Climatology

NCCS Helps NASA Scientists Create New Global Ozone Profile Reaching from Earth’s Surface to the Mesosphere

NCCS Helps NASA Scientists Create New Global Ozone Profile
Reaching from Earth’s Surface to the Mesosphere


The diagram shows the six layers of Earth’s atmosphere, with heights measured in kilometers. A new global ozone profile from the NASA Goddard Space Flight Center reaches from the surface nearly to the top of the mesosphere. Infographic by NASA Goddard.

With key support from the NASA Center for Climate Simulation (NCCS), NASA Goddard Space Flight Center scientists have created a new, multidecade global ozone profile climatology that reaches from Earth’s surface up to 80 kilometers (~ 50 miles) – far into the mesosphere, the third layer of the atmosphere.

Ozone is a gas made up of three oxygen atoms bonded together. Ozone near the surface forms when the Sun heats carbon monoxide, which comes from sources such as car and truck exhaust, with other chemicals in the atmosphere. Ozone plays both helpful (“good”) and harmful (“bad”) roles depending on its location in the atmosphere, as illustrated below.

The drawing shows how ozone plays good or bad roles at different levels of atmosphere. Image by NASA Science SpacePlace.

From top to bottom, ozone plays alternatingly good and bad roles in the atmosphere:

  • Good: At the top of the stratosphere, 50 kilometers (30 miles) high, ozone helpfully absorbs most of the harmful ultraviolet radiation from the Sun. The well-known Antarctic ozone hole occurs in this stratospheric ozone layer.
  • Bad: At the top of the troposphere, 20 kilometers (12 miles) high, ozone acts as a greenhouse gas, trapping heat and adding to global warming.
  • Good: In the middle of the troposphere, ozone helps clean up certain pollutants.
  • Bad: At the bottom of the troposphere, at Earth’s surface, ozone makes the smog that blankets many world cities.

By representing ozone from the mesosphere – the level above the stratosphere – down to the surface, the new global ozone profile climatology captures ozone at all the layers where it exists in Earth’s atmosphere. Ozone is represented by monthly averages in columns approximately 50 kilometers wide and 80 kilometers tall, with ozone sampled every 1 kilometer vertically.

“Our previous ozone profile seasonal cycle climatology was based on using very sparse ozonesonde measurements for tropospheric ozone,” said study leader Jerry Ziemke, a research scientist at NASA Goddard’s Atmospheric Chemistry and Dynamics Laboratory (ACDL). While balloon-mounted ozonesonde instruments are launched from 52 ground stations around the globe, they do not achieve anything near comprehensive coverage. “In this study we determine a new seasonal climatology based on Global Modeling Initiative profile ozone, which provides a much-improved tropospheric ozone representation,” Ziemke noted.

NASA Goddard’s new global ozone climatology has two major components:

Component Datasets Years of Coverage
Monthly Seasonal Cycle Climatology

  • NASA Aura satellite Microwave Limb Sounder (MLS) stratospheric ozone
  • Modern-Era Retrospective Analysis for Research Applications, Version 2 Global Modeling Initiative (MERRA-2 GMI) model
2004–2016 combined
Monthly Interannual Climatology 1970–2016 combined

The NCCS Discover supercomputer hosted the MERRA-2 GMI model. This multi-model system couples the Global Modeling and Assimilation Office’s Goddard Earth Observing System (GEOS) model, driven by winds, temperature, and pressure information from the MERRA-2 reanalysis, to the ACDL’s GMI stratosphere-troposphere chemical mechanism. MERRA-2 GMI simulated Earth’s atmosphere at 50-kilometer resolution over the period 1980 to 2019. The simulation used nearly 2,700 computing cores and ran for about 6 months. It produced 680 terabytes of data, which the scientists subsetted on Discover for analysis on local computing systems.

“This work to generate the MERRA-2 GMI simulation was only possible because of the NASA supercomputer resources at NCCS,” Ziemke said. “Discover enabled us to model the chemistry of the atmosphere over several decades at high spatial resolution, producing a significantly improved simulation of the 3D structure and evolution of ozone. By incorporating that information in ozone retrieval algorithms as a first guess, it is leading to improved long-term ozone datasets, one of our most important climate data records. ”


This animation shows total column ozone for July 1, 2002 to October 31, 2002 from (left) the MERRA-2 GMI simulation with hourly time resolution and (right) the Earth Probe Total Ozone Mapping Spectrometer (EP-TOMS) observations in daily composites . Both capture the onset and breakdown of the Antarctic ozone hole as well as a split of the Antarctic polar vortex into two lobes. Comparing the two sources highlights how models can fill in missing information between satellite swaths and during polar night. Visualization by Luke Oman, NASA Goddard.

Ziemke noted that the new ozone climatology’s interannual component is unique and captures a large fraction of interannual ozone changes going back to 1970. He said their main interest is using climatology as “a priori information in satellite ozone retrieval algorithms” – a key step in accurately measuring ozone from satellites. Other applications include evaluating ozone simulations and observations from NASA and other organizations, as well as studying ozone’s effects on climate.

Impact: This work provides a new and much-improved global ozone profile climatology to support the science community’s analysis of measured and modeled ozone.

Map of climatological ozone volume mixing ratio, in parts per billion by volume (ppbv), from the MERRA-2 GMI simulation at an altitude of ~ 5 kilometers (~ 3 miles) for the month of May. Blue color indicates areas with ozone concentrations of ~ 10 ppbv, and red color corresponds to regions with> 75 ppbv. Black circles show the locations of ozonesonde stations. Image from Ziemke et al., 2021.

Over the next few years, Ziemke and collaborators plan to periodically update the interannual component and, if possible, make additional improvements to both the seasonal and interannual components.

Related Links

  • Ziemke, JR, GJ Labow, NA Kramarova, RD McPeters, PK Bhartia, LD Oman, SM Frith, and DP Haffner, 2021: A Global Ozone Profile Climatology for Satellite Retrieval Algorithms Based on Aura MLS Measurements and the MERRA-2 GMI Simulation. Atmospheric Measurement Techniques,14, no. 10, 6407–6418, doi: 10.5194 / amt-14-6407-2021.
  • “NASA and NOAA Scientists Develop Method to Create Continuous Ozone Climate Data Record,” NCCS Highlight, 10/23/20.

Jarrett Cohen, NASA Goddard Space Flight Center

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