Fundamentals of Climate Change (PCC 587): Radiation
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Aerosol Effective Radiative Forcing in the Online Aerosol Coupled CAS
atmosphere Article Aerosol Effective Radiative Forcing in the Online Aerosol Coupled CAS-FGOALS-f3-L Climate Model Hao Wang 1,2,3, Tie Dai 1,2,* , Min Zhao 1,2,3, Daisuke Goto 4, Qing Bao 1, Toshihiko Takemura 5 , Teruyuki Nakajima 4 and Guangyu Shi 1,2,3 1 State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China; [email protected] (H.W.); [email protected] (M.Z.); [email protected] (Q.B.); [email protected] (G.S.) 2 Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster of Ministry of Education, Nanjing University of Information Science and Technology, Nanjing 210044, China 3 College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100029, China 4 National Institute for Environmental Studies, Tsukuba 305-8506, Japan; [email protected] (D.G.); [email protected] (T.N.) 5 Research Institute for Applied Mechanics, Kyushu University, Fukuoka 819-0395, Japan; [email protected] * Correspondence: [email protected]; Tel.: +86-10-8299-5452 Received: 21 September 2020; Accepted: 14 October 2020; Published: 17 October 2020 Abstract: The effective radiative forcing (ERF) of anthropogenic aerosol can be more representative of the eventual climate response than other radiative forcing. We incorporate aerosol–cloud interaction into the Chinese Academy of Sciences Flexible Global Ocean–Atmosphere–Land System (CAS-FGOALS-f3-L) by coupling an existing aerosol module named the Spectral Radiation Transport Model for Aerosol Species (SPRINTARS) and quantified the ERF and its primary components (i.e., effective radiative forcing of aerosol-radiation interactions (ERFari) and aerosol-cloud interactions (ERFaci)) based on the protocol of current Coupled Model Intercomparison Project phase 6 (CMIP6). -
1 Lecture 26
PHYS 445 Lecture 26 - Black-body radiation I 26 - 1 Lecture 26 - Black-body radiation I What's Important: · number density · energy density Text: Reif In our previous discussion of photons, we established that the mean number of photons with energy i is 1 n = (26.1) i eß i - 1 Here, the questions that we want to address about photons are: · what is their number density · what is their energy density · what is their pressure? Number density n Eq. (26.1) is written in the language of discrete states. The first thing we need to do is replace the sum by an integral over photon momentum states: 3 S i ® ò d p Of course, it isn't quite this simple because the density-of-states issue that we introduced before: for every spin state there is one phase space state for every h 3, so the proper replacement more like 3 3 3 S i ® (1/h ) ò d p ò d r The units now work: the left hand side is a number, and so is the right hand side. But this expression ignores spin - it just deals with the states in phase space. For every photon momentum, there are two ways of arranging its polarization (i.e., the orientation of its electric or magnetic field vectors): where the photon momentum vector is perpendicular to the plane. Thus, we have 3 3 3 S i ® (2/h ) ò d p ò d r. (26.2) Assuming that our system is spatially uniform, the position integral can be replaced by the volume ò d 3r = V. -
Albedo, Climate, & Urban Heat Islands
Albedo, Climate, & Urban Heat Islands Jeremy Gregory and CSHub research team: Xin Xu, Liyi Xu, Adam Schlosser, & Randolph Kirchain CSHub Webinar February 15, 2018 (Slides revised February 21, 2018) Albedo: fraction of solar radiation reflected from a surface Measured on a scale from 0 to 1 High Albedo http://www.nc-climate.ncsu.edu/edu/Albedo Earth’s average albedo: ~0.3 Slide 2 Climate is affected by albedo Three main factors affecting the climate of a planet: Source: Grid Arendal, http://www.grida.no/resources/7033 Slide 3 Urban heat islands are affected by albedo Slide 4 Urban surface albedo is significant In many urban areas, pavements and roofs constitute over 60% of urban surfaces Metropolitan Vegetation Roofs Pavements Other Areas Salt Lake City 33% 22% 36% 9% Sacramento 20% 20% 45% 15% Chicago 27% 25% 37% 11% Houston 37% 21% 29% 12% Source: