Subjects: Geosciences >> Geography submitted time 2022-12-14 Cooperative journals: 《干旱区研究》
Abstract：
The arid regions of Central Asia, which are“upstream”of China in terms of their influence on weather and climate, are characterized by a general shortage of water resources and the fragility of ecosystems. The atmospheric water cycle is the key link in the transformation of water resources and ecosystems in this region. In this study, we reassessed the temporal and spatial variation of water cycle elements, such as atmospheric water vapor content, water vapor budget, precipitation, and actual evaporation, in the arid region and subregions of Central Asia, from 1979 to 2018. The results of our analysis show clear spatial differences in the water cycle elements of Central Asia. Precipitation and actual evaporation are high in mountainous areas, such as Tianshan Mountains and Pamir and surrounding oasis areas, and low in the desert plain areas, whereas atmospheric water vapor content shows an opposite pattern. In terms of temporal changes, from 1979 to 2018, the water vapor content in Central Asia showed a weak decreasing trend, with obvious regional differences in the rate of change. Water vapor content in the surrounding areas of the Aral Sea decreased significantly, whereas in most of the areas of the Xinjiang and Tianshan Mountains, it increased significantly. Zonal transport is the main mode of water vapor transport in Central Asia, compared with the relatively weak meridional transport. Large differences were found in the water vapor budget over different regions; the water vapor transport tended to decrease in the western and northern boundaries and increased in the eastern and southern boundaries. Water vapor revenue and expenditure showed an increasing trend in northwestern Central Asia, southern Central Asia, the Pamir Plateau, and the Tianshan Mountains and a decreasing trend in northern Central Asia and most of Xinjiang. In contrast to the change in water vapor transport, the precipitation in Central Asia increased from 1979 to 2018, with an increase of 4.14 mm·(10a)-1 and a large interannual fluctuation. The significant increasing trend of precipitation is distributed in northern Central Asia and most of the Xinjiang and Tianshan Mountains, whereas there was a significant decreasing trend in northwestern and southern Central Asia. The actual evaporation in Central Asia showed a slight increasing trend, increasing significantly in the northern part of Central Asia, the Tianshan Mountains, and Pamir but decreasing significantly in the Caspian Sea area, Aral Sea, southern Central Asia, and southern Xinjiang. In terms of seasonal variation, the temporal and spatial distribution of seasonal and annual variations of water cycle elements was generally consistent. The results of our analysis contribute to a better understanding of the evolution and mechanism of the atmospheric water cycle in the arid regions of Central Asia.
Subjects: Geosciences >> Geography submitted time 2022-09-26 Cooperative journals: 《干旱区研究》
Abstract：基于最新CRU TS V4.05格点资料，系统分析了19512020年阿富汗气候要素时空变化特征。结果表明： （ 1）阿富汗自西南向东北部分别为极端干旱、干旱、干旱-半湿润和湿润气候区，年平均气温及潜在蒸散量自西南部 锡斯坦盆地向东北部瓦罕走廊地区递减，年降水量呈递增的空间分布。（ 2）近70 a，阿富汗年及四季平均气温表现 为全区一致性地增加且西部增温率大于东部，其中春季的增温幅度最大；阿富汗降水量区域间及季节差异性大，年 降水量呈微弱减少趋势［ -0.43 mm(10a)-1 ］，空间表现为自西南向东北呈减少-增加-减少变化；降水集中的冬、春 季，降水量为减少趋势。（ 3）阿富汗潜在蒸散量大，19512020年呈显著的增加［ 5.59 mm(10a)-1 ］，而空间变化与降 水相反，中部兴都库什山年潜在蒸散量呈减少趋势；春、夏和秋季潜在蒸散量增加，冬季减少。（ 4）近70 a以来，干湿 指数（AI）表征阿富汗干湿气候变化趋势不明显，以年际变化为主；空间变化表现为阿富汗西南部极端干旱的锡斯 坦盆地干旱加剧，中部兴都库什山经历了暖湿化，而降水量最集中的瓦罕走廊地区呈暖干化；春季平均AI减小 幅度最大，加剧了阶段性干旱风险。21世纪以来，阿富汗经历了气候暖湿化的时期，气温略增加，降水量急剧增多， 而潜在蒸散量明显减小，尤以春季变化最为显著，这将对该地区农业生产、冰冻圈风险及水资源管理带来挑战。
Hits
Hits
Downloads
Comment