JonathanGregory
commented
3 years ago Dear Andy
Thanks for these proposals, which make sense to me. I think the names you propose are pretty clear, except that it would be better if due_to_viscosity were more informative. Maybe this could be due_to_ocean_viscous_dissipation? Is this molecular viscosity, in a very thin boundary layer, or a turbulent process? Also, I think sea_surface_wave_dissipation would be more normal language than sea_surface_waves_dissipation, or you could consider dissipation_of_sea_surface_waves, like the existing phrase due_to_dissipation_of_orographic_gravity_waves.
Best wishes
Jonathan
ukmo-ansaulter
feggleton
japamment
Proposer's name : Andy Saulter Date : 1st February 2021
Notes: Sorry this is a long one! The definitions below aim to describe parameters related to a decomposition of atmosphere-ocean surface stress transfers, when considering transmission via sea surface wave growth and dissipation. Terms for the decomposition at the wavy sea-surface (where wave induced stress dominates and turbulent stress is reduced to zero) are as follows:
(atmospheric) surface stress = viscous stress + wave supported stress
where wave supported stress is a related to the dynamic form drag associated with waves in different sea-states (see also Mete Uz et al., 2002; https://link.springer.com/article/10.1023/A:1013119313063 ), then:
(ocean) surface stress = viscous stress + wave dissipation stress
where wave dissipation stress differs from the wave supported stress. This is because some of the momentum flux from the atmosphere will be absorbed by the waves in building seas, whilst the waves will pass momentum to the ocean through dissipative processes such as whitecapping when seas are both building and in the initial phases of transition from wind-sea to swell dominated conditions. Finally, there is a return flux to the atmosphere, for example swell waves passing through otherwise still airs can cause a disturbance at the atmosphere sea surface boundary.
Based on existing definitions and the recent proposals from Nan Galbraith, hopefully the following are appropriate:
Term: surface_downward_eastward_stress_due_to_sea_surface_waves Unit: Pa The surface called "surface" means the lower boundary of the atmosphere. "Surface stress" means the shear stress (force per unit area) exerted by the wind at the surface. A downward stress is a downward flux of momentum. Over large bodies of water, wind stress can drive near-surface currents. "Downward" indicates a vector component which is positive when directed downward (negative upward). "Eastward" indicates a vector component which is positive when directed northward (negative southward). "Downward eastward" indicates the ZX component of a tensor. A downward eastward stress is a downward flux of eastward momentum, which accelerates the lower medium eastward and the upper medium westward. The specification of a physical process by the phrase "dueto" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Sea surface waves" means the stress associated with form drag over sea surface waves.
Term: surface_downward_northward_stress_due_to_sea_surface_waves Unit: Pa The surface called "surface" means the lower boundary of the atmosphere. "Surface stress" means the shear stress (force per unit area) exerted by the wind at the surface. A downward stress is a downward flux of momentum. Over large bodies of water, wind stress can drive near-surface currents. "Downward" indicates a vector component which is positive when directed downward (negative upward). "Northward" indicates a vector component which is positive when directed northward (negative southward). "Downward northward" indicates the ZY component of a tensor. A downward northward stress is a downward flux of northward momentum, which accelerates the lower medium northward and the upper medium southward. The specification of a physical process by the phrase "dueto" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Sea surface waves" means the stress associated with form drag over sea surface waves.
Term: surface_downward_eastward_stress_due_to_viscosity Unit: Pa The surface called "surface" means the lower boundary of the atmosphere. "Surface stress" means the shear stress (force per unit area) exerted by the wind at the surface. A downward stress is a downward flux of momentum. Over large bodies of water, wind stress can drive near-surface currents. "Downward" indicates a vector component which is positive when directed downward (negative upward). "Eastward" indicates a vector component which is positive when directed northward (negative southward). "Downward eastward" indicates the ZX component of a tensor. A downward eastward stress is a downward flux of eastward momentum, which accelerates the lower medium eastward and the upper medium westward. The specification of a physical process by the phrase "dueto" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Viscosity" means the stress associated with viscous effects at the sea surface and is equivalent to the turbulent stress just outside the viscous sublayer.
