Staff information

Biography

Mr. Easter's research area is modeling the transport, transformation, and removal of tropospheric aerosols and trace gases, with emphasis on cloud and precipitation processes. He has developed mesoscale cloud chemistry and precipitation scavenging models and applied them for diagnostic analysis of acid deposition field studies. He has had a central role in the development and application of PNNL's global aerosol, chemistry, and climate model, and development of the PNNL version of the Weather Research and Forecasting - Chemistry (WRF-chem) model. His recent research activities focus on improving treatments of cloud-aerosol interactions in large scale models.

Research Interests

• Modeling the transport, transformation, and removal of tropospheric aerosols and trace gases, with emphasis on cloud and precipitation processes

PNNL Publications

2012

• Liu X, RC Easter, Jr, SJ Ghan, RA Zaveri, PJ Rasch, X Shi, JF Lamarque, A Gettelman, H Morrison, F Vitt, A Conley, S Park, R Neale, C Hannay, AM Ekman, P Hess, N Mahowald, WD Collins, MJ Iacono, CS Bretherton, MG Flanner, and D Mitchell. 2012. "Toward a Minimal Representation of Aerosols in Climate Models: Description and Evaluation in the Community Atmosphere Model CAM5." Geoscientific Model Development 5(3):709-739.  doi:10.5194/gmd-5-709-2012
• Gantt B, J Xu, N Meskhidze, Y Zhang, A Nenes, SJ Ghan, X Liu, RC Easter, Jr, and RA Zaveri. 2012. "Global Distribution and Climate Forcing of Marine Organic Aerosol - Part 2: Effects on Cloud Properties and Radiative Forcing." Atmospheric Chemistry and Physics 12(14):6555-6563.  doi:10.5194/acp-12-6555-2012
• Ghan SJ, X Liu, RC Easter, Jr, RA Zaveri, PJ Rasch, JH Yoon, and B Eaton. 2012. "Toward a Minimal Representation of Aerosols in Climate Models: Comparative Decomposition of Aerosol Direct, Semidirect, and Indirect Radiative Forcing." Journal of Climate 25(19):6461-6476.  doi:10.1175/JCLI-D-11-00650.1
• Koffi B, M Schultz, FM Breon, J Griesfeller, D Winker, Y Balkanski, SE Bauer, T Berntsen, M Chin, WD Collins, F Dentener, T Diehl, RC Easter, Jr, SJ Ghan, P Ginoux, S Gong, L Horowitz, T Iversen, A Kirkevag, D Koch, M Krol, G Myhre, P Stier, and T Takemura. 2012. "Application of the CALIOP Layer Product to Evaluate the Vertical Distribution of Aerosols Estimated by Global Models: AeroCom Phase I Results." Journal of Geophysical Research. D. (Atmospheres) 117:Article No. D10201.  doi:10.1029/2011JD016858
• Wang M, SJ Ghan, X Liu, TL Ecuyer, K Zhang, H Morrison, M Ovchinnikov, RC Easter, Jr, R Marchand, D Chand, Y Qian, and JE Penner. 2012. "Constraining cloud lifetime effects of aerosols using A-Train satellite observations ." Geophysical Research Letters 39:L15709.  doi:10.1029/2012GL052204
• Yang Q, WI Gustafson, Jr, JD Fast, H Wang, RC Easter, Jr, M Wang, SJ Ghan, LK Berg, LYR Leung, and H Morrison. 2012. "Impact of natural and anthropogenic aerosols on stratocumulus and precipitation in the Southeast Pacific: A regional modeling study using WRF-Chem." Atmospheric Chemistry and Physics 12(18):8777-8796.  doi:10.5194/acp-12-8777-2012
• Yu F, G Luo, X Liu, RC Easter, Jr, X Ma, and SJ Ghan. 2012. "Indirect radiative forcing by ion-mediated nucleation of aerosol." Atmospheric Chemistry and Physics 12(23):11451-11463.  doi:10.5194/acp-12-11451-2012
• Zaveri RA, WJ Shaw, DJ Cziczo, B Schmid, R Ferrare, ML Alexander, M Alexandrov, RJ Alvarez, WP Arnott, D Atkinson, S Baidar, RM Banta, JC Barnard, J Beranek, LK Berg, FJ Brechtel, WA Brewer, JF Cahill, B Cairns, CD Cappa, D Chand, S China, JM Comstock, MK Dubey, RC Easter, Jr, MH Erickson, JD Fast, C Floerchinger, BA Flowers, E Fortner, JS Gaffney, MK Gilles, K Gorkowski, WI Gustafson, Jr, MS Gyawali, J Hair, M Hardesty, JW Harworth, SC Herndon, N Hiranuma, CA Hostetler, JM Hubbe, JT Jayne, H Jeong, BT Jobson, EI Kassianov, LI Kleinman, CD Kluzek, B Knighton, KR Kolesar, C Kuang, A Kubatova, AO Langford, A Laskin, NS Laulainen, RD Marchbanks, C Mazzoleni, F Mei, RC Moffet, DA Nelson, M Obland, H Oetjen, TB Onasch, I Ortega, M Ottaviani, MS Pekour, KA Prather, JG Radney, R Rogers, SP Sandberg, A Sedlacek, C Senff, G Senum, A Setyan, JE Shilling, MKB Shrivastava, C Song, SR Springston, R Subramanian, K Suski, JM Tomlinson, RM Volkamer, HA Wallace, J Wang, AM Weickmann, DR Worsnop, XY Yu, A Zelenyuk, and Q Zhang. 2012. "Overview of the 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES)." Atmospheric Chemistry and Physics 12(16):7647-7687.  doi:10.5194/acp-12-7647-2012

