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Staff information

Samson

Samson Hagos

Regional and Cloud Modeling
Earth Scientist
Pacific Northwest National Laboratory
PO Box 999
MSIN: K9-30
Richland, WA 99352

Biography

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 inter-annual to multi-decadal variations of monsoon systems.

Education and Credentials

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

Affiliations and Professional Service

  • Member American Meteorological Society
  • Member American Geophysical Union
  • Member European Geosciences Union
  • Member AGU Fall Meeting Program Committee
  • Member AMS Climate Variability Committee
  • Member World Meteorological Organization MJO Task Force
  • Member US CLIVAR Process Studies and Model Improvement Panel

Awards and Recognitions

  • American Meteorological Society Clarence Leroy Meisinger Award

PNNL Publications

2022

  • Balaguru K., G.R. Foltz, L. Leung, and S.M. Hagos. 2022. "Impact of rainfall on tropical cyclone-induced sea surface cooling." Geophysical Research Letters 49, no. 10:Art. No. e2022GL098187. PNNL-SA-172881. doi:10.1029/2022GL098187
  • Barber K.A., C.D. Burleyson, Z. Feng, and S.M. Hagos. 2022. "The influence of shallow cloud populations on transitions to deep convection in the Amazon." Journal of the Atmospheric Sciences 79, no. 3:723743. PNNL-SA-161289. doi:10.1175/JAS-D-21-0141.1
  • Hagos S.M., J. Chen, K.A. Barber, K. Sakaguchi, R.S. Plant, Z. Feng, and H. Xiao. 2022. "A Machine-Learning-Assisted Stochastic Cloud Population Model as a Parameterization of Cumulus Convection." Journal of Advances in Modeling Earth Systems 14, no. 7:e2021MS002808. PNNL-SA-162336. doi:10.1029/2021MS002808
  • Hagos S.M., L. Leung, C. Zhang, and K. Balaguru. 2022. "An Observationally Trained Markov Model for MJO Propagation." Geophysical Research Letters 49, no. 2:Art. No. e2021GL095663. PNNL-SA-165371. doi:10.1029/2021GL095663
  • Ma P., B.E. Harrop, V.E. Larson, R. Neale, R. Neale, A. Gettelman, and H. Morrison, et al. 2022. "Better calibration of cloud parameterizations and subgrid effects increases the fidelity of E3SM Atmosphere Model version 1." Geoscientific Model Development 15, no. 7:28812916. PNNL-SA-166161. doi:10.5194/gmd-15-2881-2022

2021

  • Balaguru K., L. Leung, S.M. Hagos, and S. Krishnakumar. 2021. "An oceanic pathway for Madden-Julian Oscillation influence on Maritime Continent Tropical Cyclones." npj Climate and Atmospheric Science 4, no. 1:Art. No. 52. PNNL-SA-161677. doi:10.1038/s41612-021-00208-4
  • Hagos S.M., L. Leung, O.A. Garuba, and C.M. Patricola. 2021. "Influence of Background Divergent Moisture Flux on the Frequency of North Pacific Atmospheric Rivers." Journal of Climate 34, no. 15:6129-6139. PNNL-SA-156772. doi:10.1175/JCLI-D-21-0058.1
  • Hagos S.M., L. Leung, O.A. Garuba, C. Demott, B.E. Harrop, J. Lu, and M. Ahn. 2021. "The relationship between precipitation and precipitable water in CMIP6 simulations and implications for tropical climatology and change." Journal of Climate 34, no. 5:1587-1600. PNNL-SA-152254. doi:10.1175/JCLI-D-20-0211.1
  • Xu M., C. Zhao, J. Gu, J. Feng, S.M. Hagos, L. Leung, and Y. Luo, et al. 2021. "Convection-permitting hindcasting of diurnal variation of Mei-yu rainfall over East China with a global variable-resolution model." Journal of Geophysical Research: Atmospheres 126, no. 14:e2021JD034823. PNNL-SA-163518. doi:10.1029/2021JD034823

