Mid-Term Science and Technology Meeting RESEARCH HIGHLIGHTS AND MAJOR ACCOMPLISHMENTS D. BALA SUBRAHAMANYAM NUMERICAL ATMOSPHERE MODELLING (NAM) BRANCH SPACE PHYSICS LABORATORY,VIKRAM SARABHAI SPACE CENTRE THIRUVANANTHAPURAM - 695 022 URL: http://SPL.gov.in/ D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 1 / 23
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Mid-Term Science and Technology Meeting RESEARCH ...€¦ · MID-TERM SCIENCE & TECHNOLOGY MEETING (MARCH 2016) Coastal ABL Features over Thiruvananthapuram Diurnal/Seasonal Evolution
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Mid-Term Science and Technology Meeting
RESEARCH HIGHLIGHTS
AND MAJOR ACCOMPLISHMENTS
D. BALA SUBRAHAMANYAM
NUMERICAL ATMOSPHERE MODELLING (NAM) BRANCH
SPACE PHYSICS LABORATORY, VIKRAM SARABHAI SPACE CENTRE
THIRUVANANTHAPURAM - 695 022
URL: http://SPL.gov.in/
D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 1 / 23
MID-TERM SCIENCE & TECHNOLOGY MEETING (MARCH 2016) Why do we bother too much about this Parametrization ?
Why do we bother too much about Parametrization ???
Generally, the physical and atmospheric processes which happen to be sub-grid in
nature, require parametrization as they can not be solved directly !!!
D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 2 / 23
MID-TERM SCIENCE & TECHNOLOGY MEETING (MARCH 2016) Evolution in the Model Topography
Evolution in the Model Topography in the last 2 decades
D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 3 / 23
MID-TERM SCIENCE & TECHNOLOGY MEETING (MARCH 2016) Evolution in the Model Topography
Evolution in the Model Topography in the last 2 decades
D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 3 / 23
MID-TERM SCIENCE & TECHNOLOGY MEETING (MARCH 2016) Evolution in the Model Topography
Evolution in the Model Topography in the last 2 decades
D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 3 / 23
MID-TERM SCIENCE & TECHNOLOGY MEETING (MARCH 2016) Evolution in the Model Topography
Evolution in the Model Topography in the last 2 decades
D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 3 / 23
MID-TERM SCIENCE & TECHNOLOGY MEETING (MARCH 2016) Evolution in the Model Topography
Evolution in the Model Topography in the last 2 decades
D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 3 / 23
MID-TERM SCIENCE & TECHNOLOGY MEETING (MARCH 2016) Evolution in the Model Topography
Evolution in the Model Topography in the last 2 decades
D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 3 / 23
MID-TERM SCIENCE & TECHNOLOGY MEETING (MARCH 2016) Evolution in the Model Topography
COSMO Topography: From Past to Present
⇒
NEED OF THE HOUR:
We need to review and look back at the sub-grid scale processes and their treatment in
the Regional Atmospheric Models.
D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 4 / 23
MID-TERM SCIENCE & TECHNOLOGY MEETING (MARCH 2016) Parametrization of Different Physical Processes
Parametrization of Different Physical Processes
A Schematic on different processes being parametrized in NWP Models
D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 5 / 23
MID-TERM SCIENCE & TECHNOLOGY MEETING (MARCH 2016) Parametrization of the ABL Processes
Criticalities involved in the treatment of ABL Processes
Impact of Convective Thermals on the ABL Structure
D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 6 / 23
MID-TERM SCIENCE & TECHNOLOGY MEETING (MARCH 2016) Parametrization of the ABL Processes
Criticalities involved in the treatment of ABL Processes
Transition of the Laminar Flow to a Turbulent Flow
D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 6 / 23
MID-TERM SCIENCE & TECHNOLOGY MEETING (MARCH 2016) Parametrization of the ABL Processes
Criticalities involved in the treatment of ABL Processes
Important Unknowns in the ABL Characterization
D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 6 / 23
MID-TERM SCIENCE & TECHNOLOGY MEETING (MARCH 2016) Parametrization of the ABL Processes
Parametrization of ABL Processes based on K-theory
Assumption : Analogy between turbulent and molecular transfer
Flux is proportional to the local gradient
F = −K ∂A∂z
K is eddy diffusivity/viscosity;
similar to molecular viscosity
Based on the estimation of K, COSMO model offers
two distinct approaches for parametrization of ABL processes:
(1) MYD, Diagnostic approach
(2) MYTKE, Turbulent Kinetic Energy (TKE) based Prognostic approach
D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 7 / 23
MID-TERM SCIENCE & TECHNOLOGY MEETING (MARCH 2016) Parametrization of the ABL Processes
ABL Parametrization Schemes in the COSMO Model
MYD
1-D Diagnostic
Closure
=⇒
MYTKE
1-D TKE-based
Diagnostic Closure
⇐=
D. Bala Subrahamanyam (NAM) Mid-Term Science and Technology Meeting 22 - 29 March 2016 8 / 23