Sciences and Exploration Directorate

Sarith Prasad Mahanama

(RESEARCH SCIENTIST SR)

 sarith.p.mahanama@nasa.gov

Org Code: 617

NASA/GSFC
Mail Code: 617
Greenbelt, MD 20771

Employer: Science Application International Corp.

Brief Bio


Dr. Mahanama conducts research on the role of the land surface in the climate system; applications of land-surface models to study the impact of land surface variability on the predictability of climate and interactions between the terrestrial and atmospheric branches of the hydrologic cycle.

Education


Ph.D., 2000 in Civil and Environmental Engineering
The University of Hong Kong, Hong Kong.


B.Sc.Eng., 1993 (Honors) in Civil Engineering
University of Peradeniya, Sri Lanka.

Publications


Refereed

Nie, W., S. V. Kumar, K. R. Arsenault, et al. C. D. Peters-Lidard, I. E. Mladenova, K. Bergaoui, A. Hazra, B. F. Zaitchik, S. P. Mahanama, R. McDonnell, D. M. Mocko, and M. Navari. 2022. Towards effective drought monitoring in the Middle East and North Africa (MENA) region: implications from assimilating leaf area index and soil moisture into the Noah-MP land surface model for Morocco Hydrology and Earth System Sciences 26 (9): 2365-2386 [10.5194/hess-26-2365-2022]

Maina, F. Z., S. V. Kumar, C. Albergel, and S. P. Mahanama. 2022. Warming, increase in precipitation, and irrigation enhance greening in High Mountain Asia Communications Earth & Environment 3 (1): 43 [10.1038/s43247-022-00374-0]

Apers, S., G. J. De Lannoy, A. J. Baird, et al. A. R. Cobb, G. C. Dargie, J. Pasquel, A. Gruber, A. Hastie, H. Hidayat, T. Hirano, A. M. Hoyt, A. J. Jovani‐Sancho, A. Katimon, A. Kurnain, R. D. Koster, M. Lampela, S. P. Mahanama, L. Melling, S. E. Page, R. H. Reichle, M. Taufik, J. Vanderborght, and M. Bechtold. 2022. Tropical Peatland Hydrology Simulated With a Global Land Surface Model Journal of Advances in Modeling Earth Systems 14 (3): e2021MS002784 [10.1029/2021ms002784]

Kumar, S., A. Getirana, R. Libonati, et al. C. Hain, S. Mahanama, and N. Andela. 2022. Changes in land use enhance the sensitivity of tropical ecosystems to fire-climate extremes Scientific Reports 12 (1): 964 [10.1038/s41598-022-05130-0]

Bian, H., E. Lee, R. D. Koster, et al. D. Barahona, M. Chin, P. R. Colarco, A. Darmenov, S. Mahanama, M. Manyin, P. Norris, J. Shilling, H. Yu, and F. Zeng. 2021. The response of the Amazon ecosystem to the photosynthetically active radiation fields: integrating impacts of biomass burning aerosol and clouds in the NASA GEOS Earth system model Atmospheric Chemistry and Physics 21 (18): 14177-14197 [10.5194/acp-21-14177-2021]

Kumar, S. V., T. Holmes, N. Andela, et al. I. Dharssi, Vinodkumar, C. Hain, C. Peters‐Lidard, S. P. Mahanama, K. R. Arsenault, W. Nie, and A. Getirana. 2020. The 2019‐2020 Australian drought and bushfires altered the partitioning of hydrological fluxes Geophysical Research Letters 48 (1): [10.1029/2020gl091411]

Xiao, M., S. P. Mahanama, Y. Xue, F. Chen, and D. P. Lettenmaier. 2020. Modeling Snow Ablation over the Western United States Mountains: Patterns and Controlling Factors Journal of Hydrometeorology [10.1175/jhm-d-19-0198.1]

Maertens, M., G. J. De Lannoy, S. Apers, S. V. Kumar, and S. P. Mahanama. 2020. Simulating the Dry Chaco Hydrology under Deforestation Pressure [10.5194/hess-2020-486]

Thomas, N. P., M. G. Bosilovich, A. B. Marquardt Collow, et al. R. D. Koster, S. D. Schubert, A. Dezfuli, and S. P. Mahanama. 2020. Mechanisms Associated with Daytime and Nighttime Heat Waves over the Contiguous United States Journal of Applied Meteorology and Climatology 59 (11): 1865-1882 [10.1175/jamc-d-20-0053.1]