2020

  • Balaguru K., C. Patricola, S.M. Hagos, L. Leung, and L. Dong. 2020. "Enhanced predictability of Eastern North Pacific Tropical cyclone activity using the ENSO Longitude Index." Geophysical Research Letters 47, no. 16:Article No. e2020GL088849. PNNL-SA-153159. doi:10.1029/2020GL088849
  • Balaguru K., L. Leung, L. Van Roekel, J. Golaz, P. Ullrich, P.M. Caldwell, and S.M. Hagos, et al. 2020. "Characterizing Tropical Cyclones in the Energy Exascale Earth System Model version 1." Journal of Advances in Modeling Earth Systems 12, no. 8:Article No. e2019MS002024. PNNL-SA-150203. doi:10.1029/2019MS002024
  • Hagos S.M., C. Zhang, L. Leung, O.A. Garuba, C.D. Burleyson, and K. Balaguru. 2020. "Impacts of insolation and soil moisture on the seasonality of interactions between the Madden-Julian Oscillation and Maritime Continent." Journal of Geophysical Research: Atmospheres 125, no. 13:Article No. e2020JD032382. PNNL-SA-150515. doi:10.1029/2020JD032382
  • Hagos S.M., G. Foltz, A. Capotondi, S. Chen, C. Demott, A. Protat, and K. Reed, et al. 2020. "Atmospheric Convection and Air-Sea Interactions over the Tropical Oceans." In Atmospheric Convection and Air-Sea Interactions over the Tropical Oceans: A US CLIVAR Workshop Report, May 7-9, 2019, Boulder, CO, edited by J. Zhu and M. Patterson, Paper No. 2020-1. Washington Dc:US Climate Variability & Predictability Program. PNNL-SA-150547. doi:10.5065/aas5-c724
  • Hagos S.M., G. Foltz, C. Zhang, E. Thompson, H. Seo, S. Chen, and A. Capotondi, et al. 2020. "Atmospheric Convection and Air-Sea Interactions over the Tropical Oceans: Scientific Progress, Challenges and Opportunities." Bulletin of the American Meteorological Society 101, no. 3:E253E258. PNNL-SA-149307. doi:10.1175/BAMS-D-19-0261.1
  • Hagos S.M., Z. Feng, B. Plant, and A. Protat. 2020. "A Machine Learning Assisted Development of a Model for the Populations of Convective and Stratiform Clouds." Journal of Advances in Modeling Earth Systems 12, no. 3:Article No. e2019MS001798. PNNL-SA-144294. doi:10.1029/2019MS001798

2019

  • Hagos S.M., C. Zhang, L. Leung, C.D. Burleyson, and K. Balaguru. 2019. "A zonal migration of monsoon moisture flux convergence and the strength of Madden-Julian Oscillation Events." Geophysical Research Letters 46, no. 14:8554-8562. PNNL-SA-143132. doi:10.1029/2019GL083468
  • Hagos S.M., L. Leung, M. Ashfaq, and K. Balaguru. 2019. "South Asian Monsoon Precipitation in CMIP5: A link between Inter-model spread and the representations of Tropical Convection." Climate Dynamics 52, no. 1-2:1049-1061. PNNL-SA-122642. doi:10.1007/s00382-018-4177-4
  • Hagos S.M., Z. Feng, J.A. Ijampy, F. Sima, and S. Francis. 2019. "West Africa [in "State of the Climate in 2018"]." Bulletin of the American Meteorological Society 100, no. 9:S210-S211. PNNL-SA-146866. doi:10.1175/2019BAMSStateoftheClimate.1

