How moisture changes by altitude (MERRA-2, monthly) — M2TMNPQDT

In plain English

What it measures. Monthly snapshots of how moisture in the atmosphere is changing at different altitudes — for example how cloud water, ice, and humidity are gained or lost.

How it's made. Comes from MERRA-2, NASA's reanalysis that fuses decades of satellite data into a consistent model of past atmospheric conditions, here averaged monthly across 42 height levels.

How & where you'd use it. Researchers use it to study the water cycle, cloud and precipitation processes, and long-term atmospheric trends.

What's measured

ATMOSPHERE › ATMOSPHERIC WATER VAPOR › WATER VAPOR INDICATORS › HUMIDITY › SPECIFIC HUMIDITYATMOSPHERE › ATMOSPHERIC WATER VAPOR › WATER VAPOR PROCESSES › WATER VAPOR TENDENCYATMOSPHERE › ATMOSPHERIC WATER VAPOR › WATER VAPOR PROCESSES

Coverage & cadence

Time span1980-01-01 → ongoing
Measured byMERRA-2 (NOT APPLICABLE)
Processing levelLevel 4
Spatial extent-180, -90, 180, 90
StatusACTIVE

What you can do with it

Map air pollutants — NO₂, aerosols, ozone
Track greenhouse gases and Earth's energy budget
Feed weather and air-quality analysis

Official description

M2TMNPQDT (or tavgM_3d_qdt_Np) is a 3-dimensional monthly mean data collection in Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2). This collection consists of assimilations of moist tendencies on the 42 pressure levels, such as tendency of ice (or liquid) water due to dynamics, total ice (or liquid) water tendency due to moist, total specific humidity analysis tendency, and specific humidity tendency due to moist. The information on the pressure levels can be found in the section 4.2 of the MERRA-2 File Specification document. The collection also includes variance of certain parameters. MERRA-2 is the latest version of global atmospheric reanalysis for the satellite era produced by NASA Global Modeling and Assimilation Office (GMAO) using the Goddard Earth Observing System Model (GEOS) version 5.12.4. The dataset covers the period of 1980-present with the latency of ~3 weeks after the end of a month. Data Reprocessing: Please check “Records of MERRA-2 Data Reprocessing and Service Changes” linked from the “Documentation” tab on this page. Note that a reprocessed data filename is different from the original file. MERRA-2 Mailing List: Sign up to receive information on reprocessing of data, changing of tools and services, as well as data announcements from GMAO. Contact the GES DISC Help Desk (gsfc-dl-help-disc@mail.nasa.gov) to be added to the list. Questions: If you have a question, please read "MERRA-2 File Specification Document", “MERRA-2 Data Access – Quick Start Guide”, and FAQs linked from the ”Documentation” tab on this page. If that does not answer your question, you may post your question to the NASA Earthdata Forum (forum.earthdata.nasa.gov) or email the GES DISC Help Desk (gsfc-dl-help-disc@mail.nasa.gov).

Get the data

m2tmnpqdt_access.py

import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="M2TMNPQDT",
    version="5.12.4",
    bounding_box=(-122.5, 37.2, -121.8, 37.9),  # your area (W,S,E,N)
    temporal=("2024-01-01", "2024-12-31"),       # your dates
)
files = earthaccess.open(results)   # stream straight from GES_DISC

Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.

Official links

How to read and plot the data. VIEW RELATED INFORMATION
Access the data via HTTPS. GET DATA
Use the Earthdata Search to find and retrieve data sets across multiple data centers. GET DATA
Access the data via the OPeNDAP protocol. USE SERVICE API
MERRA-2 File Specification Document VIEW RELATED INFORMATION
README Document VIEW RELATED INFORMATION
MERRA-2 Data Access – Quick Start Guide VIEW RELATED INFORMATION
Records of MERRA-2 Data Reprocessing and Service Changes VIEW RELATED INFORMATION