“Satellite Sounder Observations of Contrasting Tropospheric Moisture Transport Regimes: Saharan Air Layers, Hadley Cells, and Atmospheric Rivers” in the Journal of Hydrometeorology, vol. 17, no. 12.

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Authors listed below:

a, b, c, c, d, e, f, a, a, a, g, and h

a I.M. Systems Group, Inc., Rockville, Maryland
b Science and Technology Corporation, Columbia, Maryland
c NOAA/NESDIS Center for Satellite Applications and Research, College Park, Maryland
d Howard University, Washington, D.C.
e Science and Technology Corporation, NOAA Earth System Research Laboratory, Boulder, Colorado
f University at Albany, State University of New York, Albany, New York
g Pacific Northwest National Laboratory, Richland, Washington
h Cooperative Institute for Research in Environmental Sciences, Boulder, Colorado
Received: 20 July 2016
Final Form: 3 October 2016
Published Online: 1 December 2016

This paper examines the performance of satellite sounder atmospheric vertical moisture profiles under tropospheric conditions encompassing moisture contrasts driven by convection and advection transport mechanisms, specifically Atlantic Ocean Saharan air layers (SALs), tropical Hadley cells, and Pacific Ocean atmospheric rivers (ARs). Operational satellite sounder moisture profile retrievals from the Suomi National Polar-Orbiting Partnership (SNPP) NOAA Unique Combined Atmospheric Processing System (NUCAPS) are empirically assessed using collocated dedicated radiosonde observations (raobs) obtained from ocean-based intensive field campaigns. The raobs from these campaigns provide uniquely independent correlative truth data not assimilated into numerical weather prediction (NWP) models for satellite sounder validation over oceans. Although ocean cases are often considered “easy” by the satellite remote sensing community, these hydrometeorological phenomena present challenges to passive sounders, including vertical gradient discontinuities (e.g., strong inversions), as well as persistent uniform clouds, aerosols, and precipitation. It is found that the operational satellite sounder 100-layer moisture profile NUCAPS product performs close to global uncertainty requirements in the SAL/Hadley cell environment, with biases relative to raob within 10% up to 350 hPa. In the more difficult AR environment, bias relative to raob is found to be within 20% up to 400 hPa. In both environments, the sounder moisture retrievals are comparable to NWP model outputs, and cross-sectional analyses show the capability of the satellite sounder for detecting and resolving these tropospheric moisture features, thereby demonstrating a near-real-time forecast utility over these otherwise raob-sparse regions.

Corresponding author e-mail: Nicholas R. Nalli,


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