get_init.py

import numpy as np
import sys

def get_init(spd, T, SST, lat, P, Rl, Rs, cskin, gust, L, tol, meth, qmeth):
    """
    Checks initial input values and sets defaults if needed

    Parameters
    ----------
    spd : float
        relative wind speed in m/s (is assumed as magnitude difference
        between wind and surface current vectors)
    T : float
        air temperature in K
    SST : float
        sea surface temperature in K
    lat : float
        latitude (deg), default 45deg
    P : float
        air pressure (hPa), default 1013hPa
    Rl : float
        downward longwave radiation (W/m^2)
    Rs : float
        downward shortwave radiation (W/m^2)
    cskin : int
        0 switch cool skin adjustment off, else 1
        default is 1
    gust : int
        3x1 [x, beta, zi] x=1 to include the effect of gustiness, else 0
        beta gustiness parameter, beta=1 for UA, beta=1.2 for COARE
        zi PBL height (m) 600 for COARE, 1000 for UA and ERA5, 800 default
        default for COARE [1, 1.2, 600]
        default for UA, ERA5 [1, 1, 1000]
        default else [1, 1.2, 800]
    L : int
        Monin-Obukhov length definition options
        0 : default for S80, S88, LP82, YT96 and LY04
        1 : following UA (Zeng et al., 1998), default for UA
        2 : following ERA5 (IFS Documentation cy46r1), default for ERA5
        3 : COARE3.5 (Edson et al., 2013), default for C30, C35 and C40
    tol : float
        4x1 or 7x1 [option, lim1-3 or lim1-6]
        option : 'flux' to set tolerance limits for fluxes only lim1-3
        option : 'ref' to set tolerance limits for height adjustment lim-1-3
        option : 'all' to set tolerance limits for both fluxes and height
                 adjustment lim1-6 ['all', 0.01, 0.01, 5e-05, 0.01, 1, 1]
    meth : str
        "S80","S88","LP82","YT96","UA","LY04","C30","C35","C40","ERA5"
    qmeth : str
        is the saturation evaporation method to use amongst
        "HylandWexler","Hardy","Preining","Wexler","GoffGratch","CIMO",
        "MagnusTetens","Buck","Buck2","WMO","WMO2000","Sonntag","Bolton",
        "IAPWS","MurphyKoop"]
        default is Buck2

    Returns
    -------
    lat : float
        latitude
    P : float
        air pressure (hPa)
    Rl : float
        downward longwave radiation (W/m^2)
    Rs : float
        downward shortwave radiation (W/m^2)
    cskin : int
        cool skin adjustment switch
    gust : int
        gustiness switch
    tol : float
        tolerance limits
    L : int
        MO length switch

    """
    if ((type(spd) != np.ndarray) or (type(T) != np.ndarray) or
         (type(SST) != np.ndarray)):
        sys.exit("input type of spd, T and SST should be numpy.ndarray")
    # if input values are nan break
    if meth not in ["S80", "S88", "LP82", "YT96", "UA", "LY04", "C30", "C35",
                    "C40","ERA5"]:
        sys.exit("unknown method")
    if qmeth not in ["HylandWexler", "Hardy", "Preining", "Wexler", "CIMO",
                      "GoffGratch", "MagnusTetens", "Buck", "Buck2", "WMO",
                      "WMO2000", "Sonntag", "Bolton", "IAPWS", "MurphyKoop"]:
        sys.exit("unknown q-method")
    if (np.all(np.isnan(spd)) or np.all(np.isnan(T)) or np.all(np.isnan(SST))):
        sys.exit("input wind, T or SST is empty")
    if (np.all(lat == None)):  # set latitude to 45deg if empty
        lat = 45*np.ones(spd.shape)
    elif ((np.all(lat != None)) and (np.size(lat) == 1)):
        lat = np.ones(spd.shape)*np.copy(lat)
    if ((np.all(P == None)) or np.all(np.isnan(P))):
        P = np.ones(spd.shape)*1013
    elif (((np.all(P != None)) or np.all(~np.isnan(P))) and np.size(P) == 1):
        P = np.ones(spd.shape)*np.copy(P)
    if (np.all(Rl == None) or np.all(np.isnan(Rl))):
        Rl = np.ones(spd.shape)*370    # set to default for COARE3.5
    if (np.all(Rs == None) or np.all(np.isnan(Rs))):
        Rs = np.ones(spd.shape)*150  # set to default for COARE3.5
    if ((cskin == None) and (meth == "S80" or meth == "S88" or meth == "LP82"
                              or meth == "YT96" or meth == "LY04")):
        cskin = 0
    elif ((cskin == None) and (meth == "UA" or meth == "C30"
                                or meth == "C35" or meth == "C40"
                                or meth == "ERA5")):
        cskin = 1
    if ((gust == None) and (meth == "C30" or meth == "C35" or meth == "C40")):
        gust = [1, 1.2, 600]
    elif ((gust == None) and (meth == "UA" or meth == "ERA5")):
        gust = [1, 1, 1000]
    elif (gust == None):
        gust = [1, 1.2, 800]
    elif (np.size(gust) < 3):
        sys.exit("gust input must be a 3x1 array")
    if (L not in [None, 0, 1, 2, 3]):
        sys.exit("L input must be either None, 0, 1, 2 or 3")
    if ((L == None) and (meth == "S80" or meth == "S88" or meth == "LP82"
                              or meth == "YT96" or meth == "LY04")):
        L = 0
    elif ((L == None) and (meth == "UA")):
        L = 1
    elif ((L == None) and (meth == "ERA5")):
        L = 2
    elif ((L == None) and (meth == "C30" or meth == "C35" or meth == "C40")):
        L = 3
    if (tol == None):
        tol = ['flux', 0.01, 1, 1]
    elif (tol[0] not in ['flux', 'ref', 'all']):
        sys.exit("unknown tolerance input")
    return lat, P, Rl, Rs, cskin, gust, tol, L