Science Features : MLS
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.
Entrainment rate (λ) in convective parameterizations is one of the most sensitive, yet uncertain, parameters affecting climate sensitivity, clouds, precipitation, and trace gas distributions.
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.
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).
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.
Changes in stratospheric ozone can induce, via atmospheric radiation balance, stratospheric circulation anomalies.
How well do a free-running and “nudged” chemistry climate model reproduce global timeseries of upper atmospheric composition (biases, variability, trends)?
OMI satellite measurements reveal for the first time many key features of ozone variability inside deep convective clouds
OMI satellite measurements identify increases in tropospheric ozone over Saudi Arabia/India/Southeast Asia and other global regions
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
MLS Water Vapor and Pressure
Time-pressure sections of zonally averaged water vapor mixing ratio, shown as the deviation from the time-mean profile.