| 1 | Discussion on wind factor influencing the distribution of biological soil crusts on surface of sand dunes显示文摘Biological soil crusts are widely distributed in arid and semi-arid regions,whose formation and development have an important impact on the restoration process of the desert ecosystem.In order to explore the relationship between surface airflow and development characteristics of biological soil crusts,we studied surface airflow pattern and development characteristics of biological soil crusts on the fixed dune profile through field observation.Results indicate that the speed of near-surface airflow is the lowest at the foot of windward slope and the highest at the crest,showing an increasing trend from the foot to the crest.At the leeward side,although near-surface airflow increases slightly at the lower part of the slope after an initial sudden decrease at upper part of the slope,its overall trend decreases from the crest.Wind velocity variation coefficient varied at different heights over each observation site.The thickness,shear strength of biological soil crusts and percentage of fine particles at crusts layer decreased from the slope foot to the upper part,showing that biological soil crusts are less developed in high wind speed areas and well developed in low wind speed areas.It can be seen that there is a close relationship between the distribution of biological soil crusts in different parts of the dunes and changes in airflow due to geomorphologic variation. | YongSheng Wu Hasi Erdun RuiPing Yin Xin Zhang Jie Ren Jian Wang XiuMin Tian ZeKun Li HengLu Miao | 2013 | Research in Cold and Arid Regions2013，5，6： | 0 |
| 2 | Responses of vegetation yield to precipitation and reference evapotranspiration in a desert steppe in Inner Mongolia,China显示文摘Drought,which restricts the sustainable development of agriculture,ecological health,and social economy,is affected by a variety of factors.It is widely accepted that a single variable cannot fully reflect the characteristics of drought events.Studying precipitation,reference evapotranspiration(ET_(0)),and vegetation yield can derive information to help conserve water resources in grassland ecosystems in arid and semi-arid regions.In this study,the interactions of precipitation,ET_(0),and vegetation yield in Darhan Muminggan Joint Banner(DMJB),a desert steppe in Inner Mongolia Autonomous Region,China were explored using two-dimensional(2D)and three-dimensional(3D)joint distribution models.Three types of Copula functions were applied to quantitatively analyze the joint distribution probability of different combinations of precipitation,ET_(0),and vegetation yield.For the precipitation–ET_(0)dry–wet type,the 2D joint distribution probability with precipitation≤245.69 mm/a or ET_(0)≥959.20 mm/a in DMJB was approximately 0.60,while the joint distribution probability with precipitation≤245.69 mm/a and ET_(0)≥959.20 mm/a was approximately 0.20.Correspondingly,the joint return period that at least one of the two events(precipitation was dry or ET_(0)was wet)occurred was 2 a,and the co-occurrence return period that both events(precipitation was dry and ET_(0)was wet)occurred was 5 a.Under this condition,the interval between dry and wet events would be short,the water supply and demand were unbalanced,and the water demand of vegetation would not be met.In addition,when precipitation remained stable and ET_(0)increased,the 3D joint distribution probability that vegetation yield would decrease due to water shortage in the precipitation–ET_(0)dry–wet years could reach up to 0.60–0.70.In future work,irrigation activities and water allocation criteria need to be implemented to increase vegetation yield and the safety of water resources in the desert steppe of Inner Mongolia. | LI Hongfang WANG Jian LIU Hu MIAO Henglu LIU Jianfeng | 2023 | Journal of Arid Land2023，15，4： | 0 |
您所在的机构暂未开通此部分的功能，请联系管理员