OH and HO₂ in the tropical Pacific: Results from PEM‐Tropics B

Abstract

OH and HO 2 data collected on NASA's Pacific Exploratory Mission ‐ Tropics B (PEM‐Tropics B) are presented here and compared to results from a photochemical box model. PEM‐Tropics B took place in the tropical Pacific in March and April of 1999 and examined photochemistry and sulfur chemistry in the remote tropical atmosphere. Altitude‐resolved HO x budgets are presented. The model showed good overall agreement with the data, with a mean model to observed ratio of 0.86 for OH and 1.03 for HO 2 . The model tends to underpredict OH at higher altitudes and overpredict at low altitudes. The model agrees well with the HO 2 observations at middle altitudes but tends to overpredict slightly at high and low altitudes.