PACIFIC EXPLORATORY MISSION-WEST A (PEM-WEST-A) - SEPTEMBER OCTOBER 1991

The NASA Pacific Exploratory Mission-West (PEM-West) is a major compon ent of the East Asia/North Pacific Regional Study (APARE), a project w ithin the International Global Atmospheric Chemistry (IGAC) program. T he broad objective of the PEM-West/APARE initiative is to study chemic al processes and long-range transport over the northwestern Pacific Oc ean and to estimate the magnitude of the human impact on the oceanic a tmosphere over this region particularly for tropospheric ozone and its precursors as well as for sulfur species, The first phase of this mis sion, PEM-West A, was conducted during September-October 1991. The PEM -West A included intensive airborne measurements of trace gases from t he NASA DC-8 aircraft coordinated with measurements at PEM-West A surf ace sites as well as with measurements obtained from; collaborating AP ARE ground and airborne platforms. This paper reports the experimental design for PEM-West A with a brief summary of the general content and focus of companion papers in this special issue.