根据西藏2607个土壤剖面资料和1：200万土壤图的数字化处理,按地区以制图单元土壤亚类为基础估算土壤有机碳密度（SOCD）和储量（SOCR）,并探讨其空间分布特征.结果表明：（1）西藏地区的SOCD平均为7.48 kg m^-2,并随土壤类型而变化,以...根据西藏2607个土壤剖面资料和1：200万土壤图的数字化处理,按地区以制图单元土壤亚类为基础估算土壤有机碳密度（SOCD）和储量（SOCR）,并探讨其空间分布特征.结果表明：（1）西藏地区的SOCD平均为7.48 kg m^-2,并随土壤类型而变化,以山地铁铝土最高（29.2 kg m^-2）,其后依次是山地淋溶土（16.6 kg m^-2）、高山草甸型土壤（12.2 kg m^-2）、山地半淋溶土（9.2kgm^-2）、高山草原型土壤（3.7kg m^-2）等,而以寒冻土（1.6kg m^-2）和高山荒漠土（1.3kg m^-2）为最低.同时土壤表层（0～20cm）的SOCD平均为4.27 kg m^-2,占全剖面总量的57﹪,反映西藏地区土壤有机碳库（SOCP）对环境变化具有较高的敏感性.（2）西藏SOCD具有独特的水平地带分布,即自藏东南向西北逐次降低,由此可大体分为高（Ⅰ）、中（Ⅱ）、低（Ⅲ）、极低（Ⅳ）4个碳密度带,其平均SOCD分别为21、10、4、＜2 kg m^-2;各带SOCD又有不同的垂直分布,总趋势是由复杂到简单,但均以最高位置的寒冻土极低碳密度为终点.（3）西藏SOCR总计为8.23 Pg,占全国SOCR总量的9.14﹪.各地SOCR分布极不平衡：就各碳密度带的SOCR相对比例（占西藏全区总量﹪）而言,Ⅰ、Ⅱ、Ⅲ、Ⅳ带分别为25﹪、50﹪、22﹪、3﹪,其中Ⅰ、Ⅱ带合计的土壤面积仅占45﹪,而SOCR却占75﹪,因而是西藏SOCP的主体;而反映土壤储碳能力的丰度指数（R）则分别为2.82、1.37、0.53、0.23.就各地区的SOCR而言,以那曲地区最大（2.19Pg）,拉萨地区最小（0.31Pg）;而R值则是林芝＞山南＞拉萨＞昌都＞日喀则＞那曲＞阿里.这些结果将为全球变化研究与区域环境评价提供有力的支撑.展开更多
For the proposed paper we report on the use of diverse digital tools for continuous student feedback collection and discuss students’ perceptions of and preferences for different approaches, with the aim of illustrat...For the proposed paper we report on the use of diverse digital tools for continuous student feedback collection and discuss students’ perceptions of and preferences for different approaches, with the aim of illustrating the influence of digital technologies on student voice. Five different digital tools have been investigated:TodaysMeet,Wiki,Padlet,Socrative, and WhatsApp. Eighty-eight non-English major freshmen from six randomly grouped classes at a Hong Kong university participated in the study. They were all enrolled in a credit-bearing course taught by one of the authors. After finishing all lectures of the course,we conducted a questionnaire survey among the participants,asking them what approach to feedback collection they felt most or least effective for communicating their feedback to teachers and classmates, which tool they felt most or least interesting, which tool they felt most or least convenient,and what advantages and disadvantages the five different digital tools have respectively. We also interviewed twenty participants to obtain further explanations of their answers to the questionnaires. The results showed that generally Padlet was regarded as the most liked and Wiki the least liked tool by the participants.Students highly valued features like effectiveness and interestingness, and considered convenience comparatively less important.展开更多
文摘根据西藏2607个土壤剖面资料和1：200万土壤图的数字化处理,按地区以制图单元土壤亚类为基础估算土壤有机碳密度（SOCD）和储量（SOCR）,并探讨其空间分布特征.结果表明：（1）西藏地区的SOCD平均为7.48 kg m^-2,并随土壤类型而变化,以山地铁铝土最高（29.2 kg m^-2）,其后依次是山地淋溶土（16.6 kg m^-2）、高山草甸型土壤（12.2 kg m^-2）、山地半淋溶土（9.2kgm^-2）、高山草原型土壤（3.7kg m^-2）等,而以寒冻土（1.6kg m^-2）和高山荒漠土（1.3kg m^-2）为最低.同时土壤表层（0～20cm）的SOCD平均为4.27 kg m^-2,占全剖面总量的57﹪,反映西藏地区土壤有机碳库（SOCP）对环境变化具有较高的敏感性.（2）西藏SOCD具有独特的水平地带分布,即自藏东南向西北逐次降低,由此可大体分为高（Ⅰ）、中（Ⅱ）、低（Ⅲ）、极低（Ⅳ）4个碳密度带,其平均SOCD分别为21、10、4、＜2 kg m^-2;各带SOCD又有不同的垂直分布,总趋势是由复杂到简单,但均以最高位置的寒冻土极低碳密度为终点.（3）西藏SOCR总计为8.23 Pg,占全国SOCR总量的9.14﹪.各地SOCR分布极不平衡：就各碳密度带的SOCR相对比例（占西藏全区总量﹪）而言,Ⅰ、Ⅱ、Ⅲ、Ⅳ带分别为25﹪、50﹪、22﹪、3﹪,其中Ⅰ、Ⅱ带合计的土壤面积仅占45﹪,而SOCR却占75﹪,因而是西藏SOCP的主体;而反映土壤储碳能力的丰度指数（R）则分别为2.82、1.37、0.53、0.23.就各地区的SOCR而言,以那曲地区最大（2.19Pg）,拉萨地区最小（0.31Pg）;而R值则是林芝＞山南＞拉萨＞昌都＞日喀则＞那曲＞阿里.这些结果将为全球变化研究与区域环境评价提供有力的支撑.
基金fully supported by a grant from the Research Grants Council of the Hong Kong Special Administrative Region,China(UGC/ FDS11/E06/14)
文摘For the proposed paper we report on the use of diverse digital tools for continuous student feedback collection and discuss students’ perceptions of and preferences for different approaches, with the aim of illustrating the influence of digital technologies on student voice. Five different digital tools have been investigated:TodaysMeet,Wiki,Padlet,Socrative, and WhatsApp. Eighty-eight non-English major freshmen from six randomly grouped classes at a Hong Kong university participated in the study. They were all enrolled in a credit-bearing course taught by one of the authors. After finishing all lectures of the course,we conducted a questionnaire survey among the participants,asking them what approach to feedback collection they felt most or least effective for communicating their feedback to teachers and classmates, which tool they felt most or least interesting, which tool they felt most or least convenient,and what advantages and disadvantages the five different digital tools have respectively. We also interviewed twenty participants to obtain further explanations of their answers to the questionnaires. The results showed that generally Padlet was regarded as the most liked and Wiki the least liked tool by the participants.Students highly valued features like effectiveness and interestingness, and considered convenience comparatively less important.
