Semi-Lagrangian semi-implicit locally one-dimensional scheme for hydrostatic atmospheric model

2006 ◽  
Vol 73 (1-4) ◽  
pp. 38-51
Author(s):  
Andrei Bourchtein
Keyword(s):  
Atmospheric Model ◽  
One Dimensional

scholarly journals A spectral nudging method for the ACCESS1.3 atmospheric model

2015 ◽  
Vol 8 (6) ◽  
pp. 1645-1658 ◽  
Author(s):  
P. Uhe ◽  
M. Thatcher
Keyword(s):  
Relaxation Method ◽  
Atmospheric Model ◽  
Care Needs ◽  
One Dimensional ◽  
Spectral Nudging ◽  
Earth Systems ◽  
Australian Community ◽  
Effectiveness And Efficiency ◽  
Convolution Approach ◽  
The Uk

Abstract. A convolution-based method of spectral nudging of atmospheric fields is developed in the Australian Community Climate and Earth Systems Simulator (ACCESS) version 1.3 which uses the UK Met Office Unified Model version 7.3 as its atmospheric component. The use of convolutions allow for flexibility in application to different atmospheric grids. An approximation using one-dimensional convolutions is applied, improving the time taken by the nudging scheme by 10–30 times compared with a version using a two-dimensional convolution, without measurably degrading its performance. Care needs to be taken in the order of the convolutions and the frequency of nudging to obtain the best outcome. The spectral nudging scheme is benchmarked against a Newtonian relaxation method, nudging winds and air temperature towards ERA-Interim reanalyses. We find that the convolution approach can produce results that are competitive with Newtonian relaxation in both the effectiveness and efficiency of the scheme, while giving the added flexibility of choosing which length scales to nudge.

scholarly journals Sensitivity studies of the recent new data on O(<sup>1</sup><i>D</i>) quantum yields in O<sub>3</sub> Hartley band photolysis in the stratosphere

2003 ◽  
Vol 3 (3) ◽  
pp. 2331-2352 ◽  
Author(s):  
N. Taniguchi ◽  
S. Hayashida ◽  
K. Takahashi ◽  
Y. Matsumi
Keyword(s):  
Atmospheric Chemistry ◽  
Atmospheric Model ◽  
Quantum Yields ◽  
Oh Radicals ◽  
One Dimensional ◽  
Near Ultraviolet ◽  
Steady State Model ◽  
Sensitivity Studies ◽  
Hartley Band ◽  
Excited Oxygen

Abstract. The production yields of excited oxygen O(1D) atoms from the near ultraviolet O3 photolysis are essential quantities for atmospheric chemistry calculations because of its importance as major sources of hydroxyl (OH) radicals and nitric oxide (NO). Recently, new O(1D) quantum yields from O3 photolysis between 230 and 305 nm in the Hartley band region were reported, which are almost independent of the photolysis wavelength (0.88-0.93) and smaller than NASA/JPL-2000 recommendation (0.95 between 240 and 300 nm). In order to assess consequences of the new data of O(1D) quantum yields on the stratospheric chemistry, the changes in stratospheric chemical partitioning and O3 concentration are examined using a one-dimensional atmospheric model. Our steady state model simulations for mid-latitude in March indicate that the smaller O(1D) quantum yields result in increases of stratospheric O3 (up to ~2% in the upper stratosphere), which are attributed to the changes in HOx, NOx, and ClOx abundance and their catalyzed O3 loss rates.

scholarly journals A spectral nudging method for the ACCESS1.3 atmospheric model

2014 ◽  
Vol 7 (5) ◽  
pp. 6677-6703
Author(s):  
P. Uhe ◽  
M. Thatcher
Keyword(s):  
Relaxation Method ◽  
Atmospheric Model ◽  
Care Needs ◽  
One Dimensional ◽  
Spectral Nudging ◽  
Earth Systems ◽  
Australian Community ◽  
Effectiveness And Efficiency ◽  
Convolution Approach ◽  
The Uk

