Incorporation of groundwater pumping in a global Land Surface Model with the representation of human impacts

Water Resources Research

Volumn 51, Issue 1, 2015, Pages 78-96

  Pokhrel, Yadu N ^a   Koirala, Sujan ^b   Yeh, Pat J F ^c   Hanasaki, Naota ^d   Longuevergne, Laurent ^e   Kanae, Shinjiro ^f   Oki, Taikan ^g  

^a Michigan State University   (United States)

^b MAX PLANCK INSTITUTE FOR BIOGEOCHEMISTRY   (Germany)

^c NATIONAL UNIVERSITY OF SINGAPORE   (Singapore)

^d NATIONAL INSTITUTE FOR ENVIRONMENTAL STUDIES   (Japan)

^e UNIVERSITÉ DE RENNES 1   (France)

^f TOKYO INSTITUTE OF TECHNOLOGY   (Japan)

^g INSTITUTE OF INDUSTRIAL SCIENCE   (Japan)

Author keywords

GRACE; groundwater pumping; human impacts; irrigation; Land Surface Model; U.S. Aquifers

Indexed keywords

AQUIFERS; GROUNDWATER; HYDROGEOLOGY; IRRIGATION; PUMPS; RESERVOIRS (WATER); SURFACE MEASUREMENT; UNCERTAINTY ANALYSIS; WATER CONSERVATION; WATER SUPPLY; WELL PUMPS;

GRACE; GROUNDWATER DYNAMICS; GROUNDWATER PUMPING; GROUNDWATER STORAGE; GROUNDWATER WITHDRAWAL; HUMAN IMPACT; LAND SURFACE MODELING; TERRESTRIAL WATER STORAGE;

GROUNDWATER RESOURCES;

ANTHROPOGENIC EFFECT; GRACE; GROUNDWATER FLOW; HYDRODYNAMICS; HYDROLOGICAL CYCLE; HYDROLOGICAL MODELING; IRRIGATION SYSTEM; PUMPING; WATER STORAGE; WATER TABLE;

CALIFORNIA; CENTRAL VALLEY [CALIFORNIA]; OGALLALA AQUIFER; UNITED STATES;

EID: 85027939265     PISSN: 00431397     EISSN: 19447973     Source Type: Journal    
DOI: 10.1002/2014WR015602     Document Type: Article

References (102)

