A yearlong effort in and around Baltimore, Maryland, reveals insights into atmospheric interactions across urban, rural, and coastal areas.

Researchers are using data from the 18-month Cloud And Precipitation Experiment at kennaook (CAPE-k) to paint a clearer picture of aerosol-cloud-precipitation interactions in a unique environment.

Learn how ARM’s newest atmospheric observatory grew in capabilities, scope, and data during its first year of operations in northern Alabama.

The Aerosol Optical Depth (AOD) value-added product derived from 7-channel normal incidence multifilter radiometer measurements is now available for the Southern Great Plains (SGP) and North Slope of Alaska (NSA) atmospheric observatories.

Value-added products providing horizontal wind profiles and vertical velocity statistics from Doppler lidar data are now available for the 2024–2025 Coast-Urban-Rural Atmospheric Gradient Experiment (CoURAGE) in the Baltimore, Maryland, area.

The Precipitation Best Estimate (PrecipBE) product provides time-series data and statistics on precipitation events measured at ground level by ARM.

This work compiles one of the most extensive global records of ice nucleating particles (INPs), which are atmospheric particles that help form ice in clouds, by systematically measuring their concentrations at the U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) User Facility's locations and often for multiple years using the same method.

New particle formation (NPF) is a major source of atmospheric nanoparticles that affect aerosol populations, air quality, human health, and the atmosphere. The complex and nonlinear interactions among radiation, gases, and meteorology make it difficult to pinpoint what conditions trigger events that form new particles. In this study, researchers applied a machine learning technique (random forest) to long-term atmospheric measurements in a rural continental environment to classify NPF and non‑NPF days and to identify which environmental factors matter most. The approach captures the intricate relationships that traditional methods often miss and provides a quantitative ranking of the controlling variables.

Prior laboratory and modelling studies have indicated that trace gases can affect the critical supersaturation required to activate a particle into a cloud droplet. This study represents the first investigation of the hypothesis that semivolatile trace gases influence cloud condensation nuclei activity in the atmosphere using field observations. To this end, we compared size-resolved activation supersaturation with and without trace gases. Activation supersaturation increased without trace gases when aerosols were wet (size-selected at higher relative humidity). This may be due to loss of semivolatiles by evaporation from the particle phase. Activation supersaturation decreased after removal of trace gases when trace gas concentrations were higher. This may be due to a change in interfacial tension by trace gas adsorption.