Inter-model differences in tropical free-tropospheric humidity and their impact on the clear-sky radiation budget in global storm-resolving simulations

2021 ◽  
Author(s):  
Theresa Lang ◽  
Ann Kristin Naumann ◽  
Bjorn Stevens ◽  
Stefan A. Buehler
Keyword(s):  
Longwave Radiation ◽  
Radiation Budget ◽  
Free Troposphere ◽  
Upper Troposphere ◽  
Convective Parameterization ◽  
Global Circulation ◽  
Clear Sky ◽  
Global Circulation Models ◽  
The Earth ◽  
A Minor

<p>Although the humidity distribution in the tropical free troposphere plays a key role in controlling the Earth’s energy budget, it is poorly simulated in Global Circulation Models (GCMs). A major uncertainty in these models arises from parameterizations of unresolved processes, above all the convective parameterization. An important step in global atmospheric modelling has been made with global storm-resolving models (GSRMs). By forgoing the convective parameterization GSRMs nourish the hope that they better represent processes relevant for humidity, but it is unclear to what extent the uncertainty in free-tropospheric humidity is reduced. The main goal of our study is to quantify this uncertainty as well as the resulting uncertainty in the clear-sky radiation budget based on the spread in an ensemble of GSRMs called DYAMOND. We find that the inter-model spread in relative humidity (RH) in DYAMOND has reduced by at least a factor of two throughout most of the free troposphere compared to the GCMs that participated in the CMIP5 AMIP experiment. However, the remaining RH differences in DYAMOND still cause a considerable inter-model spread of 1.2 Wm<sup>-2</sup> in tropical mean clear-sky outgoing longwave radiation (OLR). For the most part this spread is caused by the RH differences in the lower and mid free troposphere, whereas RH differences in the upper troposphere (above 10 km) have a minor impact on OLR. We only find a direct connection between anomalies in RH and anomalies in the resolved humidity transport in the upper troposphere, suggesting that differences in the parameterizations of unresolved processes like microphysics and turbulence play a major role in the altitude regions with the strongest impact on OLR. Comparing model fields in moisture space, i.e. sorted from the driest to the moistest atmospheric column, reveals that two tropical regimes contribute most to the spread in tropical mean OLR: the driest subsidence regimes and moist regimes at the transition from deep convective to subsidence regions.</p>

scholarly journals Evaluation of Six High-Spatial Resolution Clear-Sky Surface Upward Longwave Radiation Estimation Methods with MODIS

2020 ◽  
Vol 12 (11) ◽  
pp. 1834
Author(s):  
Boxiong Qin ◽  
Biao Cao ◽  
Hua Li ◽  
Zunjian Bian ◽  
Tian Hu ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Hybrid Methods ◽  
Longwave Radiation ◽  
Surface Radiation ◽  
Radiation Budget ◽  
Estimation Methods ◽  
Mean Bias Error ◽  
Clear Sky ◽  
Surface Radiation Budget

Surface upward longwave radiation (SULR) is a critical component in the calculation of the Earth’s surface radiation budget. Multiple clear-sky SULR estimation methods have been developed for high-spatial resolution satellite observations. Here, we comprehensively evaluated six SULR estimation methods, including the temperature-emissivity physical methods with the input of the MYD11/MYD21 (TE-MYD11/TE-MYD21), the hybrid methods with top-of-atmosphere (TOA) linear/nonlinear/artificial neural network regressions (TOA-LIN/TOA-NLIN/TOA-ANN), and the hybrid method with bottom-of-atmosphere (BOA) linear regression (BOA-LIN). The recently released MYD21 product and the BOA-LIN—a newly developed method that considers the spatial heterogeneity of the atmosphere—is used initially to estimate SULR. In addition, the four hybrid methods were compared with simulated datasets. All the six methods were evaluated using the Moderate Resolution Imaging Spectroradiometer (MODIS) products and the Surface Radiation Budget Network (SURFRAD) in situ measurements. Simulation analysis shows that the BOA-LIN is the best one among four hybrid methods with accurate atmospheric profiles as input. Comparison of all the six methods shows that the TE-MYD21 performed the best, with a root mean square error (RMSE) and mean bias error (MBE) of 14.0 and −0.2 W/m2, respectively. The RMSE of BOA-LIN, TOA-NLIN, TOA-LIN, TOA-ANN, and TE-MYD11 are equal to 15.2, 16.1, 17.2, 21.2, and 18.5 W/m2, respectively. TE-MYD21 has a much better accuracy than the TE-MYD11 over barren surfaces (NDVI < 0.3) and a similar accuracy over non-barren surfaces (NDVI ≥ 0.3). BOA-LIN is more stable over varying water vapor conditions, compared to other hybrid methods. We conclude that this study provides a valuable reference for choosing the suitable estimation method in the SULR product generation.

