get_init checks input values and sets defaults

hum_subs contains all subroutines related to humidity calculations

util_subs contains all utility subroutines

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
\ No newline at end of file

util_subs.py

+import numpy as np
+
+CtoK = 273.16  # 273.15
+""" Conversion factor for $^\circ\,$C to K """
+
+kappa = 0.4  # NOTE: 0.41
+""" von Karman's constant """
+#------------------------------------------------------------------------------
+
+
+def get_heights(h, dim_len):
+    """ Reads input heights for velocity, temperature and humidity
+
+    Parameters
+    ----------
+    h : float
+        input heights (m)
+    dim_len : int
+        length dimension
+
+    Returns
+    -------
+    hh : array
+    """
+    hh = np.zeros((3, dim_len))
+    if (type(h) == float or type(h) == int):
+        hh[0, :], hh[1, :], hh[2, :] = h, h, h
+    elif (len(h) == 2 and np.ndim(h) == 1):
+        hh[0, :], hh[1, :], hh[2, :] = h[0], h[1], h[1]
+    elif (len(h) == 3 and np.ndim(h) == 1):
+        hh[0, :], hh[1, :], hh[2, :] = h[0], h[1], h[2]
+    elif (len(h) == 1 and np.ndim(h) == 2):
+        hh = np.zeros((3, h.shape[1]))
+        hh[0, :], hh[1, :], hh[2, :] = h[0, :], h[0, :], h[0, :]
+    elif (len(h) == 2 and np.ndim(h) == 2):
+        hh = np.zeros((3, h.shape[1]))
+        hh[0, :], hh[1, :], hh[2, :] = h[0, :], h[1, :], h[1, :]
+    elif (len(h) == 3 and np.ndim(h) == 2):
+        hh = np.zeros((3, h.shape[1]))
+        hh = np.copy(h)
+    return hh
+# ---------------------------------------------------------------------
+
+
+def gc(lat, lon=None):
+    """ Computes gravity relative to latitude
+
+    Parameters
+    ----------
+    lat : float
+        latitude ($^\circ$)
+    lon : float
+        longitude ($^\circ$, optional)
+
+    Returns
+    -------
+    gc : float
+        gravity constant (m/s^2)
+    """
+    gamma = 9.7803267715
+    c1 = 0.0052790414
+    c2 = 0.0000232718
+    c3 = 0.0000001262
+    c4 = 0.0000000007
+    if lon is not None:
+        lon_m, lat_m = np.meshgrid(lon, lat)
+    else:
+        lat_m = lat
+    phi = lat_m*np.pi/180.
+    xx = np.sin(phi)
+    gc = (gamma*(1+c1*np.power(xx, 2)+c2*np.power(xx, 4)+c3*np.power(xx, 6) +
+          c4*np.power(xx, 8)))
+    return gc
+# ---------------------------------------------------------------------
+
+
+def visc_air(T):
+    """ Computes the kinematic viscosity of dry air as a function of air temp.
+    following Andreas (1989), CRREL Report 89-11.
+
+    Parameters
+    ----------
+    Ta : float
+        air temperature ($^\circ$\,C)
+
+    Returns
+    -------
+    visa : float
+        kinematic viscosity (m^2/s)
+    """
+    T = np.asarray(T)
+    if (np.nanmin(T) > 200):  # if Ta in Kelvin convert to Celsius
+        T = T-273.16
+    visa = 1.326e-5*(1+6.542e-3*T+8.301e-6*np.power(T, 2) -
+                     4.84e-9*np.power(T, 3))
+    return visa