Functions
void	fill_sea_level_pressure (MultiFab &destination, int destination_component, const MultiFab &conserved_state, const MultiFab &physical_nodal_height, int vapor_component, int klo)

AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE amrex::Real	specific_humidity_from_dry_mixing_ratio (amrex::Real vapor_mixing_ratio) noexcept

AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE amrex::Real	virtual_temperature (amrex::Real temperature, amrex::Real specific_humidity) noexcept

AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE amrex::Real	apply_shuell_correction (amrex::Real virtual_temperature_surface, amrex::Real virtual_temperature_sea_level) noexcept

AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE amrex::Real	reconstruct_surface_pressure (amrex::Real pressure_lowest_level, amrex::Real virtual_temperature_lowest_level, amrex::Real virtual_temperature_surface, amrex::Real height_lowest_level, amrex::Real height_surface) noexcept

AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE amrex::Real	reduce_surface_pressure_to_sea_level (amrex::Real surface_pressure, amrex::Real temperature_lowest_level, amrex::Real specific_humidity, amrex::Real height_lowest_level, amrex::Real height_surface) noexcept

AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE amrex::Real	compute_from_erf_lowest_level_state (amrex::Real dry_density, amrex::Real dry_density_times_potential_temperature, amrex::Real vapor_mixing_ratio, amrex::Real height_lowest_level, amrex::Real height_surface) noexcept

void	fill_sea_level_pressure (amrex::MultiFab &destination, int destination_component, const amrex::MultiFab &conserved_state, const amrex::MultiFab &physical_nodal_height, int vapor_component, int klo)

Variables
constexpr amrex::Real	lapse_rate = amrex::Real(0.0065)

constexpr amrex::Real	shuell_critical_temperature = amrex::Real(290.66)

constexpr amrex::Real	shuell_quadratic_coefficient = amrex::Real(0.005)

constexpr amrex::Real	sea_level_height = amrex::Real(0.0)

constexpr amrex::Real	surface_height_deadband = amrex::Real(1.0)

Detailed Description

NMC/NGM sea-level-pressure reduction with the Shuell correction.

The algorithm and empirical parameters are adapted from NOAA-EMC UPP, sorc/ncep_post.fd/NGMSLP.f, commit 1ee7b175c340a566287a987870d925e4708fe19b.

This ERF implementation uses ERF's native thermodynamic constants and reconstructs ground-interface pressure from the lowest cell-centered atmospheric state. It is therefore an adaptation of the UPP algorithm, not a bit-for-bit reproduction of UPP output.

Function Documentation

◆ apply_shuell_correction()

AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE amrex::Real sea_level_pressure_diagnostics::apply_shuell_correction	(	amrex::Real	virtual_temperature_surface,
		amrex::Real	virtual_temperature_sea_level
	)

noexcept

Apply the NMC/NGM Shuell correction to the sea-level virtual temperature.

The strict/non-strict comparisons reproduce NGMSLP.f exactly. The quadratic temperature form is algebraically equivalent to UPP's tau-space form.

Parameters

[in]	virtual_temperature_surface	Ground-interface virtual temperature [K].
[in]	virtual_temperature_sea_level	Uncorrected sea-level virtual temperature [K].

Returns: Corrected sea-level virtual temperature [K].

 {
     if (virtual_temperature_sea_level > shuell_critical_temperature &&
         virtual_temperature_surface <= shuell_critical_temperature) {
         return shuell_critical_temperature;
     } else if (virtual_temperature_sea_level > shuell_critical_temperature &&
                virtual_temperature_surface > shuell_critical_temperature) {
         return shuell_critical_temperature -
                shuell_quadratic_coefficient *
                (virtual_temperature_surface - shuell_critical_temperature) *
                (virtual_temperature_surface - shuell_critical_temperature);
     }
     return virtual_temperature_sea_level;
 }

Referenced by reduce_surface_pressure_to_sea_level().

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◆ compute_from_erf_lowest_level_state()

AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE amrex::Real sea_level_pressure_diagnostics::compute_from_erf_lowest_level_state	(	amrex::Real	dry_density,
		amrex::Real	dry_density_times_potential_temperature,
		amrex::Real	vapor_mixing_ratio,
		amrex::Real	height_lowest_level,
		amrex::Real	height_surface
	)

noexcept

Compute the complete NMC/NGM reduction from an ERF conserved state.

ERF stores dry density, dry density times potential temperature, and (when active) dry-density times vapor mixing ratio. The pressure and temperature are diagnosed through ERF's EOS, then pressure is reconstructed at the ground interface before the method-specific sea-level reduction.

