Knowledge of soil respiration and the influencing factors in desert ecosystems is essential to understanding carbon dynamics and responses of biotic and abiotic processes in soils to climate change. In this study, soi...Knowledge of soil respiration and the influencing factors in desert ecosystems is essential to understanding carbon dynamics and responses of biotic and abiotic processes in soils to climate change. In this study, soil respiration rate（R_s） for three land-cover types（shifting sandy land, sandy land with straw checkerboard barriers, and shelter forest land） in the hinterland of the Taklimakan Desert was measured in May 2015 using an automated soil CO_2 flux system. The effects of soil temperature（T_s） and soil water content（W_s） on R_s were also analyzed. The results showed that R_s values in shifting sandy land, sandy land with straw checkerboard barriers, and shelter forest land were all low and exhibited obvious diurnal fluctuations. The establishment of straw checkerboard barriers in sandy land had no significant effect on R_s, while the establishment of shelterbelts significantly increased R_s. Shifting sandy land and sandy land with straw checkerboard barriers were carbon sinks at night and early morning and were carbon sources in the daytime, while shelter forest land always acted as a carbon source during the whole day. The synergistic effect of T_s and W_s could better explain the diurnal dynamics in R_s than single factor. In shifting sandy land and sandy land with straw checkerboard barriers, W_s was identified as a limiting factor influencing the diurnal dynamics of R_s. Furthermore, a relatively strong hysteresis loop existed between R_s and T_s. In contrast, in shelter forest land, R_s was significantly influenced by T_s, and a relatively weaker hysteresis loop existed between R_s and W_s.展开更多
known aridity of the region is a major factor in promoting numerous dust storms. They have many diverse impacts on the environment and the climate of the region. The classification of dust storms and synoptic conditio...known aridity of the region is a major factor in promoting numerous dust storms. They have many diverse impacts on the environment and the climate of the region. The classification of dust storms and synoptic conditions related to their formation in Central Asia are discussed in the content of their diverse impact. We address dust optical properties that are representative of the region. Dust storms significantly reduce visibly and pose a human health threads. They also cause a significant impact on the radiative regime. As a result, dust storms may cause a decrease in temperature during daytime of up to 16℃ and an increase in temperature during night time from up to 7℃ compared to a clear day.展开更多
基金funded by the National Natural Science Foundation of China(41175140)the National Department of Public Benefit(Meteorology)Research Foundation(GYHY201306066)
文摘Knowledge of soil respiration and the influencing factors in desert ecosystems is essential to understanding carbon dynamics and responses of biotic and abiotic processes in soils to climate change. In this study, soil respiration rate（R_s） for three land-cover types（shifting sandy land, sandy land with straw checkerboard barriers, and shelter forest land） in the hinterland of the Taklimakan Desert was measured in May 2015 using an automated soil CO_2 flux system. The effects of soil temperature（T_s） and soil water content（W_s） on R_s were also analyzed. The results showed that R_s values in shifting sandy land, sandy land with straw checkerboard barriers, and shelter forest land were all low and exhibited obvious diurnal fluctuations. The establishment of straw checkerboard barriers in sandy land had no significant effect on R_s, while the establishment of shelterbelts significantly increased R_s. Shifting sandy land and sandy land with straw checkerboard barriers were carbon sinks at night and early morning and were carbon sources in the daytime, while shelter forest land always acted as a carbon source during the whole day. The synergistic effect of T_s and W_s could better explain the diurnal dynamics in R_s than single factor. In shifting sandy land and sandy land with straw checkerboard barriers, W_s was identified as a limiting factor influencing the diurnal dynamics of R_s. Furthermore, a relatively strong hysteresis loop existed between R_s and T_s. In contrast, in shelter forest land, R_s was significantly influenced by T_s, and a relatively weaker hysteresis loop existed between R_s and W_s.
文摘known aridity of the region is a major factor in promoting numerous dust storms. They have many diverse impacts on the environment and the climate of the region. The classification of dust storms and synoptic conditions related to their formation in Central Asia are discussed in the content of their diverse impact. We address dust optical properties that are representative of the region. Dust storms significantly reduce visibly and pose a human health threads. They also cause a significant impact on the radiative regime. As a result, dust storms may cause a decrease in temperature during daytime of up to 16℃ and an increase in temperature during night time from up to 7℃ compared to a clear day.
