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Changes of Seasonally Frozen Ground from 1967 to 1997 in Qinghai-Tibetan Plateau

Changes of Seasonally Frozen Ground from 1967 to 1997 in Qinghai-Tibetan Plateau. Lin Zhao Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences. Contents. Introduction Data Sources and Methods

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Changes of Seasonally Frozen Ground from 1967 to 1997 in Qinghai-Tibetan Plateau

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  1. Changes of Seasonally Frozen Ground from 1967 to 1997 in Qinghai-Tibetan Plateau Lin Zhao Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences

  2. Contents • Introduction • Data Sources and Methods • Climate and SFG Thickness Changes in Different Regions • Changes of freezing duration • Changes of ground surface temperatures

  3. INTRODUCTION • Study area • SFG distribution • Climate warming

  4. Permafrost Map of Tibetan Plateau

  5. AT Fluctuation in QTP and Northern Hemisphere in 20th Century QTP (Liu, et al., 1998) Northern Hemisphere (Jones and Briffa, 1992)

  6. DATA SOURCES AND METHODS • Data selection • Data used: AT, Precipitation, SFG thickness, GST • Stations selection • Data processing • Missing data • Data standardizing • Different unit, value and changing amplitude • Hierarchical Cluster Analysis

  7. DATA SOURCES AND METHODS • Missing data • Temperatures • Freezing depths • Freezing duration

  8. Meteorological Stations in QTP

  9. Climate and SFG Thickness Changes in Different Regions • To identify the differences of SFG changes in different geographic regions • Criterion used for cluster classification • Geo-location: Latitude, Longitude, elevation • Main climatic factors: MAAT and MAP

  10. Elevation: 1500~3500 m MAAT: 0.8~8˚C (mean: 4.1) AP: 16~360 mm (mean: 194) MAWAT:-0.5~-7.2 ˚C (mean: -4.2) SFG: 80~220 cm (mean: 127.8) Distribution of Different Clusters Classified based on Location and Main Climatic Factors Elevation: 800~1500 m MAAT: 10~12˚C (mean: 11.4) AP: 20~60 mm (mean: 38) MAWAT:-2~3.0 ˚C (mean: 1.5) SFG: 40~75 cm (mean: 55.7) Elevation: 2700~4300 m MAAT: -0.4~8.6˚C (mean: 3.8) AP: 270~900 mm (mean: 540) MAWAT:-7.2~4 ˚C (mean: -1.9) SFG: 8~130 cm (mean: 64.7) Elevation: 3900~4800 m MAAT: 0.3~-3˚C (mean: -1.2) AP: 430~550 mm (mean: 481) MAWAT:-6.2~-9.8 ˚C (mean: -8) SFG: 170~330 cm (mean: 232)

  11. Relationship between SFG thickness and MAWAT

  12. Changes of freezing beginning, ending dates and SFG duration

  13. Changes of ground surface temperatures

  14. Changes of ground surface temperatures

  15. QUESTIONS? THANKS!

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