Koster, R. D., S. D. Schubert, A. M. DeAngelis, A. M. Molod, and S. P. Mahanama. 2020. Using a Simple Water Balance Framework to Quantify the Impact of Soil Moisture Initialization on Subseasonal Evapotranspiration and Air Temperature Forecasts Journal of Hydrometeorology 21 (8): 1705-1722 [10.1175/jhm-d-20-0007.1]

Lee, E., F. Zeng, R. D. Koster, et al. L. E. Ott, S. P. Mahanama, B. Weir, B. Poulter, and T. Oda. 2020. Impact of a Regional US Drought on Land and Atmospheric Carbon Journal of Geophysical Research: Biogeosciences 125 (8): [10.1029/2019jg005599]

Kolassa, J., R. H. Reichle, R. D. Koster, et al. Q. Liu, S. Mahanama, and F. Zeng. 2020. An observation‐driven approach to improve vegetation phenology in a global land surface model Journal of Advances in Modeling Earth Systems 12 e2020MS002083 [10.1029/2020ms002083]

Reichle, R. H., Q. Liu, R. D. Koster, et al. W. T. Crow, G. J. De Lannoy, J. S. Kimball, J. V. Ardizzone, D. Bosch, A. Colliander, M. Cosh, J. Kolassa, S. P. Mahanama, J. Prueger, P. Starks, and J. P. Walker. 2019. Version 4 of the SMAP Level‐4 Soil Moisture Algorithm and Data Product Journal of Advances in Modeling Earth Systems 11 (10): 3106-3130 [10.1029/2019ms001729]

Koster, R. D., R. H. Reichle, S. D. Schubert, and S. P. Mahanama. 2019. Length Scales of Hydrological Variability as Inferred from SMAP Soil Moisture Retrievals Journal of Hydrometeorology 20 (11): 2129-2146 [10.1175/jhm-d-19-0070.1]

Bechtold, M., G. J. De Lannoy, R. D. Koster, et al. R. H. Reichle, S. P. Mahanama, W. Bleuten, M. A. Bourgault, C. Brümmer, I. Burdun, A. R. Desai, K. Devito, T. Grünwald, M. Grygoruk, E. R. Humphreys, J. Klatt, J. Kurbatova, A. Lohila, T. M. Munir, M. B. Nilsson, J. S. Price, M. Röhl, A. Schneider, and B. Tiemeyer. 2019. PEAT‐CLSM: A Specific Treatment of Peatland Hydrology in the NASA Catchment Land Surface Model Journal of Advances in Modeling Earth Systems 11 (7): 2130-2162 [10.1029/2018ms001574]

Girotto, M., R. H. Reichle, M. Rodell, et al. Q. Liu, S. Mahanama, and G. J. De Lannoy. 2019. Multi-sensor assimilation of SMOS brightness temperature and GRACE terrestrial water storage observations for soil moisture and shallow groundwater estimation Remote Sensing of Environment 227 12-27 [10.1016/j.rse.2019.04.001]

Koster, R. D., S. D. Schubert, H. Wang, S. P. Mahanama, and A. M. DeAngelis. 2019. Flash Drought as Captured by Reanalysis Data: Disentangling the Contributions of Precipitation Deficit and Excess Evapotranspiration Journal of Hydrometeorology 20 (6): 1241-1258 [10.1175/jhm-d-18-0242.1]

Koster, R. D., W. T. Crow, R. H. Reichle, and S. P. Mahanama. 2018. Estimating Basin-Scale Water Budgets With SMAP Soil Moisture Data Water Resources Research 54 (7): 4228-4244 [10.1029/2018wr022669]

Koster, R. D., Q. Liu, S. P. Mahanama, and R. H. Reichle. 2018. Improved Hydrological Simulation Using SMAP Data: Relative Impacts of Model Calibration and Data Assimilation Journal of Hydrometeorology 19 (4): 727-741 [10.1175/jhm-d-17-0228.1]

Dirmeyer, P. A., L. Chen, J. Wu, et al. C.-S. Shin, B. Huang, B. A. Cash, M. G. Bosilovich, S. Mahanama, R. D. Koster, J. A. Santanello, M. B. Ek, G. Balsamo, E. Dutra, and D. M. Lawrence. 2018. Verification of Land–Atmosphere Coupling in Forecast Models, Reanalyses, and Land Surface Models Using Flux Site Observations Journal of Hydrometeorology 19 (2): 375-392 [10.1175/jhm-d-17-0152.1]

Duong, T. M., R. Ranasinghe, M. Thatcher, et al. S. Mahanama, Z. B. Wang, P. K. Dissanayake, M. Hemer, A. Luijendijk, J. Bamunawala, D. Roelvink, and D. Walstra. 2018. Assessing climate change impacts on the stability of small tidal inlets: Part 2 - Data rich environments Marine Geology 395 65-81 [10.1016/j.margeo.2017.09.007]