2011

• Fast JD, WI Gustafson, Jr, EG Chapman, RC Easter, Jr, JP Rishel, RA Zaveri, G Grell, and M Barth. 2011. "The Aerosol Modeling Testbed: A community tool to objectively evaluate aerosol process modules." Bulletin of the American Meteorological Society 92(3):343-360.  doi:10.1175/2010BAMS2868.1
• Huneeus N, M Schulz, Y Balkanski, J Griesfeller, J Prospero, S Kinne, S Bauer, O Boucher, M Chin, F Dentener, T Diehl, RC Easter, Jr, D Fillmore, SJ Ghan, P Ginnoux, A Grini, L Horowitz, D Koch, M Krol, W Landing, X Liu, N Mahowald, R Miller, JJ Morcrette, G Myhre, J Penner, J Perlwitz, P Stier, T Takemura, and CS Zender. 2011. "Global dust model intercomparison in AeroCom phase I." Atmospheric Chemistry and Physics 11(15):7781-7816.  doi:10.5194/acp-11-7781-2011
• Koch D, Y Balkanski, S Bauer, RC Easter, Jr, S Ferrachat, SJ Ghan, C Hoose, T Iversen, A Kirkevag, JE Kristjansson, X Liu, U Lohmann, S Menon, J Quaas, M Schulz, O Seland, T Takemura, and N Yan. 2011. "Soot microphysical effects on liquid clouds, a multi-model investigation." Atmospheric Chemistry and Physics 11(3):1051-1064.  doi:10.5194/acp-11-1051-2011
• Meskhidze N, J Xu, B Gantt, Y Zhang, A Nenes, SJ Ghan, X Liu, RC Easter, Jr, and RA Zaveri. 2011. "Global distribution and climate forcing of marine organic aerosol: 1. Model improvements and evaluation." Atmospheric Chemistry and Physics 11(22):11689-11705.  doi:10.5194/acp-11-11689-2011
• Shrivastava MKB, JD Fast, RC Easter, Jr, WI Gustafson, Jr, RA Zaveri, JL Jimenez, P Saide, and A Hodzic. 2011. "Modeling Organic Aerosols in a Megacity: Comparison of Simple and Complex Representations of the Volatility Basis Set Approach." Atmospheric Chemistry and Physics 11(13):6639-6662.  doi:10.5194/acp-11-6639-2011
• Wang M, SJ Ghan, M Ovchinnikov, X Liu, RC Easter, Jr, EI Kassianov, Y Qian, and H Morrison. 2011. "Aerosol Indirect effects in a multi-scale aerosol-climate model PNNL-MMF." Atmospheric Chemistry and Physics 11(11):5431-5455.  doi:10.5194/acp-11-5431-2011
• Wang M, SJ Ghan, RC Easter, Jr, M Ovchinnikov, X Liu, EI Kassianov, Y Qian, WI Gustafson, Jr, VE Larson, D Schanen, M Khairoutdinov, and H Morrison. 2011. "The multi-scale aerosol-climate model PNNL-MMF: model description and evaluation." Geoscientific Model Development 4(1):137-168.  doi:10.5194/gmd-4-137-2011
• Yang Q, WI Gustafson, Jr, JD Fast, H Wang, RC Easter, Jr, H Morrison, YN Lee, EG Chapman, SN Spak, and MA Mena-Carrasco. 2011. "Assessing regional scale predictions of aerosols, marine stratocumulus, and their interactions during VOCALS-REx using WRF-Chem." Atmospheric Chemistry and Physics 11(23):11951-11975.  doi:10.5194/acp-11-11951-2011

