The NOAA Global Monitoring Division (GMD) plays a critical leadership role in the global atmospheric monitoring community.  GMD scientists have unique and globally recognized expertise in making sustained atmospheric observations over decades, interpreting those observations, and communicating their findings to other researchers and the public.  Without observations like these the science community would struggle to diagnose how the climate system functions as climate change unfolds, now and into the far future.

To find out more about GMD research, click on different sections of the image below.

GMD Research Themes standards baseline observatories greenhouse gases surface radiation, clouds and aerosols stratospheric ozone

The first two GMD research themes are related to the Grand Challenges of the World Climate Research Programme (WCRP). The third theme is a legal requirement under the 1990 Clean Air Act.

For more information, you can read the GMD Research Plan.

Research Theme #1:
Tracking Greenhouse Gases and Understanding Carbon Cycle Feedbacks

Today’s anthropogenic climate change is largely driven by increasing greenhouse gases (GHGs) in the atmosphere, modified to some extent by the distribution of aerosols and aerosol properties.  To understand the influence of changing atmospheric composition on climate change and minimize its eventual magnitude, society needs the best possible information on the trends, distributions, emissions and removals of greenhouse gases.  It is necessary to develop a solid scientific understanding of their natural cycles, and how human management and the changing climate influence those cycles. Our atmospheric measurements can also provide fully transparent and objective quantification of emissions, supporting national and regional emissions reduction policies and generating trust in international agreements.

Research Theme #2:
Monitoring and Understanding Changes in Surface Radiation, Clouds, and Aerosol Distributions

Changes in the radiative energy balance at Earth’s surface and at the top of the atmosphere result from forcing by greenhouse gases, aerosols, and related changes in the global atmospheric circulation.  The distribution of clouds is the primary influence on the surface radiation budget and is sensitive to changes in the circulation, but the nature of the response of different cloud types in different climatic regions is uncertain.  Cloud radiative properties are also sensitive to aerosol particles which are highly variable in space, time, and composition. Their role in radiative forcing is complex and can be either positive or negative and, in addition to their impacts on clouds, can influence the climate directly via long term changes in light absorption and scattering.  The uncertainty in cloud responses to climate forcing constituents, either through direct interaction with aerosols or through circulation changes, is the primary factor limiting our ability to narrow estimates of the climate sensitivity (the warming resulting from a change in a climate forcing agent).

Research Theme #3:
Guiding Recovery of Stratospheric Ozone

Depletion of stratospheric ozone can result in enhanced UV radiation levels that increase skin cancer rates and adversely affect organisms and ecosystems.  Concern over these effects provided impetus for ratifying the 1987 Montreal Protocol, enacting the U.S. Clean Air Act of 1990, and initiating GMD’s global-scale monitoring of stratospheric ozone and the gases responsible for its destruction.

Supporting Infrastructure #1: Calibrations and Standards

Accurate and reliable calibrations are an essential component of all high-quality measurement programs. This is particularly true of measurements made to carry out research within GMD. Bias or drift in reference materials can have a significant impact on our ability to interpret measured spatial gradients and trends. Further, for data from multiple instruments or measurement networks to be interpreted together, they must be linked to common calibration scales.

Supporting Infrastructure #2: Atmospheric Baseline Observatories

At the core of the Global Monitoring Division’s global observation networks are the Atmospheric Baseline Observatories (ABOs). GMD’s four ABOs are strategically located far from human influence and local pollutants, to prevent contamination and sample the cleanest air possible. The long-term measurements from the ABOs are considered among the best in the world for understanding background atmospheric composition.

ESRL/GMD Research Groups


Global Greenhouse Gases Reference Network

The Global Greenhouse Gases Reference Network makes ongoing discrete measurements from land and sea surface sites and aircraft, and continuous measurements from baseline observatories and tall towers. These measurements document the spatial and temporal distributions of carbon-cycle gases and provide essential constraints to our understanding of the global carbon cycle.


Halocarbons and other Trace Species

The HATS group quantifies the distributions and magnitudes of the sources and sinks for atmospheric nitrous oxide (N2O) and halogen containing compounds and other important ozone-depleting and greenhouse gases.



The goals of this regional-scale monitoring program are to characterize means, variability, and trends of climate-forcing properties of different types of aerosols, and to understand the factors that control these properties. GMD's measurements also provide ground-truth for satellite measurements and global models, as well as key aerosol parameters for global-scale models.


Solar Radiation

The G-Rad group's activities involve empirical and theoretical research of the Earth's surface radiation budget. The group specializes in the investigation of climatically significant variations in long-term radiation, relative observations of spectral solar radiation for the purpose of remote sensing of certain atmospheric constituents and the absolute measurement of spectral solar UV for the investigation of the interaction of ozone and solar radiation.


Ozone and Water Vapor

The Ozone and Water Vapor Group conducts research on the nature and causes of the depletion of the stratospheric ozone layer and the role of stratospheric and tropospheric ozone and water vapor in forcing climate change and in modifying the chemical cleansing capacity of the atmosphere. This mission is accomplished through long-term observations and intensive field programs that measure total column ozone, ozone vertical profiles (ozonesondes and umkehrs), ground level ozone, and water vapor vertical profiles in the upper troposphere and stratosphere.


Observatory Operations

NOAA/ESRL operates staffed atmospheric baseline observatories at Barrow, Alaska; Mauna Loa, Hawaii; American Samoa; and the South Pole from which numerous in situ and remote atmospheric and solar measurements are conducted. The overall scientific programs and administrative functions of the four observatories are handled from Boulder with on-site station chiefs caring for day-to-day station activities.

Related ESRL Research Themes