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Title: ARM Value-Added Product (VAP) Monthly Status Report (March 2007)

Abstract

The original temporal resolution of the Atmospheric Radiation Measurement (ARM) AERI instruments was 8 minutes, where each cycle consisted of a 3-minute sky-view period and 2-minute views at each of the two blackbody targets. This sampling strategy was chosen to achieve the desired signal-to-noise ratio for clear-sky spectroscopy and profiling studies. To make the AERI observations more useful for cloud research, the temporal resolution has been decreased by an order of magnitude; however, this greatly increases the random error in these observations. This VAP uses a principle component analysis noise filter to significantly reduce the amount of uncorrelated random error in the AERI observations. The noise-filtered 'rapid-sample' AERI observations have approximately the same amount of random error as the original AERI radiance data. The AEROSOL BE VAP provides temporally and spatially continuous vertical profiles of ambient aerosol optical properties including scattering, absorption, and extinction coefficients, single scattering albedo and asymmetry parameter. It uses a combination of passive radiometers, in-situ surface measurements, empirical relationships, climatologies, and model input. It is a direct input to the BBHRP VAP, an ACRF programmatic metric.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
DOE Office of Science Atmospheric Radiation Measurement (ARM) Program (United States)
Sponsoring Org.:
USDOE Office of Environmental Management (EM), Acquisition and Project Management (EM-50)
OSTI Identifier:
1021007
Report Number(s):
DOE/SC-ARM/P-07-005.1
PNNL-17087; TRN: US201120%%406
DOE Contract Number:
DE-AC05-7601830
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; ABSORPTION; AEROSOLS; ALBEDO; ASYMMETRY; CLOUDS; OPTICAL PROPERTIES; RADIATIONS; RADIOMETERS; RESOLUTION; SAMPLING; SCATTERING; SIGNAL-TO-NOISE RATIO; SPECTROSCOPY; TARGETS

Citation Formats

Comstock, J, Flynn, C, Jensen, M, Long, C, Turner, D, and Xie, S. ARM Value-Added Product (VAP) Monthly Status Report (March 2007). United States: N. p., 2007. Web. doi:10.2172/1021007.
Comstock, J, Flynn, C, Jensen, M, Long, C, Turner, D, & Xie, S. ARM Value-Added Product (VAP) Monthly Status Report (March 2007). United States. doi:10.2172/1021007.
Comstock, J, Flynn, C, Jensen, M, Long, C, Turner, D, and Xie, S. Thu . "ARM Value-Added Product (VAP) Monthly Status Report (March 2007)". United States. doi:10.2172/1021007. https://www.osti.gov/servlets/purl/1021007.
@article{osti_1021007,
title = {ARM Value-Added Product (VAP) Monthly Status Report (March 2007)},
author = {Comstock, J and Flynn, C and Jensen, M and Long, C and Turner, D and Xie, S},
abstractNote = {The original temporal resolution of the Atmospheric Radiation Measurement (ARM) AERI instruments was 8 minutes, where each cycle consisted of a 3-minute sky-view period and 2-minute views at each of the two blackbody targets. This sampling strategy was chosen to achieve the desired signal-to-noise ratio for clear-sky spectroscopy and profiling studies. To make the AERI observations more useful for cloud research, the temporal resolution has been decreased by an order of magnitude; however, this greatly increases the random error in these observations. This VAP uses a principle component analysis noise filter to significantly reduce the amount of uncorrelated random error in the AERI observations. The noise-filtered 'rapid-sample' AERI observations have approximately the same amount of random error as the original AERI radiance data. The AEROSOL BE VAP provides temporally and spatially continuous vertical profiles of ambient aerosol optical properties including scattering, absorption, and extinction coefficients, single scattering albedo and asymmetry parameter. It uses a combination of passive radiometers, in-situ surface measurements, empirical relationships, climatologies, and model input. It is a direct input to the BBHRP VAP, an ACRF programmatic metric.},
doi = {10.2172/1021007},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 2007},
month = {Thu Mar 01 00:00:00 EST 2007}
}

Technical Report:

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  • This document describes the input requirements, output data products, and methodology for the Spectral Surface Albedo (SURFSPECALB) value-added product (VAP). The SURFSPECALB VAP produces a best-estimate near-continuous high spectral resolution albedo data product using measurements from multifilter radiometers (MFRs). The VAP first identifies best estimates for the MFR downwelling and upwelling shortwave irradiance values, and then calculates narrowband spectral albedo from these best-estimate irradiance values. The methodology for finding the best-estimate values is based on a simple process of screening suspect data and backfilling screened and missing data with estimated values when possible. The resulting best-estimate MFR narrowband spectral albedosmore » are used to determine a daily surface type (snow, 100% vegetation, partial vegetation, or 0% vegetation). For non-snow surfaces, a piecewise continuous function is used to estimate a high spectral resolution albedo at 1 min temporal and 10 cm-1 spectral resolution.« less
  • The purpose of this report is to provide a concise status update for value-added products (VAP) implemented by the Atmospheric Radiation Measurement Climate Research Facility. The report is divided into the following sections: (1) new VAPs for which development has begun, (2) progress on existing VAPs, and (3) future VAPs that have been recently approved.
  • The Radiatively Important Parameters Best Estimate (RIPBE) VAP was developed to create a complete set of clearly identified set of parameters on a uniform vertical and temporal grid to use as input to a radiative transfer model. One of the main drivers for RIPBE was as input to the Broadband Heating Rate Profile (BBHRP) VAP, but we also envision using RIPBE files for user-run radiative transfer codes, as part of cloud/aerosol retrieval testbeds, and as input to averaged datastreams for model evaluation.
  • The Min and Harrison algorithm has been incorporated into an ARM Value-Added Product (VAP) called MFRSR CLDOD. This version of the VAP (1Min) uses the diffuse transmission at 415 nm from the MFRSR. Therefore, the results are only valid for “horizontally homogeneous” stratiform clouds with optical depths larger than approximately 7. The retrieval assumes a single cloud layer consisting solely of liquid water drops. As specified by Min and Harrison (1996), the wavelength at 415 nm was chosen due to the lack of gaseous absorption and the relatively constant surface albedo (in the absence of snow) at this wavelength. Themore » MFRSR CLDOD VAP (henceforth referred to as “the VAP”) retrieves cloud optical depth (τ) from the MFRSR measurements. If the LWP is available from a coincident MWR observation, then the droplet effective radius (re) can be determined. Knowledge of the estimated re can be used to improve the estimate of τ because there is a slight dependence on the extinction coefficient, single scattering albedo, and asymmetry parameter on effective radius at this wavelength. However, if the MWR’s LWP is not available, then the VAP assumes that re = 8.0 μm. The primary output from the VAP is τ and re.« less
  • Simple single black detector pyranometers, such as the Eppley Precision Spectral Pyranometer (PSP) used by the Atmospheric Radiation Measurement (ARM) Program, are known to lose energy via infrared (IR) emission to the sky. This is especially a problem when making clear-sky diffuse shortwave (SW) measurements, which are inherently of low magnitude and suffer the greatest IR loss. Dutton et al. (2001) proposed a technique using information from collocated pyrgeometers to help compensate for this IR loss. The technique uses an empirically derived relationship between the pyrgeometer detector data (and alternatively the detector data plus the difference between the pyrgeometer casemore » and dome temperatures) and the nighttime pyranometer IR loss data. This relationship is then used to apply a correction to the diffuse SW data during daylight hours. We developed an ARM value-added product (VAP) called the SW DIFF CORR 1DUTT VAP to apply the Dutton et al. correction technique to ARM PSP diffuse SW measurements.« less