Aura MLS Radiance Average Retrievals (RAR) BrO product guideline

In short, the retrieval algorithm produces a pair of zonal-mean abundance fields for each day, one for the ascending part of the orbit (mostly daytime) and the other for the descending part (mostly nighttime) on a grid with 6 surfaces per decade change in pressure (∼3 km). These are obtained from a 10◦ latitude bin zonal mean of radiances interpolated onto a 6 surface per decade pressure grid using the limb tangent pressure from the standard production data.

To minimize biases, ascending-minus-descending (i.e., mostly day-minus-night) differences must be used as a more accurate measure of daytime BrO. This restricts the usable data to between 50◦S and 50◦N, avoiding the polar regions, where both ascending and descending orbits are either day (summer) or night (winter).

Due to the small spectral signature of BrO in the MLS radiances, significant averaging (such as monthly zonal means) is required to obtain scientifically useful results.

This document is for MLS L3 v6 products.