Rose et al. (2003) 20%~25% 30%~45% Global change of urban surface albedo could reduce radiative forcing equivalent to 44 Gt of CO2 with $1 billion in energy savings per year in US (Akbari et al. 2009) Slide 5 Cool pavements are a potential mitigation mechanism for climate change and UHI heatisland.lbl.gov https://www.nytimes.com/2017/07/07/us/california-today-cool-pavements-la.html Slide 6 Evaluating the impacts of pavement albedo is complicated Regional Climate Radiative forcing Urban Buildings Energy Demand Climate feedback Earth’s Energy Balance Incident radiation Ambient Temperature Pavement life cycle environmental impacts Materials Design & Use End-of-Life Production Construction Slide 7 Contexts vary significantly Location Urban morphology Climate Building properties Electricity grid Slide 8 Key research questions 1. -
Global Dimming
Agricultural and Forest Meteorology 107 (2001) 255–278 Review Global dimming: a review of the evidence for a widespread and significant reduction in global radiation with discussion of its probable causes and possible agricultural consequences Gerald Stanhill∗, Shabtai Cohen Institute of Soil, Water and Environmental Sciences, ARO, Volcani Center, Bet Dagan 50250, Israel Received 8 August 2000; received in revised form 26 November 2000; accepted 1 December 2000 Abstract A number of studies show that significant reductions in solar radiation reaching the Earth’s surface have occurred during the past 50 years. This review analyzes the most accurate measurements, those made with thermopile pyranometers, and concludes that the reduction has globally averaged 0.51 0.05 W m−2 per year, equivalent to a reduction of 2.7% per decade, and now totals 20 W m−2, seven times the errors of measurement. Possible causes of the reductions are considered. Based on current knowledge, the most probable is that increases in man made aerosols and other air pollutants have changed the optical properties of the atmosphere, in particular those of clouds. The effects of the observed solar radiation reductions on plant processes and agricultural productivity are reviewed. While model studies indicate that reductions in productivity and transpiration will be proportional to those in radiation this conclusion is not supported by some of the experimental evidence. This suggests a lesser sensitivity, especially in high-radiation, arid climates, due to the shade tolerance of many crops and anticipated reductions in water stress. Finally the steps needed to strengthen the evidence for global dimming, elucidate its causes and determine its agricultural consequences are outlined. -
Consideration of Land Use Change-Induced Surface Albedo Effects in Life-Cycle Analysis of Biofuels† Cite This: Energy Environ
Energy & Environmental Science View Article Online PAPER View Journal | View Issue Consideration of land use change-induced surface albedo effects in life-cycle analysis of biofuels† Cite this: Energy Environ. Sci., 2016, 9,2855 H. Cai,*a J. Wang,b Y. Feng,b M. Wang,a Z. Qina and J. B. Dunna Land use change (LUC)-induced surface albedo effects for expansive biofuel production need to be quantified for improved understanding of biofuel climate impacts. We addressed this emerging issue for expansive biofuel production in the United States (U.S.) and compared the albedo effects with greenhouse gas emissions highlighted by traditional life-cycle analysis of biofuels. We used improved spatial representation of albedo effects in our analysis by obtaining over 1.4 million albedo observations from the Moderate Resolution Imaging Spectroradiometer flown on NASA satellites over a thousand counties representative of six Agro-Ecological Zones (AEZs) in the U.S. We utilized high-spatial-resolution, crop-specific cropland cover data from the U.S. Department of Agriculture and paired the data with the albedo data to enable consideration of various LUC scenarios. We simulated the radiative effects of LUC-induced albedo Creative Commons Attribution-NonCommercial 3.0 Unported Licence. changes for seven types of crop covers using the Monte Carlo Aerosol, Cloud and Radiation model, which employs an advanced radiative transfer mechanism coupled with spatially and temporally resolved meteorological and aerosol conditions. These simulations estimated the net radiative fluxes at the top of the atmosphere as a result of the LUC-induced albedo changes, which enabled quantification of the albedo effects on the basis of radiative forcing defined by the Intergovernmental Panel on Climate Change for CO2 and other greenhouse gases effects. -
