The Radiative Heating in Underexplored Bands Campaigns

Turner, David D.; Mlawer, E. J.

doi:10.1175/2010bams2904.1

Cited by 71 publications

(53 citation statements)

References 32 publications

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“…We also use ARM data collected during a 3-month experiment at a 5300 m m.s.l. site at Cerro Toco (CJC) in northern Chile (Turner and Mlawer, 2010). Utilizing several distinct climate locations ensures a more accurate and in-depth analysis of the two correction algorithms.…”

Section: A M Dzambo Et Al: Comparing Radiosonde Humidity Correctiomentioning

confidence: 99%

“…The ARM program conducted the second phase of the Radiative Heating in Underexplored Bands Campaign (RHUBC-II) in CJC in August through October 2009 (Turner and Mlawer, 2010). The CJC site is located approximately 5.3 km above sea level in the Atacama Desert; this site can be considered a mid-tropospheric site due to its altitude and water vapor conditions.…”

Section: A M Dzambo Et Al: Comparing Radiosonde Humidity Correctiomentioning

confidence: 99%

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Evaluation of two Vaisala RS92 radiosonde solar radiative dry bias correction algorithms

2016

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Abstract. Solar heating of the relative humidity (RH) probe on Vaisala RS92 radiosondes results in a large dry bias in the upper troposphere. Two different algorithms (Miloshevich et al., 2009, MILO hereafter; and Wang et al., 2013, WANG hereafter) have been designed to account for this solar radiative dry bias (SRDB). These corrections are markedly different with MILO adding up to 40 % more moisture to the original radiosonde profile than WANG; however, the impact of the two algorithms varies with height. The accuracy of these two algorithms is evaluated using three different approaches: a comparison of precipitable water vapor (PWV), downwelling radiative closure with a surface-based microwave radiometer at a high-altitude site (5.3 km m.s.l.), and upwelling radiative closure with the space-based Atmospheric Infrared Sounder (AIRS).The PWV computed from the uncorrected and corrected RH data is compared against PWV retrieved from groundbased microwave radiometers at tropical, midlatitude, and arctic sites. Although MILO generally adds more moisture to the original radiosonde profile in the upper troposphere compared to WANG, both corrections yield similar changes to the PWV, and the corrected data agree well with the groundbased retrievals.The two closure activities -done for clear-sky scenesuse the radiative transfer models MonoRTM and LBLRTM to compute radiance from the radiosonde profiles to compare against spectral observations. Both WANG-and MILOcorrected RHs are statistically better than original RH in all cases except for the driest 30 % of cases in the downwelling experiment, where both algorithms add too much water vapor to the original profile. In the upwelling experiment, the RH correction applied by the WANG vs. MILO algorithm is statistically different above 10 km for the driest 30 % of cases and above 8 km for the moistest 30 % of cases, suggesting that the MILO correction performs better than the WANG in clear-sky scenes. The cause of this statistical significance is likely explained by the fact the WANG correction also accounts for cloud cover -a condition not accounted for in the radiance closure experiments.

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Section: A M Dzambo Et Al: Comparing Radiosonde Humidity Correctiomentioning

confidence: 99%

Section: A M Dzambo Et Al: Comparing Radiosonde Humidity Correctiomentioning

confidence: 99%

Evaluation of two Vaisala RS92 radiosonde solar radiative dry bias correction algorithms

2016

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“…The primary focus of RHUBC-II was to characterize and improve the accuracy of gas absorption models using high spectral resolution radiance observations in spectral regions that are normally opaque at lower altitudes due to strong water vapor absorption and high air pressure (Turner and Mlawer, 2010). The measurement site was set up at 5320 m a.m.s.l.…”

Section: Measurement Campaignmentioning

confidence: 99%

“…As radiative transfer models employ absorption line parameters that are obtained from laboratory measurements, field measurements are needed for independent evaluation. The aim of the Radiative Heating in Underexplored Bands Campaign (RHUBC-II) (Turner and Mlawer, 2010), which is part of the Atmospheric Radiation Measurement (ARM) program (Stokes and Schwartz, 1994), is to evaluate and improve existing absorption models. In addition to frequent radiosonde profiles of temperature, pressure and humidity, RHUBC-II data offer a unique set of accurate radiation measurements of the middle-to-upper troposphere.…”

