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基于卫星遥感数据集揭示青藏高原海拔依赖性变暖

Revisiting Recent Elevation‐Dependent Warming on the Tibetan Plateau Using Satellite‐Based Data Sets

[2019-09-04]


【中文介绍】


气候变暖海拔依赖性指海拔越高变暖率越大。由于青藏高原固态水资源主要分布在海拔相对更高的地区,因此气候变暖海拔依赖性可能会加速这些固态水消融,对其可持续供给具有重要影响。卫星数据因其高分辨率和广泛的区域覆盖,在研究观测资料稀缺的高山区海拔依赖性变暖方面具有一定优势。以前相关研究主要基于卫星地表温度数据,且研究时期较短。


竺南中心(郭东林、孙建奇)、清华大学(阳坤)、朴次茅斯大学(Nick Pepin)、南京信息工程大学(徐永明)研究人员,利用多种卫星数据集(2m气温、地表温度、雪盖、白天和夜间的云量),对20012015年青藏高原海拔依赖性变暖进行了综合研究。


结果显示,在20004500m阶段,2m气温变暖率随海拔增加而增大,但在海拔高于4500m后,变暖率随海拔增加而减小。这不同于以前基于地表温度的研究结果。4500m以上变暖率的减小,意味着青藏高原83%固态水资源(按面积计算的冰川,积雪和多年冻土)的消融可能没有想象中的快。进一步揭示,夜间云量和积雪与青藏高原海拔依赖性显著相关,但年平均和四季的主导因子有所不同。


这些结果可为认识高山区海拔依赖性及其机理提供了重要依据。相关成果在JGR: Atmos.期刊发表。



【英文介绍】


 Satellite data, characterized by extensive regional coverage and relatively high spatial resolution, have a distinct advantage for examining elevation‐dependent warming (EDW) across rugged topography in mountain regions where there are sparse in situ observations. Based on recent (2001–2015) comprehensive satellite‐based data sets (2 m air temperature, land surface temperature, snow cover, and daytime and nighttime cloud), this study finds that annual mean 2 m air temperature warming rates show rapid decrease above 4,500 m despite increasing from 2,000 to 4,500 m. This indicates a reversal in EDW at the highest elevations on the Tibetan Plateau, which is somehow different from the EDW derived from short‐term land surface temperature presented in earlier research. The decrease of warming rate above 4,500 m coincides with the elevation at which most of the current solid water resources reside. Thus, their decline may be less rapid than previously thought. Trends in nighttime cloud and snow cover are both correlated with patterns of EDW on the Tibetan Plateau, but the leading factor varies on an annual and seasonal basis. These results provide important evidence for understanding EDW and its controlling mechanisms in an extreme high‐elevation context.



【关键图表】

 


    4. 年平均气象站2m气温(黄色)和卫星2m气温(青色)趋势(20012015),以及固体水资源(冰川、积雪、多年冻土)面积百分比随海拔的变化。趋势为每个海拔区间的平均值。右侧y轴的百分比计算如下:海拔区间内水资源面积÷整个高原(20008000m)水资源面积×100%。图顶部的数字为对应海拔区间的卫星象元总数。误差为95%信度区间。

Figure 4. Change of annual mean weather station 2 m air temperature (yellow bar) and satellitebased 2 m air temperature (cyan bar) trends for 2001 to 2015 compared with the elevation distribution of solid water resources (glacial extent, snow, and permafrost areas). Trends are mean values over individual elevation bins. Percentages (right axis) are calculated as (water resource area in individual elevation bin)/(water resource area over the whole Tibetan Plateau: 2,0008,000 m) × 100%. The number on the top of the figure is the number of satellite pixels in the corresponding elevation bin. Blue error bars are based on 95% confidence intervals around the mean.



【引用格式】

         

         Guo Donglin, Sun Jianqi, Yang Kun, Pepin Nick, Xu Yongming, 2019: Revisiting recent elevation‐dependent warming on the Tibetan Plateau using satellite‐based data sets. Journal of Geophysical Research: Atmospheres, 124, 8511–8521.











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