Author
Wenying Su
Other affiliations: University of Alabama in Huntsville, Hampton University
Bio: Wenying Su is an academic researcher from Langley Research Center. The author has contributed to research in topics: Shortwave & Radiative flux. The author has an hindex of 18, co-authored 43 publications receiving 1398 citations. Previous affiliations of Wenying Su include University of Alabama in Huntsville & Hampton University.
Topics: Shortwave, Radiative flux, Radiance, Cloud cover, Radiative transfer
Papers
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TL;DR: The Clouds and the Earth's Radiant Energy System (CERES) Energy Balanced and Filled (EBAF) top-of-atmosphere (TOA), Edition 4.0 (Ed4.0) data product is described in this article.
Abstract: The Clouds and the Earth’s Radiant Energy System (CERES) Energy Balanced and Filled (EBAF) top-of-atmosphere (TOA), Edition 4.0 (Ed4.0), data product is described. EBAF Ed4.0 is an update to EBAF Ed2.8, incorporating all of the Ed4.0 suite of CERES data product algorithm improvements and consistent input datasets throughout the record. A one-time adjustment to shortwave (SW) and longwave (LW) TOA fluxes is made to ensure that global mean net TOA flux for July 2005–June 2015 is consistent with the in situ value of 0.71 W m−2. While global mean all-sky TOA flux differences between Ed4.0 and Ed2.8 are within 0.5 W m−2, appreciable SW regional differences occur over marine stratocumulus and snow/sea ice regions. Marked regional differences in SW clear-sky TOA flux occur in polar regions and dust areas over ocean. Clear-sky LW TOA fluxes in EBAF Ed4.0 exceed Ed2.8 in regions of persistent high cloud cover. Owing to substantial differences in global mean clear-sky TOA fluxes, the net cloud radiative eff...
408 citations
TL;DR: The algorithm to produce the Clouds and the Earth's Radiant Energy System (CERES) Edition 4.0 (Ed4) Energy Balanced and Filled (EBAF)-surface data product is explained in this article.
Abstract: The algorithm to produce the Clouds and the Earth’s Radiant Energy System (CERES) Edition 4.0 (Ed4) Energy Balanced and Filled (EBAF)-surface data product is explained. The algorithm forces...
264 citations
TL;DR: In this paper, the emerging record of satellite observations from the Earth Observation System (EOS) and A-Train constellation are advancing our ability to more completely document and understand the underlying processes associated with variations in the Earth's top-of-atmosphere (TOA) radiation budget.
Abstract: This paper highlights how the emerging record of satellite observations from the Earth Observation System (EOS) and A-Train constellation are advancing our ability to more completely document and understand the underlying processes associated with variations in the Earth’s top-of-atmosphere (TOA) radiation budget. Large-scale TOA radiation changes during the past decade are observed to be within 0.5 Wm−2 per decade based upon comparisons between Clouds and the Earth’s Radiant Energy System (CERES) instruments aboard Terra and Aqua and other instruments. Tropical variations in emitted outgoing longwave (LW) radiation are found to closely track changes in the El Nino-Southern Oscillation (ENSO). During positive ENSO phase (El Nino), outgoing LW radiation increases, and decreases during the negative ENSO phase (La Nina). The coldest year during the last decade occurred in 2008, during which strong La Nina conditions persisted throughout most of the year. Atmospheric Infrared Sounder (AIRS) observations show that the lower temperatures extended throughout much of the troposphere for several months, resulting in a reduction in outgoing LW radiation and an increase in net incoming radiation. At the global scale, outgoing LW flux anomalies are partially compensated for by decreases in midlatitude cloud fraction and cloud height, as observed by Moderate Resolution Imaging Spectrometer and Multi-angle Imaging SpectroRadiometer, respectively. CERES data show that clouds have a net radiative warming influence during La Nina conditions and a net cooling influence during El Nino, but the magnitude of the anomalies varies greatly from one ENSO event to another. Regional cloud-radiation variations among several Terra and A-Train instruments show consistent patterns and exhibit marked fluctuations at monthly timescales in response to tropical atmosphere-ocean dynamical processes associated with ENSO and Madden–Julian Oscillation.
134 citations
TL;DR: In this article, the authors developed a new scene-type-dependent angular distribution model (ADM) for Terra and Aqua using all available CERES rotating azimuth plane radiance measurements, which can change the monthly mean instantaneous fluxes by up to 5 W m−2 on a regional scale of 1° latitude × 1° longitude.