Lecture 17 : the Cosmic Microwave Background
Let’s think about the early Universe… Lecture 17 : The Cosmic ! From Hubble’s observations, we know the Universe is Microwave Background expanding ! This can be understood theoretically in terms of solutions of GR equations !Discovery of the Cosmic Microwave ! Earlier in time, all the matter must have been Background (ch 14) squeezed more tightly together ! If crushed together at high enough density, the galaxies, stars, etc could not exist as we see them now -- everything must have been different! !The Hot Big Bang This week: read Chapter 12/14 in textbook 4/15/14 1 4/15/14 3 Let’s think about the early Universe… Let’s think about the early Universe… ! From Hubble’s observations, we know the Universe is ! From Hubble’s observations, we know the Universe is expanding expanding ! This can be understood theoretically in terms of solutions of ! This can be understood theoretically in terms of solutions of GR equations GR equations ! Earlier in time, all the matter must have been squeezed more tightly together ! If crushed together at high enough density, the galaxies, stars, etc could not exist as we see them now -- everything must have been different! ! What was the Universe like long, long ago? ! What were the original contents? ! What were the early conditions like? ! What physical processes occurred under those conditions? ! How did changes over time result in the contents and structure we see today? 4/15/14 2 4/15/14 4 The Poetic Version ! In a brilliant flash about fourteen billion years ago, time and matter were born in a single instant of creation. -
Measurement of the Cosmic Microwave Background Radiation at 19 Ghz
Measurement of the Cosmic Microwave Background Radiation at 19 GHz 1 Introduction Measurements of the Cosmic Microwave Background (CMB) radiation dominate modern experimental cosmology: there is no greater source of information about the early universe, and no other single discovery has had a greater impact on the theories of the formation of the cosmos. Observation of the CMB confirmed the Big Bang model of the origin of our universe and gave us a look into the distant past, long before the formation of the very first stars and galaxies. In this lab, we seek to recreate this founding pillar of modern physics. The experiment consists of a temperature measurement of the CMB, which is actually “light” left over from the Big Bang. A radiometer is used to measure the intensity of the sky signal at 19 GHz from the roof of the physics building. A specially designed horn antenna allows you to observe microwave noise from isolated patches of sky, without interference from the relatively hot (and high noise) ground. The radiometer amplifies the power from the horn by a factor of a billion. You will calibrate the radiometer to reduce systematic effects: a cryogenically cooled reference load is periodically measured to catch changes in the gain of the amplifier circuit over time. 2 Overview 2.1 History The first observation of the CMB occurred at the Crawford Hill NJ location of Bell Labs in 1965. Arno Penzias and Robert Wilson, intending to do research in radio astronomy at 21 cm wavelength using a special horn antenna designed for satellite communications, noticed a background noise signal in all of their radiometric measurements. -
Black Body Radiation
