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Title: Marine ARM GPCI Investigation of Clouds Psychrometer Field Campaign Report

Abstract

One of the most critical measurements in the suite of meteorological measurements used for the calculation of evaporation and latent heat flux is the relative humidity (RH). In order to achieve an overall net flux uncertainty < 10 W/m2 (Bradley and Fairall, 2006), the RH must be accurate to < 2 %RH. Anyone experienced in shipboard meteorological measurements will recognize that this is a tough specification. During the U.S. Department of Energy (DOE) Marine Atmospheric Radiation Measurement (ARM) Climate Research Facility Global Energy and Water Experiment (GEWEX) Cloud System Study (GCSS) Pacific Cross-Section Intercomparison (GPCI) Investigation of Clouds (MAGIC) experiment, the meteorological package used three different RH sensors. We found approximately 3-4 % differences between units. To arbitrate the differences and to track calibration drift over the months of exposure, we used a precision psychrometer. The Assmann Psychrometer, Model 430101 is a classic, mercury-in-glass instrument that gives a precise measure of the wet and dry bulb temperatures from which atmospheric humidity and RH are computed. On a regular basis, typically after each balloon launch, a technician took the psychrometer to an exposed location on the bridge roof. That was just below the instruments on the mast and high enough intomore » the mixed layer that the difference is negligible.« less

Authors:
 [1];  [2]
  1. Remote Measurements & Research Company, Seattle, WA (United States)
  2. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Research Org.:
DOE Office of Science Atmospheric Radiation Measurement (ARM) Program (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER)
OSTI Identifier:
1324981
Report Number(s):
DOE/SC-ARM-16-049
DOE Contract Number:  
AC05-7601830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; psychrometer; relative humidity; MAGIC campaign; meteorological measurements at sea

Citation Formats

Reynolds, R Michael, and Lewis, Ernie. Marine ARM GPCI Investigation of Clouds Psychrometer Field Campaign Report. United States: N. p., 2016. Web. doi:10.2172/1324981.
Reynolds, R Michael, & Lewis, Ernie. Marine ARM GPCI Investigation of Clouds Psychrometer Field Campaign Report. United States. https://doi.org/10.2172/1324981
Reynolds, R Michael, and Lewis, Ernie. 2016. "Marine ARM GPCI Investigation of Clouds Psychrometer Field Campaign Report". United States. https://doi.org/10.2172/1324981. https://www.osti.gov/servlets/purl/1324981.
@article{osti_1324981,
title = {Marine ARM GPCI Investigation of Clouds Psychrometer Field Campaign Report},
author = {Reynolds, R Michael and Lewis, Ernie},
abstractNote = {One of the most critical measurements in the suite of meteorological measurements used for the calculation of evaporation and latent heat flux is the relative humidity (RH). In order to achieve an overall net flux uncertainty < 10 W/m2 (Bradley and Fairall, 2006), the RH must be accurate to < 2 %RH. Anyone experienced in shipboard meteorological measurements will recognize that this is a tough specification. During the U.S. Department of Energy (DOE) Marine Atmospheric Radiation Measurement (ARM) Climate Research Facility Global Energy and Water Experiment (GEWEX) Cloud System Study (GCSS) Pacific Cross-Section Intercomparison (GPCI) Investigation of Clouds (MAGIC) experiment, the meteorological package used three different RH sensors. We found approximately 3-4 % differences between units. To arbitrate the differences and to track calibration drift over the months of exposure, we used a precision psychrometer. The Assmann Psychrometer, Model 430101 is a classic, mercury-in-glass instrument that gives a precise measure of the wet and dry bulb temperatures from which atmospheric humidity and RH are computed. On a regular basis, typically after each balloon launch, a technician took the psychrometer to an exposed location on the bridge roof. That was just below the instruments on the mast and high enough into the mixed layer that the difference is negligible.},
doi = {10.2172/1324981},
url = {https://www.osti.gov/biblio/1324981}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Sep 01 00:00:00 EDT 2016},
month = {Thu Sep 01 00:00:00 EDT 2016}
}