1. Aeschbach-Hertig, W., and, T. Gleeson, (2012), Regional strategies for the accelerating global problem of groundwater depletion, Nat. Geosci., 5, 853-861.
2. Alcamo, J., P. Döll, T. Henrichs, F. Kaspar, B. Lehner, T. Rösch, and, S. Siebert, (2003), Development and testing of the WaterGAP 2 global model of water use and availability, Hydrol. Sci. J., 48, 317-337.
3. Alkama, R., B. R. Decharme, H. Douville, M. Becker, A. Cazenave, J. Sheffield, A. Voldoire, S. Tyteca, and, P. Le Moigne, (2010), Global evaluation of the ISBA-TRIP continental hydrological system. Part I: Comparison with GRACE terrestrial water storage estimates and in situ river discharges, J. Hydrometeorol., 11, 583-600.
4. Alley, W. M., R. W. Healy, J. W. LaBaugh, and, T. E. Reilly, (2002), Hydrology-flow and storage in groundwater systems, Science, 296, 1985-1990.
5. Alsdorf, D. E., and, D. P. Lettenmaier, (2003), Tracking fresh water from space, Science, 301, 1491-1494.
6. Beven, K. J., and, M. J. Kirkby, (1979), A physically based variable contributing area model of basin hydrology, Hydrol. Sci. Bull., 24, 43-69.
7. Collatz, G., J. T. Ball, C. Grivet, and, J. A. Berry, (1991), Physiological and environmental regulation of stomatal conductance, photosynthesis and transpiration: A model that includes a laminar boundary layer, Agric. For. Meteorol., 54, 107-136.
8. Condon, L. E., and, R. M. Maxwell, (2014), Feedbacks between managed irrigation and water availability: Diagnosing temporal and spatial patterns using an integrated hydrologic model, Water Resour. Res., 50, 2600-2616, doi: 10.1002/2013WR014868.
9. Crosbie, R. S., B. R. Scanlon, F. S. Mpelasoka, R. C. Reedy, J. B. Gates, and, L. Zhang, (2013), Potential climate change effects on groundwater recharge in the High Plains Aquifer, USA, Water Resour. Res., 49, 3936-3951, doi: 10.1002/wrcr.20292.
10. de Rosnay, P., J. Polcher, K. Laval, and, M. Sabre, (2003), Integrated parameterization of irrigation in the land surface model ORCHIDEE, Validation over Indian Peninsula, Geophys. Res. Lett., 30 (19), 1986, doi: 10.1029/2003GL018024.
11. DeAngelis, A., F. Dominguez, Y. Fan, A. Robock, M. D. Kustu, and, D. Robinson, (2010), Evidence of enhanced precipitation due to irrigation over the Great Plains of the United States, J. Geophys. Res., 115, D15115, doi: 10.1029/2010JD013892.
12. Döll, P., and, S. Siebert, (2002), Global modeling of irrigation water requirements, Water Resour. Res., 38 (4), doi: 10.1029/2001WR000355.
13. Döll, P., H. Hoffman-Dobrev, F. T. Portmann, S. Siebert, A. Eicker, M. Rodell, G. Strassberg, and, B. R. Scanlon, (2012), Impact of water withdrawals from groundwater and surface water on continental water storage variations, J. Geodyn., 59-60, 143-156.
14. Döll, P., H. Müller Schmied, C. Schuh, F. T. Portmann, and, A. Eicker, (2014), Global-scale assessment of groundwater depletion and related groundwater abstractions: Combining hydrological modeling with information from well observations and GRACE satellites, Water Resour. Res., 50, 5698-5720, doi: 10.1002/2014WR015595.
15. Famiglietti, J., M. Lo, S. Ho, J. Bethune, K. Anderson, T. Syed, S. Swenson, C. de Linage, and, M. Rodell, (2011), Satellites measure recent rates of groundwater depletion in California's central valley, Geophys. Res. Lett., 38, L03403, doi: 10.1029/2010GL046442.
16. Fan, Y., G. Miguez-Macho, C. P. Weaver, R. Walko, and, A. Robock, (2007), Incorporating water table dynamics in climate modeling: 1. Water table observations and the equilibrium water table simulations, J. Geophys. Res., 112, D10125, doi: 10.1029/2006JD008111.
17. Fan, Y., H. Li, and, G. Miguez-Macho, (2013), Global patterns of groundwater table depth, Science, 339 (6122), 940-943.
18. Faunt, C. C., (Ed.) (2009), Groundwater availability of the Central Valley Aquifer, California, U.S. Geol. Surv. Prof. Pap., 1766, 173 pp.