scholarly journals Development of the HIRS Outgoing Longwave Radiation Climate Dataset

2007 ◽  
Vol 24 (12) ◽  
pp. 2029-2047 ◽  
Author(s):  
Hai-Tien Lee ◽  
Arnold Gruber ◽  
Robert G. Ellingson ◽  
Istvan Laszlo
Keyword(s):  
Time Series ◽  
High Resolution ◽  
Outgoing Longwave Radiation ◽  
Longwave Radiation ◽  
Radiation Budget ◽  
Validation Data ◽  
The Earth ◽  
Data Record ◽  
Earth Radiation Budget ◽  
Earth Radiation

Abstract The Advanced Very High Resolution Radiometer (AVHRR) outgoing longwave radiation (OLR) product, which NOAA has been operationally generating since 1979, is a very long data record that has been used in many applications, yet past studies have shown its limitations and several algorithm-related deficiencies. Ellingson et al. have developed the multispectral algorithm that largely improved the accuracy of the narrowband-estimated OLR as well as eliminated the problems in AVHRR. NOAA has been generating High Resolution Infrared Radiation Sounder (HIRS) OLR operationally since September 1998. In recognition of the need for a continuous and long OLR data record that would be consistent with the earth radiation budget broadband measurements in the National Polar-orbiting Operational Environmental Satellite System (NPOESS) era, and to provide a climate data record for global change studies, a vigorous reprocessing of the HIRS radiance for OLR derivation is necessary. This paper describes the development of the new HIRS OLR climate dataset. The HIRS level 1b data from the entire Television and Infrared Observation Satellite N-series (TIROS-N) satellites have been assembled. A new radiance calibration procedure was applied to obtain more accurate and consistent HIRS radiance measurements. The regression coefficients of the HIRS OLR algorithm for all satellites were rederived from calculations using an improved radiative transfer model. Intersatellite calibrations were performed to remove possible discontinuity in the HIRS OLR product from different satellites. A set of global monthly diurnal models was constructed consistent with the HIRS OLR retrievals to reduce the temporal sampling errors and to alleviate an orbital-drift-induced artificial trend. These steps significantly improved the accuracy, continuity, and uniformity of the HIRS monthly mean OLR time series. As a result, the HIRS OLR shows a comparable stability as in the Earth Radiation Budget Satellite (ERBS) nonscanner OLR measurements. HIRS OLR has superb agreement with the broadband observations from Earth Radiation Budget Experiment (ERBE) and Clouds and the Earth’s Radiant Energy System (CERES) in the ENSO-monitoring regions. It shows compatible ENSO-monitoring capability with the AVHRR OLR. Globally, HIRS OLR agrees with CERES with an accuracy to within 2 W m−2 and a precision of about 4 W m−2. The correlation coefficient between HIRS and CERES global monthly mean is 0.997. Regionally, HIRS OLR agrees with CERES to within 3 W m−2 with precisions better than 3 W m−2 in most places. HIRS OLR could be used for constructing climatology for applications that plan to use NPOESS ERBS and previously used AVHRR OLR observations. The HIRS monthly mean OLR data have high accuracy and precision with respect to the broadband observations of ERBE and CERES. It can be used as an independent validation data source. The uniformity and continuity of HIRS OLR time series suggest that it could be used as a reliable transfer reference for the discontinuous broadband measurements from ERBE, CERES, and ERBS.

