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Staff information


Samson Hagos

Earth Systems Analysis & Modeling
Pacific Northwest National Laboratory
PO Box 999
MSIN: K9-30
Richland, WA 99352


Dr. Hagos earned his PhD in Atmospheric Sciences in 2008 from Cornell University and was a Postdoctoral Research Associate at the University of Miami, Rosenstiel School of Marine and Atmospheric Sciences before joining PNNL in 2009.

Research Interests

  • Dr. Hagos’ research interests are focused on understanding and modeling of precipitation processes over a wide range of spatio-temporal scales, from the life-cycles of individual convective cells, to tropical intra-seasonal oscillations, atmospheric rivers and monsoon systems as well as their responses to global climate change.

Education and Credentials

  • PhD Atmospheric Sciences Cornell University Ithaca NY
  • MS Atmospheric Sciences Cornell University Ithaca NY
  • BS Physics University of Asmara Asmara Eritrea

PNNL Publications


  • Feng Z, LY Leung, SM Hagos, RA Houze, CD Burleyson, and K Balaguru. 2016. "More frequent intense and long-lived storms dominate the springtime trend in central U.S. rainfall." Nature Communications 7:13429.  doi:10.1038/ncomms13429
  • Ahmed F, C Schumacher, Z Feng, and SM Hagos. 2016. "A retrieval of tropical latent heating using the 3D structure of precipitation features." Journal of Applied Meteorology and Climatology 55(9):1965-1982.  doi:10.1175/JAMC-D-15-0038.1
  • Burleyson CD, Z Feng, SM Hagos, JD Fast, L Machado, and ST Martin. 2016. " Spatial Variability of the Background Diurnal Cycle of Deep Convection around the GoAmazon2014/15 Field Campaign Sites." Journal of Applied Meteorology and Climatology 55(7):1579-1598.  doi:10.1175/JAMC-D-15-0229.1
  • Hagos SM, Z Feng, CD Burleyson, C Zhao, M Martini, and LK Berg. 2016. "Moist process biases in simulations of the Madden-Julian Oscillation episodes observed during the AMIE/DYNAMO field campaign." Journal of Climate 29(3):1091-1107.  doi:10.1175/JCLI-D-15-0349.1
  • Hagos SM, JA Ijampy, F Sima, S Francis, and Z Feng. 2016. "West Africa [in ”State of the Climate in 2015”]." Bulletin of the American Meteorological Society 97(8 Special Supplement):188-189.  doi:10.1175/2016BAMSStateoftheClimate.1
  • Hagos SM, LYR Leung, JH Yoon, J Lu, and Y Gao. 2016. "A Projection of Changes in Landfilling Atmospheric River Frequency and Extreme Precipitation over Western North America from the Large Ensemble CESM Simulations." Geophysical Research Letters 43(3):1357-1363.  doi:10.1002/2015GL067392
  • Qian Y, H Yan, LK Berg, SM Hagos, Z Feng, B Yang, and M Huang. 2016. "Assessing impacts of PBL and surface layer schemes in simulating the surface-atmosphere interactions and precipitation over the tropical ocean using observations from AMIE/DYNAMO." Journal of Climate 29(22):8191-8210.  doi:10.1175/JCLI-D-16-0040.1
  • Tao WK, YN Takayabu, S Lang, S Shige, WS Olson, A Hou, G Skofronick-Jackson, X Jiang, C Zhang, WK Lau, T Krishnamurti, D Waliser, M Grecu, P Ciesielski, R Johnson, RA Houze, R Kakar, K Nakamura, S Braun, SM Hagos, R Oki, and A Bhardwaj. 2016. "TRMM Latent Heating Retrieval: Applications and Comparisons with Field Campaigns and Large-Scale Analyses." In Meteorological Monographs, vol. 56, pp. 2.1-2.34.  American Meteorological Society, Boston, MA.  doi:10.1175/AMSMONOGRAPHS-D-15-0013.1
  • Zhao C, LYR Leung, S Park, SM Hagos, J Lu, K Sakaguchi, JH Yoon, BE Harrop, W Skamarock, and M Duda. 2016. "Exploring the impacts of physics and resolution on aqua-planet simulations from a non-hydrostatic global variable-resolution modeling framework." Journal of Advances in Modeling Earth Systems 8(4):1751-1768.  doi:10.1002/2016MS000727