19. Ferguson, I. M., and, R. M. Maxwell, (2012), Human impacts on terrestrial hydrology: Climate change versus pumping and irrigation, Environ. Res. Lett., 7, 044022.
20. Fetter, C. W., (1994), Applied Hydrogeology, 3rd ed., Prentice Hall, Upper Saddle River, N. J.
21. Foster, S. S. D., and, P. J. Chilton, (2003), Groundwater: The processes and global significance of aquifer degradation, Philos. Trans. R. Soc. B, 358, 1957-1972.
22. Giordano, M., (2009), Global groundwater? Issues and solutions, Annu. Rev. Environ. Resour., 34, 153-178.
23. Gleeson, T., Y. Wada, M. Bierkens, and, P. Ludovicus, (2012), Water balance of global aquifers revealed by groundwater footprint, Nature, 488, 197-200.
24. Gleick, P. H., (2003), Global freshwater resources: Soft-Path solutions for the 21st century, Science, 302 (5650), 1524-1528.
25. Gleick, P. H., and, M. Palaniappan, (2010), Peak water limits to freshwater withdrawal and use, Proc. Natl. Acad. Sci. U. S. A., 107, 11,155-11,162.
26. Gutentag, E. D., F. J. Heimes, N. C. Krothe, R. R. Luckey, and, J. B. Weeks, (1984), Geohydrology of the High Plains aquifer in parts of Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming, U.S. Geol. Surv. Prof. Pap., 1400-B, 66 pp.
27. Haddeland, I., T. Skaugen, and, D. P. Lettenmaier, (2006), Anthropogenic impacts on continental surface water fluxes, Geophys. Res. Lett., 33, L08406, doi: 10.1029/2006GL026047.
28. Hanasaki, N., S. Kanae, and, T. Oki, (2006), A reservoir operation scheme for global river routing models, J. Hydrol., 327, 22-41.
29. Hanasaki, N., S. Kanae, T. Oki, K. Masuda, K. Motoya, N. Shirakawa, Y. Shen, and, K. Tanaka, (2008), An integrated model for the assessment of global water resources-Part 1: Model description and input meteorological forcing, Hydrol. Earth Syst. Sci., 12, 1007-1025.
30. Hanasaki, N., T. Inuzuka, S. Kanae, and, T. Oki, (2010), An estimation of global virtual water flow and sources of water withdrawal for major crops and livestock products using a global hydrological model, J. Hydrol., 384, 232-244.
31. Hasumi, and, Emori, (2004), K-1 coupled model (MIROC) description, K-1 technical report, 34 pp., Cent. for Clim. Syst. Res., Univ. of Tokyo, Tokyo, Japan.
32. Hirabayashi, Y., S. Kanae, I. Struthers, and, T. Oki, (2005), A 100-year (1901-2000) global retrospective estimation of the terrestrial water cycle, J. Geophys. Res., 110, D19101, doi: 10.1029/2004JD005492.
33. Jackson, R. B., S. R. Carpenter, C. N. Dahm, D. M. McKnight, R. J. Naiman, S. L. Postel, and, S. W. Running, (2001), Water in a changing world, Ecol. Appl., 11, 1027-1045.
34. Jones, J., (2010), California's Drought of 2007-2009: An Overview, vol. 1, 116 pp., Nat. Resour. Agency, Calif. Dep. of Water Resour., Calif.
35. Kim, H., P. J.-F. Yeh, T. Oki, and, S. Kanae, (2009), Role of rivers in the seasonal variations of terrestrial water storage over global basins, Geophys. Res. Lett., 36, L17402, doi: 10.1029/2009GL039006.
36. Koirala, S., P. J.-F. Yeh, Y. Hirabayashi, S. Kanae, and, T. Oki, (2014), Global-scale land surface hydrologic modeling with the representation of water table dynamics, J. Geophys. Res. Atmos., 119, 75-89, doi: 10.1002/2013JD020398.
37. Konikow, L. F., (2011), Contribution of global groundwater depletion since 1900 to sea-level rise, Geophys. Res. Lett., 38, L17401, doi: 10.1029/2011GL048604.
38. Konikow, L. F., (2013), Groundwater depletion in the United States (1900-2008), U.S. Geol. Surv. Sci. Invest. Rep., 2013-5079, 63 p.
39. Konikow, L. F., and, E. Kendy, (2005), Groundwater depletion: A global problem, Hydrogeol. J., 13, 317-320.
40. Krakauer, N. Y., H. Li, and, Y. Fan, (2014), Groundwater flow across spatial scales: Importance for climate modeling, Environ. Res. Lett., 9, 034003.
41. Krysanova, V., D.-I. Müller-Wohlfeil, and, A. Becker, (1998), Development and test of a spatially distributed hydrological/water quality model for mesoscale watersheds, Ecol. Modell., 106, 261-289.
