Atmospheric Radiation Measurement Climate Research Facility US Department of Energy

Surface Atmosphere Integrated Field Laboratory (SAIL)

1 September 2021 - 15 June 2023

Lead Scientist: Daniel Feldman

Observatory: amf, guc

Mountains are the natural water towers of the world, but Earth System Models (ESMs) have persistently been unable to predict the timing and availability of water resources from mountains. The source(s) of model error are difficult to isolate in complex terrain with limited atmospheric or land-surface observations. Further complications arise from the gross scale mismatch between ESM grid box sizes and the relevant scales of mountainous hydrological processes. The mountain hydrometeorology community has repeatedly called for integrated atmospheric and surface observations of water and energy budgets in complex terrain that span these scales to establish benchmarks against which scale-dependent models can be developed. In response to these calls, the Surface Atmosphere Integrated Field Laboratory (SAIL) will make measurements using the second ARM Mobile Facility (AMF2) and a scanning X-band dual polarimetric radar near Crested Butte, Colorado. The campaign will focus on the East River Watershed, which is a 300-km2 mountainous watershed that is part of the Upper Colorado River Basin. SAIL will advance atmosphere-through-bedrock understanding of mountainous water cycles by collocating ARM atmospheric observations with long-standing collaborative resources including the ongoing surface and subsurface hydrologic observations from the Department of Energy’s Watershed Function Science Focus Area (SFA). The main science goal of the SAIL campaign is to develop a quantitative understanding of the atmosphere and land-atmosphere interaction processes, at their relevant scales, that impact mountain hydrology in the midlatitude continental interior of the United States.

To achieve this goal, the campaign will extend from September 2021 to June 2023, and will measure the seasonally varying controls on the surface energy and water budgets in high-altitude complex terrain in order to address four key science questions:

1. How do multi-scale dynamic and microphysical processes control the spatial and temporal distribution, phase, amount, and intensity of precipitation?

2. How strongly do aerosols affect the surface energy and water balance by altering clouds, precipitation, and surface albedo, and how do these impacts vary seasonally?

3. What are the contributions of snow sublimation, radiation, and turbulent fluxes of latent and sensible heat to the water and energy balance of the snowpack?

4. How do atmospheric and surface processes set the net radiative absorption that is known to drive the regional flow of water into the continental interior during the summer monsoon?

To answer these questions, SAIL measurements will pursue the following science objectives:

1. Characterize the spatial distribution of orographic and convective precipitation processes on diurnal to seasonal time scales and how those processes interact with large-scale circulation.

2. Quantify cold-season land-atmosphere interactions that alter snowpack mass balance through wind redistribution and sublimation and the spatial scaling of those processes.

3. Establish aerosol regimes, the processes controlling the life cycle of aerosols in those regimes, and quantify the impacts of aerosols in those regimes on the atmospheric and surface radiative budget.

4. Quantify the sensitivity of cloud phase and precipitation to cloud condensation nuclei (CCN) and ice-nucleating particle (INP) concentrations.

5. Quantify the seasonally varying surface energy balance, the land-surface and atmospheric factors controlling it, and the spatial variability in those factors.

By measuring the inputs to, outputs from, and processes within a heavily studied mountainous watershed, SAIL will produce a benchmark data set for atmospheric and surface process representation studies. Those studies, in turn, will be used to develop a robust foundation for advancing the sub-grid representation of these processes in ESMs.

SAIL is complemented by a concurrent NOAA-led campaign in the region: the Study of Precipitation, the Lower Atmosphere, and Surface for Hydrometeorology (SPLASH). The yearlong SPLASH campaign is designed to gain detailed insight into the physical processes that drive basin-scale weather and water availability in the Mountain West. SPLASH will run through summer 2022.


Allison Aiken Alejandro Flores Alan Rhoades
William Boos David Gochis James Smith
V. Chandrasekar Jerry Harrington Ryan Sullivan
William Collins Matthew Kumjian Paul Ullrich
Scott Collis L. Ruby Leung Adam Varble
Paul DeMott Travis OBrien Kenneth Hurst Williams
Jiwen Fan Mark Raleigh


  • Child Campaign


Sedlar J, T Meyers, C Cox, and B Adler. 2024. "Low-Level Liquid-Bearing Clouds Contribute to Seasonal Lower Atmosphere Stability and Surface Energy Forcing over a High-Mountain Watershed Environment." Journal of Hydrometeorology, 25(6), 10.1175/JHM-D-23-0144.1.

