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MLS Science Features


Improving Hurricane Forecasts with Machine Learning and NASA Satellite Data
Improving Hurricane Forecasts with Machine Learning and NASA Satellite Data

In the US, hurricane damage comes at an annual cost of $24 billion, over half the cost of all natural disasters. The National Hurricane Center (NHC) has an impressive record predicting where hurricanes might make landfall. But less successful are predictions of so-called "rapid-intensification" of the strength of landfalling hurricanes.

Transport From the Asian Summer Monsoon Anticyclone Over the Western PacificTransport From the Asian Summer Monsoon Anticyclone Over the Western Pacific

The Western Pacific is an accessible location that provides rich opportunities for investigating the impact of the Asian summer monsoon on global upper troposphere / lower stratosphere composition, e.g., through aircraft-based research campaigns.

Aura MLS measures record-low levels of Arctic ozoneAura MLS measures record-low levels of Arctic ozone

Unusually prolonged cold stratospheric conditions in 2019/2020 have led to record-high chemical ozone loss and thus record-low ozone levels; only 2010/2011 came close. This behavior resembles that seen in the Antarctic, where an ozone "hole" recurs each winter.

Plume from Australian fires influences stratospheric dynamics and composition Plume from Australian fires influences stratospheric dynamics and composition

An extraordinary complex of Australian fire-driven pyrocumulonimbus (pyroCb) storms at the end of 2019 produced an unprecedented stratospheric plume of fire emissions that circled the globe, rising from 15 to 31 km and persisting for more than two months.

Solar Cycle Modulation of Nighttime Ozone Near the Mesopause  Solar Cycle Modulation of Nighttime Ozone Near the Mesopause

What do long-term observations of ozone profiles from the Microwave Limb Sounder (MLS) aboard the Aura satellite tell us about the drivers of O3 variations near 90 km altitude (the secondary ozone maximum region), notably in relation to the 11-year solar cycle?

 Energetic particle precipitation and the quasi-biennial oscillation modulate Antarctic springtime stratospheric column Nitrogen Dioxide Energetic particle precipitation and the quasi-biennial oscillation modulate Antarctic springtime stratospheric column Nitrogen Dioxide

Aura Microwave Limb Sounder (MLS) measurements have previously shown that the easterly phase of the QBO is associated with increases in nitrogen in the Antarctic stratosphere.

 Impact of convectively lofted ice on the seasonal cycle of water vapor in the tropical tropopause layer Impact of Convectively Lofted Ice on the Seasonal Cycle of Water Vapor in the Tropical Tropopause Layer

Aura's MLS observes patterns of stratospheric humidity in the “Tropical Tropopause Layer” .

Aura MLS measures record-low levels of Arctic ozone Aura MLS measures record-low levels of Arctic ozone

Aura's MLS observations of Arctic vortex-average chlorine monoxide improve the understanding of stratospheric ozone trends and their uncertainties

The Efficiency of transport into the stratosphere via the Asian and North American summer monsoon circulationsThe Efficiency of transport into the stratosphere via the Asian and North American summer monsoon circulations

This study confirms the important role of monsoon regions in moistening the lower stratosphere in boreal summer using data collected from Aura's Microwave Limb Sounder (MLS) .

Vortex-wide detection of large polar stratospheric cloud particles in the Arctic winter stratosphereVortex-wide detection of large polar stratospheric cloud particles in the Arctic winter stratosphere

Depletion of gas-phase nitric acid observed by Aura's Microwave Limb Sounder (MLS)

 Ice injected into the tropopause by deep convection Ice injected into the tropopause by deep convection

Convective processes play a major role in controlling the abundances of cloud ice and water vapor in the tropical tropopause layer, which in turn strongly modulate climate.

Convective entrainment rates estimated from Aura CO and CloudSat and CALIPSO observations Convective entrainment rates estimated from Aura CO and CloudSat/CALIPSO observations

Entrainment rate (λ) in convective parameterizations is one of the most sensitive, yet uncertain, parameters affecting climate sensitivity, clouds, precipitation, and trace gas distributions.

Structural changes in the shallow and transition branch of the Brewer–Dobson circulation induced by El Niño Structural changes in the shallow and transition branch of the Brewer–Dobson circulation induced by El Niño

The global meridional overturning of mass in the stratosphere, generally known as the Brewer-Dobson circulation (BDC), plays a crucial role in Earth’s climate system by controlling the distributions of atmospheric constituents.

Response of stratospheric water vapor and ozone to the unusual timing of El Niño and the Quasi-Biennial Oscillation disruption of 2015-2016 Response of stratospheric water vapor and ozone to the unusual timing of El Niño and the Quasi-Biennial Oscillation disruption of 2015-2016

Two major modes of climate variability that affect the stratospheric circulation, and consequently trace gas distributions, are the El Niño–Southern Oscillation (ENSO) and the Quasi-Biennial Oscillation (QBO).

