Sciences and Exploration Directorate

Santha Akella



Org Code: 610.1

Mail Code: 610.1
Greenbelt, MD 20771

Employer: NASA

Brief Bio

Dr. Akella works at the Global Modeling and Assimilation Office (GMAO). His research focuses on the development, testing and operational integration of the next generation atmosphere-ocean coupled, Integrated Earth Analysis System (IESA), with emphasis on the ocean and ocean-atmosphere coupling.



Research Oceanographer


November 2018 - Present

Support Scientist


2010 - November 2018

Postdoc Researcher

Johns Hopkins Univ. - Baltimore, MD

May 2008 - December 2010

Postdoc Researcher

Texas A&M Univ. - College Station, TX

May 2007 - April 2008

Postdoc Researcher

University of Pennsylvania - Philadelphia, PA

July 2006 - April 2007

Teaching and Graduate Research Assistant

Florida State Univ. - Tallahassee, FL

September 2000 - June 2006



Hackert, E., S. Akella, L. Ren, et al. K. Nakada, J. A. Carton, and A. Molod. 2023. Impact of the TAO/TRITON Array on Reanalyses and Predictions of the 2015 El Niño Journal of Geophysical Research: Oceans 128 (11): [10.1029/2023jc020039]

Chattopadhyay, M., S. Akella, J. Kim, and C. Bloecker. 2023. Direct assimilation of AVHRR satellite radiance measurements in a reanalysis system Quarterly Journal of the Royal Meteorological Society [10.1002/qj.4583]

Luo, B., P. J. Minnett, M. Szczodrak, and S. Akella. 2022. Regional and Seasonal Variability of the Oceanic Thermal Skin Effect Journal of Geophysical Research: Oceans 127 (5): [10.1029/2022jc018465]

Luo, B., P. J. Minnett, P. Zuidema, N. R. Nalli, and S. Akella. 2021. Saharan dust effects on North Atlantic sea‐surface skin temperatures Journal of Geophysical Research: Oceans [10.1029/2021jc017282]

Gentemann, C. L., J. P. Scott, P. L. Mazzini, et al. C. Pianca, S. Akella, P. J. Minnett, P. Cornillon, B. Fox-Kemper, I. Cetinić, T. M. Chin, J. Gomez-Valdes, J. Vazquez-Cuervo, V. Tsontos, L. Yu, R. Jenkins, S. De Halleux, D. Peacock, and N. Cohen. 2020. Saildrone: adaptively sampling the marine environment Bulletin of the American Meteorological Society 101 (6): E744–E762 [10.1175/bams-d-19-0015.1]

Penny, S. G., S. Akella, M. A. Balmaseda, et al. P. Browne, J. A. Carton, M. Chevallier, F. Counillon, C. Domingues, S. Frolov, P. Heimbach, P. Hogan, I. Hoteit, D. Iovino, P. Laloyaux, M. J. Martin, S. Masina, A. M. Moore, P. de Rosnay, D. Schepers, B. M. Sloyan, A. Storto, A. Subramanian, S. Nam, F. Vitart, C. Yang, Y. Fujii, H. Zuo, T. O’Kane, P. Sandery, T. Moore, and C. C. Chapman. 2019. Observational Needs for Improving Ocean and Coupled Reanalysis, S2S Prediction, and Decadal Prediction Frontiers in Marine Science 6 [10.3389/fmars.2019.00391]

Moore, A. M., M. J. Martin, S. Akella, et al. H. G. Arango, M. Balmaseda, L. Bertino, S. Ciavatta, B. Cornuelle, J. Cummings, S. Frolov, P. Lermusiaux, P. Oddo, P. R. Oke, A. Storto, A. Teruzzi, A. Vidard, and A. T. Weaver. 2019. Synthesis of Ocean Observations Using Data Assimilation for Operational, Real-Time and Reanalysis Systems: A More Complete Picture of the State of the Ocean Frontiers in Marine Science 6 [10.3389/fmars.2019.00090]

Gentemann, C. L., and S. Akella. 2018. Evaluation of NASA GEOS-ADAS Modeled Diurnal Warming Through Comparisons to SEVIRI and AMSR2 SST Observations Journal of Geophysical Research: Oceans [10.1002/2017jc013186]

Gelaro, R., W. McCarty, M. J. Suárez, et al. R. Todling, A. Molod, L. Takacs, C. Randles, A. Darmenov, M. G. Bosilovich, R. Reichle, K. Wargan, L. Coy, R. Cullather, C. Draper, S. Akella, V. Buchard, A. Conaty, A. da Silva, W. Gu, G.-K. Kim, R. Koster, R. Lucchesi, D. Merkova, J. E. Nielsen, G. Partyka, S. Pawson, W. Putman, M. Rienecker, S. D. Schubert, M. Sienkiewicz, and B. Zhao. 2017. The Modern-Era Retrospective Analysis for Research and Applications, Version 2 (MERRA-2) Journal of Climate 30 5419–5454 [10.1175/jcli-d-16-0758.1]

Akella, S., R. Todling, and M. J. Suarez. 2017. Assimilation for skin SST in the NASA GEOS atmospheric data assimilation system Quarterly Journal of the Royal Meteorological Society 143 (703): 1032-1046 [10.1002/qj.2988]