Parameters

[in]	dry_density	Lowest-level dry-air density [kg/m^3].
[in]	dry_density_times_potential_temperature	Lowest-level rho_d theta [kg K/m^3].
[in]	vapor_mixing_ratio	Lowest-level vapor mixing ratio [kg/kg dry air].
[in]	height_lowest_level	Lowest cell-center physical height [m].
[in]	height_surface	Ground-interface physical height [m].

Returns: Pressure reduced to physical z=0 [Pa].

Precondition: State and heights are finite and physically valid; use zero mixing ratio for dry runs.

 {
     const amrex::Real specific_humidity =
         specific_humidity_from_dry_mixing_ratio(vapor_mixing_ratio);
     const amrex::Real pressure_lowest =
         getPgivenRTh(dry_density_times_potential_temperature,
                      vapor_mixing_ratio);
     const amrex::Real temperature_lowest =
         getTgivenRandRTh(dry_density,
                          dry_density_times_potential_temperature,
                          vapor_mixing_ratio);
     const amrex::Real virtual_temperature_lowest =
         virtual_temperature(temperature_lowest, specific_humidity);
     const amrex::Real virtual_temperature_surface =
         virtual_temperature_lowest + lapse_rate *
         (height_lowest_level - height_surface);
     const amrex::Real pressure_surface = reconstruct_surface_pressure(
         pressure_lowest, virtual_temperature_lowest, virtual_temperature_surface,
         height_lowest_level, height_surface);
  
     return reduce_surface_pressure_to_sea_level(
         pressure_surface, temperature_lowest, specific_humidity,
         height_lowest_level, height_surface);
 }

Referenced by fill_sea_level_pressure().

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◆ fill_sea_level_pressure() [1/2]

void sea_level_pressure_diagnostics::fill_sea_level_pressure	(	amrex::MultiFab &	destination,
		int	destination_component,
		const amrex::MultiFab &	conserved_state,
		const amrex::MultiFab &	physical_nodal_height,
		int	vapor_component,
		int	klo
	)

Fill one selected 2D field from each column's lowest ERF state.

Parameters

[out]	destination	2D destination MultiFab; only destination_component is written.
[in]	destination_component	Component to fill in destination.
[in]	conserved_state	Cell-centered ERF conserved state MultiFab.
[in]	physical_nodal_height	Absolute physical nodal heights [m].
[in]	vapor_component	Conserved vapor component, or -1 for a dry run.
[in]	klo	Lowest valid source-state vertical index for this AMR level.

◆ fill_sea_level_pressure() [2/2]

void sea_level_pressure_diagnostics::fill_sea_level_pressure	(	MultiFab &	destination,
		int	destination_component,
		const MultiFab &	conserved_state,
		const MultiFab &	physical_nodal_height,
		int	vapor_component,
		int	klo
	)

 {
     AMREX_ALWAYS_ASSERT(destination_component >= 0);
     AMREX_ALWAYS_ASSERT(destination_component < destination.nComp());
     AMREX_ALWAYS_ASSERT(conserved_state.nComp() > Rho_comp);
     AMREX_ALWAYS_ASSERT(conserved_state.nComp() > RhoTheta_comp);
     AMREX_ALWAYS_ASSERT(vapor_component < 0 || vapor_component < conserved_state.nComp());
  
 #ifdef _OPENMP
 #pragma omp parallel if (amrex::Gpu::notInLaunchRegion())
 #endif
     for (MFIter mfi(destination, TilingIfNotGPU()); mfi.isValid(); ++mfi) {
         const Box& bx = mfi.tilebox();
         const auto destination_arr = destination.array(mfi);
         const auto conserved_arr = conserved_state.const_array(mfi);
         const auto height_arr = physical_nodal_height.const_array(mfi);
  
         ParallelFor(bx, [=] AMREX_GPU_DEVICE (int i, int j, int k) noexcept {
             const Real dry_density = conserved_arr(i, j, klo, Rho_comp);
             const Real dry_density_times_potential_temperature =
                 conserved_arr(i, j, klo, RhoTheta_comp);
             const Real vapor_mixing_ratio = vapor_component < 0
                 ? zero
                 : conserved_arr(i, j, klo, vapor_component) / dry_density;
             const Real height_lowest_level =
                 Compute_Z_AtCellCenter(i, j, klo, height_arr);
             const Real height_surface = Compute_Z_AtWFace(i, j, klo, height_arr);
  
             destination_arr(i, j, k, destination_component) =
                 compute_from_erf_lowest_level_state(
                     dry_density, dry_density_times_potential_temperature,
                     vapor_mixing_ratio, height_lowest_level, height_surface);
         });
     }
 }

Referenced by ERF::Write2DPlotFile().