  • Feng Z, SM Hagos, A Rowe, CD Burleyson, M Martini, and S de Szoeke. 2015. "Mechanisms of Convective Cloud Organization by Cold Pools over Tropical Warm Ocean during the AMIE/DYNAMO Field Campaign." Journal of Advances in Modeling Earth Systems 7(2):357-381.  doi:10.1002/2014MS000384
  • Gao Y, J Lu, LYR Leung, Q Yang, SM Hagos, and Y Qian. 2015. "Dynamical and thermodynamical modulations of future changes in landfalling atmospheric rivers over North America." Geophysical Research Letters 42(17):7179-7186.  doi:10.1002/2015GL065435
  • Hagos SM, JA Ijampy, F Sima, and S Francis. 2015. "West Africa [in "State of the Climate in 2014"]." Bulletin of the American Meteorological Society 96(7):S185-S187.  doi:10.1175/2015BAMSStateoftheClimate.1
  • Sakaguchi K, LYR Leung, C Zhao, Q Yang, J Lu, SM Hagos, S Rauscher, L Dong, T Ringler, and PH Lauritzen. 2015. "Exploring a Multi-resolution Approach Using AMIP Simulations." Journal of Climate 28(14):55495574.  doi:10.1175/JCLI-D-14-00729.1
  • Chen Q, J Fan, SM Hagos, WI Gustafson, Jr, and LK Berg. 2015. "Roles of Wind Shear at Different Vertical Levels: Cloud System Organization and Properties." Journal of Geophysical Research. D. (Atmospheres) 120(13):6551-6574.  doi:10.1002/2015JD023253
  • Hagos SM, LYR Leung, Q Yang, C Zhao, and J Lu. 2015. "Resolution and Dynamical Core Dependence of Atmospheric River Frequency in Global Model Simulations." Journal of Climate 28(7):2764-2776.  doi:10.1175/JCLI-D-14-00567.1
  • Lu J, G Chen, LYR Leung, DA Burrows, Q Yang, K Sakaguchi, and SM Hagos. 2015. "Toward the Dynamical Convergence on the Jet Stream in Aquaplanet AGCMs." Journal of Climate 28(17):67636782.  doi:10.1175/JCLI-D-14-00761.1
  • Taraphdar S, LYR Leung, and SM Hagos. 2015. "Linkages of Remote Sea Surface Temperatures and Atlantic Tropical Cyclone Activity Mediated by the African Monsoon." Geophysical Research Letters 42(2):572-578.  doi:10.1002/2014GL062600
  • Xiao H, WI Gustafson, Jr, SM Hagos, CM Wu, and H Wan. 2015. "Resolution-dependent behavior of subgrid-scale vertical transport in the Zhang-McFarlane convection parameterization." Journal of Advances in Modeling Earth Systems 7(2):537-550.  doi:10.1002/2014MS000356


  • Hagos SM, Z Feng, CD Burleyson, KS Lim, CN Long, D Wu, and G Thompson. 2014. "Evaluation of convection-permitting model simulations of cloud populations associated with the Madden-Julian Oscillation using data collected during the AMIE/DYNAMO field campaign." Journal of Geophysical Research. D. (Atmospheres) 119(21):12,05212,068.  doi:10.1002/2014JD022143
  • Hagos SM, Z Feng, K Landu, and CN Long. 2014. "Advection, Moistening, and Shallow-to-deep Convection Transitions During the Initiation and Propagation of Madden-Julian Oscillation." Journal of Advances in Modeling Earth Systems 6(3):938-949.  doi:10.1002/2014MS000335
  • Hagos SM, LYR Leung, WI Gustafson, Jr, and B Singh. 2014. "Eddy Fluxes and Sensitivity of the Water Cycle to Spatial Resolution in Idealized Regional Aquaplanet Model Simulations." Climate Dynamics 42(3-4):931-940.  doi:10.1007/s00382-013-1857-y
  • Hagos SM, LYR Leung, Y Xue, A Boone, F de Sales, N Neupane, M Huang, and JH Yoon. 2014. "Assessment of Uncertainties in the Response of the African Monsoon Precipitation to Land Use change simulated by a regional model." Climate Dynamics 43(9-10):2765-2775.  doi:10.1007/s00382-014-2092-x
  • Landu K, LYR Leung, SM Hagos, V Vinoj, S Rauscher, T Ringler, and M Taylor. 2014. "The Dependence of ITCZ Structure on Model Resolution and Dynamical Core in Aquaplanet Simulations." Journal of Climate 27(6):23752385.  doi:10.1175/JCLI-D-13-00269.1