scholarly journals The Diurnal Cycle of Outgoing Longwave Radiation from Earth Radiation Budget Experiment Measurements

2003 ◽  
Vol 60 (13) ◽  
pp. 1529-1542 ◽  
Author(s):  
G. Louis Smith ◽  
David A. Rutan
Keyword(s):  
Diurnal Cycle ◽  
Outgoing Longwave Radiation ◽  
Longwave Radiation ◽  
Empirical Orthogonal Functions ◽  
Radiation Budget ◽  
Cloud Formation ◽  
Lag Effects ◽  
The Earth ◽  
Earth Radiation Budget ◽  
Earth Radiation

Abstract The diurnal cycle of outgoing longwave radiation (OLR) from the earth is analyzed by decomposing satellite observations into a set of empirical orthogonal functions (EOFs). The observations are from the Earth Radiation Budget Experiment (ERBE) scanning radiometer aboard the Earth Radiation Budget Satellite, which had a precessing orbit with 57° inclination. The diurnal cycles of land and ocean differ considerably. The first EOF for land accounts for 73% to 85% of the variance, whereas the first EOF for ocean accounts for only 16% to 20% of the variance, depending on season. The diurnal cycle for land is surprisingly symmetric about local noon for the first EOF, which is approximately a half-sine during day and flat at night. The second EOF describes lead–lag effects due to surface heating and cloud formation. For the ocean, the first EOF and second EOF are similar to that of land, except for spring, when the first ocean EOF is a semidiurnal cycle and the second ocean EOF is the half-sine. The first EOF for land has a daytime peak of about 50 W m−2, whereas the first ocean EOF peaks at about 25 W m−2. The geographical and seasonal patterns of OLR diurnal cycle provide insights into the interaction of radiation with the atmosphere and surface and are useful for validating and upgrading circulation models.

Trends in spectrally resolved OLR from 10 years of IASI measurements

2021 ◽  
Author(s):  
Simon Whitburn ◽  
Lieven Clarisse ◽  
Andy Delcloo ◽  
Steven Dewitte ◽  
Marie Bouillon ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Data Retrieval ◽  
Radiation Budget ◽  
Retrieval Algorithm ◽  
Earth Atmosphere ◽  
Clear Sky ◽  
The Earth ◽  
Atmosphere System ◽  
Spectrally Resolved ◽  
The Impact

&lt;p&gt;The Earth's Outgoing Longwave Radiation (OLR) is a key component in the study of climate. As part of the Earth's radiation budget, it reflects how the Earth-atmosphere system compensates the incoming solar radiation at the top of the atmosphere. At equilibrium, the two quantities compensate each other on average. Any variation of the climate drivers (e.g. greenhouse gases) causes an energy imbalance which leads to a climate response (e.g. surface temperature increase), with the effect of bringing the radiation budget back to equilibrium. Considerable improvements in our understanding of the Earth-atmosphere system and of its long-term changes have been achieved in the last four decades through the exploitation of measurements from dedicated broadband instruments. However, such instruments only provide spectrally integrated OLR over a broad spectral range and are therefore not well suited for tracking separately the impact of the different parameters affecting the OLR.&lt;/p&gt;&lt;p&gt;Better constraints can, in principle, be obtained from spectrally resolved OLR (i.e. the integrand of broadband OLR, in units of W m&lt;sup&gt;-2&lt;/sup&gt; cm&lt;sup&gt;-1&lt;/sup&gt;) derived from infrared hyperspectral sounders. Recently, a dedicated algorithm was developed to derive clear-sky spectrally resolved OLR from the Infrared Atmospheric Sounding Interferometer (IASI) at the 0.25 cm&lt;sup&gt;-1&lt;/sup&gt; native spectral sampling of the L1C spectra (Whitburn et al. 2020).&amp;#160; Here, we analyze the changes in 10 years (2008-2017) of the IASI-derived OLR and we relate them to known changes in greenhouse gases concentrations (CO&lt;sub&gt;2&lt;/sub&gt;, CH&lt;sub&gt;4&lt;/sub&gt;, H&lt;sub&gt;2&lt;/sub&gt;O, &amp;#8230;) and climate phenomena activity such as El Ni&amp;#241;o-Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO).&lt;/p&gt;&lt;p&gt;Whitburn, S., Clarisse, L., Bauduin, S., George, M., Hurtmans, D., Safieddine, S., Coheur, P. F., and Clerbaux, C. (2020). &lt;strong&gt;Spectrally Resolved Fuxes from IASI Data: Retrieval algorithm for Clear-Sky Measurements&lt;/strong&gt;. Journal of Climate. doi: 10.1175/jcli-d-19-0523.1&lt;/p&gt;

