def alt2pres(altitude):
    """
    Determine site pressure from altitude.

    Parameters
    ----------
    altitude : numeric
        Altitude in meters above sea level

    Returns
    -------
    pressure : numeric
        Atmospheric pressure (Pascals)

    Notes
    ------
    The following assumptions are made

    ============================   ================
    Parameter                      Value
    ============================   ================
    Base pressure                  101325 Pa
    Temperature at zero altitude   288.15 K
    Gravitational acceleration     9.80665 m/s^2
    Lapse rate                     -6.5E-3 K/m
    Gas constant for air           287.053 J/(kgK)
    Relative Humidity              0%
    ============================   ================

    References
    -----------
    .. [1] "A Quick Derivation relating altitude to air pressure" from
       Portland State Aerospace Society, Version 1.03, 12/22/2004.
    """
    press = 100 * ((44331.514 - altitude) / 11880.516) ** (1 / 0.1902632)
    return press
