| 1979—2100年青藏高原夏季大气0 ℃层高度变化分析 |
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| 引用本文： | 张怡,段克勤,石培宏.1979—2100年青藏高原夏季大气0 ℃层高度变化分析[J].冰川冻土,2022,44(1):34-45. |
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| 作者姓名： | 张怡 段克勤 石培宏 |
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| 作者单位： | 陕西师范大学 地理科学与旅游学院，陕西 西安 710119 |
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| 基金项目： | 国家自然科学基金项目（41571062）；;中国博士后基金项目（2017M610622）资助； |
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| 摘 要： | 大气0 ℃层高度是决定青藏高原冰冻圈消融状态的重要指标。基于ERA5再分析资料，分析了1979—2019年青藏高原夏季大气0 ℃层高度时空变化，发现青藏高原夏季大气0 ℃层高度介于4 423~5 972 m之间，以高原中南部（30°~32° N，83.5°~88.5° E）为高值中心，呈纬向分带状向四周逐渐降低。过去41 a青藏高原夏季大气0 ℃层高度总体呈持续上升趋势，高原北部上升趋势大于南部，祁连山地区上升趋势最为明显，为60 m?（10a）-1，而在高原西南部略呈下降趋势。平均而言，青藏高原夏季地面温度每升高1 ℃，大气0 ℃层高度升高122 m。利用CMIP6模式数据，预估在SSP1-2.6、SSP2-4.5、SSP3-7.0和SSP5-8.5四种社会共享路径情景下，2020—2100年期间青藏高原夏季大气0 ℃层高度都呈现升高趋势，但不同情景下升高趋势在空间上差别较大。相对于1979—2014年参考时段，在四种情景下，到2081—2100年青藏高原夏季平均大气0 ℃层高度将分别升高265 m、394 m、576 m 和729 m；相对应的是到2081—2100年，在高原上处于夏季大气0 ℃层高度以下的冰川面积分别为第二次冰川编目数据的79%、86%、94%和98%。仅从夏季大气0 ℃层高度变化角度看，在SSP5-8.5情景下，到本世纪末期，预估除帕米尔高原和昆仑山西北部地区外，青藏高原其他地区的冰川在夏季将不存在积累区。
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| 关 键 词： | 青藏高原 大气0 ℃层高度 ERA5 CMIP6 |
| 收稿时间： | 2021-03-30 |
| 修稿时间： | 2021-12-10 |
Analysis of the 0℃level height variation over the Qinghai-Tibet Plateau in summer from 1979 to 2100 |
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| ZHANG Yi,DUAN Keqin,SHI Peihong.Analysis of the 0℃level height variation over the Qinghai-Tibet Plateau in summer from 1979 to 2100[J].Journal of Glaciology and Geocryology,2022,44(1):34-45. |
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| Authors: | ZHANG Yi DUAN Keqin SHI Peihong |
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| Institution: | School of Geography and Tourism，Shaanxi Normal University，Xi’an 710119，China |
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| Abstract: | As an Asian water tower， the Qinghai-Tibet Plateau is extremely sensitive to global warming due to its unique cryosphere landform. At present， due to the warming of the plateau， a series of ecological and environmental problems have been caused， such as glacier retreat， frozen soil melting and so on. In recent years， the near-surface air temperature of the Qinghai-Tibet Plateau has been increasing at the rate of 0.3~0.4 ℃ （10a）-1， which is twice the global average. The near-surface air temperature increase will affect the upper atmospheric temperature in the form of long wave radiation. An important indicator of the change of upper air temperature is the 0 ℃ level height. As the lowest height of free air temperature of 0 ℃， the 0 ℃ level height is also an important indicator of global change. The height of atmospheric 0 ℃ layer determines the height of water vapor phase transition in the air. If the 0 ℃ level height is higher than the surface， the cryosphere on the surface is in a state of melting， otherwise it is in a state of freezing. Therefore， the 0 ℃ level height directly determines the state of melting of the cryosphere on the surface of the plateau. Therefore， quantifying the change of the 0 ℃ level height over the Qinghai-Tibet Plateau is very important for understanding the climate change of the plateau and the change state of the cryosphere. Based on ERA5 reanalysis data， the temporal and spatial variation of the 0 ℃ level height in summer over the Qinghai-Tibet Plateau from 1979 to 2019 is analyzed. It is found that the 0 ℃ level height in summer over the Qinghai-Tibet Plateau ranges from 4 423 to 5 972 m， with the central and southern part of the Plateau （30~32° N， 83.5~88.5° E） as the high value center， and gradually decreases in zonal direction. In the past 41 years， the 0 ℃ level height in summer over the Qinghai-Tibet Plateau has been increasing continuously. The increasing trend in the north of the plateau is greater than that in the south. The increasing trend in the Qilian Mountains is the most obvious， which is 60 m?（10a）-1， while it is slightly decreasing in the southwest of the plateau. On average， the 0 ℃ level height increases by 122 m for every 1 ℃ rise in summer near-surface air temperature over the Qinghai-Tibet Plateau. Using CMIP6 model data， it is estimated that the 0 ℃ level height in summer over the Qinghai-Tibet Plateau will increase during 2020—2100 under SSP1-2.6， SSP2-4.5， SSP3-7.0 and SSP5-8.5 social shared path scenarios， but the increasing trend under different scenarios is quite different in space. Compared with the reference period of 1979—2014， under the four scenarios， the summer mean the 0 ℃ level height of the Qinghai-Tibet Plateau will increase by 265 m， 394 m， 576 m and 729 m respectively in 2081—2100； Correspondingly， from 2081 to 2100， the area of glaciers below 0 ℃ in summer on the plateau is 79%， 86%， 94% and 98% of the second glacial catalogue data， respectively. Only from the perspective of the 0 ℃ level height change in summer， it is estimated that the accumulation area of glaciers in the Qinghai-Tibet Plateau will disappear in summer under SSP5-8.5 scenario until the end of this century， except for the Pamir Plateau and the northern Kunlun Mountains. |
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| Keywords: | Qinghai-Tibet Plateau the 0 ℃ level height ERA5 CMIP6 |
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