On the role of heterogeneous chemistry in ozone depletion and recoveryOn the role of heterogeneous chemistry in ozone depletion and recovery

Conclusive verification that stratospheric ozone destruction is lessening as expected in response to international controls on anthropogenic ozone-depleting substances (ODSs) enacted under the Montreal Protocol is one of today’s atmospheric science imperatives, but robust detection of such ozone “recovery” is complicated by large natural variability.

 Effects of Arctic stratospheric ozone changes on precipitation in the northwestern United StatesEffects of Arctic stratospheric ozone changes on precipitation in the northwestern United States

Changes in stratospheric ozone can induce, via atmospheric radiation balance, stratospheric circulation anomalies.

Evaluating models of stratospheric composition Evaluating models of stratospheric composition

How well do a free-running and “nudged” chemistry climate model reproduce global timeseries of upper atmospheric composition (biases, variability, trends)?

>The Nature of Ozone in Deep Convective Clouds The Nature of Ozone in Deep Convective Clouds As Measured from Aura OMI/MLS

OMI satellite measurements reveal for the first time many key features of ozone variability inside deep convective clouds

Trends in Global Tropospheric Ozone Trends in Global Tropospheric Ozone Inferred from a Composite Record of TOMS/OMI/MLS/OMPS Satellite Measurements and the MERRA-2 GMI Simulation

OMI satellite measurements identify increases in tropospheric ozone over Saudi Arabia/India/Southeast Asia and other global regions

 Examining Impact of Boreal Summer El Niño–Southern Oscillation Events on Tropical Lower Stratospheric Ozone  Examining Impact of Boreal Summer El Niño–Southern Oscillation Events on Tropical Lower Stratospheric Ozone : Using Aura MLS Ozone Observations

The interannual variability of tropical lower stratosphere ozone and its connections to sea surface temperatures in the equatorial Pacific are examined using a combination of chemistry climate model simulations, satellite observations, and reanalyses.

Multiple Aura Datasets Contribute to the Tropospheric Ozone Assessment Report (TOAR) Multiple Aura Datasets Contribute to the Tropospheric Ozone Assessment Report (TOAR)

In the troposphere, ozone is both a major pollutant and a strong greenhouse gas. Although spaceborne and ground-based observations largely agree on the overall tropospheric ozone loading, estimates of decadal-scale trends vary significantly between datasets.

Quantifying Convective Hydration of the Stratosphere Quantifying Convective Hydration of the Stratosphere Using Aura Microwave Limb Sounder & CALIPSO Data

Variations in stratospheric water vapor are known to have a significant impact on surface climate, yet the processes controlling the long-term evolution of stratospheric humidity remain incompletely understood.

 Using A-Train Polar Stratospheric Cloud Information to Validate Polar Stratospheric Reanalysis Temperatures Using A-Train Polar Stratospheric Cloud Information to Validate Polar Stratospheric Reanalysis Temperatures

Stratospheric polar processes, such as the potential for ozone loss via heterogeneous chemical reactions, depend critically on temperature. We have assessed the temperature biases of several modern meteorological reanalysis datasets.

  Detecting Impacts on Global Ozone Detecting Impacts on Global Ozone

How well can the impacts of changes in ozone depleting substances (ODSs) and greenhouse gases (GHGs) on global ozone (O3 ) be detected and distinguished? Aura Microwave Limb Sounder (MLS) Global O3 profiles are used to detect fingerprints of ODS & GHG impacts.

 Unusual Variability in Tropical Measurements   Unusual Variability in Tropical Measurements Linked to the Unprecedented 2015-16 Disruption of the Quasi-Biennial Oscillation

The quasi-biennial oscillation (QBO) consists of alternating easterly (east-to-west) and westerly (west-to-east) directions of the wind in the tropical stratosphere with an average period of 28 months.

The Nature of Ozone in Deep Convective Clouds  The Nature of Ozone in Deep Convective Clouds

Ozone within deep convective clouds is controlled by several factors involving photochemical reactions and transport. Gas-phase photochemical reactions and heterogeneous surface chemical reactions involving ice, water particles, and aerosols inside the clouds all contribute to the distribution and net production and loss of ozone.

science feature N2O measurements are key to quantifying the photochemical and transport processes that affect Arctic spring ozone

The Arctic seasonal evolution of simulated O3 and the long lived trace gas N2O from the Global Modeling Initiative Chemistry and Transport Model (GMI CTM) both closely agree with MLS observations for all years since Aura's launch in 2004.

science feature Large ozone holes will continue to occur in very cold Antarctic winters until 2040

The next three decades will see an end of the era of big ozone holes. In a new study, scientists from NASA Goddard Space Flight Center say that the ozone hole will be consistently smaller than 8 million square miles by the year 2040.

science feature

The Quasi-Biennial Oscillation in Tropical Winds Controls Chlorine Variability inside the Antarctic Ozone Hole

A decade of MLS Nitrous oxide reveals a remarkable transport pipeline from the midlatitude middle stratosphere to the Antarctic lower stratosphere, allowing tropical winds to modulate how much chlorine reaches the Antarctic ozone hole each year.

science feature

Low ozone over Europe doesn't mean the sky is falling, it's actually rising

To quantitatively understand anthropogenic impacts to the stratospheric ozone layer, we must be able to distinguish between low ozone caused by ozone depleting substances and that caused by natural dynamical variability in the atmosphere.