Reichle, R. H., G. J. De Lannoy, Q. Liu, et al. J. V. Ardizzone, A. Colliander, A. Conaty, W. Crow, T. J. Jackson, L. A. Jones, J. S. Kimball, R. D. Koster, S. P. Mahanama, E. B. Smith, A. Berg, S. Bircher, D. Bosch, T. G. Caldwell, M. Cosh, C. D. Holifield Collins, K. H. Jensen, S. Livingston, E. Lopez-Baeza, J. Martínez-Fernández, H. McNairn, M. Moghaddam, A. Pacheco, T. Pellarin, J. Prueger, T. Rowlandson, M. Seyfried, P. Starks, Z. Su, M. Thibeault, R. van der Velde, J. Walker, X. Wu, and Y. Zeng. 2017. Assessment of the SMAP Level-4 Surface and Root-Zone Soil Moisture Product Using In Situ Measurements Journal of Hydrometeorology 18 (10): 2621-2645 [10.1175/jhm-d-17-0063.1]

Reichle, R. H., C. S. Draper, Q. Liu, et al. M. Girotto, S. P. Mahanama, R. D. Koster, and G. J. De Lannoy. 2017. Assessment of MERRA-2 Land Surface Hydrology Estimates Journal of Climate 30 (8): 2937-2960 [10.1175/jcli-d-16-0720.1]

Koster, R. D., R. H. Reichle, and S. P. Mahanama. 2017. A Data-Driven Approach for Daily Real-Time Estimates and Forecasts of Near-Surface Soil Moisture Journal of Hydrometeorology 18 (3): 837-843 [10.1175/jhm-d-16-0285.1]

Reichle, R. H., Q. Liu, R. D. Koster, et al. C. S. Draper, S. P. Mahanama, and G. S. Partyka. 2017. Land Surface Precipitation in MERRA-2 Journal of Climate 30 (5): 1643-1664 [10.1175/jcli-d-16-0570.1]

Xue, Y., F. D. Sales, W. K. Lau, et al. A. Boone, K.-M. Kim, G. Wang, F. Kucharski, K. Schiro, M. Hosaka, S. Li, C. R. Mechoso, L. M. Druyan, I. S. Sanda, W. Thiaw, N. Zeng, R. E. Comer, Y.-K. Lim, S. Mahanama, G. Song, Y. Gu, M. Chin, P. Dirmeyer, S. M. Hagos, E. Kalnay, A. Kitoh, L. R. Leung, C.-H. Lu, N. M. Mahowald, S. D. Schubert, and Z. Zhang. 2016. West African monsoon decadal variability and drought and surface-related forcings: Second West African monsoon modeling and evaluation project experiment (WAMME II) Climate Dynamics 47 (11): 3517-3545 [10.1007/s00382-016-3224-2]

Boone, A. A., Y. Xue, F. De Sales, et al. R. E. Comer, S. Hagos, S. Mahanama, K. Schiro, G. Song, G. Wang, S. Li, and C. R. Mechoso. 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 [10.1007/s00382-016-3252-y]

Yasunari, T. J., P. R. Colarco, W. K. Lau, et al. K. Osada, M. Kido, S. P. Mahanama, K.-M. Kim, and A. M. Da Silva. 2016. Total dust deposition flux during precipitation in Toyama, Japan, in the spring of 2009: A sensitivity analysis with the NASA GEOS-5 Model Atmospheric Research 167 298–313 [10.1016/j.atmosres.2015.08.005]

De Lannoy, G. J., R. Koster, R. H. Reichle, S. Mahanama, and Q. Liu. 2014. An updated treatment of soil texture and associated hydraulic properties in a global land modeling system J. Adv. Model. Earth Sys 6 957-979 [10.1002/2014MS000330]

Koster, R. D., G. K. Walker, S. P. Mahanama, and R. H. Reichle. 2014. Soil Moisture Initialization Error and Subgrid Variability of Precipitation in Seasonal Streamflow Forecasting J. Hydrometeor. 15 (1): 69-88 [10.1175/JHM-D-13-050.1]

Yasunari, T., W. K. Lau, P. R. Colarco, et al. A. M. Da Silva, T. Aoki, K. Aoki, N. Murao, S. Yamagata, Y. Kodama, and S. P. Mahanama. 2014. The GOddard SnoW Impurity Module (GOSWIM) for the NASA GEOS-5 Earth System Model: Preliminary Comparisons with Observations in Sapporo, Japan SOLA 10 (0): 50-56 [10.2151/sola.2014-011]

