The total mass of the atmosphere

Accurate but approximate formulae for determining the mass of the atmosphere in terms of the surface pressure p_s are derived and applied to globally analyzed data from the European Centre for Medium-Range Weather Forecasts (ECMWF) for 1985 through 1993. For the recent 4-year period 1990 to 1993 the mean annual p_s was 984.76 mbar with a maximum in July of 984.98 mbar and a minimum in December of 984.61 mbar which correspond to a total mean mass of the atmosphere of 5.1441 × 10¹⁸ kg with a range of 1.93 × 10¹⁵ kg throughout the year associated with changes in water vapor in the atmosphere. The global mean p_w for 1985-1993 is a 2.58 mbar, but values are 5 to 10% lower, after mid-1992. Using the Special Sensor Micorwave Imager data to make adjustments, the best estimate of the annual global p_w is 2.4 mbar, corresponding to ~2.5 cm of precipitable water. The total atmospheric moisture as given by p_w varies with an annual cycle range of 0.36 mbar, a maximum in July, and a minimum in December. Thus the mean mass of water vapor is 1.25 × 10¹⁶ kg and the dry air mass is 5.132 × 10¹⁸ kg, corresponding to a mean surface pressure of 982.4 mbar. -from Authors