Ozone feature

A Deep Ozone Hole in Spite of Low Chlorine: How Transport Affects Chemistry

MLS ClO in the 2011 Antarctic vortex was 20% lower than 2006, yet the 2011 ozone hole is very similar to the 2006 hole, the largest ever observed.

OMI feature

Destruction of Mesospheric Arctic Ozone Caused by Solar Protons

Microwave Limb Sounder (MLS) observations quantify the changes in the hydroxyl radical (OH), hydrogen dioxide (HO2), and ozone due to Solar Proton Events (SPE)

HIRDLS feature

Hydroxyl radical (OH) response to the 11-year solar cycle

OH data from the Microwave Limb Sounder (MLS) on Aura and a ground-based FTUVS suggest a response of the OH column to the solar cycle that is significantly larger than model results using established solar forcing.

What caused unusually low Arctic O3 in Spring 2011?

The Microwave Limb Sounder (MLS) on NASA's Aura shows weaker than usual ozone transport and strong photochemical loss

Aura MLS observations of unprecedented 2011 Arctic ozone loss

Unusually prolonged cold conditions in the spring 2011 Arctic stratosphere promoted levels of chlorine activation and chemical ozone loss never before observed in the Arctic, comparable to those in the Antarctic in some winters.

Aerosol-Clouds-Water Vapor Interactions

Aerosol-Clouds-Water Vapor Interactions

The properties of the polluted clouds indicate a warming and moistening effect on air entering the stratosphere by the pollutants in Asia.

OMI Iceland

Strongest El Niño Event Since Aura Launch

Aura MLS observations show clear imprint of 2010 El Niño in the upper troposphere

Aura Science Result Image

'Double Record Breaker'
2006 Antarctic Ozone Hole seen by MLS

Prolonged low temperatures in September 2006 increased by the longevity of 'active chlorine', leading to a record area and depth of the ozone hole.

OMI & MLS Tropospheric Ozone maps

First global tropospheric maps show streams of tropospheric ozone crossing the oceans

OMI & MLS can estimate the tropospheric ozone residual by subtracting the MLS stratospheric ozone from OMI column ozone. These maps show pollution streaming from the U.S., Europe and China to the west in summer and pollution from biomass burning in the equatorial zone.

MLS Cloud Ice

First Global Measurement of Cloud Ice in Upper Troposphere

Cloud ice measurement will improve global circulation models used for weather and climate forecasts.
The measurements will also help quantify the upper tropospheric hydrological cycle, including water vapor feedbacks on climate change.

MLS Sub-Visual Cirrus

First Maps of Sub-Visual Cirrus in the Upper Tropical Troposphere

MLS sees cloud ice, but HIRDLS sees the clouds themselves, even clouds that are so thin that people cannot see them. Just as in the MLS cloud ice map we see large amounts of this cirrus in regions of significant cloud ice.

CO pertubation

Measurement of CO in Upper Troposphere

CO is a signature of pollution and can be transported a long way from its source. Not surprisingly, that transport can be vertical as well as horizontal. These images show how CO detected in the lower stratosphere can tell us something about where convection is occurring.

HCI measurements

Continuous measurement of HCl in stratosphere

The continuous measurement of HCl in the stratosphere shows the rapid recovery of this major chlorine reservoir after polar ozone loss, and continues the long-term measurements from UARS HALOE. Monitoring HCl tells us about ozone loss processes and the recovery of the ozone layer.

OH MEasurements

First Measurement of OH in the Middle Stratosphere

The MLS measurements of OH and HO2 have provided the first tests of global stratospheric hydrogen chemistry and resolved the disagreement between model estimates of OH and earlier observations - these data suggest earlier observations are suspect.

Aura Science Result Image

The Carbon Monoxide Tape Recorder

As tropical air rises into the stratosphere it carries with it trace gases, such as CFC's that are responsible for ozone depletion.

Aura Science Result Image

Destruction of Arctic Ozone this Winter

An unprecedended suite of simultaneous measurements by MLS allows more accurate quantification of ozone destruction in the 2004-2005 Arctic winter.

Aura Science Result Image

MLS detects SO2 and HCI injected into the stratosphere by the 27 January 2005 New Guinea Manam volcano.

These images show MLS detection of enhanced SO2 and HCI in the lower stratosphere over New Guinea on January 28, following eruption of Manam volcano on January 27.

Aura Science Result Image

MLS Water Vapor and Pressure

Time-pressure sections of zonally averaged water vapor mixing ratio, shown as the deviation from the time-mean profile.

Aura Science Result Image

MLS HCI - Observations of Antarctic Polar Vortex Breakup

Maps of MLS HCI in the lower stratosphere (520 K, 20km) detailing the springtime breakup of the 2004 Antarctic vortex.

Aura Science Result ImageSolar Proton Flare Affects Mesospheric OH and Ozone

Aura MLS has provided first observation of this connection