A time stamp encoded as a string 'YYYY-MM-DDThh:mm:ss[.dd]' or 'YYYY-DDDThh:mm:ss[.dd]', where 'YYYY' is the year, 'MM' is the two-digit month, 'DD' is the two-digit day, 'DDD' is the three digit day of year, 'T' is constant, 'hh:mm:ss[.dd]' is the UTC time in hours, minutes, seconds, and optional fractional seconds. As many 'd' characters to the right of the period as required may be used to obtain the required precision. All fields require leading zeros.