tc_utils.py

# ============================*
 # ** Copyright UCAR (c) 2020
 # ** University Corporation for Atmospheric Research (UCAR)
 # ** National Center for Atmospheric Research (NCAR)
 # ** Research Applications Lab (RAL)
 # ** P.O.Box 3000, Boulder, Colorado, 80307-3000, USA
 # ============================*
 
 
 
import os
import sys
import logging
import calendar
import math
import numpy as np
from netCDF4 import Dataset

# nautical miles to kilometers conversion factor
nm_to_km = 1.852

def format_valid_time(valid_time):
    """
    Format valid time.
    """
    year = valid_time // 1000000
    month = valid_time // 10000 - 100 * year
    day = valid_time // 100 - 10000 * year - 100 * month
    hour = valid_time - 1000000 * year - 10000 * month - 100 * day
    month_name = calendar.month_name[month]
    valid_time_str = '%d %s %2.2d %2.2d:00Z' % (year, month_name, day, hour)
    return valid_time_str

def read_tcrmw(filename):
    """
    Read pressure level variables from
    netcdf file generated by the TCRMW tool.
    """

    try:
        file_id = Dataset(filename, 'r')
        logging.info('reading ' + filename)
    except IOError:
        logging.error('failed to open ' + filename)
        sys.exit()

    valid_time = file_id.variables['valid_time'][:]
    # read grid variables
    lat_grid = file_id.variables['lat'][:]
    lon_grid = file_id.variables['lon'][:]
    range_grid = file_id.variables['range'][:]
    azimuth_grid = file_id.variables['azimuth'][:]
    pressure_grid = file_id.variables['pressure'][:]

    logging.debug('lat_grid.shape=' + str(lat_grid.shape))
    logging.debug('lon_grid.shape=' + str(lon_grid.shape))

    # read track center and cyclone radius
    track_data = {}
    track_data['Lat'] = file_id.variables['Lat'][:]
    track_data['Lon'] = file_id.variables['Lon'][:]
    track_data['RMW'] = file_id.variables['RMW'][:] * nm_to_km
    track_data['TrackLines'] = file_id.variables['TrackLines'][:]

    # possible U, V variable names
    u_vars = set(['U', 'UGRD'])
    v_vars = set(['V', 'VGRD'])

    grid_vars = set(['valid_time', 'lat', 'lon',
        'range', 'azimuth', 'pressure'])
    track_vars = set(['Lat', 'Lon', 'RMW', 'TrackLines'])
    wind_data = {}
    scalar_data = {}

    # read all variables and group as either wind or scalar
    for var in file_id.variables:
        logging.info(var)
        if var in u_vars:
            wind_data['U'] = file_id.variables[var][:]
        if var in v_vars:
            wind_data['V'] = file_id.variables[var][:]
        if var not in grid_vars.union(track_vars).union(u_vars).union(v_vars):
            scalar_data[var] = file_id.variables[var][:]

    file_id.close()

    return valid_time, lat_grid, lon_grid, \
        range_grid, azimuth_grid, pressure_grid, \
        track_data, wind_data, scalar_data

def read_vert_interp_tcrmw(filename):
    """
        Read pressure level variables from the
        netcdf file generated by the METcalcpy vertical_interpolation tool.

        Args:
            @param filename: The input filename that has the vertically interpolated levels.  This is
                             the netCDF file created by the METcalcpy vertical_interpolation.py module/tool.

        Returns:
        @param valid_time: The valid time
        @param range_grid:  A grid of range values
        @param azimuth_grid: Grid of the azimuthal values
        @param pressure_grid: Corresponds to the 'lev' in the input netCDF file generated by METcalcpy vertical_interpolation
        @param wind_data:  wind data used to calculate the radial and tangential winds



    """

    try:
        file_id = Dataset(filename, 'r')
        logging.info('reading ' + filename)
    except IOError:
        logging.error('failed to open ' + filename)
        sys.exit()

    valid_time = file_id.variables['valid_time'][:]

    # read grid variables
    range_grid = file_id.variables['range'][:]
    azimuth_grid = file_id.variables['azimuth'][:]
    pressure_grid = file_id.variables['lev'][:]


    # possible U, V variable names
    u_vars = set(['U', 'UGRD'])
    v_vars = set(['V', 'VGRD'])

    # grid_vars = set(['valid_time', 'lat', 'lon',
    #     'range', 'azimuth', 'pressure'])
    grid_vars = set(['valid_time',
                     'range', 'azimuth', 'pressure'])
    wind_data = {}
    scalar_data = {}

    # read all variables and group as either wind or scalar
    for var in file_id.variables:
        logging.info(var)
        if var in u_vars:
            wind_data['U'] = file_id.variables[var][:]
        if var in v_vars:
            wind_data['V'] = file_id.variables[var][:]

    file_id.close()

    return valid_time,  \
        range_grid, azimuth_grid, pressure_grid, \
        wind_data

def read_tcrmw_levels(filename, levels=['L0']):
    """
    Read level-labeled variables from
    netcdf file generated by the TCRMW tool.
    """

    try:
        file_id = Dataset(filename, 'r')
        logging.info('reading ' + filename)
    except IOError:
        logging.error('failed to open ' + filename)
        sys.exit()

    valid_time = file_id.variables['valid_time'][:]
    lat_grid = file_id.variables['lat'][:]
    lon_grid = file_id.variables['lon'][:]

    logging.debug('lat_grid.shape=' + str(lat_grid.shape))
    logging.debug('lon_grid.shape=' + str(lon_grid.shape))

    grid_vars = set(['lat', 'lon', 'range', 'azimuth'])
    wind_data = {}
    scalar_data = {}

    for level in levels:
        u_vars = set(['U_' + level, 'UGRD_' + level])
        v_vars = set(['V_' + level, 'VGRD_' + level])

        for var in file_id.variables:
            logging.info(var)
            if var in u_vars:
                wind_data['U'] = file_id.variables[var][:]
            if var in v_vars:
                wind_data['V'] = file_id.variables[var][:]
            if var not in grid_vars.union(u_vars).union(v_vars):
                scalar_data[var] = file_id.variables[var][:]

    file_id.close()

    return valid_time, lat_grid, lon_grid, wind_data, scalar_data
   
   
if __name__ == '__main__':
    print(format_valid_time(2019050123))