  • Hagos SM, LYR Leung, S Rauscher, and T Ringler. 2013. "Errors Characteristics of Two Grid Refinement Approaches in Aquaplanet Simulations: MPAS-A and WRF." Monthly Weather Review 141(9):3022-3036.  doi:10.1175/MWR-D-12-00338.1
  • Hagos SM, Z Feng, SA McFarlane, and LYR Leung. 2013. "Environment and the Lifetime of Tropical Deep Convection in a Cloud-Permitting Regional Model Simulation." Journal of the Atmospheric Sciences 70(8):24092425.  doi:10.1175/JAS-D-12-0260.1
  • Lee TY, X Tong, HW Shen, PC Wong, SM Hagos, and LYR Leung. 2013. "Feature Tracking and Visualization of Madden-Julian Osciallation in Climate Simulation." IEEE Computer Graphics and Applications 33(4):29-37.  doi:10.1109/MCG.2013.36
  • O'Brien TA, F Li, WD Collins, S Rauscher, T Ringler, M Taylor, SM Hagos, and LYR Leung. 2013. "Observed Scaling in Clouds and Precipitation and Scale Incognizance in Regional to Global Atmospheric Models." Journal of Climate 26(23):93139333.  doi:10.1175/JCLI-D-13-00005.1


  • Hagos SM, and LYR Leung. 2012. "Large-scale Environmental Variables and Transition to Deep Convection in Cloud Resolving Model Simulations: A Vector Representation." Journal of Advances in Modeling Earth Systems 4:M11001.  doi:10.1029/2012MS000155
  • Hagos SM, and LYR Leung. 2012. "On the relationship between uncertainties in tropical divergence and the hydrological cycle in global models." Journal of Climate 25(1):381-391.  doi:10.1175/JCLI-D-11-00058.1


  • Hagos SM, and LYR Leung. 2011. "Moist thermodynamics of the Madden-Julian Oscillation in a cloud resolving simulation." Journal of Climate 24(21):55715583.  doi:10.1175/2011JCLI4212.1
  • Hagos SM, LYR Leung, and J Dudhia. 2011. "Thermodynamics of the Madden-Julian Oscillation in a Regional Model with Constrained Moisture." Journal of the Atmospheric Sciences 68(9):1974-1989.  doi:10.1175/2011JAS3592.1
  • Zhao C, X Liu, LYR Leung, and SM Hagos. 2011. "Radiative impact of mineral dust on monsoon precipitation variability over West Africa ." Atmospheric Chemistry and Physics 11(5):1879-1893.  doi:10.5194/acp-11-1879-2011


  • Hagos SM, C Zhang, WK Tao, S Lang, YN Takayabu, S Shige, M Katsumata, B Olson, and TS L'Ecuyer. 2010. "Estimates of Tropical Diabatic Heating Profiles: Commonalities and Uncertainties." Journal of Climate 23(3):542-558.  doi:10.1175/2009JCLI3025.1
  • Hagos SM. 2010. "Building Blocks of Tropical Diabatic Heating." Journal of the Atmospheric Sciences 67(7):2341-2354.  doi:10.1175/2010JAS3252.1
  • Zhang C, J Ling, SM Hagos, WK Tao, S Lang, YN Takayabu, S Shige, M Katsumata, WS Olson, and TS L'Ecuyer. 2010. "MJO Signals in Latent Heating: Results from TRMM Retrievals." Journal of the Atmospheric Sciences 67(11):34883508.  doi:10.1175/2010JAS3398.1


  • Hagos SM, and C Zhang. 2009. "Diabatic heating, divergent circulation and moisture transport in the African monsoon system." Quarterly Journal of the Royal Meteorological Society 136(S1):411-425.  doi:10.1002/qj.538

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