2018

  • Balaguru K., G. Foltz, L. Leung, S.M. Hagos, and D.R. Judi. 2018. "On the use of ocean dynamic temperature for hurricane intensity forecasting." Weather and Forecasting 33, no. 2:411-418. PNNL-SA-129386. doi:10.1175/WAF-D-17-0143.1
  • Burleyson C.D., S.M. Hagos, Z. Feng, B. Kerns, and D. Kim. 2018. "Large-scale Environmental Characteristics of MJOs that Strengthen and Weaken Over the Maritime Continent." Journal of Climate 31, no. 14:5731-5748. PNNL-SA-128529. doi:10.1175/JCLI-D-17-0576.1
  • Feng Z., L. Leung, R.A. Houze, S.M. Hagos, J.C. Hardin, Q. Yang, and B. Han, et al. 2018. "Structure and Evolution of Mesoscale Convective Systems: Sensitivity to Cloud Microphysics in Convection-Permitting Simulations over the United States." Journal of Advances in Modeling Earth Systems 10, no. 7:1470-1494. PNNL-SA-133754. doi:10.1029/2018MS001305
  • Foltz G., K. Balaguru, and S.M. Hagos. 2018. "Interbasin Differences in the Relationship Between SST and Tropical Cyclone Intensification." Monthly Weather Review 146, no. 3:853-870. PNNL-SA-126415. doi:10.1175/MWR-D-17-0155.1
  • Hagos S.M., J.A. Ijampy, F. Sima, S. Francis, and Z. Feng. 2018. "West Africa [in "State of the Climate in 2017"]." Bulletin of the American Meteorological Society 99, no. 8:S214 - S216. PNNL-SA-138430. doi:10.1175/2018BAMSStateoftheClimate.1
  • Hagos S.M., L. Leung, C. Zhao, Z. Feng, and K. Sakaguchi. 2018. "How do microphysical processes influence large-scale precipitation variability and extremes?." Geophysical Research Letters 45, no. 3:1661-1667. PNNL-SA-130576. doi:10.1002/2017GL076375
  • Hagos S.M., Z. Feng, R.S. Plant, R.A. Houze, and H. Xiao. 2018. "A stochastic framework for modeling the population dynamics of convective clouds." Journal of Advances in Modeling Earth Systems 10, no. 2:448-465. PNNL-SA-130047. doi:10.1002/2017MS001214

2017

  • Gao Y., L. Leung, C. Zhao, and S.M. Hagos. 2017. "Sensitivity of U.S. Summer Precipitation to Model Resolution and Convective Parameterizations Across Gray Zone Resolutions." Journal of Geophysical Research: Atmospheres 122, no. 5:2714-2733. PNNL-SA-120761. doi:10.1002/2016JD025896
  • Hagos S.M., J.A. Ijampy, F. Sima, S. Francis, and Z. Feng. 2017. "West Africa [in State of the Climate in 2016]." Bulletin of the American Meteorological Society 98, no. 8:S193-S195. PNNL-SA-128495. doi:10.1175/2017BAMSStateoftheClimate.1
  • Yang Q., L. Leung, J. Lu, Y. Lin, S.M. Hagos, K. Sakaguchi, and Y. Gao. 2017. "Exploring the effects of a nonhydrostatic dynamical core in high-resolution aquaplanet simulations." Journal of Geophysical Research: Atmospheres 122, no. 6:3245-3265. PNNL-SA-124394. doi:10.1002/2016JD025287