Validation of Clear-Sky Global LAnd Surface Satellite (GLASS) Longwave Radiation Product

2020 ◽  
Author(s):  
Qi Zeng ◽  
Jie Cheng ◽  
Feng Yang
Keyword(s):  
Land Surface ◽  
Water Cycle ◽  
Radiant Energy ◽  
Remote Sensing Data ◽  
Longwave Radiation ◽  
Energy System ◽  
Surface Radiation ◽  
Radiation Budget ◽  
Clear Sky ◽  
Global Land

&lt;p&gt;Surface longwave (LW) radiation plays an important rolein global climatic change, which is consist of surface longwave upward radiation (LWUP), surface longwave downward radiation (LWDN) and surface longwave net radiation (LWNR). Numerous studies have been carried out to estimate LWUP or LWDN from remote sensing data, and several satellite LW radiation products have been released, such as the International Satellite Cloud Climatology Project&amp;#8208;Flux Data (ISCCP&amp;#8208;FD), the Global Energy and Water cycle Experiment&amp;#8208;Surface Radiation Budget (GEWEX&amp;#8208;SRB) and the Clouds and the Earth&amp;#8217;s Radiant Energy System&amp;#8208;Gridded Radiative Fluxes and Clouds (CERES&amp;#8208;FSW). But these products share the common features of coarse spatial resolutions (100-280 km) and lower validation accuracy.&lt;/p&gt;&lt;p&gt;Under such circumstance, we developed the methods of estimating long-term high spatial resolution all sky&amp;#160; instantaneous LW radiation, and produced the corresponding products from MODIS data from 2000 through 2018 (Terra and Aqua), named as Global LAnd Surface Satellite (GLASS) Longwave Radiation product, which can be free freely downloaded from the website (http://glass.umd.edu/Download.html).&lt;/p&gt;&lt;p&gt;In this article, ground measurements collected from 141 sites in six independent networks (AmerciFlux, AsiaFlux, BSRN, CEOP, HiWATER-MUSOEXE and TIPEX-III) are used to evaluate the clear-sky GLASS LW radiation products at global scale. The bias and RMSE is -4.33 W/m&lt;sup&gt;2 &lt;/sup&gt;and 18.15 W/m&lt;sup&gt;2 &lt;/sup&gt;for LWUP, -3.77 W/m&lt;sup&gt;2 &lt;/sup&gt;and 26.94 W/m&lt;sup&gt;2&lt;/sup&gt; for LWDN, and 0.70 W/m&lt;sup&gt;2 &lt;/sup&gt;and 26.70 W/m&lt;sup&gt;2&lt;/sup&gt; for LWNR, respectively. Compared with validation results of the above mentioned three LW radiation products, the overall accuracy of GLASS LW radiation product is much better. We will continue to improve the retrieval algorithms and update the products accordingly.&lt;/p&gt;

scholarly journals Downward longwave radiation estimates for clear-sky conditions over northeast Brazil

