||Since the 2nd half of the 20th century, anthropogenic greenhouse effect has caused the rapidest global warming trend ever in human history. The global-mean surface air temperature increased greater than 0.6℃ in the past fifty years. In this thesis research, we used a high-resolution precipitation reanalysis data, the “Asian Precipitation - Highly - Resolved Observational Data Integration Towards Evaluation” (APHRODITE，V1101) to examine changes of precipitation amount, precipitation days, trace days and dry days in Monsoon Asia over the period from 1951 to 2007. The results showed that precipitation intensity is larger over coastal areas of Asian continent and maritime continent. Precipitation day shows a significant non-homogeneous distribution in Monsoon Asia which also implies the strong non-homogeneity of precipitation intensity. Under global warming, the precipitation intensity tends to weaken in tropical equator, the precipitation amount and precipitation intensity appears to decrease in northeast China, the precipitation intensity tends to strengthen in southeast China, and the precipitation intensity appears to weaken in India.|
Examining changes in frequency of five precipitation categories showed that differences in precipitation intensity of very light and light precipitation events are largest over the study period. We also found that, no matter in which climatic zones, the very light and light precipitation events mainly contribute to changes in precipitation amount in Monsoon Asia. We also used five precipitation categories (very light, light, moderate, heavy, and very heavy) to analyze changes of precipitation amount and precipitation days. Only modest changes of precipitation amount were found over the study period in nine climate zones except for the tropical rainforest climate, subtropical monsoon climate, and temperate maritime climate zones.
Under global warming, trends of precipitation amount were all reduced in nine climate zones. Trend of precipitation amount in Tropical rainforest climate was obviously reduced among nine climate zones. Changes in precipitation frequency were found mainly on moderate and heavy precipitation events. the relative change of precipitation frequency increases in temperate maritime climate, with values around 100-300％. Conversely, the relative change of precipitation frequency decreases in Tropical rainforest climate and subtropical monsoon climate, with values around 20-80％. Next, relative changes of precipitation intensity are similar to relative changes of precipitation frequency, i.e., the relative change of intensity largely increases for heavy precipitation among all precipitation events in temperate maritime climate, and largest decrease in tropical rainforest climate. Consequently, it is expected that changes of precipitation trend and the associated non-uniform distribution for all climate regions must be related to environment factors.
For the quantitative analysis, we used the moisture budget equation to explore mechanism responsible for changes of precipitation amount in tropical rainforest climate, subtropical monsoon climate, and temperate maritime climate. The vertical moisture advection due to convection change is the main contribution effect leading to precipitation changes term in the tropical rainforest climate, subtropical monsoon climate, and temperate maritime climate. In other words, anomalous divergence and subsidence lead to reduce rainfall in tropical rainforest climate, subtropical monsoon climate, and temperate maritime climate.
In conclusion, changes of precipitation showed a non-uniform geographical distribution in Monsoon Asia, in general, disobeying the “wet-get-wetter and dry-get-drier” hypothesis. Specifically, changes in precipitation are controlled by changes in convection. As for the nine climate zones, changes of various rainfall events are not always the same in all climate zones. In the future, we will use different data to analyze how global warming impacts precipitation frequency and intensity.
||Allan, R. P., and B. J. Soden, 2007: Large discrepancy between observed and simulated precipitation trends in the ascending and descending branches of the tropical circulation. Geophys. Res. Lett., 34, L18705.|
Chen, Y.-C., 2014: Flood - Drought Variability in Monsoon Asia. Master of Science Thesis， Graduate School of Earth Science (Atmospheric Sciences Section) College of Science Chinese Culture University. 1-110.
Chou, C., and J. D. Neelin, 2004: Mechanisms of global warming impacts on regional tropical precipitation. J. Climate, 17, 2688–2701.
Chou, C., J.-Y. Tu, and P.-H. Tan, 2007: Asymmetry of tropical precipitation change under global warming. Geophys. Res. Lett., 34, L17708.
Chou, C., and C.-A. Chen, 2010: Depth of convection and the weakening of tropical circulation in global warming. J. Climate, 23, 3019–3030.
Chou, C., C.-A. Chen, P.-H. Tan, and K.-T. Chen, 2012: Mechanisms for Global Warming Impacts on Precipitation Frequency and Intensity. J. Climate, 25, 3291–3306.
Emori, S., and S. J. Brown, 2005: Dynamic and thermodynamicchanges in mean and extreme precipitation under changedclimate. Geophys. Res. Lett., 32, L17706.
Gong, D.-Y., and C.-H. Ho, 2002: Shift in the summer rainfall over the Yangtze River valley in the late 1970s. Geophys. Res. Lett., 29, 1436.
Gutowski, W.J., G. C. Hegerl, G. J. Holland, T. R. Knutson, L.O. Mearns, et al. 2008: Causes of Observed Changes in Extremes and Projections of Future Changes. In
Weather and Climate Extremes in a Changing Climate, US Climate Change Science Program SAP 3.3, T. Karl et al., Eds. pp 81-116.
IPCC, 2013: Climate Change 2013: The Physical Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T. F., D. Qin, G.-K. Plattner, M. Tignor, S. K. Allen, J.
Boschung, A. Nauels, Y. Xia, V. Bex and P. M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1535pp.
Liu, S. C., C. Fu, C.-J. Shiu, J.-P. Chen, and F. Wu, 2009: Temperature dependence of global precipitation extremes. Geophys. Res. Lett., 36, L17702.
Ma, S., Tianjun Z., A. Dai, and Z. Han, 2015: Observed Changes in the Distributions of Daily Precipitation Frequency and Amount over China from 1960 to 2013. J.
Climate, 20, 4801–4818.
McAlpine, C. A., J. Alex, S. Alvaro, S. Jozef, W. Kerrie, M. Erik, S. Leonie, D. Paul, N. Haziq, and S. Douglas, 2018: Forest loss and Borneo’s climate. Environ. Res.
Lett. 13, (2018) 044009.
Peel, M. C., B. L. Finlayson, and T. A. McMahon, 2007: Updated world map of the Koppen-Geiger climate classification. Hydrol. Earth Syst. Sci., 11, 1633–1644.
Stephens, G. L., and T. D. Ellis, 2007: Controls of Global-Mean Precipitation Increases in Global Warming GCM Experiments. J. Climate, 25, 6141–6155.
Sun, Y., S. Solomon, A. Dai, and R. W. Portmann, 2007: How Often Will It Rain? J. Climate, 20, 4801–4818.
Shiu, C.-J., S. C. Liu, C. Fu, A. Dai, and Y. Sun, 2012: How much doprecipitation extremes change in a warming climate? Geophys. Res. Lett., 39, L17707.
Trenberth, A. Dai, R. M. Rasmussen, and D. B. Parsons, 2003: The changing character of precipitation. Bull. Amer. Meteor. Soc., 84, 1205–1217.
Wentz, F. J., L. Ricciardulli, K. Hilburn, and C. Mears, 2007: How much more rain will global warming bring? Science, 13, 317, 233–235.
Watterson, I. G., and M. R. Dix, 2003: Simulated changes due toglobal warming in daily precipitation means and extremesand their interpretation using the gamma
distribution. J. Geophys Res., 108, 4379.
Zhu, J., Y. Zhang, and D. Huang, 2009: Analysis of changes in different-class precipitation over eastern China under global warming. Plateau Meteor., 28,
Zhang, X., F. W. Zwiers, G. C. Hegerl, F. H. Lambert, N. P. Gillett, S. Solomon, P. A. Stott, and T. Nozawa, 2007: Detection of human influence on twentieth-century precipitation trends. Nature, 448, 461–465.