Galewski J. 2024. SAIL-Isotopologue (SAIL-iso) Field Campaign Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-24-008. 10.2172/2335707.

Sedlacek AJ and RC Jackson. 2024. Single-Particle Soot Photometer (SP2) Black Carbon Number and Mass Concentrations. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-TR-301. 10.2172/2341496.

Rudisill W, A Rhoades, Z Xu, and D Feldman. 2024. "Are atmospheric models too cold in the mountains? The state of science and insights from the SAIL field campaign." Bulletin of the American Meteorological Society, , 10.1175/BAMS-D-23-0082.1.
Research Highlight

Feldman D, A Aiken, W Boos, R Carroll, V Chandrasekar, S Collis, J Creamean, G de Boer, J Deems, P DeMott, J Fan, A Flores, D Gochis, M Grover, T Hill, A Hodshire, E Hulm, C Hume, R Jackson, F Junyant, A Kennedy, M Kumjian, E Levin, J Lundquist, J O'Brien, M Raleigh, J Reithel, A Rhoades, K Rittger, W Rudisill, Z Sherman, E Siirila-Woodburn, S McKenzie Skiles, J Smith, R Sullivan, A Theisen, M Tuftedal, A Varble, A Wiedlea, S Wielandt, K Williams, and Z Xu. 2024. Surface Atmosphere Integrated Field Laboratory (SAIL) Field Campaign Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-24-009. 10.2172/2341871.

Laskin A, R Moffet, S Sharpe, T Olayemi, F Rivera-Adorno, E Hulm, M Fraund, and S China. 2024. Multimodal Chemical Characterization of Brown Carbon in Atmosphere and Snowpack during SAIL Field Campaign Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-24-007. 10.2172/2336741.

China S, Z Cheng, G Vandergrift, and NN Lata. 2024. Cloud Processing of Aerosol during SAIL Field Campaign Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-24-004. 10.2172/2324623.

Dexheimer D, G Whitson, Z Cheng, J Sammon, K Gaustad, F Mei, and C Longbottom. 2024. Tethered Balloon System (TBS) Instrument Handbook. Ed. by Robert Stafford, ARM Climate Research Facility. DOE/SC-ARM-TR-206. 10.2172/1415858.

Creamean JM, TC Hill, CC Hume, and T Devadoss. 2024. Ice Nucleation Spectrometer (INS) Instrument Handbook. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-TR-278. 10.2172/1846263.

Maahn M, D Moisseev, I Steinke, N Maherndl, and M Shupe. 2024. "Introducing the Video In Situ Snowfall Sensor (VISSS)." Atmospheric Measurement Techniques, 17(2), 10.5194/amt-17-899-2024.

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Campaign Data Sets

IOP Participant Data Source Name Final Data
Curtis Beutler Manual Snowboard and Snowstakes Order Data
Joseph Galewsky Water Vapor Isotope Analyzer Order Data
Leah Gibson Cloud Condensation Nuclei Counter Order Data
Leah Gibson printed optical particle spectrometer or portable optical particle spectrometer Order Data
Stephen Jones Three Waveband Spectrally Agile Technique Sensor (TWST) Order Data
Heike Kalesse-Los W-Band Cloud Radar Order Data
Maximilian Maahn Video In Situ Snowfall Sensor Order Data
Steven Sharpe Time Resolved Aerosol Collectors Order Data
Steven Sharpe aethalometer Order Data
Abu Sayeed Md Shawon Direct sensor measurement of or algorithmically derived particulate matter (e.g. PM1, PM10, PM2.5) size distributions, mass concentrations and/or other related PM descriptive variables Order Data
Abu Sayeed Md Shawon Wideband Integrated Bioaerosol Sensor Order Data
Gabrielle Whitson camera onboard a tethered balloon system (TBS) Order Data
Zexuan Xu Weather Research and Forecasting (WRF) Model Output Order Data