Abstract: . The top-of-atmosphere (TOA) radiative fluxes are critical components to advancing our understanding of the Earth's radiative energy balance, radiative effects of clouds and aerosols, and climate feedback. The Clouds and the Earth's Radiant Energy System (CERES) instruments provide broadband shortwave and longwave radiance measurements. These radiances are converted to fluxes by using scene-type-dependent angular distribution models (ADMs). This paper describes the next-generation ADMs that are developed for Terra and Aqua using all available CERES rotating azimuth plane radiance measurements. Coincident cloud and aerosol retrievals, and radiance measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS), and meteorological parameters from Goddard Earth Observing System (GEOS) data assimilation version 5.4.1 are used to define scene type. CERES radiance measurements are stratified by scene type and by other parameters that are important for determining the anisotropy of the given scene type. Anisotropic factors are then defined either for discrete intervals of relevant parameters or as a continuous functions of combined parameters, depending on the scene type. Significant differences between the ADMs described in this paper and the existing ADMs are over clear-sky scene types and polar scene types. Over clear ocean, we developed a set of shortwave (SW) ADMs that explicitly account for aerosols. Over clear land, the SW ADMs are developed for every 1° latitude × 1° longitude region for every calendar month using a kernel-based bidirectional reflectance model. Over clear Antarctic scenes, SW ADMs are developed by accounting the effects of sastrugi on anisotropy. Over sea ice, a sea-ice brightness index is used to classify the scene type. Under cloudy conditions over all surface types, the longwave (LW) and window (WN) ADMs are developed by combining surface and cloud-top temperature, surface and cloud emissivity, cloud fraction, and precipitable water. Compared to the existing ADMs, the new ADMs change the monthly mean instantaneous fluxes by up to 5 W m−2 on a regional scale of 1° latitude × 1° longitude, but the flux changes are less than 0.5 W m−2 on a global scale.
118 citations
TL;DR: In this paper, a radiative perturbation analysis is performed for the ideal case in which the perturbations in global mean aerosol properties are given by published values of systematic uncertainty in Aerosol Robotic Network (AERONET) measurements.
Abstract: To provide a lower bound for theuncertaintyin measurement-based clear- and all-skydirectaerosolradiative forcing (DARF), a radiative perturbation analysis is performed for the ideal case in which the perturbations in global mean aerosol properties are given by published values of systematic uncertainty in Aerosol Robotic Network (AERONET) aerosol measurements. DARF calculations for base-state climatological cloud and aerosol properties over ocean and land are performed, and then repeated after perturbing individual aerosol optical properties (aerosol optical depth, single-scattering albedo, asymmetry parameter, scale height, and anthropogenic fraction) from their base values, keeping all other parameters fixed. The total DARF uncertainty from all aerosol parameters combined is 0.5‐1.0 W m 22 , a factor of 2‐4 greater than the value cited in the Intergovernmental Panel on Climate Change’s (IPCC’s) Fourth Assessment Report. Most of the total DARF uncertaintyinthisanalysisisassociatedwithsingle-scatteringalbedouncertainty.Owingtothegreatersensitivity tosingle-scatteringalbedoincloudycolumns,DARFuncertaintyinall-skyconditionsisgreaterthaninclear-sky conditions, even though the global mean clear-sky DARF is more than twice as large as the all-sky DARF.
108 citations
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TL;DR: In this article, an update on the Earth's global annual mean energy budget in the light of new observations and analyses is provided, with the top-of-atmosphere (TOA) values constrained by Earth Radiation Budget Experiment values from 1985 to 1989, when the TOA values were approximately in balance.
Abstract: An update is provided on the Earth's global annual mean energy budget in the light of new observations and analyses. In 1997, Kiehl and Trenberth provided a review of past estimates and performed a number of radiative computations to better establish the role of clouds and various greenhouse gases in the overall radiative energy flows, with top-of-atmosphere (TOA) values constrained by Earth Radiation Budget Experiment values from 1985 to 1989, when the TOA values were approximately in balance. The Clouds and the Earth's Radiant Energy System (CERES) measurements from March 2000 to May 2004 are used at TOA but adjusted to an estimated imbalance from the enhanced greenhouse effect of 0.9 W m−2. Revised estimates of surface turbulent fluxes are made based on various sources. The partitioning of solar radiation in the atmosphere is based in part on the International Satellite Cloud Climatology Project (ISCCP) FD computations that utilize the global ISCCP cloud data every 3 h, and also accounts for increased ...
1,283 citations
TL;DR: A review of the evidence for these changes, their magnitude, their possible causes, their representation in climate models, and their potential implications for climate change can be found in this paper.