2011 ◽  
Vol 26 (3) ◽  
pp. 443-450 ◽  
Author(s):  
Carlos Antonio Costa dos Santos ◽  
Bernardo Barbosa da Silva ◽  
Tantravahi Venkata Ramana Rao ◽  
Prakki Satyamurty ◽  
Antonio Ocimar Manzi
Keyword(s):  
Arid Regions ◽  
Longwave Radiation ◽  
Radiation Budget ◽  
Semiarid Region ◽  
Northeast Brazil ◽  
Hydrological Models ◽  
Experimental Site ◽  
Clear Sky ◽  
Downward Longwave Radiation ◽  
Sky Conditions

The main objective of this paper is to assess the performance of nine downward longwave radiation equations for clear-sky condition and develop a locally adjusted equation using the observed vapor pressure and air temperature data. The radiation and atmospheric parameters were measured during the months of October 2005 to June 2006 at a micrometeorological tower installed at the experimental site in a banana orchard in the semiarid region of Northeast Brazil. The comparative statistics for the performance of the downward longwave radiation calculation models during daytime and nighttime compared to measured data have shown that the parameterizations with more physical foundations have the best results. The locally adjusted equation and Sugita and Brutsaert model developed in 1993 showed errors less than 1.0% in comparison with measured values. Downward longwave radiation is one of the most expensive and difficult component of the radiation budget to be monitored in micrometeorological studies. Hence, the locally adjusted equation can be used to estimate downward longwave energy, needed as input to some agricultural and hydrological models, in semi-arid regions of the Northeast Brazil, where this component is not monitored.

scholarly journals Decadal Changes of Earth’s Outgoing Longwave Radiation

2018 ◽  
Vol 10 (10) ◽  
pp. 1539 ◽  
Author(s):  
Steven Dewitte ◽  
Nicolas Clerbaux
Keyword(s):  
Outgoing Longwave Radiation ◽  
Radiant Energy ◽  
Longwave Radiation ◽  
Energy System ◽  
Radiation Budget ◽  
The Arctic ◽  
Regional Patterns ◽  
The Earth ◽  
Earth Radiation Budget ◽  
Earth Radiation

The Earth Radiation Budget (ERB) at the top of the atmosphere quantifies how the earth gains energy from the sun and loses energy to space. Its monitoring is of fundamental importance for understanding ongoing climate change. In this paper, decadal changes of the Outgoing Longwave Radiation (OLR) as measured by the Clouds and Earth’s Radiant Energy System from 2000 to 2018, the Earth Radiation Budget Experiment from 1985 to 1998, and the High-resolution Infrared Radiation Sounder from 1985 to 2018 are analysed. The OLR has been rising since 1985, and correlates well with the rising global temperature. An observational estimate of the derivative of the OLR with respect to temperature of 2.93 +/− 0.3 W/m 2 K is obtained. The regional patterns of the observed OLR change from 1985–2000 to 2001–2017 show a warming pattern in the Northern Hemisphere in particular in the Arctic, as well as tropical cloudiness changes related to a strengthening of La Niña.

scholarly journals Developing Clear-Sky Flux Products for the Geostationary Earth Radiation Budget Experiment

2005 ◽  
Vol 44 (9) ◽  
pp. 1361-1374 ◽  
Author(s):  
J. M. Futyan ◽  
J. E. Russell
Keyword(s):  
Diurnal Cycle ◽  
Radiant Energy ◽  
Longwave Radiation ◽  
Energy System ◽  
Radiation Budget ◽  
Sampling Errors ◽  
Clear Sky ◽  
Temporal Sampling ◽  
Earth Radiation Budget ◽  
Earth Radiation