BLACK BODY RADIATION hemispherical Stefan-Boltzmann law This law states that the energy radiated from a black body is proportional to the fourth power of the absolute temperature. Wien Displacement Law FormulaThe Wien's Displacement Law provides the wavelength where the spectral radiance has maximum value. This law states that the black body radiation curve for different temperatures peaks at a wavelength inversely proportional to the temperature. Maximum wavelength = Wien's displacement constant / Temperature The equation is: λmax= b/T Where: λmax: The peak of the wavelength b: Wien's displacement constant. (2.9*10(−3) m K) T: Absolute Temperature in Kelvin. Emissive power The value of the Stefan-Boltzmann constant is approximately 5.67 x 10 -8 watt per meter squared per kelvin to the fourth (W · m -2 · K -4 ). If the radiation emitted normal to the surface and the energy density of radiation is u, then emissive power of the surface E=c u If the radiation is diffuse Emitted uniformly in all directions 1 E= 푐푢 4 Thermal radiation exerts pressure on the surface on which they are Incident. If the intensity of directed beam of radiations incident normally to The surface is I 퐼 Then Pressure P=u= 푐 If the radiation is diffused 1 P= 푢 3 The value of the constant is approximately 1.366 kilowatts per square metre. When the emissivity of non-black surface is constant at all temperatures and throughout the entire range of wavelength, the surface is called Gray Body. PROBLEMS 1. The temperature of a person’s skin is 350 C. -
Ground Albedo Measurements and Modeling
Ground Albedo Measurements and Modeling Bill Marion 2018 Bifacial PV Workshop Lakewood, Colorado September 11, 2018 • Publication number or conference Albedo • Albedo of a surface is the fraction of the incident sunlight that the surface reflects • Not a constant for a surface • Varies with spectral and angular distribution of light – Cloudy versus sunny – Sun position (time of day, season, latitude) Incident Albedo = Reflected ÷ Incident Reflected NREL | 2 Spectral Reflectance • Spectral reflectance is a surface property • Can use with spectral irradiance data (SMARTS modeled) to calculate ground-reflected radiation and albedo • Data sources – USGS, https://pubs.er.usgs.gov/publication/ds1035 – SMARTS has ~ 130 files NREL | 3 Ground Reflected Spectral Mismatch • SMARTS modeled ground-reflected spectral irradiance • Dry Long Grass spectral reflectance data • For x-Si cells, clear skies NREL | 4 Albedo Data Sources • Averages from studies (climate and latitude sensitive) Item Values Grass 0.15 – 0.26 Black earth 0.08 – 0.13 White sand, New Mexico 0.60 Snow 0.55 – 0.98 Asphalt pavement 0.09 – 0.18 Concrete pavement 0.20 – 0.40 • Satellite-Derived – Albedo is an essential parameter for determining the earth’s energy balance and climate change • Measurements – SURFRAD, AmeriFlux, BSRN networks NREL | 5 Satellite-Derived Method • Ground reflection measured from a changing satellite viewpoint over several days • Multi-angle data for clear skies used to determine the Bidirectional Reflectance Distribution Function (BRDF) – BRDF describes mathematically the changes in reflectance observed when an illuminated surface is viewed from Sun behind observer. Sun opposite observer. different angles. NREL | 6 Moderate Resolution Imaging Spectroradiometer (MODIS) Data • A primary source of albedo products, sensors onboard Terra and Aqua satellites beginning in 2001 • MODIS product MCD43GF - Cloud and snow-free, gap- filled – World-wide coverage with 30 arc-second (~500 m) spatial resolution, 8-day temporal resolution. -
Class 12 I : Blackbody Spectra
Class 12 Spectra and the structure of atoms Blackbody spectra and Wien’s law Emission and absorption lines Structure of atoms and the Bohr model I : Blackbody spectra Definition : The spectrum of an object is the distribution of its observed electromagnetic radiation as a function of wavelength or frequency Particularly important example… A blackbody spectrum is that emitted from an idealized dense object in “thermal equilibrium” You don’t have to memorize this! h=6.626x10-34 J/s -23 kB=1.38x10 J/K c=speed of light T=temperature 1 2 Actual spectrum of the Sun compared to a black body 3 Properties of blackbody radiation… The spectrum peaks at Wien’s law The total power emitted per unit surface area of the emitting body is given by finding the area under the blackbody curve… answer is Stephan-Boltzmann Law σ =5.67X10-8 W/m2/K4 (Stephan-Boltzmann constant) II : Emission and absorption line spectra A blackbody spectrum is an example of a continuum spectrum… it is smooth as a function of wavelength Line spectra: An absorption line is a sharp dip in a (continuum) spectrum An emission line is a sharp spike in a spectrum Both phenomena are caused by the interaction of photons with atoms… each atoms imprints a distinct set of lines in a spectrum The precise pattern of emission/absorption lines tells you about the mix of elements as well as temperature and density 4 Solar spectrum… lots of absorption lines 5 Kirchhoffs laws: A solid, liquid or dense gas produces a continuous (blackbody) spectrum A tenuous gas seen against a hot -