2010

• Ovchinnikov M, and RC Easter, Jr. 2010. "Modeling aerosol growth by aqueous chemistry in nonprecipitating stratiform cloud." Journal of Geophysical Research. D. (Atmospheres) 115(D14210):, doi:10.1029/2009JD012816
• Zelenyuk A, D Imre, M Earle, RC Easter, Jr, A Korolev, WR Leaitch, P Liu, AM Macdonald, M Ovchinnikov, and W Strapp. 2010. "In-Situ Characterization of Cloud Condensation Nuclei, Interstitial, and background Particles using Single Particle Mass Spectrometer, SPLAT II." Analytical Chemistry 82(19):7943-7951.  doi:10.1021/ac1013892
• Riemer N, M West, RA Zaveri, and RC Easter, Jr. 2010. "Estimating Black Carbon Aging Time-Scales with a Particle-Resolved Aerosol Model." Journal of Aerosol Science (41):143-158. 
• Zaveri RA, JC Barnard, RC Easter, Jr, N Riemer, and M West. 2010. "Particle-resolved simulation of aerosol size, composition, mixing state, and the associated optical and cloud condensation nuclei activation properties in an evolving urban plume." Journal of Geophysical Research. D. (Atmospheres) 115:Article No. D17210.  doi:10.1029/2009JD013616
• Zhao C, X Liu, LYR Leung, B Johnson, SA McFarlane, WI Gustafson, Jr, JD Fast, and RC Easter, Jr. 2010. "The spatial distribution of mineral dust and its shortwave radiative forcing over North Africa: Modeling sensitivities to dust emissions and aerosol size treatments ." Atmospheric Chemistry and Physics 10(18):8821-8838.  doi:10.5194/acp-10-8821-2010

2009

• Ovtchinnikov M, and RC Easter, Jr. 2009. "Nonlinear Advection Algorithms Applied to Inter-related Tracers: Errors and Implications for Modeling Aerosol-Cloud Interactions ." Monthly Weather Review 137(2):632-644.  doi:10.1175/2008MWR2626.1
• Chapman EG, WI Gustafson, Jr, RC Easter, Jr, JC Barnard, SJ Ghan, MS Pekour, and JD Fast. 2009. "Coupling Aerosol-Cloud-Radiative Processes in the WRF-Chem Model: Investigating the Radiative Impact of Elevated Point Sources." Atmospheric Chemistry and Physics 9(3):945-964. 
• Koch D, M Schulz, S Kinne, CS McNaughton, JR Spackman, Y Balkanski, S Bauer, T Berntsen, TC Bond, O Boucher, M Chin, AD Clarke, N De Luca, F Dentener, T Diehl, O Dubovik, RC Easter, Jr, DW Fahey, J Feichter, D Fillmore, S Freitag, SJ Ghan, P Ginoux, S Gong, L Horowitz, T Iversen, A Kirkevag, Z Klimont, Y Kondo, M Krol, X Liu, R Miller, V Montanaro, N Moteki, G Myhre, J Penner, J Perlwitz, G Pitari, S Reddy, L Sahu, H Sakamoto, G Schuster, JP Schwarz, O Seland, P Stier, N Takegawa, T Takemura, C Textor, J van Aardenne, and Y Zhao. 2009. "Evaluation of Black Carbon Estimations in Global Aerosol Models." Atmospheric Chemistry and Physics 9:9001-9026. 
• Quaas J, Y Ming, S Menon, T Takemura, M Wang, JE Penner, A Gettelman, U Lohmann, N Bellouin, O Boucher, AM Sayer, GE Thomas, A McComiskey, G Feingold, C Hoose, JE Kristjansson, X Liu, Y Balkanski, LJ Donner, P Ginoux, P Stier, B Grandey, J Feichter, I Sednev, SE Bauer, D Koch, RG Grainger, A Kirkevag, T Iversen, O Seland, RC Easter, Jr, SJ Ghan, PJ Rasch, H Morrison, JF Lamarque, MJ Iacono, S Kinne, and M Schulz. 2009. "Aerosol indirect effects - general circulation model intercomparison and evaluation with satellite data." Atmospheric Chemistry and Physics 9(22):8697-8717 . 
• Riemer N, M West, RA Zaveri, and RC Easter, Jr. 2009. "Simulating the Evolution of Soot Mixing State with a Particle-Resolved Aerosol Model." Journal of Geophysical Research. D. (Atmospheres) 114:D09202.  doi:10.1029/2008JD011073

