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创新驱动发展提高气象灾害防御能力——第30届中国气象...

作者： Shuyun Zhao Hua Zhang Song Feng Qiang Fu Chinese Academy of Meteorological Sciences Laboratory for Climate Studies National Climate Center China Meteorological Administration Department of Geosciences University of Arkansas Department of Atmospheric Sciences University of Washington

This work uses an aerosol-climate coupled system to study the direct climatic effects of dust aerosol on global arid （including hyper-arid） and semi-arid regions. Results show that dust aerosol can cause surface cooling over these regions. The cooling effects of dust aerosol are larger in the Northern Hemisphere （NH） than the Southern Hemisphere （SH）. This asymmetric cooling forces a thermal meridional circulation between 30°S and 30°N, with air descending （ascending） in the NH （SH）, leading to a decrease （increase） in precipitation over the arid and semi-arid regions over the NH （SH）. Dust aerosol can decrease the potential evapotranspiration in arid and semi-arid regions mainly by decreasing the net radiation flux at the top of the atmosphere, which compensates for the decrease in precipitation caused by dust aerosol. Therefore, as the dominant aerosol in the arid and semi-arid regions, dust aerosol does not exacerbate the aridity over most of these regions. The effects of dust aerosol are indiscernible in the expansion of arid and semi-arid areas on a global scale.

关键词： dust aerosol arid and semi-arid AGCM

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Effects of vegetation near-soil-surface factors on runoff and sediment reduction in typical grasslands on the Loess Plateau,China

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Journal of arid Land 2022年第3期14卷 325-340页

作者： LI Panpan WANG Bing YANG Yanfen LIU Guobin State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationNorthwest A&F UniversityYangling 712100China State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau Institute of Soil and Water ConservationChinese Academy of Sciences and Ministry of Water ResourcesYangling 712100China

Vegetation near-soil-surface factors can protect topsoil from erosion,however,their contributions to the reduction of soil erosion,especially under natural rainfall events,have not been systematically recognized.This study was performed to quantify the effects of near-soil-surface factors on runoff and sediment under natural rainfall events on grasslands dominated by Bothriochloa ischaemum(Linn.)Keng(BI grassland)and Artemisia gmelinii Thunb.(AG grassland)in two typical watersheds on the Loess Plateau,China in 2018.By successive removal of the plant canopy,litter,biological soil crusts(BSCs)and plant roots,we established five treatments including plant roots,plant roots+BSCs,plant roots+BSCs+litter,intact grassland and bare land in each grassland type.In total,twenty runoff plots(5 m×3 m)with similar slopes and aspects were constructed in the two types of grasslands.Results showed that plant canopy,litter and roots reduced runoff,while BSCs,which swelled in the presence of water,increased runoff.In contrast,all of these factors reduced sediment yield.In addition,the reductions in runoff and sediment yield increased with I30(maximum 30-min rainfall intensity)for each vegetation near-soil-surface factor except for BSCs.Among these factors,plant canopy had the largest contribution to runoff reduction,accounting for 48.8% and 39.9% in the BI and AG grasslands,respectively.The contributions of these vegetation near-soil-surface factors to sediment yield reduction were similar(21.3%-29.9%)in the two types of grasslands except for BSCs in the AG grassland(10.3%).The total reduction in runoff in the BI grassland(70.8%)was greater than that in the AG grassland(53.1%),while the reduction in sediment yield was almost the same in both grasslands(97.4%and 96.7%).In conclusion,according to the effects of different vegetation near-soil-surface factors on runoff and sediment production,our results may provide more complete insight and scientific basis into the effects of various vegetation related factors in controlling soil ero

关键词： vegetation near-soil-surface factor grassland arid and semi-arid soil erosion Loess Plateau

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