Right-handed rectangular coordinates
From AMS Glossary
right-handed rectangular coordinates
Rectangular Cartesian coordinates in which the coordinates x, y, and z are measured along three mutually perpendicular axes such that a rotation of the positive x axis into the positive y axis will drive a right-handed screw in the direction of the positive z axis.
The Cartesian coordinates most often used in meteorology form a right-handed system: x increasing to east, y to north, z to zenith.