2008

• Gustafson WI, Jr, LK Berg, RC Easter, Jr, and SJ Ghan. 2008. "The Explicit-Cloud Parameterized-Pollutant Hybrid Approach for Aerosol-Cloud Interactions in Multiscale Modelling Framework Models: Tracer Transport Results." Environmental Research Letters 3(2):Art. No. 025005.  doi:10.1088/1748-9326/3/2/025005
• Zaveri RA, RC Easter, Jr, JD Fast, and LK Peters. 2008. "Model for Simulating Aerosol Interactions and Chemistry (MOSAIC)." Journal of Geophysical Research. D. (Atmospheres) 113(D13):Art. No. D13204.  doi:10.1029/2007JD008782

2007

• Ghan SJ, and RC Easter, Jr. 2007. "Corrigendum to "Impact of cloud-borne aerosol representation on aerosol direct and indirect effects" published in Atmos. Chem. Phys., 6, 4163-4174, 2006 ." Atmospheric Chemistry and Physics 7:293-294. 
• Gustafson WI, Jr, EG Chapman, SJ Ghan, RC Easter, Jr, and JD Fast. 2007. "Impact on Modeled Cloud Characteristics Due to Simplified Treatment of Uniform Cloud Condensation Nuclei During NEAQS 2004." Geophysical Research Letters 34(19):L19809.  doi:10.1029/2007GL030021

2006

• Ghan SJ, and RC Easter, Jr. 2006. "Impact of Cloud-Borne Aerosol Representation on Aerosol Direct and Indirect Effects." Atmospheric Chemistry and Physics 6:4163-4174. 
• Fast JD, WI Gustafson, Jr, RC Easter, Jr, RA Zaveri, JC Barnard, EG Chapman, G Grell, and SE Peckham. 2006. "Evolution of Ozone, Particulates, and Aerosol Direct Radiative Forcing in the Vicinity of Houston Using a Fully Coupled Meteorology-Chemistry-Aerosol Model." Journal of Geophysical Research. D. (Atmospheres) 111(D21):D21305.  doi:10.1029/2005JD006721
• Kinne S, M Schulz, C Textor, S Guibert, Y Balkanski, S Bauer, T Berntsen, T Berglen, O Boucher, M Chin, W Collins, F Dentener, T Diehl, RC Easter, Jr, H Feichter, D Fillmore, SJ Ghan, P Ginoux, S Gong, A Grini, J Hendricks, M Herzog, L Horrowitz, I Isaksen, T Iversen, A Kirkevag, S Kloster, D Koch, JE Kristjansson, M Krol, A Lauer, JF Lamarque, G Lesins, X Liu, U Lohmann, V Montanaro, G Myhre, JE Penner, G Pitari, S Reddy, O Seland, P Stier, T Takemura, and X Tie. 2006. "An AeroCom Initial Assessment - Optical Properties in Aerosol Component Modules of Global Models." Atmospheric Chemistry and Physics 6(7):1815-1834. 
• Textor C, M Schulz, S Guibert, S Kinne, Y Balkanski, S Bauer, T Berntsen, T Berglen, O Boucher, M Chin, F Dentener, T Diehl, RC Easter, Jr, H Feichter, D Fillmore, SJ Ghan, P Ginoux, S Gong, A Grini, J Hendricks, L Horrowitz, P Huang, I Isaksen, T Iversen, S Kloster, D Koch, A Kirkevag, JE Kristjansson, M Krol, A Lauer, JF Lamarque, X Liu, V Montanaro, G Myhre, JE Penner, G Pitari, S Reddy, O Seland, P Stier, T Takemura, and X Tie. 2006. "Analysis and Quantification of the Diversities of Aerosol Life Cycles within AeroCom." Atmospheric Chemistry and Physics 6(7):1777-1813. 

