Landwater variation in four major river basins of the Indochina peninsula as revealed by GRACE
Tóm tắt
We estimated mass variations in four major river basins—the Mekong, Irrawaddy, Salween and Chao Phraya river basins—of the Indochina Peninsula using the newly released GRACE (Gravity Recovery and Climate Experiment) monthly gravity field solutions of UTCSR RL02 (University of Texas at Austin, Center for Space Research Release 02), JPL RL02 (Jet Propulsion Laboratory Release 02) and GFZ RL03 (GeoForschungsZentrum Potsdam Release 03). The estimated variations were compared with that calculated from a numerical model. The results show that there is a good agreement between the GRACE estimations and the model calculation for the Mekong and Irrawaddy basins, while the aggreement for the Salween and Chao Phraya basins is poor, mainly due to the spatial scale of the areas concerned. The comparison over the combined area of the four river basins shows fairly good agreement, although there are small quantitative discrepancies. The amplitudes of the annual signals of the GRACE solutions are 0.9- to 1.4-fold larger than that of the hydrological model, and the phases are delayed about 1 month compared with the model signal. The phase differences are probably due to improper treatments of the groundwater storage process in the hydrological model, suggesting that the GRACE data possibly provide constraints to the model parameters.
Tài liệu tham khảo
Bettadpur, S., UTCSR Level-2 Processing Standards Document For Level-2 Product Release 0002 (Draft, November 4, 2005), GRACE 327-742 (CSR-GR-03-03), 2005.
Chen, J. L., C. R. Wilson, J. S. Famiglietti, and M. Rodell, Spatial sensitivity of the Gravity Recovery and Climate Experiment (GRACE) time-variable gravity observations, J. Geophys. Res., 110, B08408, doi:10.1029/2004JB003536, 2005a.
Chen, J. L., M. Rodell, C. R. Wilson, and J. S. Famiglietti, Low degree spherical harmonic influences on Gravity Recovery and Climate Experiment (GRACE) water storage estimates, Geophys. Res. Lett., 32, L14405, doi:10.1029/2005GL022964, 2005b.
Chambers, D. P., J. Wahr, and R. S. Nerem, Preliminary observations of global ocean mass variations with GRACE, Geophys. Res. Lett., 31, L13310, doi:10.1029/2004GL020461, 2004.
Flechtner, F., GFZ Level-2 Processing Standards Document For Level-2 Product Release 0003 (Rev. 1.1, November 04, 2005), GRACE 327-743 (GR-GFZ-STD-001), 2005a.
Flechtner, F., AOD1B Product Description Document (Rev. 2.1, November 04, 2005), GRACE 327-750 (GR-GFZ-AOD-0001), 2005b.
Fukumori, I., R. Raghunath, L. Fu, and Y. Chao, Assimilation of TOPEX/POSEIDON data into a global ocean circulation model: How good are the results?, J. Geophys. Res., 104(C11), 25647–25666, doi:10. 1029/1999JC900193, 1999.
Han, S. C., C. K. Shum, C. Jekeli, C. Y. Kuo, C. Wilson, and K. W. Seo, Non-isotropic filtering of GRACE temporal gravity for geophysical signal enhancement, Geophys. J. Int., 163, 18–25, doi:10.1111/j.1365-246X.2005.02756.x, 2005.
Han, S. C., C. K. Shum, M. Bevis, J. Chen, and C. Y. Kuo, Crustal Dilatation Observed by GRACE After the 2004 Sumatra-Andaman Earthquake, Science, 33, 658–662, 2006.
Hosaka, M., D. Nohara, T. Nakaegawa, and S. Yukimoto, MRI Global River flow model using TRIP, J. Meteor. Soc. Jpn., 2006 (to be submitted).
Kanzow, T., F. Flechtner, A. Chave, R. Schmidt, P. Schwitzer, and U. Send, Seasonal variation of ocean bottom pressure derived from Gravity Recovery and Climate Experiment (GRACE): Local variation and global patterns, J. Geophys. Res., 110, C09001, doi:10.1029/2004JC002772, 2005.
Nohara, D., A. Kitoh, M. Hosaka, and T. Oki, Impact of Climate Change on River Discharge Projected by Multimodel Ensemble, J. Hydromet., 7, 1076–1089, doi:10.1175/JHM531.1, 2006.
Research Institute for Humanity and Nature, Research Project 2–4, Human Impacts on Urban Subsurface Environments, http://www.chikyu.ac.jp/USE/, 2005.
Rodell, M., P. R. Houser, U. Jambor, J. Gottschalck, K. Mitchell, C.-J. Meng, K. Arsenault, B. Cosgrove, J. Radakovich, M. Bosilovich, J. K. Entin, J. P. Walker, D. Lohmann, and D. Toll, The Global Land Data Assimilation System, Bull. Amer. Meteor. Soc., 85, 381–394, doi:10. 1175/BAMS-85-3-381, 2004.
Sellers, P. J., Y. Mintz, Y. C. Sud, and A. Dalcher, Simple Biosphere model (SiB) for use within general circulation model, J. Atmos. Sci., 43, 505–531, 1988.
Swenson, S. and J. Wahr, Methods for inferring regional surface-mass anomalies from Gravity Recovery and Climate Experiment (GRACE) measurements of time-variable gravity, J. Geophys. Res., 107(B9), 2193, doi:10.1029/2001JB000576, 2002.
Swenson, S., J. Wahr, and P. C. D. Milly, Estimated accuracies of regional water storage variations inferred from the Gravity Recovery and Climate Experiment (GRACE), Water Resour. Res., 39(8), 1223, doi:10.1029/ 2002WR001808, 2003.
Swenson, S. and J. Wahr, Post-processing removal of correlated errors in GRACE data, Geophys. Res. Lett., 33, L08402, doi:10.1029/2005GL025285, 2006.
Tapley, B. D., S. Bettadpur, M. Watkins, and C. Reigber, The Gravity Recovery and Climate Experiment: Mission overview and early results, Geophys. Res. Lett., 31, L09607, doi:10.1029/2004GL019920, 2004a.
Tapley, B. D., S. Bettadpur, J. C. Ries, P. F. Thompson, and M. M. Watkins, GRACE Measurements of Mass Variability in the Earth System, Science, 203, 503–505, 2004b.
Velicogna, I. and J. Wahr, Measurements of Time-Variable Gravity Show Mass Loss in Antarctica, Science, 311, 1754–1756, 2006.
Wagner, C., D. Mcado, J. Klokocnik, and J. Kostelecky, Degradation of Geopotential Recovery from Short Repeat Cycle Orbits: Application to GRACE Monthly Fields, J. Geod., 80, 94–103, doi:10.1007/s00190-006-0036-x, 2006.
Wahr, J., M. Molenaar, and F. Bryan, Time variability of the Earth’s gravity field: Hydrological and oceanic effects and their possible detection using GRACE, J. Geophys. Res., 103(B12), 30205–30229, doi:10.1029/98JB02844, 1998.
Wahr, J., S. Swenson, V. Zlotnicki, and I. Velicogna, Time-variable gravity from GRACE: First results, Geophys. Res. Lett., 31, L11501, doi:10. 1029/2004GL019779, 2004.
Watkins, M. M., JPL Level-2 Processing Standards Document For Level-2 Product Release 02, GRACE 327-744, v2.0, 2005.
Yamamoto, K., T. Otsubo, T. Kubooka, and Y. Fukuda, A simulation study of effects of GRACE orbit decay on the gravity field recovery, Earth Planets Space, 57, 291–295, 2005.