Koster, R. D., and S. P. Mahanama. 2012. Land Surface Controls on Hydroclimatic Means and Variability Journal of Hydrometeorology 13 (5): 1604-1620 [10.1175/JHM-D-12-050.1]

Mahanama, S., B. Livneh, R. D. Koster, D. Lettenmaier, and R. H. Reichle. 2012. Soil Moisture, Snow, and Seasonal Streamflow Forecasts in the United States Journal of Hydrometeorology 13 (1): 189-203 [10.1175/JHM-D-11-046.1]

Koster, R. D., S. P. Mahanama, T. J. Yamada, et al. G. Balsamo, A. A. Berg, M. Boisserie, P. A. Dirmeyer, F. J. Doblas-Reyes, G. Drewitt, C. T. Gordon, Z. Guo, J. H. Jeong, W. S. Lee, Z. Li, L. Luo, S. Malyshev, W. J. Merryfield, S. I. Seneviratne, T. Stanelle, B. J. van den Hurk, F. Vitart, and W. F. Wood. 2011. The Second Phase of the Global Land-Atmosphere Coupling Experiment: Soil Moisture Contributions to Subseasonal Forecast Skill Journal of Hydrometeorology 12 805-822 [DOI: 10.1175/2011JHM1365.1]

Reichle, R. H., R. D. Koster, G. J. De Lannoy, et al. B. A. Forman, Q. Liu, S. P. Mahanama, and A. Toure. 2011. Assessment and Enhancement of MERRA Land Surface Hydrology Estimates Journal of Climate 24 (24): 6322-6338 [10.1175/JCLI-D-10-05033.1]

Menon, S., H. Akbari, S. Mahanama, I. Sednev, and R. Levinson. 2010. Radiative forcing and temperature response to changes in urban albedos and associated CO₂ offsets Environ. Res. Lett. 5 (1): 014005 [10.1088/1748-9326/5/1/014005]

Koster, R. D., S. P. Mahanama, T. J. Yamada, et al. G. Balsamo, A. A. Berg, M. Boisserie, P. A. Dirmeyer, F. J. Doblas-Reyes, G. Drewitt, C. T. Gordon, Z. Guo, J. H. Jeong, D. M. Lawrence, W. S. Lee, Z. Li, L. Luo, S. Malyshev, W. J. Merryfield, S. I. Seneviratne, T. Stanelle, B. J. van den Hurk, F. Vitart, and W. F. Wood. 2010. Contribution of land surface initialization to subseasonal forecast skill: First results from a multi-model experiment Geophysical Research Letters 37 0-0 [DOI: 10.1029/2009GL041677]

Koster, R. D., S. P. Mahanama, B. Livneh, B. P. Letternmaier, and R. H. Reichle. 2010. Skill in streamflow forecasts derived from large-scale estimates of soil moisture and snow Nature Geoscience 3 (9): 613-616 [10.1038/NGEO944]

Reichle, R. H., S. V. Kumar, S. P. Mahanama, R. D. Koster, and Q. Liu. 2010. Assimilation of Satellite-Derived Skin Temperature Observations into Land Surface Models J. Hydrometeor 11 (5): 1103-1122 [10.1175/2010JHM1262.1]

Wang, A., T. J. Bohn, S. P. Mahanama, D. Lettenmaier, and R. D. Koster. 2009. Multimodel Ensemble Reconstruction of Drought over the Continental United States Journal of Climate 22 2694-2712 [DOI: 10.1175/2008JCLI2586.1]

Koster, R. D., H. Wang, S. D. Schubert, M. J. Suarez, and S. P. Mahanama. 2009. Drought-Induced Warming in the Continental United States under Different SST Regimes Journal of Climate 22 5385-5400 [DOI: 10.1175/2009JCLI3075.1]

Reichle, R. H., W. T. Crow, R. D. Koster, H. O. Sharif, and S. P. Mahanama. 2008. Contribution of soil moisture retrievals to land data assimilation products Geophysical Research Letters 35 (1): L01404 [10.1029/2007GL031986]

Mahanama, S. P., R. D. Koster, R. H. Reichle, and M. J. Suarez. 2008. Impact of Subsurface Temperature Variability on Surface Air Temperature Variability: An AGCM Study J. Hydrometeor. 9 (4): 804-815 [10.1175/2008JHM949.1]

Mahanama, S. P., R. D. Koster, R. H. Reichle, and L. Zubair. 2008. The role of soil moisture initialization in subseasonal and seasonal streamflow prediction – A case study in Sri Lanka Advances in Water Resources 31 (10): 1333-1343 [10.1016/j.advwatres.2008.06.004]

