Principal Investigator (PI): Lucien Froidevaux, NASA's Jet Propulsion Laboratory

This proposal will provide a commonly-formatted Earth System Data Record (ESDR) for stratospheric composition, which is of high relevance to the issue of ozone decline and recovery. These ozone and related trace gas data records are needed to evaluate the representation of atmospheric composition in models ranging from classic 2-D stratospheric dynamical-chemical models that have formed the basis of previous ozone depletion assessments to a newly emerging class of 3-D chemistry climate models.

The data records will be drawn from satellite-derived global stratospheric composition measurements from 1979 to the present, along with on-going data, as well as from Global Modeling and Assimilation Office (GMAO) Goddard Earth Observing System Model, Version 4 (GEOS-4) and GEOS-5 meteorological analyses. The data records will be time series of averaged profiles as a function of latitude and equivalent latitude for ozone (O₃), hydrogen chloride (HCl), chlorine monoxide (ClO), nitric acid (HNO₃), water vapor (H₂O), nitrous oxide (N₂O), nitrogen dioxide (NO₂), nitrogen oxide (NO), methane (CH₄), and hydrogen fluoride (HF). Additional "derived data records," using a constrained photochemical model, will be provided for active chlorine (ClO_x) and odd nitrogen (NO_x).

Along with this stratospheric trace gases ESDR, we will provide a temperature record using existing long-term meteorological analyses (GEOS-4 and GEOS-5). The GMAO daily data will also lead to a consistent set of stratospheric O₃ columns; we will also produce derived quantities relating to O₃ loss in polar regions, where polar stratospheric clouds (PSCs) can form and heterogeneous chemistry leads to O₃ depletion and the Antarctic ozone hole phenomenon. These quantities will include the volume (V_PSC) and area (A_PSC) of air with temperatures below PSC formation thresholds, as well as estimates of PSC "lifetimes."

The satellite-based profiles come, in part, from high quality data that are now discontinued, namely solar occultation data from Stratospheric Aerosol Gas Experiment (SAGE I) for O₃ and NO₂; SAGE II; SAGE III; Polar Ozone and Aerosol Measurement (POAM II); POAM III (for O₃, H₂O, and NO₂); Halogen Occultation Experiment (HALOE) for O₃, HCl, H₂O, NO, NO₂, CH₄, and HF; and Upper Atmosphere Research Satellite (UARS) Microwave Limb Sounder (MLS) for O₃, ClO, and H₂O. The records going forward in time will depend on Aura MLS (for O₃, HCl, ClO, HNO₃, H₂O, N₂O) and Scientific Satellite Atmospheric Chemistry Experiment 1 (SciSat-1) Atmospheric Chemistry Experiment (ACE)-Fourier Transform Spectrometer (FTS) profiles (for O₃, HCl, ClO, HNO₃, H₂O, N₂O, NO, NO₂, CH_4, and HF). Data records will be zonal means on a common vertical (pressure and/or height) grid, with time resolution of one month (one day when possible). Records binned in equivalent latitude and potential temperature will also be provided, as this is best for evaluating polar processes.

The establishment of such data records involves the evaluation of offsets and assessments of time consistency using ground-based data. We will strive to provide both the original records and merged data records. Web-based data access to commonly-formatted files and various related plots will be provided. We also plan to actively participate in Earth Science Data System Working Groups (ESDSWG) meetings.

Distributed by NASA's Goddard Earth Sciences Data and Information Services Center (GES DISC)