swirlspy.qpf package

Submodules

swirlspy.qpf.persistence module

swirlspy.qpf.persistence.persistence(xr2d, timesteps, timesteps_size)

Forecast by persistence, accepting an observation xarray and returning a forecast xarray. Persistence means that the forecast is exactly same as the observation. While it sounds trivial, this is usefulf for benchmarking the performacne of another QPF algorithm. Parameters

xr2d: xarray.DataArray (2-dimensional, in ‘x’ ‘y’)

The xarray containing data to be forecasted.

timesteps: int

Number of timesteps to be forecasted.

timesteps_size: int

Time interval between each steps, in minutes.

Returns

persistence_xrnd – Data values in ‘xr2d’ being copied along the ‘end_time’ axis, coordinates of ‘end_time’ axis have a unique value for each timestep.

Return type

xarray.DataArray

swirlspy.qpf.qpfrover module

swirlspy.qpf.qpfrover.flip_grid(grid)

Flip a grid vertically (in y-axis).

Parameters

grid (numpy.ndarray) –

Returns

flipped grid

Return type

numpy.ndarray

swirlspy.qpf.qpfrover.grid2ascii(grid_number, gridded_flip, ncols, nrows, xllcenter, yllcenter, cellsize, nodata_value, valid_time, steps, time_step_size, start_level, end_level, rho, alpha, sigma)

Export 2 radar data grid (cartesian coordinates) in consecutive timesteps and rover parameters on a text file (.txt) in ascii format.

Text file returned by this function is the input file for “rover” for extrpolation.

Parameters

  • grid_number –

  • gridded_flip –

  • ncols –

  • nrows –

  • xllcenter –

  • yllcenter –

  • cellsize –

:param : :param nodata_value: :param valid_time: :param steps: :param time_step_size: :param start_level: :param end_level: :param : :param rho: :param alpha: :param sigma:

Returns

  • “rover-input.txt”,

  • a text file located at directory “./input”.

swirlspy.qpf.qpfrover.grid2txt(file, grid)

Export a data grid on a .txt file.

Parameters

  • file (str) – Name of the output text file.

  • grid (numpy.ndarray) – Data grid to be exported.

Returns

  • A .txt file named according to the above input parameter “file”,

  • where number of lines equals row number of the input grid,

  • number of data on each line equals column number of the input grid.

swirlspy.qpf.qpfrover.rover_colorimage(path, output)

Plot radar data from “rover-output-[timestep].txt” as color images.

(“rover-output-[timestep].txt” are output files located at “./output” from the program “rover” (Default path)).

Parameters

path (str) – Directory to look for “rover-output-[timestep].txt”.

Returns

  • Color images named “rover-output-[timestep].png”, located at

  • ”./output”(Default path).

swirlspy.qpf.qpfrover.rover_map(reflectivity, path)

Plots a radar image from rover

Parameters

  • reflectivity (xarray.DataArray) – The output of rover

  • path (str) – path of the python script calling this function

Return type

Radar images named “rover-output-[timestep].png”

swirlspy.qpf.qpfrover.rover_qpf(qpf_xarray, xllcenter, yllcenter, valid_time, steps, time_step_size, path)

Perform qpf by calling ‘rover.so’ and using xarray.

Parameters

  • qpf_xarray (xarray.DataArray) – A ‘xrnd’ (Two ‘xr2d’ concatenated) from function ‘xrnd’.

  • xllcenter (float) – Radar site longitude.

  • yllcenter (float) – Radar site latitude.

  • valid_time (str) – [YYYYMMDDhhmm] of the first-timestep radar file.

  • steps (int) – Number of timesteps to extrapolate. Default is 6.

  • time_step_size (int) – Separation time between 2 input radar files in minutes.

  • path (str) – stores the path of the file calling the module

Returns

  • motion_u (x.array.DataArray) – x component of motion field

  • motion_v (x.array.DataArray) – y component of motion field

  • reflectivity (x.array.DataArray) – reflectivity in dBz

swirlspy.qpf.qpfrover.time_update(initial, time_step_size)

Shift time by a certain amount.

Parameters

  • initial (str) – Base time, in YYYYMMDDhhmm.

  • time_step_size (str) – Amount of time to shift, in minutes.

Returns

end – Updated time, in YYYYMMDDhhmm.

Return type

str

swirlspy.qpf.qpfrover.txt2image(file)

Plot a data grid in text file as a color image.

Parameters

file (str) – Filename of text file containing data grid.

Return type

Color image named “filename_of_input_text_file.png”