42. Leng, G., M. Huang, Q. Tang, W. J. Sacks, H. Lei, and, L. R. Leung, (2013), Modeling the effects of irrigation on land surface fluxes and states over the conterminous United States: Sensitivity to input data and model parameters, J. Geophys. Res. Atmos., 118, 9789-9803, doi: 10.1002/jgrd.50792.
43. Lettenmaier, D. P., and, J. S. Famiglietti, (2006), Water from on high, Nature, 444, 562-563.
44. Lo, M., and, J. Famiglietti, (2010), Effect of water table dynamics on land surface hydrologic memory, J. Geophys. Res., 115, D22118, doi: 10.1029/2010JD014191.
45. Lo, M.-H., and, J. S. Famiglietti, (2013), Irrigation in California's Central Valley strengthens the southwestern U.S. water cycle, Geophys. Res. Lett., 40, 301-306, doi: 10.1002/grl.50108.
46. Longuevergne, L., B. R. Scanlon, and, C. R. Wilson, (2010), GRACE hydrological estimates for small basins: Evaluating processing approaches on the high plains aquifer, USA, Water Resour. Res., 46, W11517, doi: 10.1029/2009WR008564.
47. Maupin, M. A., and, N. L. Barber, (2005), Estimated withdrawals from principal aquifers in the United States, 2000, U.S. Geol. Surv. Circ., 1279, 46 pp.
48. Maxwell, R. M., and, N. L. Miller, (2005), Development of a coupled land surface and groundwater model, J. Hydrometeorol., 6, 233-247.
49. McGuire, V. L., (2011), Water-level changes in the High Plains aquifer, predevelopment to 2009, 2007-08, and 2008-09, and change in water in storage, predevelopment to 2009, U.S. Geol. Surv. Sci. Invest. Rep., 2011-5089, 13 pp.
50. Miguez-Macho, G., and, Y. Fan, (2012), The role of groundwater in the Amazon water cycle: 1. Influence on seasonal streamflow, flooding and wetlands, J. Geophys. Res., 117, D15113, doi: 10.1029/2012JD017539.
51. Morris, B. L., A. R. L. Lawrence, P. J. C. Chilton, B. Adams, R. C. Calow, and, B. A. Klinck, (2003), Groundwater and Its Susceptibility to Degradation: A Global Assessment of the Problem and Options for Management, Early Warning Assess. Rep. Ser., vol. 03-3, 126 pp., U. N. Environ. Prog., Nairobi.
52. Nilsson, C., C. A. Reidy, M. Dynesius, and, C. Revenga, (2005), Fragmentation and flow regulation of the World's Large River Systems, Science, 308, 405-408.
53. Niu, G.-Y., Z.-L. Yang, R. E. Dickinson, L. E. Gulden, and, H. Su, (2007), Development of a simple groundwater model for use in climate models and evaluation with Gravity Recovery and Climate Experiment data, J. Geophys. Res., 112, D07103, doi: 10.1029/2006JD007522.
54. Oki, T., and, S. Kanae, (2006), Global hydrological cycles and world water resources, Science, 313, 1068-1072.
55. Oki, T., and, Y. Sud, (1998), Design of Total Runoff Integrating Pathways (TRIP)-A global river channel network, Earth Interact., 2, 1-37.
56. Ozdogan, M., M. Rodell, H. K. Beaudoing, and, D. L. Toll, (2010), Simulating the effects of irrigation over the United States in a land surface model based on satellite-derived agricultural data, J. Hydrometeorol., 11, 171-184.
57. Pokhrel, Y., N. Hanasaki, P. Yeh, T. Yamada, S. Kanae, and, T. Oki, (2012a), Model estimates of sea-level change due to anthropogenic impacts on terrestrial water storage, Nat. Geosci., 5, 389-392.
58. Pokhrel, Y., N. Hanasaki, S. Koirala, J. Cho, H. Kim, P. J.-F. Yeh, S. Kanae, and, T. Oki, (2012b), Incorporating anthropogenic water regulation modules into a land surface model, J. Hydrometeorol., 13, 255-269.
59. Pokhrel, Y. N., Y. Fan, G. Miguez-Macho, P. J.-F. Yeh, and, S.-C. Han, (2013), The role of groundwater in the Amazon water cycle: 3. Influence on terrestrial water storage computations and comparison with GRACE, J. Geophys. Res. Atmos., 118, 3233-3244, doi: 10.1002/jgrd.50335.
60. Postel, S., G. Daily, and, P. Ehrlich, (1996), Human appropriation of renewable fresh water, Science, 271, 785-788.
61. Postel, S. L., (1999), Pillars of Sand: Can the Irrigation Miracle Last?, W. W. Norton, N. Y.