Reichle, R. H., R. D. Koster, P. Liu, et al. S. Mahanama, E. Njoku, and M. Owe. 2007. Comparison and assimilation of global soil moisture retrievals from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) and the Scanning Multichannel Microwave Radiometer (SMMR) J Geophys Res 112 (D09108): 14 pp [10.1029/2006JD008033]

Reichle, R. H., R. D. Koster, P. Liu, et al. S. P. Mahanama, E. G. Njoku, and M. Owe. 2007. Comparison and assimilation of global soil moisture retrievals from the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) and the Scanning Multichannel Microwave Radiometer (SMMR) J. Geophys. Res. 112 (D9): D09108 [10.1029/2006JD008033]

Mahanama, S. P., and R. D. Koster. 2005. AGCM biases in evaporation regime: Impacts on soil moisture memory and land-atmosphere feedback Journal of Hydrometeorology 6 656-669 [DOI: 10.1175/JHM446.1]

Boone, A., F. Habets, J. Noilhan, et al. D. Clark, P. Dirmeyer, S. Fox, Y. Gusev, I. Haddeland, R. D. Koster, D. Lohmann, S. P. Mahanama, K. Mitchell, O. Nasonova, G. Y. Niu, A. J. Pitman, J. Polcher, A. B. Shmakin, K. Tanaka, B. van den Hurk, S. Verant, D. Verseghy, P. Viterbo, and Z. L. Yang. 2004. The Rhone-aggregation land surface scheme intercomparison project: An overview Journal of Climate 17 187-208 [DOI: 10.1175/1520-0442(2004)017<0187:TRLSSI>2.0.CO]

Bowling, L. C., D. P. Lettenmaier, B. Nijssen, et al. L. P. Graham, D. B. Clark, M. E. Maayar, R. Essery, S. Goers, Y. M. Gusev, F. Haberts, B. V. Hurk, J. Jin, D. Kahan, D. Lohmann, X. Ma, S. Mahanama, D. M. Mocko, O. Nasonova, G.-Y. Niu, P. Samuelsson, A. B. Shmakin, K. Takata, D. Verseghy, R. Viterbo, Y. Xia, Y. Xue, and Z.-L. Yang. 2003. Simulation of high-latitude hydrological processes in the Torne-Kalix basin: PILPS Phase 2(e): 1: Experiment description and summary intercomparisons Global and Planetary Change 38 (1-2): 1-30 [10.1016/S0921-8181(03)00003-1]

Nijssen, B., L. C. Bowling, D. P. Lettenmaier, et al. D. B. Clark, M. E. Maayar, R. Essery, S. Goers, Y. M. Gusev, F. Haberts, B. V. Hurk, J. Jin, D. Kahan, D. Lohmann, X. Ma, S. Mahanama, D. M. Mocko, O. Nasonova, G.-Y. Niu, P. Samuelsson, A. B. Shmakin, K. Takata, D. Verseghy, R. Viterbo, Y. Xia, Y. Xue, and Z.-L. Yang. 2003. Simulation of high-latitude hydrological processes in the Torne-Kalix basin: PILPS Phase 2(e): 2: Comparison of model results with observations Global and Planetary Change 38 (1-2): 31-53 [10.1016/S0921-8181(03)00004-3]

Mahanama, S. P., and R. D. Koster. 2003. Intercomparison of Soil Moisture Memory in Two Land Surface Models J. Hydrometeor 4 (6): 1134-1146 [10.1175/1525-7541(2003)004<1134:IOSMMI>2.0.CO;2]

Guillevic, P., R. D. Koster, M. J. Suarez, et al. L. Bounoua, G. J. Collatz, S. O. Los, and S. P. Mahanama. 2002. Influence of the inter annual variability of vegetation on the surface energy balance - a global sensitivity study Journal of Hydrometeorology 3 (6): 617-629

Non-Refereed

Collow, A., S. P. Mahanama, M. G. Bosilovich, R. D. Koster, and S. D. Schubert. 2017. An Evaluation of Teleconnections Over the United States in an Ensemble of AMIP Simulations with the MERRA-2 Configuration of the GEOS Atmospheric Model NASA Technical Report Series on Global Modeling and Data Assimilation, NASA/TM-2016-104606 47 68

Mahanama, S. P., R. D. Koster, G. K. Walker, et al. L. L. Takacs, R. H. Reichle, G. J. De Lannoy, Q. Liu, B. Zhao, and M. J. Suarez. 2015. Land Boundary Conditions for the Goddard Earth Observing System Model Version 5 (GEOS-5) Climate Modeling System - Recent Updates and Data File Descriptions NASA/TM–2015-104606 39 55