Peter Scicluna – Systematic Effects in Dust-Mass Determinations
The other side of the equation Systematic effects in the determination of dust masses Peter Scicluna ASIAA JCMT Users’ Meeting, Nanjing, 13th February 2017 Peter Scicluna JCMT Users’ Meeting, Nanjing, 13th February 2017 1 / 9 Done for LMC (Reibel+ 2012), SMC (Srinivasan+2016) Total dust mass ∼ integrated dust production over Hubble time What about dust destruction? Dust growth in the ISM? Are the masses really correct? The dust budget crisis: locally Measure dust masses in FIR/sub-mm Measure dust production in MIR Gordon et al., 2014 Peter Scicluna JCMT Users’ Meeting, Nanjing, 13th February 2017 2 / 9 What about dust destruction? Dust growth in the ISM? Are the masses really correct? The dust budget crisis: locally Measure dust masses in FIR/sub-mm Measure dust production in MIR Done for LMC (Reibel+ 2012), SMC (Srinivasan+2016) Total dust mass ∼ integrated dust production over Hubble time Gordon et al., 2014 Peter Scicluna JCMT Users’ Meeting, Nanjing, 13th February 2017 2 / 9 Dust growth in the ISM? Are the masses really correct? The dust budget crisis: locally Measure dust masses in FIR/sub-mm Measure dust production in MIR Done for LMC (Reibel+ 2012), SMC (Srinivasan+2016) Total dust mass ∼ integrated dust production over Hubble time What about dust destruction? Gordon et al., 2014 Peter Scicluna JCMT Users’ Meeting, Nanjing, 13th February 2017 2 / 9 How important are supernovae? Are there even enough metals yet? Dust growth in the ISM? Are the masses really correct? The dust budget crisis: at high redshift Rowlands et al., 2014 Measure -
Paleoclimatology
Paleoclimatology ATMS/ESS/OCEAN 589 • Ice Age Cycles – Are they fundamentaly about ice, about CO2, or both? • Abrupt Climate Change During the Last Glacial Period – Lessons for the future? • The Holocene – Early Holocene vs. Late Holocene – The last 1000 years: implications for interpreting the recent climate changes and relevance to projecting the future climate. Website: faculty.washington.edu/battisti/589paleo2005 Class email: [email protected] Theory of the Ice Ages: Orbital induced insolation changes and global ice volume “Strong summer insolation peaks pace rapid deglaciation” Theory of the Ice Ages: Ice Volume and Atmospheric Carbon Dioxide are highly correlated •Summer (NH) insulation tends to lead ice volume. •Ice Volume and Carbon Dioxide seem to be in phase (except for in rapid deglaciation, when Ice volume leads Carbon Dioxide) CO2 measured at Vostok, South Pole The Ice Age Cycles: Some big unsolved questions we will examine • Is the Ice Age cycle fundamentaly about cycles in ice volume induced by high latitude insolation changes (with CO2 being a weak positive feedback)? • Or, is the Ice Age cycle fundamentally about changes in CO2 that are driven by insolation changes (with weak positive feedbacks associated with ice albedo feedbacks)? • Why do (high latitude) insolation changes cause changes in atmospheric CO2? Why is it CO2 so highly correlated with ice volume? Abrupt Climate Change during the Last Glacial Period During Glacial stages, the climate system featured large rapid rearrangements. Dansgaard/Oeschger (D/O) events show: – Rapid onset of warming at Greenland ( 10 K in < 30 years!) – Long-lived (~ 200 - 600 years) Greenland Temperature Tropical-Extratropical Linkages during Glacial Times: Extratropics forcing Tropics • Paleo data show strong linkages between the millennial variability in the North Atlantic, the tropical Atlantic and the Northern Hemisphere during the last Glacial Period.