GUC Data Sources

Name Full Name Browse Data
ACSM Aerosol Chemical Speciation Monitor Browse Data
ACSMCDCE ACSM, corrected for composition-dependent collection efficiency Browse Data
AERI Atmospheric Emitted Radiance Interferometer Browse Data
AERINF AERI Noise Filtered Browse Data
AOP Aerosol Optical Properties Browse Data
AOS Aerosol Observing System Browse Data
AOSMET Meteorological Measurements associated with the Aerosol Observing System Browse Data
ARMBE ARM Best Estimate Data Products Browse Data
CAMINST camera that monitors an instrument Browse Data
CAMSITE camera that monitors a site area Browse Data
CCN Cloud Condensation Nuclei Particle Counter Browse Data
CCNKAPPA CCN Counter derived hygroscopicity parameter kappa Browse Data
CEIL Ceilometer Browse Data
CEILPBLHT Boundary-layer height data with CEIL Browse Data
CLDTYPE Cloud Type Classification Browse Data
CO-ANALYZER Carbon Monoxide Analyzer Browse Data
CPC Condensation Particle Counter Browse Data
CPC-AIR Condensation particle counter aboard aircraft Browse Data
CSPHOT Sunphotometer Browse Data
DL Doppler Lidar Browse Data
DLPROF-WIND Doppler Lidar Horizontal Wind Profiles Browse Data
DLPROF-WSTATS Doppler Lidar Wind Statistics Profiles Browse Data
ECMWFDIAG European Centre for Medium Range Weather Forecasts Diagnostic Analyses Browse Data
ECOR Eddy Correlation Flux Measurement System Browse Data
GENSTATE Generator State Browse Data
GNDRAD Ground Radiometers on Stand for Upwelling Radiation Browse Data
HSRL High Spectral Resolution Lidar Browse Data
HTDMA Humidified Tandem Differential Mobility Analyzer Browse Data
INS Ice Nucleation Spectrometer for INP measurement Browse Data
INS-AIR Ice Nucleation Spectrometer for INP measurements aboard aircraft Browse Data
INTERPSONDE Interpolated Sonde Browse Data
IRT Infrared Thermometer Browse Data
KAZR Ka ARM Zenith Radar Browse Data
KAZRARSCL Active Remote Sensing of CLouds (ARSCL) product using Ka-band ARM Zenith Radars Browse Data
KAZRCFRCOR Ka-Band ARM Zenith RADAR (KAZR) CF-Radial, Corrected VAP Browse Data
LDIS Laser Disdrometer Browse Data
LDQUANTS Laser Disdrometer Quantities Browse Data
MAWS Automatic Weather Station Browse Data
MET Surface Meteorological Instrumentation Browse Data
MFR Multifilter Radiometer Browse Data
MFRSR Multifilter Rotating Shadowband Radiometer Browse Data
MPL Micropulse Lidar Browse Data
MPLCMASK Cloud mask from Micropulse Lidar Browse Data
MPLCMASKML Micropulse Lidar Cloud Mask Machine Learning VAP Browse Data
MWR Microwave Radiometer Browse Data
MWR3C Microwave Radiometer, 3 Channel Browse Data
MWRRET MWR Retrievals Browse Data
NEPHELOMETER Nephelometer Browse Data
OPC Optical Particle Counter Browse Data
OZONE Ozone Monitor Browse Data
PBLHT Planetary Boundary Layer Height Browse Data
POPS-AIR portable optical particle spectrometer aboard an airborne platform Browse Data
PSAP Particle Soot Absorption Photometer Browse Data
QCECOR Quality Controlled Eddy Correlation Flux Measurement Browse Data
QCRAD Data Quality Assessment for ARM Radiation Data Browse Data
RAIN Rain Gauge Browse Data
RWP Radar Wind Profiler Browse Data
SEBS Surface Energy Balance System Browse Data
SKYRAD Sky Radiometers on Stand for Downwelling Radiation Browse Data
SMPS Scanning mobility particle sizer Browse Data
SONDE Balloon-Borne Sounding System Browse Data
SONDEGRID Gridded Sonde VAP Product Browse Data
SONDEPARAM convective parameters derived from radiosonde data Browse Data
SP2 Single Particle Soot Photometer Browse Data
SQUIRE Surface QUantitatIve pRecipitation Estimation (SQUIRE) Browse Data
TBS Tethered Balloon System Browse Data
TBSMERGED Tethered Balloon System (TBS) Merged Data Product Browse Data
TROPOE Tropospheric Optimal Estimation Retrieval Browse Data
TSI Total Sky Imager Browse Data
UHSAS Ultra-High Sensitivity Aerosol Spectrometer Browse Data
VARANAL Constrained Variational Analysis Browse Data
VISST Minnis Cloud Products Using Visst Algorithm Browse Data
WB Weighing Bucket Precipitation Gauge Browse Data
XPRECIPCMAC CSU X-Band Precip Radar (XPRECIPRADAR) PPI Corrected Moments to Antenna Coord Browse Data
XPRECIPRADAR X-Band Precipitation Radar Browse Data