MAC-LWP: Monthly Ocean Cloud and Total Water Path Estimates at 1-Degree Resolution

Monthly 1.0-degree ocean-only estimates of cloud liquid water path and total water path, along with diurnal cycle climatologies. The data is produced by NASA using a multi-sensor algorithm that ingests and bias-corrects satellite retrievals from seven sensors including SSM/I and AMSR-E. The algorithm mitigates spurious trends from drifting satellite overpass times, as detailed in referenced publications from 2008 and 2017.

Use Cases

• Modeling cloud radiative effects based on monthly cloud liquid water path estimates.
• Analyzing diurnal cycles of cloud water based on the provided amplitude and phase climatologies.
• Performing quality control on cloud retrievals using the total water path field as a screen.
• Studying long-term trends in oceanic cloud properties from the multi-sensor, bias-corrected record.

Strengths

• Algorithm applies a bias correction based on AMSR-E matchups to clear-sky MODIS scenes.
• Simultaneously solves for monthly averages and diurnal cycles to mitigate spurious trends from satellite drift.
• Integrates data from seven satellite sensors (SSM/I, AMSR-E, TMI, AMSR-2, GMI, SSMIS, WindSat) for a multi-decade record.

Limitations

• Row count and dataset size are unknown, which may limit suitability assessment.
• Column-level documentation is absent; field semantics must be inferred after download.
• Data is ocean-only, limiting analysis over land masses.

Provenance

Source

National Aeronautics and Space Administration (NASA)

Collection Method

Algorithm processes 0.25-degree Remote Sensing Systems (RSS) Version 7 retrieval products from multiple satellite sensors.

Time Range

Monthly data; temporal coverage is not explicitly stated.

Freshness

Last updated 2026-03-12 23:34:40.564196; freshness should be verified.

Geography

Global ocean coverage at 1.0-degree spatial resolution.