2005

• Gustafson WI, Jr, JD Fast, RC Easter, Jr, and SJ Ghan. 2005. "Triumphs and Tribulations of WRF-Chem Development and Use." In 2005 Joint WRF/MM5 User's Workshop, June 27-30, 2005, Boulder, Colorado, p. Paper No. 8.4.  National Center for Atmospheric Research, Boulder, CO. 
• Zaveri RA, RC Easter, Jr, and AS Wexler. 2005. "A New Method for Multicomponent Activity Coefficients of Electrolytes in Aqueous Atmospheric Aerosols." Journal of Geophysical Research. D. (Atmospheres) 110(D2):D02201.  doi:10.1029/2004JD004681
• Zaveri RA, RC Easter, Jr, and LK Peters. 2005. "A Computationally Efficient Multicomponent Equilibrium Solver for Aerosols (MESA)." Journal of Geophysical Research. D. (Atmospheres) 110(D24):D24203.  doi:10.1029/2004JD005618
• Zhang Y, CH Bischof, RC Easter, Jr, and PT Wu. 2005. "Sensitivity Analysis of Photochemical Indicators for O3 Chemistry Using Automatic Differentiation." Journal of Atmospheric Chemistry 51(1):1-41. 

2004

• Zaveri RA, RC Easter, Jr, and AS Wexler. 2004. "A Computationally Efficient Model for Multicomponent Activity Coefficients in Aqueous Solutions." In American Association for Aerosol Research 23rd Annual Conference, October 4-8, 2004, Atlanta, Georgia.  American Association for Aerosol Research, Mt. Laurel, NJ. 
• Zaveri RA, RC Easter, Jr, LK Peters, and AS Wexler. 2004. "A Computationally Efficient Algorithm for Aerosol Phase Equilibrium." In American Association for Aerosol Research 23rd Annual Conference, October 4-8, 2004, Atlanta, Georgia.  American Association for Aerosol Research, Mt. Laurel, NJ. 
• Benkovitz C, SE Schwartz, MP Jensen, MA Miller, RC Easter, Jr, and TS Bates. 2004. "Modeling Atmospheric Sulfur Over the Northern Hemisphere during the Aerosol Characterization Experiment 2 Experimental Period." Journal of Geophysical Research. D. (Atmospheres) 109(D22):D22207.  doi:10.1029/2004JD004939
• Easter RC, Jr, SJ Ghan, Y Zhang, RD Saylor, EG Chapman, NS Laulainen, H Abdul-Razzak, LR Leung, X Bian, and RA Zaveri. 2004. "MIRAGE: Model Description and Evaluation of Aerosols and Trace Gases." Journal of Geophysical Research. D. (Atmospheres) 109(D20):D20210.  doi:10.1029/2004JD004571
• Ghan SJ, X Bian, EG Chapman, RC Easter, Jr, GI Fann, SC Kothari, RA Zaveri, and Y Zhang. 2004. Simulation of Climate Forcing by Aerosols. PNNL-14634, Pacific Northwest National Laboratory, Richland, WA. 