62. Richards, L. A., (1931), Capillary conduction of liquids through porous mediums, Physics, 1, 318-333.
63. Rockström, J., et al. (2009), A safe operating space for humanity, Nature, 461, 472-475.
64. Rodell, M., and, J. S. Famiglietti, (2002), The potential for satellite-based monitoring of groundwater storage changes using GRACE: The High Plains aquifer, central U.S., J. Hydrol., 263, 245-256.
65. Rodell, M., et al. (2004), The Global Land Data Assimilation System, Bull. Am. Meteorol. Soc., 85 (3), 381-394, doi: 10.1175/BAMS-85-3-381.
66. Rodell, M., I. Velicogna, and, J. S. Famiglietti, (2009), Satellite-based estimates of groundwater depletion in India, Nature, 460, 999-1002.
67. Rosegrant, W. M., and, X. Cai, (2002), Global water demand and supply projections. Part 2: Results and prospects to 2025, Water Int., 27 (3), 170-181.
68. Rost, S., D. Gerten, A. Bondeau, W. Lucht, J. Rohwer, and, S. Schaphoff, (2008), Agricultural green and blue water consumption and its influence on the global water system, Water Resour. Res., 44, W09405, doi: 10.1029/2007WR006331.
69. Sahagian, D., F. Schwartz, and, D. Jacobs, (1994), Direct anthropogenic contributions to sea level rise in the twentieth century, Nature, 367, 54-57.
70. Scanlon, B. R., K. E. Keese, A. L. Flint, L. E. Flint, C. B. Gaye, W. M. Edmunds, and, I. Simmers, (2006), Global synthesis of groundwater recharge in semiarid and arid regions, Hydrol. Processes, 20, 3335-3370.
71. Scanlon, B. R., C. C. Faunt, L. Longuevergne, R. C. Reedy, W. M. Alley, V. L. McGuire, and, P. B. McMahon, (2012a), Groundwater depletion and sustainability of irrigation in the US High Plains and Central Valley, Proc. Natl. Acad. Sci. U. S. A., 109 (24), 9320-9325.
72. Scanlon, B. R., L. Longuevergne, and, D. Long, (2012b), Ground referencing GRACE satellite estimates of groundwater storage changes in the California Central Valley, USA, Water Resour. Res., 48, W04520, doi: 10.1029/2011WR011312.
73. Schwartz, F. W., and, M. Ibaraki, (2011), Groundwater: A resource in decline, Elements, 7, 175-179, doi: 10.2113/gselements.7.3.175.
74. Shah, T., D. Molden, R. Sakthivadivel, and, D. Seckler, (2000), Global Groundwater Situation: Opportunities and Challenges, Int. Water Manage. Inst., Colombo.
75. Shah, T., J. Burke, and, K. Villholth, (2007), Groundwater: A global assessment of scale and significance, in Water for Food, Water for Life, edited by, D. Molden, pp. 395-423, Earthscan, London, U. K.
76. Shiklomanov, I. A., (2000), Appraisal and assessment of world Water Resources, Water Int., 25, 11-32.
77. Siebert, S., P. Döll, S. Feick, J. Hoogeveen, and, K. Frenken, (2007), Global Map of Irrigation Areas Version 4.0.1, Univ. of Frankfurt (Main), Frankfurt, Germany.
78. Siebert, S., J. Burke, J. M. Faures, K. Frenken, J. Hoogeveen, P. Döll, and, F. T. Portmann, (2010), Groundwater use for irrigation-A global inventory, Hydrol. Earth Syst. Sci., 14, 1863-1880.
79. Sophocleous, M., (2002), Interactions between groundwater and surface water: The state of the science, Hydrogeol. J., 10 (1), 52-67.
80. Sorooshian, S., J. Li, K.-L. Hsu, and, X. Gao, (2011), How significant is the impact of irrigation on the local hydroclimate in California's Central Valley? Comparison of model results with ground and remote-sensing data, J. Geophys. Res., 116, D06102, doi: 10.1029/2010JD014775.
81. Stanton, J. S., S. L. Qi, D. W. Ryter, S. E. Falk, N. A. Houston, S. M. Peterson, S. M. Westenbroek, and, S. C. Christenson, (2011), Selected approaches to estimate water-budget components of the high plains, 1940 through 1949 and 2000 through 2009, U.S. Geol. Surv. Sci. Invest. Rep., 2011-5183, 79 pp.
82. Stieglitz, M., D. Rind, J. Famiglietti, and, C. Rosenzweig, (1997), An efficient approach to modeling the topographic control of surface hydrology for regional and global climate modeling, J. Clim., 10, 118-137.
