ADGEO Advances in Geosciences ADGEO Adv. Geosci. 1680-7359 Copernicus Publications Göttingen, Germany 10.5194/adgeo-31-57-2012 Assessment of data uncertainty and plausibility over the Nam Co Region, Tibet Biskop S. 1 Krause P. 1 Helmschrot J. 1 2 Fink M. 1 Flügel W.-A. 1 Department for Geoinformatics, Hydrology and Modelling, Friedrich-Schiller-University, Jena, Germany Department of Civil and Environmental Engineering, University of Washington, Seattle, USA 27 07 2012 31 57 65 Copyright: © 2012 S. Biskop et al. 2012 This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/ This article is available from https://adgeo.copernicus.org/articles/31/57/2012/adgeo-31-57-2012.html The full text article is available as a PDF file from https://adgeo.copernicus.org/articles/31/57/2012/adgeo-31-57-2012.pdf

One of the major challenges for water balance studies in the remote and mostly ungauged region of the Tibetan Plateau is the lack of suitable and reliable climate data to drive hydrological models. Ground observations are rare in the high-mountainous region of the Nam Co basin and only global and regional gridded climate products are available as model input data, but these data sets need to be carefully analysed if used as driving force for hydrological modelling. In this study, various global and regional gridded data products for temperature and precipitation were compared to assess spatio-temporal deviations between several data sets. For the comparison absolute and relative differences of annual and seasonal long-term means were calculated. Climatic trends were analysed by using the non-parametric Mann-Kendall trend test. In addition, gridded climate data sets were compared to meteorological observations in order to evaluate their plausibility. The comparative statistical analysis showed significant differences in the magnitude, the seasonality, the spatial pattern and the trend behaviour of the analysed climate variables, in particular for precipitation data. The identified inconsistencies underpin the necessity to quantify the uncertainty of such climate data. Moreover, the presented study highlights the importance of further research efforts to develop regional climate data sets with finer resolutions to reduce the model's uncertainty resulting from climate input data. Such higher resolution is needed for a sufficient representation of regional topographic and orographic effects in order to simulate important hydrological processes in mountainous areas like snow accumulation and melting.

 References Bian, D., Bianba, C., Li, L., Wang, W., and Zhaxi, Y.: The response of lake change to climate fluctuation in north Qinghai-Tibet Plateau in last 30 years, J. Geogr. Sciences, 19, 131–142, 2009. Burn, D. H. and Elnur, M. A. H.: Detection of hydrologic trends and variability, J. Hydrol., 255, 107–122, 2002. Chinese Acadamy of Sciences (CAS): Scientific working group on the Qinghai-Tibet Plateau: The climate of Xizang. The series of the scientific expedition to the Qinghai-Xizang Plateau, Beijing, 304pp., 1984. Ding, Y., Liu, S., Ye, B., and Zhao, L.: Climatic implications on variations of lakes in the cold and arid regions of China during the recent 50 years, Journal of Glaciology and Geocryology, 28(5), 623–632, 2006. Dobler, A., Yaoming, M., Sharma, N., Kienberger, S., and Ahrens, B.: Regional climate projections in two alpine river basins: Upper Danube and Upper Brahmaputra, Adv. Sci. Res., 7, 11–20, https://doi.org/10.5194/asr-7-11-2011, 2011. Eriksson, M., Xu, J., Shrestha, A., Vaidya, R. S. N., and Sandstrom, K.: The changing Himalayas: impact of climate change on water resources and livelihoods in the greater Himalayas, ICIMOD, Kathmandu, 2009. Fekete, M. and Vörösmarty, C. J.: Uncertainties in precipitation and their impacts on runoff estimates, J. Climate, 17, 294–304, 2003. Hipel, K. W. and McLeod, A. I: Time series modelling of water resources and environmental systems, Amsterdam, Netherlands, 2005. Huffman, G. J., Adler, R. F., Bolvin, D. T., Gu, G., Nelkin, E. J., Bowman, K .P., Hong, Y., Stocker, E. F., and Wolff, D. B.: The TRMM multi-satellite precipitation analysis: Quasi-global, multi-year, combined-sensor precipitation estimates at fine scale, J. Hydrometeor., 8(1), 38–55, 2007. Gourley, J. J. and Vieux, B. E.: A method for identifying sources of model uncertainty in rainfall-runoff simulations, J. Hydrol., 327, 68–80, 2006. Kang, S., Xu, Y., You, Q., Flügel, W.