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◆ reconstruct_surface_pressure()

AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE amrex::Real sea_level_pressure_diagnostics::reconstruct_surface_pressure	(	amrex::Real	pressure_lowest_level,
		amrex::Real	virtual_temperature_lowest_level,
		amrex::Real	virtual_temperature_surface,
		amrex::Real	height_lowest_level,
		amrex::Real	height_surface
	)

noexcept

Reconstruct pressure at the lower terrain interface from the lowest cell.

Parameters

[in]	pressure_lowest_level	Lowest cell-center pressure [Pa].
[in]	virtual_temperature_lowest_level	Lowest cell-center virtual temperature [K].
[in]	virtual_temperature_surface	Ground-interface virtual temperature [K].
[in]	height_lowest_level	Lowest cell-center physical height [m].
[in]	height_surface	Ground-interface physical height [m].

Returns: Ground-interface pressure [Pa].

 {
     const amrex::Real mean_tau = (R_d / CONST_GRAV) *
         (virtual_temperature_lowest_level + virtual_temperature_surface) /
         amrex::Real(2.0);
     return pressure_lowest_level * std::exp(
         (height_lowest_level - height_surface) / mean_tau);
 }

Referenced by compute_from_erf_lowest_level_state().

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◆ reduce_surface_pressure_to_sea_level()

AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE amrex::Real sea_level_pressure_diagnostics::reduce_surface_pressure_to_sea_level	(	amrex::Real	surface_pressure,
		amrex::Real	temperature_lowest_level,
		amrex::Real	specific_humidity,
		amrex::Real	height_lowest_level,
		amrex::Real	height_surface
	)

noexcept

Reconstruct ground-interface pressure and reduce it to physical z=0.

Parameters

[in]	surface_pressure	Ground-interface pressure [Pa].
[in]	temperature_lowest_level	Lowest cell-center temperature [K].
[in]	specific_humidity	Lowest-level specific humidity [kg/kg].
[in]	height_lowest_level	Lowest cell-center physical height [m].
[in]	height_surface	Ground-interface physical height [m].

Returns: Pressure reduced to the physical z=0 datum [Pa].

 {
     const amrex::Real virtual_temperature_lowest =
         virtual_temperature(temperature_lowest_level, specific_humidity);
     const amrex::Real virtual_temperature_surface =
         virtual_temperature_lowest + lapse_rate *
         (height_lowest_level - height_surface);
     const amrex::Real virtual_temperature_sea_level =
         virtual_temperature_lowest + lapse_rate *
         (height_lowest_level - sea_level_height);
     const amrex::Real corrected_virtual_temperature_sea_level =
         apply_shuell_correction(virtual_temperature_surface,
                                 virtual_temperature_sea_level);
     const amrex::Real mean_tau_surface_sea_level =
         (R_d / CONST_GRAV) *
         (virtual_temperature_surface + corrected_virtual_temperature_sea_level) /
         amrex::Real(2.0);
  
     if (amrex::Math::abs(height_surface - sea_level_height) <=
         surface_height_deadband) {
         return surface_pressure;
     }
     return surface_pressure * std::exp(
         (height_surface - sea_level_height) / mean_tau_surface_sea_level);
 }

Referenced by compute_from_erf_lowest_level_state().

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◆ specific_humidity_from_dry_mixing_ratio()

AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE amrex::Real sea_level_pressure_diagnostics::specific_humidity_from_dry_mixing_ratio ( amrex::Real vapor_mixing_ratio )

noexcept

Convert ERF dry-air water-vapor mixing ratio to specific humidity.

Parameters

[in] vapor_mixing_ratio Water vapor mass per unit dry-air mass [kg/kg].

Returns: Specific humidity used by the NMC/NGM reduction [kg/kg].

Precondition: The mixing ratio is finite and nonnegative.

 {
     return vapor_mixing_ratio / (amrex::Real(1.0) + vapor_mixing_ratio);
 }

Referenced by compute_from_erf_lowest_level_state().

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◆ virtual_temperature()

AMREX_GPU_HOST_DEVICE AMREX_FORCE_INLINE amrex::Real sea_level_pressure_diagnostics::virtual_temperature	(	amrex::Real	temperature,
		amrex::Real	specific_humidity
	)

noexcept

Compute virtual temperature using ERF's native gas constants.

Parameters

[in]	temperature	Physical temperature [K].
[in]	specific_humidity	Specific humidity [kg/kg].

Returns: Virtual temperature [K].

 {
     // UPP uses rounded 0.608; ERF uses the equivalent coefficient from its
     // shared R_d and R_v so the diagnostic remains EOS-consistent.
     return temperature * (amrex::Real(1.0) + epsv * specific_humidity);
 }