Section: Introductionmentioning

confidence: 99%

Investigation of ground-based microwave radiometer calibration techniques at 530 hPa

et al. 2013

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Abstract. Ground-based microwave radiometers (MWR) are becoming more and more common for remotely sensing the atmospheric temperature and humidity profile as well as path-integrated cloud liquid water content. The calibration accuracy of the state-of-the-art MWR HATPRO-G2 (Humidity And Temperature Profiler -Generation 2) was investigated during the second phase of the Radiative Heating in Underexplored Bands Campaign (RHUBC-II) in northern Chile (5320 m above mean sea level, 530 hPa) conducted by the Atmospheric Radiation Measurement (ARM) program conducted between August and October 2009. This study assesses the quality of the two frequently used liquid nitrogen and tipping curve calibrations by performing a detailed error propagation study, which exploits the unique atmospheric conditions of RHUBC-II. Both methods are known to have open issues concerning systematic offsets and calibration repeatability. For the tipping curve calibration an uncertainty of ±0.1 to ±0.2 K (K-band) and ±0.6 to ±0.7 K (V-band) is found. The uncertainty in the tipping curve calibration is mainly due to atmospheric inhomogeneities and the assumed air mass correction for the Earth curvature. For the liquid nitrogen calibration the estimated uncertainty of ±0.3 to ±1.6 K is dominated by the uncertainty of the reflectivity of the liquid nitrogen target. A direct comparison between the two calibration techniques shows that for six of the nine channels that can be calibrated with both methods, they agree within the assessed uncertainties. For the other three channels the unexplained discrepancy is below 0.5 K. Systematic offsets, which may cause the disagreement of both methods within their estimated uncertainties, are discussed.

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“…There are a limited number of far-IR measurements from balloon (7), aircraft (8), and ground campaigns (9), and from measurements out to 25 μm from the Infrared Interferometer Sounder-D (IRIS-D) instrument in 1970 (45). Proposed instrumentation such as the CLimate Absolute Radiance and Refractivity Observatory (CLARREO) (46) would provide far-IR spectra that, if averaged appropriately to reduce instrumental noise and then cloudcleared, could constrain this quantity.…”

Section: Discussionmentioning

confidence: 99%

Far-infrared surface emissivity and climate

Feldman

Collins

Pincus

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Presently, there are no global measurement constraints on the surface emissivity at wavelengths longer than 15 μm, even though this surface property in this far-IR region has a direct impact on the outgoing longwave radiation (OLR) and infrared cooling rates where the column precipitable water vapor (PWV) is less than 1 mm. Such dry conditions are common for high-altitude and highlatitude locations, with the potential for modeled climate to be impacted by uncertain surface characteristics. This paper explores the sensitivity of instantaneous OLR and cooling rates to changes in far-IR surface emissivity and how this unconstrained property impacts climate model projections. At high latitudes and altitudes, a 0.05 change in emissivity due to mineralogy and snow grain size can cause a 1.8-2.0 W m −2 difference in the instantaneous clearsky OLR. A variety of radiative transfer techniques have been used to model the far-IR spectral emissivities of surface types defined by the International Geosphere-Biosphere Program. Incorporating these far-IR surface emissivities into the Representative Concentration Pathway (RCP) 8.5 scenario of the Community Earth System Model leads to discernible changes in the spatial patterns of surface temperature, OLR, and frozen surface extent. The model results differ at high latitudes by as much as 2°K, 10 W m −2 , and 15%, respectively, after only 25 y of integration. Additionally, the calculated difference in far-IR emissivity between ocean and sea ice of between 0.1 and 0.2, suggests the potential for a far-IR positive feedback for polar climate change.climate change | positive feedback | emissivity | remote sensing | polar amplification

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The Radiative Heating in Underexplored Bands Campaigns

Abstract: Spectral radiance observations in extremely dry surface locations can be used to reduce the uncertainty in radiative heating and cooling in the mid-to-upper troposphere due to water vapor absorption.

Cited by 71 publications

References 32 publications

Evaluation of two Vaisala RS92 radiosonde solar radiative dry bias correction algorithms

Evaluation of two Vaisala RS92 radiosonde solar radiative dry bias correction algorithms

Investigation of ground-based microwave radiometer calibration techniques at 530 hPa

Far-infrared surface emissivity and climate

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