽  
Memory Consumption ◽  
Structured Meshes ◽  
Coupling Mode ◽  
Solution Accuracy

To overcome the large time and memory consumption problems in large-scale high-resolution contaminant transport simulations, an efficient approach was presented to parallelize the modular three-dimensional transport model for multi-species (MT3DMS) (University of Alabama, Tuscaloosa, AL, USA) program on J adaptive structured meshes applications infrastructures (JASMIN). In this approach, a domain decomposition method and a stencil-based method were used to accomplish parallel implementation, while a ghost cell strategy was used for communication. The MODFLOW-MT3DMS coupling mode was optimized to achieve the parallel coupling of flow and contaminant transport. Five types of models were used to verify the correctness and test the parallel performance of the method. The developed parallel program JMT3D (China University of Geosciences (Beijing), Beijing, China) can increase the speed by up to 31.7 times, save memory consumption by 96% with 46 processors, and ensure that the solution accuracy and convergence do not decrease as the number of domains increases. The BiCGSTAB (Bi-conjugate gradient variant algorithm) method required the least amount of time and achieved high speedup in most cases. Coupling the flow and contaminant transport further improved the efficiency of the simulations, with a 33.45 times higher speedup achieved on 46 processors. The AMG (algebraic multigrid) method achieved a good scalability, with an efficiency above 100% on hundreds of processors for the simulation of tens of millions of cells.

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