Term: surface_downward_northward_stress_due_to_viscosity Unit: Pa The surface called "surface" means the lower boundary of the atmosphere. "Surface stress" means the shear stress (force per unit area) exerted by the wind at the surface. A downward stress is a downward flux of momentum. Over large bodies of water, wind stress can drive near-surface currents. "Downward" indicates a vector component which is positive when directed downward (negative upward). "Northward" indicates a vector component which is positive when directed northward (negative southward). "Downward northward" indicates the ZY component of a tensor. A downward northward stress is a downward flux of northward momentum, which accelerates the lower medium northward and the upper medium southward. The specification of a physical process by the phrase "dueto" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Viscosity" means the stress associated with viscous effects at the sea surface and is equivalent to the turbulent stress just outside the viscous sublayer.
Term: sea_surface_downward_eastward_stress_due_to_sea_surface_waves_dissipation Unit: Pa The surface called "sea surface" means the upper boundary of the ocean. "Surface stress" means the shear stress (force per unit area) exerted at the surface. A downward stress is a downward flux of momentum. Over large bodies of water, surface stress can drive near-surface currents. "Downward" indicates a vector component which is positive when directed downward (negative upward). "Eastward" indicates a vector component which is positive when directed northward (negative southward). "Downward eastward" indicates the ZX component of a tensor. A downward eastward stress is a downward flux of eastward momentum, which accelerates the lower medium eastward and the upper medium westward. The specification of a physical process by the phrase "dueto" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Sea surface waves dissipation" means the stress associated with sea surface waves dissipation processes such as whitecapping.
Term: sea_surface_downward_northward_stress_due_to_sea_surface_waves_dissipation Unit: Pa The surface called "sea surface" means the upper boundary of the ocean. "Surface stress" means the shear stress (force per unit area) exerted at the surface. A downward stress is a downward flux of momentum. Over large bodies of water, surface stress can drive near-surface currents. "Downward" indicates a vector component which is positive when directed downward (negative upward). "Northward" indicates a vector component which is positive when directed northward (negative southward). "Downward northward" indicates the ZY component of a tensor. A downward northward stress is a downward flux of northward momentum, which accelerates the lower medium northward and the upper medium southward. The specification of a physical process by the phrase "dueto" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Sea surface waves dissipation" means the stress associated with sea surface waves dissipation processes such as whitecapping.
Term: surface_upward_eastward_stress_due_to_sea_surface_waves Unit: Pa The surface called "surface" means the lower boundary of the atmosphere. "Surface stress" means the shear stress (force per unit area) exerted at the surface. An upward stress is an upward flux of momentum into the atmosphere. "Upward" indicates a vector component which is positive when directed upward (negative downward). "Eastward" indicates a vector component which is positive when directed northward (negative southward). "Upward eastward" indicates the ZX component of a tensor. An upward eastward stress is an upward flux of eastward momentum, which accelerates the upper medium eastward and the lower medium westward. The specification of a physical process by the phrase "dueto" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Sea surface waves" means the stress associated with oscillatory motions of a wavy sea surface.
Term: surface_upward_northward_stress_due_to_sea_surface_waves Unit: Pa The surface called "surface" means the lower boundary of the atmosphere. "Surface stress" means the shear stress (force per unit area) exerted at the surface. An upward stress is an upward flux of momentum into the atmosphere. "Upward" indicates a vector component which is positive when directed upward (negative downward). "Northward" indicates a vector component which is positive when directed northward (negative southward). "Upward northward" indicates the ZY component of a tensor. An upward northward stress is an upward flux of northward momentum, which accelerates the upper medium northward and the lower medium southward. The specification of a physical process by the phrase "dueto" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Sea surface waves" means the stress associated with oscillatory motions of a wavy sea surface.