Accessing regridded JRA55 velocities

[suhanidalal]

I am setting up a near-global simulation with ClimaOcean, loosely based on this example. I want to compute the gas transfer velocity using the regridded atmospheric wind components (u and v velocities), but I'm running into issues accessing the regridded values – I can only seem to extract the native JRA grid (640x320) data. Since the JRA55 wind components are stored as FieldTimeSeries, I can't directly construct a Field from them on the model grid.

This sets up the atmospheric forcings and is how I eventually am trying to access the wind components.

atmosphere = ClimaOcean.JRA55PrescribedAtmosphere(arch)
u10 = atmosphere.velocities.u
v10 = atmosphere.velocities.v

I also tried extracting the surface velocity at the current simulation time like this:

t = time(sim)
times = u10.times
ti = findlast(tt -> tt ≤ t, times)
u10_surface = interior(u10[ti])[:, :, end]

But again, this just gives me the data on the JRA grid.

Is there a way to access the regridded wind components (u and v)? Separately, if I want to modify the wind product, can I still retain the rest of the JRA55 forcings?

Thank you!

[glwagner]

Hi @suhanidalal, the regridded atmosphere u velocity for example is currently located at

coupled_model.interfaces.exchanger.exchange_atmosphere_state.u

This information is not documented as you have noticed! The source code is here:

ClimaOcean.jl/src/OceanSeaIceModels/InterfaceComputations/component_interfaces.jl

Lines 50 to 77 in b53fcf1

	mutable struct ComponentInterfaces{AO, ASI, SIO, C, AP, OP, SIP, EX, P}
	atmosphere_ocean_interface :: AO
	atmosphere_sea_ice_interface :: ASI
	sea_ice_ocean_interface :: SIO
	atmosphere_properties :: AP
	ocean_properties :: OP
	sea_ice_properties :: SIP
	exchanger :: EX
	net_fluxes :: C
	properties :: P
	end
	mutable struct StateExchanger{G, AST, AEX}
	exchange_grid :: G
	exchange_atmosphere_state :: AST
	atmosphere_exchanger :: AEX
	end
	mutable struct ExchangeAtmosphereState{F}
	u :: F
	v :: F
	T :: F
	q :: F
	p :: F
	Qs :: F
	Qℓ :: F
	Mp :: F
	end

thank you for opening this discussion. I think adding documentation for the regridded atmosphere fields (or more completely, all regridded fields) should be added in the future in a tutorial of some kind.

Note that the internal code structure is subject to change. We are hoping to refactor things to make it easier to access for users. If we do that, we can create documentation for the new interface which will hopefully help you migrate your code at that time.

@seamanticscience may be interested in this application.