Somigliana-Pizzetti gravity: the international gravity formula accurate tothe sub-nanoGal level

The Somigliana-Pizzetti gravity field (the International gravity formula), namely the gravity field of the level ellipsoid (the International Referenc e Ellipsoid), is derived to the sub-nanoGal accuracy level in order to fulf il the demands of modern gravimetry (absolute gravimeters, super conducting gravimeters, atomic gravimeters). Equations (53), (54) and (59) summarise Somigliana-Pizzetti gravity Gamma(phi, u) as a function of Jacobi spheroida l latitude phi and height it to the order O(10(-10) Gal), and Gamma (B,H) a s a function of Gauss (surface normal) ellipsoidal latitude B and height H to the order O(10(-10) Gal) as determined by GPS ('global problem solver'). Within the test area of the state of Baden-Wurttemberg, Somigliana-Pizzett i gravity disturbances of an average of 25.452 mGal were produced. Computer programs for an operational application of the new international gravity f ormula with (L,B,H) or (lambda, phi, u) coordinate inputs to a subnanoGal l evel of accuracy are available on the Internet.