2016

  • Ahmed F., C. Schumacher, Z. Feng, and S.M. Hagos. 2016. "A retrieval of tropical latent heating using the 3D structure of precipitation features." Journal of Applied Meteorology and Climatology 55, no. 9:1965-1982. PNNL-SA-107838. doi:10.1175/JAMC-D-15-0038.1
  • Boone A., Y. Xue, F. de Sales, R.E. Comer, S.M. Hagos, S. Mahanama, and K. Schiro, et al. 2016. "The regional impact of Land-Use Land-cover Change (LULCC) over West Africa from an ensemble of global climate models under the auspices of the WAMME2 project." Climate Dynamics 47, no. 11:3547-3573. PNNL-SA-111780. doi:10.1007/s00382-016-3252-y
  • Burleyson C.D., Z. Feng, S.M. Hagos, J.D. Fast, L. Machado, S.T. Martin, and S.T. 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, no. 7:1579-1598. PNNL-SA-111694. doi:10.1175/JAMC-D-15-0229.1
  • Feng Z., L. Leung, S.M. Hagos, R.A. Houze, C.D. Burleyson, and K. Balaguru. 2016. "More frequent intense and long-lived storms dominate the springtime trend in central U.S. rainfall." Nature Communications 7. PNNL-SA-122022. doi:10.1038/ncomms13429
  • Hagos S.M., C. Zhang, Z. Feng, C.D. Burleyson, C. DeMott, B. Kerns, and J. Benedict, et al. 2016. "The impact of the diurnal cycle on the propagation of Madden-Julian Oscillation convection across the Maritime Continent." Journal of Advances in Modeling Earth Systems 8, no. 4:15521564. PNNL-SA-118613. doi:10.1002/2016MS000725
  • Hagos S.M., J.A. 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, no. 8 Special Supplement:188-189. PNNL-SA-119982. doi:10.1175/2016BAMSStateoftheClimate.1
  • Hagos S.M., L. Leung, J. 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, no. 3:1357-1363. PNNL-SA-115451. doi:10.1002/2015GL067392
  • Hagos S.M., Z. Feng, C.D. Burleyson, C. Zhao, M. Martini, and L.K. Berg. 2016. "Moist process biases in simulations of the Madden-Julian Oscillation episodes observed during the AMIE/DYNAMO field campaign." Journal of Climate 29, no. 3:1091-1107. PNNL-SA-110414. doi:10.1175/JCLI-D-15-0349.1
  • Qian Y., H. Yan, L.K. Berg, S.M. 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, no. 22:8191-8210. PNNL-SA-114620. doi:10.1175/JCLI-D-16-0040.1
  • Sakaguchi K., J. Lu, L. Leung, C. Zhao, Y. Li, and S.M. Hagos. 2016. "Sources and Pathways of the Upscale Effects on the Southern Hemisphere Jet in MPAS-CAM4 Variable-Resolution Simulations." Journal of Advances in Modeling Earth Systems 8, no. 4:1786-1805. PNNL-SA-120998. doi:10.1002/2016MS000743
  • Tao W., Y.N. Takayabu, S. Lang, S. Shige, W.S. Olson, A. Hou, and G. Skofronick-Jackson, et al. 2016. "TRMM Latent Heating Retrieval: Applications and Comparisons with Field Campaigns and Large-Scale Analyses." In Meteorological Monographs. 2.1-2.34. Boston, Massachusetts:American Meteorological Society. PNNL-SA-103710. doi:10.1175/AMSMONOGRAPHS-D-15-0013.1
  • Xue Y., F. de Sales, W. Lau, A. Boone, K. Kim, C. Mechoso, and G. Wang, et al. 2016. "West African monsoon decadal variability and surface-related forcings: Second West African Monsoon Modeling and Evaluation Project Experiment (WAMME II)." Climate Dynamics 47, no. 11:3517-3545. PNNL-SA-112235. doi:10.1007/s00382-016-3224-2
  • Zhao C., L. Leung, S. Park, S.M. Hagos, J. Lu, K. Sakaguchi, and J. Yoon, et al. 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, no. 4:1751-1768. PNNL-SA-118452. doi:10.1002/2016MS000727