83. Strassberg, G., B. Scanlon, and, D. Chambers, (2009), Evaluation of groundwater storage monitoring with the GRACE satellite: Case study of the high plains aquifer, central United States, Water Resour. Res., 45, W05410, doi: 10.1029/2008WR006892.
84. Takata, K., S. Emori, and, T. Watanabe, (2003), Development of the minimal advanced treatments of surface interaction and runoff, Global Planet. Change, 38, 209-222.
85. Tapley, B. D., S. Bettadpur, J. C. Ries, P. F. Thompson, and, M. M. Watkins, (2004), GRACE measurements of mass variability in the Earth system, Science, 305, 503-505.
86. Taylor, R. G., et al. (2013), Ground water and climate change, Nat. Clim. Change, 3 (4), 322-329.
87. van Beek, L. P. H., Y. Wada, and, M. F. P. Bierkens, (2011), Global monthly water stress: 1. Water balance and water availability, Water Resour. Res., 47, W07517, doi: 10.1029/2010WR009791.
88. Voisin, N., H. Li, D. Ward, M. Huang, M. Wigmosta, and, L. R. Leung, (2013), On an improved sub-regional water resources management representation for integration into earth system models, Hydrol. Earth Syst. Sci., 17, 3605-3622.
89. Vörösmarty, C. J., P. Green, J. Salisbury, and, R. B. Lammers, (2000), Global water resources: Vulnerability from climate change and population growth, Science, 289, 284-288.
90. Wada, Y., L. P. H. van Beek, C. M. van Kempen, J. W. T. M. Reckman, S. Vasak, and, M. F. P. Bierkens, (2010), Global depletion of groundwater resources, Geophys. Res. Lett., 37, L20402, doi: 10.1029/2010GL044571.
91. Wada, Y., L. P. H. van Beek, D. Viviroli, H. H. Dürr, R. Weingartner, and, M. F. P. Bierkens, (2011), Global monthly water stress: 2. Water demand and severity of water stress, Water Resour. Res., 47, W07518, doi: 10.1029/2010WR009792.
92. Wada, Y., L. P. H. vanBeek, F. C. Sperna Weiland, B. F. Chao, Y.-H. Wu, and, M. F. P. Bierkens, (2012), Past and future contribution of global groundwater depletion to sea-level rise, Geophys. Res. Lett., 39, L09402, doi: 10.1029/2012GL051230.
93. Wada, Y., D. Wisser, and, M. F. P. Bierkens, (2014), Global modeling of withdrawal, allocation and consumptive use of surface water and groundwater resources, Earth Syst. Dyn., 5, 15-40.
94. Watanabe, T., (1994), Bulk parameterization for a vegetated surface and its application to a simulation of nocturnal drainage flow, Boundary Layer Meteorol., 70, 13-35.
95. Watanabe, M., et al. (2010), Improved climate simulation by MIROC5: Mean states, variability, and climate sensitivity, J. Clim., 23 (23), 6312-6335.
96. Wisser, D., B. M. Fekete, C. J. Vörösmarty, and, A. H. Schumann, (2010), Reconstructing 20th century global hydrography: A contribution to the Global Terrestrial Network-Hydrology (GTN-H), Hydrol. Earth Syst. Sci., 14, 1-24.
97. Wood, E. F., et al. (2011), Hyperresolution global land surface modeling: Meeting a grand challenge for monitoring Earth's terrestrial water, Water Resour. Res., 47, W05301, doi: 10.1029/2010WR010090.
98. Yeh, P. J. F., and, E. A. B. Eltahir, (2005a), Representation of water table dynamics in a land surface scheme. Part I: Model development, J. Clim., 18, 1861-1880.
99. Yeh, P. J. F., and, E. A. B. Eltahir, (2005b), Representation of water table dynamics in a land surface scheme. Part II: Subgrid variability, J. Clim., 18, 1881-1901.
100. Yeh, P. J.-F., S. C. Swenson, J. S. Famiglietti, and, M. Rodell, (2006), Remote sensing of GW storage changes in Illinois using the Gravity Recovery and Climate Experiment (GRACE), Water Resour. Res., 42, W12203, doi: 10.1029/2006WR005374.
101. Yeh, P. J. F., and, J. S. Famiglietti, (2009), Regional groundwater evapotranspiration in Illinois, J. Hydrometeorol., 10, 464-478.
102. Yoshimura, K., S. Miyazaki, S. Kanae, and, T. Oki, (2006), Iso-MATSIRO, a land surface model that incorporates stable water isotopes, Global Planet. Change, 51 (1-2), 90-107.