2003

• Kinne S, U Lohmann, J Feichter, M Schulz, C Timmreck, SJ Ghan, RC Easter, Jr, M Chin, P Ginoux, T Takemura, I Tegen, D Koch, M Herzog, J Penner, G Pitari, BN Holben, T Eck, A Smirnov, O Dubovik, I Slutsker, D Tanre, O Torres, M Mishchenko, I Geogdzhayev, DA Chu, and YJ Kaufman. 2003. "Monthly Averages of Aerosol Properties: A Global Comparison Among Models, Satellite Data, and AERONET Ground Data." Journal of Geophysical Research. D. (Atmospheres) 108(D20):4634.  doi:10.1029/2001JD001253

2002

• Chapman EG, WJ Shaw, RC Easter, Jr, X Bian, and SJ Ghan. 2002. "The Influence of Wind Speed Averaging on Estimates of Dimethylsulfide Emission Fluxes." Journal of Geophysical Research. D. (Atmospheres) 107(D23: art. no.4672):, doi:10.1029/2001JD001564
• Fast JD, RA Zaveri, RX Bian, EG Chapman, and RC Easter, Jr. 2002. "Effect of Regional-Scale Transport on Oxidants in the Vicinity of Philadelphia During the 1999 NE-OPS Field Campaign." Journal of Geophysical Research. D. (Atmospheres) 107(D16):, doi:10.1029/2001JD000980
• Zhang Y, RC Easter, Jr, SJ Ghan, and H Abdul-Razzak. 2002. "Impact of Aerosol Size Representation on Modeling Aerosol-Cloud Interactions." Journal of Geophysical Research. D. (Atmospheres) 107(D21 art.no.4558):, doi:10.1029/2001JD001549

2001

• Ghan SJ, RC Easter, Jr, JD Hudson, and F Breon. 2001. "Evaluation of Aerosol Indirect Radiative Forcing in MIRAGE." Journal of Geophysical Research. D. (Atmospheres) 106(D6):5317-5334. 
• Barrie LA, Y Yi, WR Leaitch, U Lohmann, P Kasibhatla, GJ Roelofs, J Wilson, F Mcgovern, C Benkovitz, MA Melieres, K Law, J Prospero, M Kritz, D Bergmann, C Bridgeman, M Chin, J Christiansen, RC Easter, Jr, J Feichter, C Land, A Jeuken, E Kjellstrom, D Koch, and P Rasch. 2001. "A Comparison of Large-Scale Atmospheric Sulphate Aerosol Models (COSAM): Overview and Highlights." Tellus Series B, Chemical and Physical Meteorology 53(5):615-645. 
• Ghan SJ, NS Laulainen, RC Easter, Jr, R Wagener, S Nemesure, EG Chapman, Y Zhang, and LR Leung. 2001. "Evaluation of Aerosol Direct Radiative Forcing in MIRAGE." Journal of Geophysical Research. D. (Atmospheres) 106(D6):5295-5316. 
• Ghan SJ, RC Easter, Jr, EG Chapman, H Abdul-Razzak, Y Zhang, LR Leung, NS Laulainen, RD Saylor, and RA Zaveri. 2001. "A Physically-Based Estimate of Radiative Forcing by Anthropogenic Sulfate Aerosol." Journal of Geophysical Research. D. (Atmospheres) 106(D6):5279-5293. 
• Lohmann U, WR Leaitch, LA Barrie, K Law, Y Yi, D Bergmann, C Bridgeman, M Chin, J Christensen, RC Easter, Jr, J Feichter, A Jeuken, E Kjellstrom, D Koch, C Land, P Rasch, and GJ Roelofs. 2001. "Vertical Distributions of Sulfur Species Simulated by Large Scale Atmospheric Models in COSAM: Comparison with Observations." Tellus Series B, Chemical and Physical Meteorology 53(5):646-672. 
• Roelofs GJ, P Kasibhatla, LA Barrie, D Bergmann, C Bridgeman, M Chin, J Christensen, RC Easter, Jr, J Feichter, A Jeuken, E Kjellstrom, D Koch, C Land, U Lohmann, and P Rasch. 2001. "Analysis of Regional Budgets of Sulfur Species Modeled for the COSAM Exercise." Tellus Series B, Chemical and Physical Meteorology 53B(5):673-694. 

2000

• Berkowitz CM, JD Fast, and RC Easter, Jr. 2000. "Boundary Layer Vertical Exchange Processes and the Mass Budget of Ozone: Observations and Model Results." Journal of Geophysical Research. D. (Atmospheres) 105(D11):14,789-14,805. 

1999

• Lee PS, RA Zaveri, RC Easter, Jr, and LK Peters. 1999. "Technical Note: On the Parallelization of a Global Climate-Chemistry Modeling System." Atmospheric Environment 33(4):675-681.