WACCM: The High-Top Model - CESM - UCAR

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D12305 TILMES ET AL.: IMPACT OF THE GEOENGINEERED AEROSOLS D12305 Volcanic heating in WACCM D12305 TILMES ET AL.: IMPACT OF THE 30 GEOENGINEERED hPa occurred after AEROSOLS 1991 for both the differencesD12305 in the simulations (black line) and radiosonde anomalies (grey 30 line) hPa (Figure occurred 1). For afterall 1991 three forpressure both thelevels, differences temperature in the simulations anomalies Temperature agree (blackwell line) between and radiosonde model anomalies and anomalies observations. (grey line) Therefore, (Figurewe 1). expect For alla three reliable pressure response levels, of temperature the aerosol anomalies heating in the agree model well runbetween when using model geoengineered and observations. volcanic- Therefore, sized aerosols. we expect a reliable response of the aerosol heating in the model run when using geoengineered volcanicsized 2.2. aerosols. Setup of the Future Control and Geoengineering Model Runs pressures in the lower 2.2. [14] Setup We performed of the Future two simulations Control and to analyze Geoengineering the impact Model of geoengineered Runs aerosols on the tropospheric and stratospheric [14] We dynamics, performed andtwo stratospheric simulations chemistry. to analyzeThe thecontrol, impact of or ‘‘baseline’’ geoengineered model aerosols run, is on initialized the tropospheric as a REF2 and model strato- run, spheric following dynamics, the CCMVal and stratospheric definition [Eyring chemistry. et al., The 2006],and control, or covers ‘‘baseline’’ the period modelbetween run, is initialized 2010 and as a2050. REF2 model Increasing run, following greenhousethe gases, CCMVal baseddefinition on the IPCC [Eyring A1Betscenario al., 2006],and [IPCC, covers 2007], are theincluded period in between this simulation, 2010 and as well 2050. as Increasing changes in greenhouse anthropogenic gases, halogen basedemissions. on the IPCC Initialized A1B scenario SAD and [IPCC, the 2007], resulting areHincluded 2SO4 mass in this in the simulation, model are as prescribed well as changes usingina anthropogenic climatology for halogen a nonvolcanic emissions. Initialized period from SADSAGE and the II resulting [Thomason H et al., 2SO4 mass 1997]. in the model are prescribed using a climatology [15] The geoengineering for a nonvolcanic model run period is set from up identically SAGE to II [Thomason the baselineet run al., between 1997]. 2010 and 2020. However, starting in[15] the year The geoengineering 2020, the SAD model is increased run isfrom set upbackground identically to to the an enhanced, baseline run fixed between SAD2010 distribution. and 2020. This However, SAD isstarting calcu- in lated the from year 2020, the SO the4 SAD distribution is increased derived frominbackground the study of to an Rasch enhanced, et al. [2008b]. fixed SAD Rasch distribution. et al. [2008b] Thisused SADtheisNCAR calculated CAM from model thetoSO derive 4 distribution aerosol distributions derived in the for study different of Rasch scenarios, et al. with [2008b]. varying Rasch amounts et al. of [2008b] sulfur used injection the NCAR in the CAM tropics, Figure model two 1. different-sized toTemperature derive aerosol aerosol difference distributions types, between and two forthe different REF1.3v Pinatubo 1991 Pinatubo 1991 calculated with WACCM (black lines) and observed (grey lines) at stratosphere (Tilmes et al., 2009) Pinatubo 1991 Model Run [14] We p of geoengin spheric dyn or ‘‘baseline following th covers the greenhouse 2007], are i anthropogen resulting H 2 climatology [Thomason [15] The g the baseline in the year 2 an enhance lated from Rasch et al. CAM mode scenarios, w tropics, two CO 2 conditi al. [2008b], into a prese sols are assu astandardd effective rad [16] The is an appro size spectru ulation time scheme (in aerosols alr by Rasch et distribution considered Tilmes et a
Grading of Chemistry in CCMs: Chapter 6 of the SPaRC CCMVal • CCMs were evaluated on their ability to represent longlived constituents (precursors) and short-lived substances (radicals). • WACCM graded out high in all categories (i.e., grade of 1 is the highest possible). • This is a reflection of the: 1) completeness of the chemical processes included 2) accuracy of photolysis rates (J’s) 3) and accuracy of the numerical solution approach. SPARC CCMVal, Report on the Evaluation of Chemistry-Climate Models, V.Eyring, T. G. Shepherd, D. W. Waugh (EDs.), SPARC Reprot No.4, WCRP-X, WMO/TD-No. X, http://www.atmosp.physics.utoronto.ca/SPARC, 2010.
Page 1 and 2: WACCM: The High-Top Model WACCM top
Page 3 and 4: WACCM Motivation Roble, Geophysical
Page 5 and 6: 50N EQ 50S Stratospheric Sulfate Su
Page 7: Volcanic heating in WACCM 2°N Surf
Page 11 and 12: WACCM Ozone Trend: CCMVal and WMO A
Page 13 and 14: Acceleration of the Brewer-Dobson C
Page 15 and 16: Altitude (km) Impact of geoengineer
Page 17 and 18: Nuclear winter in WACCM4 Black Carb

WACCM: The High-Top Model - CESM - UCAR

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