-A., Pepin, N., and Yao, T.: Review of climate and cryospheric change in the Tibetan Plateau, Environ. Res. Lett., 5, 015101 (8pp.), 2010. Kendall, M. G.: Rank correlation measures, Charles Griffin, London, UK, 1975. Krause, P., Biskop, S., Helmschrot, J., Flügel, W.-A., Kang, S., and Gao, T.: Hydrological system analysis and modelling of the Nam Co basin in Tibet, Adv. Geosci., 27, 29–36, https://doi.org/10.5194/adgeo-27-29-2010, 2010. Kropacek, J., Braun, A., Kang, S., Feng, C., Ye, Q., and Hochschild, V.: Analysis of lake level changes of Nam Co in Central Tibet by synergy of satellite altimetry and evaluation of optical satellite imagery, Int. J. Appl. Earth Obs. Geoinf., 17, 3–11, 2012. Leber, D., Holawe, F., and Häusler, H.: Climatic classification of the Tibet Autonomous Region using multivariate statistical methods, GeoJournal, 37, 4, 451–473, 1995. Liu, J., Kang, S., Gong, T., and Lu, A.: Growth of a high-elevation large inland lake, associated with climate change and permafrost degradation in Tibet, Hydrol. Earth Syst. Sci., 14, 481–489, https://doi.org/10.5194/hess-14-481-2010, 2010. Lu, A., Yao, T., Wang, L., Liu, S., and Guo, Z.: Study on the fluctuations of typical glaciers and lakes in the Tibetan Plateau using remote sensing (in Chinese), J. Glaciol. Geocryol., 6, 783–792, 2005. Mann, H. B.: Non-parametric tests against trend, Econometrica, 13, 245–259, 1945. Marke, T.: Development and Application of a Model Interface to couple Regional Climate Models with Land Surface Models for Climate Change Risk Assessment in the Upper Danube Watershed, Dissertation LMU München, available at: http://edoc.ub.uni-muenchen.de/9162/, München, 2008. Maussion, F., Scherer, D., Finkelnburg, R., Richters, J., Yang, W., and Yao, T.: WRF simulation of a precipitation event over the Tibetan Plateau, China – an assessment using remote sensing and ground observations, Hydrol. Earth Syst. Sci., 15, 1795–1817, https://doi.org/10.5194/hess-15-1795-2011, 2011. Mitchell, T. D. and Jones, P. D.: An improved method of constructing a database of monthly climate observations and associated high-resolution grids, Int. J. Climatol., 25, 693–712, 2005. Prasch, M., Marke, T., Strasser, U., and Mauser, W.: Large scale integrated hydrological modelling of the impact of climate change on the water balance with DANUBIA, Adv. Sci. Res., 7, 61–70, https://doi.org/10.5194/asr-7-61-2011, 2011. Wu, Y. and Zhu, L.: The response of lake-glacier variations to climate change in Nam Co catchment, central Tibetan Plateau, during 1970–2000, J. Geogr. Sci., 18, 177–189, 2008. Yao, T., Li, Z., Yang, W., Guo, X. Zhu, L., Kang, S., Wu, Y., and Yu, W.: Glacier distribution and mass balance in the Yarlung Zangbo River and its influence on lakes, Chinese Science Bulletin, 55(20), 2072–2078, 2010. Yatagai, A. O., Arakawa, K. ,Kamiguchi, H., Kawamoto, Nodzu, M. I., and Hamada, A.: A 44-year daily gridded precipitation dataset for Asia based on a dense network of rain gauges, SOLA, 5, 137–140, 2009. Ye, Q., Yao, T., and Chen, F.: Response of glacier and lake covariations to climate change in Mapam Yumco basin on Tibetan Plateau during 1974–2003, Journal of China University of Geosciences, 19(2), 135–145, 2008. Zhu, L., Xie, M., and Wu, Y.: Quantitative analysis of lake area variations and the influence factors from 1971 to 2004 in the Nam Co basin of the Tibetan Plateau, Chinese Science Bulletin, 55(13), 1294–1303, 2010.