Abstract This paper describes the planned processing of monthly mean and monthly mean diurnal cycle flux products for the Geostationary Earth Radiation Budget (GERB) experiment. The use of higher-spatial-resolution flux estimates based on multichannel narrowband imager data to improve clear-sky sampling is investigated. Significant improvements in temporal sampling are found, leading to reduced temporal sampling errors and less dependence on diurnal models for the monthly mean products. The reduction in temporal sampling errors is found to outweigh any spatial sampling errors that are introduced. The resulting flux estimates are used to develop an improved version of the half-sine model that is used for the diurnal interpolation of clear-sky longwave fluxes over land in the Earth Radiation Budget Experiment (ERBE) and Clouds and the Earth’s Radiant Energy System (CERES) missions. Maximum outgoing longwave radiation occurs from 45 min to 1.5 h after local noon for most of the GERB field of view. Use of the ERBE half-sine model for interpolation therefore results in significant distortion of the diurnal cycle shape. The model that is proposed here provides a well-constrained fit to the true diurnal shape, even for limited clear-sky sampling, making it suitable for use in the processing of both GERB and CERES second-generation monthly mean clear-sky data products.

Inversion and space-time-averaging algorithms for ScaRaB (Scanner for the Earth Radiation Budget). Comparison with ERBE

1995 ◽  
Vol 13 (9) ◽  
pp. 959-968 ◽  
Author(s):  
M. Viollier ◽  
R. Kandel ◽  
P. Raberanto
Keyword(s):  
Spectral Response ◽  
Space Time ◽  
Radiation Budget ◽  
Time Averaging ◽  
Radiometric Calibration ◽  
Clear Sky ◽  
The Earth ◽  
Earth Radiation Budget ◽  
Scene Identification ◽  
Earth Radiation

Abstract. Establishment of a uniform long-term record of "top-of-the atmosphere" (TOA) Earth radiation budget (ERB) components, on a scale appropriate to the study of cloud radiation interactions, requires that the data obtained from different observation missions satisfy two basic conditions: (1) the broadband shortwave (SW:0.2–4 µm) and longwave (LW: 4–50 µm) radiances must be demonstrably made on the same absolute scale; and (2) the methods used first to convert the instantaneous (filtered) radiances into (unfiltered) SW and LW radiant fluxes, and then to perform the space-time integrations to yield regional monthly means, must be consistent. Here we consider mainly the second point, with regard to the ScaRaB/Meteor mission in orbit since 25 January 1994 and observing the Earth since 24 February 1994. The objective of this mission is to determine the TOA ERB components and so to provide a continuation of the NASA ERBE scanner mission (November 1984–February 1990). We show how results compatible with ERBE can be obtained by taking into account the instrumental characteristics and the satellite orbit parameters: spectral response of the broadband channels, Earth local time of observation. Considering the spectral response of the ScaRaB broadband channels, we show that no spectral correction is required in the longwave domain, whereas a correction of +4.5% must be applied in the shortwave domain for clear and partly cloudy ocean, in order to compensate for underestimation at the shortest wavelengths. Despite possible differences between ERBE and ScaRaB procedures in values assumed for certain parameters of the scene/cloud identifications, application of these procedures to the same set of ERBE data (spectrally corrected, i.e. "unfiltered" radiances) shows that scene identification agreement is close to 90% and that, where there is disagreement, resulting differences in LW fluxes are negligible, those in SW fluxes small. We show that regional and global mean quantities are in excellent agreement, considering that differences between (ERBS+NOAA-9) and (NOAA-9 only) results may be taken as illustrating time-sampling effects. We find that biases may occur from the undersampling, specifically for the night-time clear-sky estimation over land and desert. Preliminary results using ScaaB data of March 1994 show that clear-sky regional estimates may be less numerous than in ERBE scanner products, due to either the larger pixel size or the auxiliary parameters used in the scene identification, and that expected uncertainties in the global monthly mean values depend mainly on the instrument radiometric calibration.

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