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Title: Assessing the accuracy of microwave radiometers and radio acoustic sounding systems for wind energy applications

To assess current remote-sensing capabilities for wind energy applications, a remote-sensing system evaluation study, called XPIA (eXperimental Planetary boundary layer Instrument Assessment), was held in the spring of 2015 at NOAA's Boulder Atmospheric Observatory (BAO) facility. Several remote-sensing platforms were evaluated to determine their suitability for the verification and validation processes used to test the accuracy of numerical weather prediction models.The evaluation of these platforms was performed with respect to well-defined reference systems: the BAO's 300 m tower equipped at six levels (50, 100, 150, 200, 250, and 300 m) with 12 sonic anemometers and six temperature ( T) and relative humidity (RH) sensors; and approximately 60 radiosonde launches.In this study we first employ these reference measurements to validate temperature profiles retrieved by two co-located microwave radiometers (MWRs) as well as virtual temperature ( T v) measured by co-located wind profiling radars equipped with radio acoustic sounding systems (RASSs). Results indicate a mean absolute error (MAE) in the temperature retrieved by the microwave radiometers below 1.5 K in the lowest 5?km of the atmosphere and a mean absolute error in the virtual temperature measured by the radio acoustic sounding systems below 0.8 K in the layer of the atmosphere coveredmore » by these measurements (up to approximately 1.6-2 km). We also investigated the benefit of the vertical velocity correction applied to the speed of sound before computing the virtual temperature by the radio acoustic sounding systems. We find that using this correction frequently increases the RASS error, and that it should not be routinely applied to all data.Water vapor density (WVD) profiles measured by the MWRs were also compared with similar measurements from the soundings, showing the capability of MWRs to follow the vertical profile measured by the sounding and finding a mean absolute error below 0.5 g m -3 in the lowest 5 km of the atmosphere. However, the relative humidity profiles measured by the microwave radiometer lack the high-resolution details available from radiosonde profiles. Furthermore, an encouraging and significant finding of this study was that the coefficient of determination between the lapse rate measured by the microwave radiometer and the tower measurements over the tower levels between 50 and 300 m ranged from 0.76 to 0.91, proving that these remote-sensing instruments can provide accurate information on atmospheric stability conditions in the lower boundary layer.« less
Authors:
 [1] ;  [2] ;  [3] ;  [1] ;  [1] ; ORCiD logo [4] ;  [5] ; ORCiD logo [6]
  1. Cooperative Institute for Research in Environmental Sciences (CIRES), Boulder, CO (United States); National Oceanic and Atmospheric Administration, Boulder, CO (United States)
  2. Univ. of Colorado, Boulder, CO (United States)
  3. National Oceanic and Atmospheric Administration, Boulder, CO (United States)
  4. Univ. of Maryland Baltimore County (UMBC), Baltimore, MD (United States)
  5. National Center for Atmospheric Research, Boulder, CO (United States)
  6. Univ. of Colorado, Boulder, CO (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
Publication Date:
Report Number(s):
NREL/JA-5000-68699
Journal ID: ISSN 1867-8548
Grant/Contract Number:
AC36-08GO28308
Type:
Accepted Manuscript
Journal Name:
Atmospheric Measurement Techniques (Online)
Additional Journal Information:
Journal Name: Atmospheric Measurement Techniques (Online); Journal Volume: 10; Journal Issue: 5; Journal ID: ISSN 1867-8548
Publisher:
European Geosciences Union
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Wind and Water Technologies Office (EE-4W)
Country of Publication:
United States
Language:
English
Subject:
17 WIND ENERGY; wind; remote sensing; XPIA
OSTI Identifier:
1364154

Bianco, Laura, Friedrich, Katja, Wilczak, James M., Hazen, Duane, Wolfe, Daniel, Delgado, Ruben, Oncley, Steven P., and Lundquist, Julie K.. Assessing the accuracy of microwave radiometers and radio acoustic sounding systems for wind energy applications. United States: N. p., Web. doi:10.5194/amt-10-1707-2017.
Bianco, Laura, Friedrich, Katja, Wilczak, James M., Hazen, Duane, Wolfe, Daniel, Delgado, Ruben, Oncley, Steven P., & Lundquist, Julie K.. Assessing the accuracy of microwave radiometers and radio acoustic sounding systems for wind energy applications. United States. doi:10.5194/amt-10-1707-2017.
Bianco, Laura, Friedrich, Katja, Wilczak, James M., Hazen, Duane, Wolfe, Daniel, Delgado, Ruben, Oncley, Steven P., and Lundquist, Julie K.. 2017. "Assessing the accuracy of microwave radiometers and radio acoustic sounding systems for wind energy applications". United States. doi:10.5194/amt-10-1707-2017. https://www.osti.gov/servlets/purl/1364154.
@article{osti_1364154,
title = {Assessing the accuracy of microwave radiometers and radio acoustic sounding systems for wind energy applications},
author = {Bianco, Laura and Friedrich, Katja and Wilczak, James M. and Hazen, Duane and Wolfe, Daniel and Delgado, Ruben and Oncley, Steven P. and Lundquist, Julie K.},
abstractNote = {To assess current remote-sensing capabilities for wind energy applications, a remote-sensing system evaluation study, called XPIA (eXperimental Planetary boundary layer Instrument Assessment), was held in the spring of 2015 at NOAA's Boulder Atmospheric Observatory (BAO) facility. Several remote-sensing platforms were evaluated to determine their suitability for the verification and validation processes used to test the accuracy of numerical weather prediction models.The evaluation of these platforms was performed with respect to well-defined reference systems: the BAO's 300 m tower equipped at six levels (50, 100, 150, 200, 250, and 300 m) with 12 sonic anemometers and six temperature (T) and relative humidity (RH) sensors; and approximately 60 radiosonde launches.In this study we first employ these reference measurements to validate temperature profiles retrieved by two co-located microwave radiometers (MWRs) as well as virtual temperature (Tv) measured by co-located wind profiling radars equipped with radio acoustic sounding systems (RASSs). Results indicate a mean absolute error (MAE) in the temperature retrieved by the microwave radiometers below 1.5 K in the lowest 5?km of the atmosphere and a mean absolute error in the virtual temperature measured by the radio acoustic sounding systems below 0.8 K in the layer of the atmosphere covered by these measurements (up to approximately 1.6-2 km). We also investigated the benefit of the vertical velocity correction applied to the speed of sound before computing the virtual temperature by the radio acoustic sounding systems. We find that using this correction frequently increases the RASS error, and that it should not be routinely applied to all data.Water vapor density (WVD) profiles measured by the MWRs were also compared with similar measurements from the soundings, showing the capability of MWRs to follow the vertical profile measured by the sounding and finding a mean absolute error below 0.5 g m-3 in the lowest 5 km of the atmosphere. However, the relative humidity profiles measured by the microwave radiometer lack the high-resolution details available from radiosonde profiles. Furthermore, an encouraging and significant finding of this study was that the coefficient of determination between the lapse rate measured by the microwave radiometer and the tower measurements over the tower levels between 50 and 300 m ranged from 0.76 to 0.91, proving that these remote-sensing instruments can provide accurate information on atmospheric stability conditions in the lower boundary layer.},
doi = {10.5194/amt-10-1707-2017},
journal = {Atmospheric Measurement Techniques (Online)},
number = 5,
volume = 10,
place = {United States},
year = {2017},
month = {5}
}