Abstract: [1] There is increasing evidence that the amount of solar radiation incident at the Earth's surface is not stable over the years but undergoes significant decadal variations. Here I review the evidence for these changes, their magnitude, their possible causes, their representation in climate models, and their potential implications for climate change. The various studies analyzing long-term records of surface radiation measurements suggest a widespread decrease in surface solar radiation between the 1950s and 1980s (“global dimming”), with a partial recovery more recently at many locations (“brightening”). There are also some indications for an “early brightening” in the first part of the 20th century. These variations are in line with independent long-term observations of sunshine duration, diurnal temperature range, pan evaporation, and, more recently, satellite-derived estimates, which add credibility to the existence of these changes and their larger-scale significance. Current climate models, in general, tend to simulate these decadal variations to a much lesser degree. The origins of these variations are internal to the Earth's atmosphere and not externally forced by the Sun. Variations are not only found under cloudy but also under cloud-free atmospheres, indicative of an anthropogenic contribution through changes in aerosol emissions governed by economic developments and air pollution regulations. The relative importance of aerosols, clouds, and aerosol-cloud interactions may differ depending on region and pollution level. Highlighted are further potential implications of dimming and brightening for climate change, which may affect global warming, the components and intensity of the hydrological cycle, the carbon cycle, and the cryosphere among other climate elements.
936 citations
TL;DR: In this paper, the authors provided a detailed error analysis of TOA fluxes based on the latest generation of Clouds and the Earth's Radiant Energy System (CERES) gridded monthly mean data products [the monthly TOA/surface averages geostationary (SRBAVG-GEO)] and used an objective constrainment algorithm to adjust reflected solar (SW) and emitted thermal (LW) top-of-atmosphere (TOA) radiative fluxes within their range of uncertainty.
Abstract: Despite recent improvements in satellite instrument calibration and the algorithms used to determine reflected solar (SW) and emitted thermal (LW) top-of-atmosphere (TOA) radiative fluxes, a sizeable imbalance persists in the average global net radiation at the TOA from satellite observations. This imbalance is problematic in applications that use earth radiation budget (ERB) data for climate model evaluation, estimate the earth’s annual global mean energy budget, and in studies that infer meridional heat transports. This study provides a detailed error analysis of TOA fluxes based on the latest generation of Clouds and the Earth’s Radiant Energy System (CERES) gridded monthly mean data products [the monthly TOA/surface averages geostationary (SRBAVG-GEO)] and uses an objective constrainment algorithm to adjust SW and LW TOA fluxes within their range of uncertainty to remove the inconsistency between average global net TOA flux and heat storage in the earth–atmosphere system. The 5-yr global mean...
858 citations
University of Colorado Boulder1, University of New South Wales2, Purdue University3, Western Kentucky University4, University of Queensland5, Tennessee Technological University6, Netherlands Environmental Assessment Agency7, University of Alabama in Huntsville8, Hadley Centre for Climate Prediction and Research9, Tuskegee University10, Max Planck Society11, Centre national de la recherche scientifique12
TL;DR: The authors summarizes the changes in landscape structure because of human land management over the last several decades, and using observed and model-eddata, documents how these changes have altered biogeophysical and biogeochemical surface fluxes on the local, mesoscale, and regional scales.
Abstract: This article summarizes the changes in landscape structure because of human land managementoverthelastseveralcenturies,andusingobservedandmodeleddata, documents how these changes have altered biogeophysical and biogeochemical surface fluxes on the local, mesoscale, and regional scales. Remaining research issues are presented including whether these landscape changes alter large-scale atmospheric circulation patterns far from where the land use and land cover changes occur. We conclude that existing climate assessments have not yet adequately factored in this climate forcing. For those regions that have undergone intensive human landscape change, or would undergo intensive change in the future, we conclude that the failure to factor in this forcing risks a misalignment of investment in climate mitigation and adaptation. 2011 John Wiley & Sons, Ltd.
672 citations
Western Kentucky University1, Cooperative Institute for Research in Environmental Sciences2, University of Nebraska–Lincoln3, Purdue University4, University of Queensland5, Pennsylvania State University6, Cooperative Institute for Research in the Atmosphere7, Agriculture and Agri-Food Canada8, John Deere9, Oak Ridge National Laboratory10, University of Alabama in Huntsville11, University of Delaware12, University of Georgia13, Chinese Academy of Sciences14, University of Colorado Boulder15, Texas A&M University16, Tuskegee University17
TL;DR: In this article, the authors provide an overview and synthesis of some of the most notable types of land cover changes and their impacts on climate, including agriculture, deforestation and afforestation, desertification, and urbanization.
Abstract: Land cover changes (LCCs) play an important role in the climate system. Research over recent decades highlights the impacts of these changes on atmospheric temperature, humidity, cloud cover, circulation, and precipitation. These impacts range from the local- and regional-scale to sub-continental and global-scale. It has been found that the impacts of regional-scale LCC in one area may also be manifested in other parts of the world as a climatic teleconnection. In light of these findings, this article provides an overview and synthesis of some of the most notable types of LCC and their impacts on climate. These LCC types include agriculture, deforestation and afforestation, desertification, and urbanization. In addition, this article provides a discussion on challenges to, and future research directions in, assessing the climatic impacts of LCC.
560 citations