Brassington, G., M. Martin, H. Tolman, et al. S. Akella, M. Balmeseda, C. Chambers, E. Chassignet, J. Cummings, Y. Drillet, P. Jansen, P. Laloyaux, D. Lea, A. Mehra, I. Mirouze, H. Ritchie, G. Samson, P. Sandery, G. Smith, M. Suarez, and R. Todling. 2015. Progress and challenges in short- to medium-range coupled prediction Journal of Operational Oceanography 8 (sup2): s239-s258 [10.1080/1755876x.2015.1049875]

Vernieres, G. R., R. M. Kovach, C. L. Keppenne, et al. S. R. Akella, L. Brucker, and E. P. Dinnat. 2014. The impact of the assimilation of Aquarius sea surface salinity data in the GEOS ocean data assimilation system J. Geophys. Res. Oceans 119 (10): 6974-6987 [10.1002/2014JC010006]

Akella, S. R. 2011. Reservoir Multiscale Data Assimilation Using the Ensemble Kalman Filter Applied Mathematics 02 (02): 165-180 [10.4236/am.2011.22019]

Chen, X., S. Akella, and I. M. Navon. 2011. A dual-weighted trust-region adaptive POD 4-D Var applied to a finite-volume shallow water equations model on the sphere International Journal for Numerical Methods in Fluids 68 (3): 377-402 [10.1002/fld.2523]

Akella, S., A. Datta-Gupta, and Y. Efendiev. 2011. ASSIMILATION OF COARSE-SCALEDATAUSINGTHE ENSEMBLE KALMAN FILTER International Journal for Uncertainty Quantification 1 (1): 49-76 [10.1615/int.j.uncertaintyquantification.v1.i1.40]

Akella, S., and I. M. Navon. 2008. Different approaches to model error formulation in 4D-Var: a study with high-resolution advection schemes Tellus A 61 (1): 112-128 [10.1111/j.1600-0870.2008.00362.x]

Akella, S., and I. M. Navon. 2005. A comparative study of the performance of high resolution advection schemes in the context of data assimilation International Journal for Numerical Methods in Fluids 51 (7): 719-748 [10.1002/fld.1145]

Mandal, N., and S. R. Akella. 2000. A Finite Difference Model for Prediction of Welding Thermal History (Part 1) Journal of the Mechanical Behavior of Materials 11 (5): [10.1515/jmbm.2000.11.5.381]


Akella, S., and M. J. Suarez. 2018. The Atmosphere-Ocean Interface Layer of NASA’s Goddard Earth Observing System Model and Data Assimilation System NASA Technical Report Series on Global Modeling and Data Assimilation, NASA/TM-2018-104606 51 42pp.

Kim, J. G., S. R. Akella, A. M. Da Silva, R. Todling, and W. R. Mccarty. 2018. Preliminary evaluation of influence of aerosols on the simulation of brightness temperature in the NASA’s Goddard Earth Observing System Atmospheric Data Assimilation System NASA Technical Report Series on Global Modeling and Data Assimilation, NASA/TM-2018-104606 49 44pp

Akella, S. R., R. Todling, and M. J. Suarez. 2016. Estimation of the Ocean Skin Temperature using the NASA GEOS Atmospheric Data Assimilation System NASA Technical Report Series on Global Modeling and Data Assimilation, NASA/TM-2016-10460 44 88pp

Bosilovich, M. G., S. R. Akella, L. Coy, et al. R. I. Cullather, C. S. Draper, R. Gelaro, R. M. Kovach, Q. Liu, A. M. Molod, P. M. Norris, K. Wargan, C. Yang, R. H. Reichle, L. L. Takacs, Y. V. Vikhliaev, S. C. Bloom, A. Collow, S. Firth, G. J. Labow, G. S. Partyka, S. Pawson, O. Reale, S. D. Schubert, and M. J. Suarez. 2015. MERRA-2: Initial Evaluation of the Climate NASA Technical Report Series on Global Modeling and Data Assimilation 43 (NASA/TM–2015–10) 139 pp.


  • NASA Honor Award, Group Achievement Award, MERRA-2 Science Team, August, 2019
  • Travel award to present invited talk ``Skin SST assimilation using GEOS-ADAS" at the International workshop on coupled data assimilation, Toulouse, France, October, 2016 []
  • Scientific achievement award for successfully implementing skin temperature analysis in GEOS-5, January, 2016



Implementing a physically motivated source of sea salt for aerosol and cloud applications in GEOS-5 through improved wind-wave coupling - NASA - Awarded: 2017-03-17

Effectively constraining both atmosphere and ocean components in an Integrated Earth System Analysis Data Assimilation System - NASA - Awarded: 2020-04-02

Towards Full Utilization of Satellite Sea Surface Salinity for El Niño/Southern Oscillation Prediction - NASA - Awarded: 2020-01-10

Evaluating the tropical Pacific Ocean observing system using ECCO and GMAO systems: impacts on seasonal prediction - NASA - Awarded: 2021-03-11

Developing Coupled Data Assimilation for Integrated Earth System Analysis with GEOS - NASA - Awarded: 2021-03-11

Development of a well calibrated ocean at multiple spatial scales within the GMAO Integrated Earth System Analysis - NASA - Awarded: 2021-03-11

Assessing and Improving the Realism of MOM6 Simulations at Time Scales from Hours to Years - NOAA - Awarded: 2022-09-01

Selected Public Outreach

OceanPredict Coupled Task Team

2021 - Present

  • Co-chair 2021- present
  • Member 2013- present

OceanPredict Data Assimilation Task Team

2017 - Present

  • Member 2017- present


2021 - Present

  • Member 2021- present

ForeSea - Steering Committee

2021 - Present

A UN Decade of Ocean Science for Sustainable Development project