2015

  • Chen Q., J. Fan, S.M. Hagos, W.I. Gustafson, and L.K. Berg. 2015. "Roles of Wind Shear at Different Vertical Levels: Cloud System Organization and Properties." Journal of Geophysical Research: Atmospheres 120, no. 13:6551-6574. PNNL-SA-98941. doi:10.1002/2015JD023253
  • Feng Z., S.M. Hagos, A. Rowe, C.D. 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, no. 2:357-381. PNNL-SA-105094. doi:10.1002/2014MS000384
  • Gao Y., J. Lu, L. Leung, Q. Yang, S.M. Hagos, and Y. Qian. 2015. "Dynamical and thermodynamical modulations of future changes in landfalling atmospheric rivers over North America." Geophysical Research Letters 42, no. 17:7179-7186. PNNL-SA-110116. doi:10.1002/2015GL065435
  • Hagos S.M., J.A. Ijampy, F. Sima, and S. Francis. 2015. "West Africa [in "State of the Climate in 2014"]." Bulletin of the American Meteorological Society 96, no. 7:S185-S187. PNNL-SA-110969. doi:10.1175/2015BAMSStateoftheClimate.1
  • Hagos S.M., L. 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, no. 7:2764-2776. PNNL-SA-104683. doi:10.1175/JCLI-D-14-00567.1
  • Lu J., G. Chen, L. Leung, D.A. Burrows, Q. Yang, K. Sakaguchi, and S.M. Hagos. 2015. "Toward the Dynamical Convergence on the Jet Stream in Aquaplanet AGCMs." Journal of Climate 28, no. 17:67636782. PNNL-SA-111542. doi:10.1175/JCLI-D-14-00761.1
  • Sakaguchi K., L. Leung, C. Zhao, Q. Yang, J. Lu, S.M. Hagos, and S. Rauscher, et al. 2015. "Exploring a Multi-resolution Approach Using AMIP Simulations." Journal of Climate 28, no. 14:55495574. PNNL-SA-106250. doi:10.1175/JCLI-D-14-00729.1
  • Taraphdar S., L. Leung, and S.M. Hagos. 2015. "Linkages of Remote Sea Surface Temperatures and Atlantic Tropical Cyclone Activity Mediated by the African Monsoon." Geophysical Research Letters 42, no. 2:572-578. PNNL-SA-105745. doi:10.1002/2014GL062600
  • Xiao H., W.I. Gustafson, S.M. Hagos, C. 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, no. 2:537-550. PNNL-SA-103534. doi:10.1002/2014MS000356

2014

  • Hagos S.M., L. Leung, W.I. Gustafson, and B. Singh. 2014. "Eddy Fluxes and Sensitivity of the Water Cycle to Spatial Resolution in Idealized Regional Aquaplanet Model Simulations." Climate Dynamics 42, no. 3-4:931-940. PNNL-SA-90821. doi:10.1007/s00382-013-1857-y
  • Hagos S.M., L. Leung, Y. Xue, A. Boone, F. de Sales, N. Neupane, and M. Huang, et al. 2014. "Assessment of Uncertainties in the Response of the African Monsoon Precipitation to Land Use change simulated by a regional model." Climate Dynamics 43, no. 9-10:2765-2775. PNNL-SA-96599. doi:10.1007/s00382-014-2092-x
  • Hagos S.M., Z. Feng, C.D. Burleyson, K. Lim, C.N. 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: Atmospheres 119, no. 21:12,05212,068. PNNL-SA-100601. doi:10.1002/2014JD022143
  • Hagos S.M., Z. Feng, K. Landu, and C.N. 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, no. 3:938-949. PNNL-SA-97931. doi:10.1002/2014MS000335
  • Landu K., L. Leung, S.M. 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, no. 6:23752385. PNNL-SA-95463. doi:10.1175/JCLI-D-13-00269.1

2010

  • Hagos S.M. 2010. "Building Blocks of Tropical Diabatic Heating." Journal of the Atmospheric Sciences 67, no. 7:2341-2354. PNNL-SA-71870. doi:10.1175/2010JAS3252.1
  • Hagos S.M., and C. Zhang. 2010. "Diabatic heating, divergent circulation and moisture transport in the African monsoon system." Quarterly Journal of the Royal Meteorological Society 136, no. S1:411-425. PNNL-SA-70976. doi:10.1002/qj.538
  • Hagos S.M., C. Zhang, W. Tao, S. Lang, Y.N. Takayabu, S. Shige, and M. Katsumata, et al. 2010. "Estimates of Tropical Diabatic Heating Profiles: Commonalities and Uncertainties." Journal of Climate 23, no. 3:542-558. PNNL-SA-70981. doi:10.1175/2009JCLI3025.1
  • Zhang C., J. Ling, S.M. Hagos, W. Tao, S. Lang, Y.N. Takayabu, and S. Shige, et al. 2010. "MJO Signals in Latent Heating: Results from TRMM Retrievals." Journal of the Atmospheric Sciences 67, no. 11:34883508. PNNL-SA-74067. doi:10.1175/2010JAS3398.1

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