metpy.calc.
q_vector
Calculate Q-vector at a given pressure level using the u, v winds and temperature.
This formula follows equation 5.7.55 from [Bluestein1992], and can be used with the the below form of the quasigeostrophic omega equation to assess vertical motion ([Bluestein1992] equation 5.7.54):
u ((…, M, N) xarray.DataArray or pint.Quantity) – x component of the wind (geostrophic in QG-theory)
xarray.DataArray
pint.Quantity
v ((…, M, N) xarray.DataArray or pint.Quantity) – y component of the wind (geostrophic in QG-theory)
temperature ((…, M, N) xarray.DataArray or pint.Quantity) – Array of temperature at pressure level
pressure (pint.Quantity) – Pressure at level
dx (pint.Quantity, optional) – The grid spacing(s) in the x-direction. If an array, there should be one item less than the size of u along the applicable axis. Optional if xarray.DataArray with latitude/longitude coordinates used as input.
dy (pint.Quantity, optional) – The grid spacing(s) in the y-direction. If an array, there should be one item less than the size of u along the applicable axis. Optional if xarray.DataArray with latitude/longitude coordinates used as input.
static_stability (pint.Quantity, optional) – The static stability at the pressure level. Defaults to 1 if not given to calculate the Q-vector without factoring in static stability.
x_dim (int, optional) – Axis number of x dimension. Defaults to -1 (implying […, Y, X] order). Automatically parsed from input if using xarray.DataArray.
y_dim (int, optional) – Axis number of y dimension. Defaults to -2 (implying […, Y, X] order). Automatically parsed from input if using xarray.DataArray.
tuple of (…, M, N) xarray.DataArray or pint.Quantity – The components of the Q-vector in the u- and v-directions respectively
Changed in version 1.0: Changed signature from (u, v, temperature, pressure, dx, dy, static_stability=1)
(u, v, temperature, pressure, dx, dy, static_stability=1)
See also
static_stability