Microwave Limb Sounder (MLS)

The Microwave Limb Sounder (MLS) makes measurements of atmospheric composition, temperature, humidity, and cloud ice.

Version Update Notice: The upgraded MLS NRT Version 5.0 dataset is now available. This upgrade uses an artificial neural network (ANN) approach (trained on the v5 MLS standard product dataset) to estimate the NRT temperature, water vapor, ozone, carbon monoxide, sulfur dioxide, nitric acid, and nitrous oxide profiles using radiances from the nearest limb scan. The data file will have the same data format and structure as the existing files. 

Note: The updated version is only available in a forward processing stream; older data will not be routinely re-processed. More information is available in the Upgraded Version 5 dataset section below.


MLS NRT Data and Information

The Microwave Limb Sounder (MLS) instrument aboard NASA’s Aura satellite acquires measurements of atmospheric composition, temperature, humidity, and cloud ice. MLS near real-time (NRT) data are available through LANCE generally within 45 to 140 minutes after a satellite observation.

To download MLS data, register for an Earthdata Login. Use the table below to access specific LANCE data products.

MLS / Aura - Collection 5

Product Download Description Volume (GB/day) Browse
ML2CO_NRT.005 Carbon Monoxide (CO) MLS/Aura NRT L2 CO Mixing Ratio 0.03 Worldview Browse
ML2H2O_NRT.005 Water Vapor (H2O) MLS/Aura NRT L2 H2O Mixing Ratio 0.03 Worldview Browse
ML2HNO3_NRT.005 Nitric Acid (HNO3) MLS/Aura NRT L2 HNO3 Mixing Ratio 0.03 Worldview Browse
ML2N2O_NRT.005 Nitrous Oxide (N2O) MLS/Aura NRT L2 N2O Mixing Ratio 0.03 Worldview Browse
ML2O3_NRT.005 Ozone (O3) MLS/Aura NRT L2 O3 Mixing Ratio 0.03 Worldview Browse
ML2SO2_NRT.005 Sulfur Dioxide (SO2) MLS/Aura NRT L2 SO2 Mixing Ratio 0.02 Worldview Browse
ML2T_NRT.005 Temperature MLS/Aura NRT L2 Temperature 0.03 Worldview Browse

Upgraded Version 5 dataset

This upgrade uses an artificial neural network (ANN) approach (trained on the v5 MLS standard product dataset) to estimate the NRT temperature, water vapor, ozone, carbon monoxide, sulfur dioxide, nitric acid, and nitrous oxide profiles using radiances from the nearest limb scan. (The team had previously considered discontinuing the nitrous oxide and nitric acid products, but they remain in this dataset release.) The networks were trained on 75% of the valid v5 MLS standard temperature product retrievals between January 2005 and August 2022 and their associated, nearest radiance profiles. The ANN processed results were validated using the remaining 25% of profiles. As the MLS v5.0 standard products are used as "truth" in the training, the best-case output of the ANN is a computationally-inexpensive, high-fidelity preview of the v5.0 standard-production profiles.

Note that the Version 5.0 NRT data is only available in a forward processing stream and that older data will not be routinely re-processed.

An overview of the Aura MLS NRT products and comparison with the MLS standard data products is given in an updated v5 NRT data user guide.

Users are urged to read the MLS v5.0-NRT user guide and encouraged to contact the MLS science team (mls-data@jpl.nasa.gov) with any questions.

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