def test_eis_isentropic_profile():
# make an atmosphere which cools only half as fast with height as
# isentropic, making it very stable
dTdz = -0.5 * g / cp_d
ds = make_fixed_lapse_rate_dry_profile(dTdz=dTdz, z_max=5.0e3)
ds[nom.POTENTIAL_TEMPERATURE] = atmos.potential_temperature(
ds=ds, vertical_coord=nom.ALTITUDE)
# add a moist layer need the surface (z < 500m)
ds[nom.RELATIVE_HUMIDITY] = 0.9 * xr.ones_like(ds[nom.TEMPERATURE]).where(
ds[nom.ALTITUDE] < 500.0, 0.0)
ds[nom.RELATIVE_HUMIDITY].attrs["units"] = "1"
ds[nom.RELATIVE_HUMIDITY].attrs["long_name"] = "relative humidity"
ds[nom.RELATIVE_HUMIDITY].attrs["standard_name"] = nom.CF_STANDARD_NAMES[
nom.RELATIVE_HUMIDITY]
LCL_name = bl_variables.lcl.find_LCL_Bolton.name
LTS_name = tropical_variables.lower_tropospheric_stability.name
da_lts = tropical_variables.lower_tropospheric_stability(
ds=ds, pressure=nom.PRESSURE)
ds[LTS_name] = da_lts
da_lcl = bl_variables.lcl.find_LCL_Bolton(ds=ds)
ds[LCL_name] = da_lcl
da_eis = tropical_variables.estimated_inversion_strength(ds=ds,
LCL=LCL_name,
LTS=LTS_name)
assert da_eis.units == "K"
assert np.all(da_eis > 0.0)
def test_lts_linear_profile_pressure_coord():
dtheta = 2.0 # [K]
theta0 = 300.0
theta1 = theta0 + dtheta
p0 = 100000.0 # [Pa], surface pressure
p1 = 70000.0 # [Pa], pressure at height of theta1
ds = make_pressure_grid(p0=p0, p_min=p1, dp=10.0)
da_theta = (
theta0
+ (ds[nom.PRESSURE] - p0) * (theta1 - theta0) / (p1 - p0)
+ 0.0 * ds.timestep
)
da_theta.attrs["units"] = "K"
da_theta.attrs["long_name"] = "potential temperature"
ds[nom.POTENTIAL_TEMPERATURE] = da_theta
lts = tropical_variables.lower_tropospheric_stability(
ds=ds, pressure=nom.PRESSURE, vertical_coord=nom.PRESSURE
)
assert lts.units == "K"
# TODO: after adding linear interpolation inside the LTS routine this
# should become more accurate
assert np.allclose(lts, dtheta, rtol=1.0e-3)
def test_lts_isentropic_profile():
ds = make_fixed_lapse_rate_dry_profile(dTdz="isentropic")
ds[nom.POTENTIAL_TEMPERATURE] = atmos.potential_temperature(
ds=ds, vertical_coord=nom.ALTITUDE)
lts = tropical_variables.lower_tropospheric_stability(
ds=ds, pressure=nom.PRESSURE)
assert lts.units == "K"
assert np.allclose(lts, 0.0)
def test_eis_joanne_profile():
ds = eurec4a_environment.source_data.open_joanne_dataset()
ds = ds.isel(sonde_id=slice(0, 10))
LCL_name = bl_variables.lcl.find_LCL_Bolton.name
da_lcl = bl_variables.lcl.find_LCL_Bolton(ds=ds)
ds[LCL_name] = da_lcl
LTS_name = tropical_variables.lower_tropospheric_stability.name
da_lts = tropical_variables.lower_tropospheric_stability(
ds=ds, pressure=nom.PRESSURE
)
ds[LTS_name] = da_lts
da_eis = tropical_variables.estimated_inversion_strength(ds=ds, LCL=LCL_name, LTS=LTS_name)
assert da_eis.units == "K"
assert np.all(da_eis > 0.0)