Abstract. A convolution based method of spectral nudging of atmospheric fields is developed in the Australian Community Climate and Earth Systems Simulator (ACCESS) version 1.3 which uses the UK Met Office Unified Model version 7.3 as its atmospheric component. The use of convolutions allow flexibility in application to different atmospheric grids. An approximation using one-dimensional convolutions is applied, improving the time taken by the nudging scheme by 10 to 30 times compared with a version using a two-dimensional convolution, without measurably degrading its performance. Care needs to be taken in the order of the convolutions and the frequency of nudging to obtain the best outcome. The spectral nudging scheme is benchmarked against a Newtonian relaxation method, nudging winds and air temperature towards ERA-Interim reanalyses. We find that the convolution approach can produce results that are competitive with Newtonian relaxation in both the effectiveness and efficiency of the scheme, while giving the added flexibility of choosing which length scales to nudge.

scholarly journals Sensitivity studies of the recent new data on O(<sup>1</sup><i>D</i>) quantum yields in O<sub>3</sub> Hartley band photolysis in the stratosphere

2003 ◽  
Vol 3 (5) ◽  
pp. 1293-1300 ◽  
Author(s):  
N. Taniguchi ◽  
S. Hayashida ◽  
K. Takahashi ◽  
Y. Matsumi
Keyword(s):  
Atmospheric Chemistry ◽  
Atmospheric Model ◽  
Quantum Yields ◽  
Oh Radicals ◽  
One Dimensional ◽  
Near Ultraviolet ◽  
Steady State Model ◽  
Sensitivity Studies ◽  
Hartley Band ◽  
Excited Oxygen

Abstract. The production yields of excited oxygen O(1D) atoms from the near ultraviolet O3 photolysis are essential quantities for atmospheric chemistry calculations because of its importance as major sources of hydroxyl (OH) radicals and nitric oxide (NO). Recently, new O(1D) quantum yields from O3 photolysis between 230 and 305 nm in the Hartley band region were reported, which are almost independent of the photolysis wavelength (0.88-0.93) and smaller than NASA/JPL-2000 recommendations (0.95 between 240 and 300 nm). In order to assess consequences of the new data of O(1D) quantum yields on the stratospheric chemistry, the changes in stratospheric chemical partitioning and O3 concentration are examined using a one-dimensional atmospheric model. Our steady state model simulations for 40° N in March indicate that the smaller O(1D) quantum yields result in increases of stratospheric O3 (up to ~2% in the upper stratosphere), which are attributed to the changes in HOx, NOx, and ClOx abundance and their catalyzed O3 loss rates.

Application of the Ensemble Kalman Filter to a One-Dimensional Linear Advection Model

2015 ◽  
Vol 804 ◽  
pp. 287-290
Author(s):  
Somsiri Payakkarak ◽  
Dusadee Sukawat
Keyword(s):  
Kalman Filter ◽  
Data Assimilation ◽  
Ensemble Kalman Filter ◽  
Weather Prediction ◽  
Atmospheric Model ◽  
Ensemble Member ◽  
Observation Data ◽  
State Estimate ◽  
One Dimensional ◽  
Weather Forecasts

Data assimilation is used in numerical weather prediction to improve weather forecasts by incorporating observation data into the model forecast. The Ensemble Kalman Filter (EnKF) is a method of data assimilation which updates an ensemble of states to provide a state estimate and associated error at each step. The atmospheric model that is used in this research is a one-dimensional linear advection model. This model describes the motion of a scalar field as it is advected by a known speed field. The result shows that by selecting appropriate initial ensemble, model noise and measurement perturbations, it is possible to achieve a significant improvement in the EnKF results. The accuracy of the EnKF increases when the number of ensemble member grows. That is, the larger ensemble sizes perform better than those of smaller sizes.

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