潜热通量产品的验证与分析对于研究气候变化及能量循环具有重要意义。全球陆表高分辨率蒸散产品(high resolution global lAnd surface evapotranspiration product,Hi-GLASS ET)融合了5种传统蒸散算法,能够生产出较高精度的陆表潜热通...潜热通量产品的验证与分析对于研究气候变化及能量循环具有重要意义。全球陆表高分辨率蒸散产品(high resolution global lAnd surface evapotranspiration product,Hi-GLASS ET)融合了5种传统蒸散算法,能够生产出较高精度的陆表潜热通量产品,但目前没有针对此产品的验证研究。利用Ameriflux通量观测站点的潜热通量观测值与相应的Hi-GLASS陆表潜热通量产品估算值进行对比,获取多组有效验证数据。验证结果显示,所选站点实际观测值与产品估算值的决定系数(R 2)为0.6,均方根误差(RMSE)为34.4 W/m^(2),平均偏差(Bias)为-13.4 W/m^(2),克林-古普塔效率(Kling-Gupta efficiency,KGE)为0.49,Hi-GLASS潜热通量产品具有较高的精度,算法的拟合结果较好;此外,空间分布也表明Hi-GLASS陆表潜热通量产品符合正常的自然规律。由于数据获取的局限性,仅采用了美国地区18个站点数据对产品进行验证,在其他地区仍需进一步验证。展开更多
As a key parameter for indicating the fraction of surface-reflected solar incident radiation, land surface albedo plays an important role in the Earth’s surface energy budget(SEB). Since the Sanjiang Plain has been s...As a key parameter for indicating the fraction of surface-reflected solar incident radiation, land surface albedo plays an important role in the Earth’s surface energy budget(SEB). Since the Sanjiang Plain has been severely affected by human activities(e.g., reclamation and shrinking of wetlands), it is important to assess the spatiotemporal variations of surface albedo in this region using a long-term remote sensing dataset. In order to investigate the surface albedo climatology, trends, and mechanisms of change, we evaluated the surface albedo variations in the Sanjiang Plain, China from 1982 to 2015 using the Global LAnd Surface Satellite(GLASS) broadband surface albedo product. The results showed that: 1) an increasing annual trend(+0.000 58/yr) of surface albedo was discovered in the Sanjiang Plain based on the GLASS albedo dataset, with a much stronger increasing trend(+0.001 26/yr) occurring during the winter. Most of the increasing trends occurred over the cultivated land, unused land, and land use conversion types located in the northeastern Sanjiang Plain. 2) The increasing trend of land surface albedo in Sanjiang Plain can be largely explained by the changes of both snow cover extent and land use. The surface albedo in winter is highly correlated with the snow cover extent in the Sanjiang Plain, and the increasing trend of surface albedo can be further enhanced by the land use changes.展开更多
长期以来,对新疆营盘和扎滚鲁克墓地发现的3件磨面纹玻璃杯的产地的认识以罗马或萨珊为主,本文即尝试对它们的来源进行重新考察。对罗马和萨珊的典型磨面纹玻璃器的仔细勾稽排除了上述任一可能,而新疆玻璃杯与Hans Jürgen Eggers...长期以来,对新疆营盘和扎滚鲁克墓地发现的3件磨面纹玻璃杯的产地的认识以罗马或萨珊为主,本文即尝试对它们的来源进行重新考察。对罗马和萨珊的典型磨面纹玻璃器的仔细勾稽排除了上述任一可能,而新疆玻璃杯与Hans Jürgen Eggers所定义的223,226或228等3型存在诸多相似性则表明它们应属欧洲"蛮族"玻璃,其具体产地很可能在黑海北岸地区。它们既可由罗马玻璃料加工成型,亦可在罗马成品玻璃器上直接再造而成;后一种可能性从扎滚鲁克玻璃杯上所呈现的人为改造迹象上略见端倪。此外,本文还根据其前身Varpelev类型和后继E 230类型的年代范围推断此3型玻璃杯的时间框架大致为公元3世纪中期至4世纪中期。展开更多
基金the auspices of the National Key R&D Program of China(No.2016YFA0602301)National Natural Science Foundation of China(No.41971287,41601349)+1 种基金Science and Technology Development Program of Jilin Province(No.20180520220JH,20180623058TC)Fundamental Research Funds for the Central Universities(No.2412019FZ003)。
文摘As a key parameter for indicating the fraction of surface-reflected solar incident radiation, land surface albedo plays an important role in the Earth’s surface energy budget(SEB). Since the Sanjiang Plain has been severely affected by human activities(e.g., reclamation and shrinking of wetlands), it is important to assess the spatiotemporal variations of surface albedo in this region using a long-term remote sensing dataset. In order to investigate the surface albedo climatology, trends, and mechanisms of change, we evaluated the surface albedo variations in the Sanjiang Plain, China from 1982 to 2015 using the Global LAnd Surface Satellite(GLASS) broadband surface albedo product. The results showed that: 1) an increasing annual trend(+0.000 58/yr) of surface albedo was discovered in the Sanjiang Plain based on the GLASS albedo dataset, with a much stronger increasing trend(+0.001 26/yr) occurring during the winter. Most of the increasing trends occurred over the cultivated land, unused land, and land use conversion types located in the northeastern Sanjiang Plain. 2) The increasing trend of land surface albedo in Sanjiang Plain can be largely explained by the changes of both snow cover extent and land use. The surface albedo in winter is highly correlated with the snow cover extent in the Sanjiang Plain, and the increasing trend of surface albedo can be further enhanced by the land use changes.
文摘长期以来,对新疆营盘和扎滚鲁克墓地发现的3件磨面纹玻璃杯的产地的认识以罗马或萨珊为主,本文即尝试对它们的来源进行重新考察。对罗马和萨珊的典型磨面纹玻璃器的仔细勾稽排除了上述任一可能,而新疆玻璃杯与Hans Jürgen Eggers所定义的223,226或228等3型存在诸多相似性则表明它们应属欧洲"蛮族"玻璃,其具体产地很可能在黑海北岸地区。它们既可由罗马玻璃料加工成型,亦可在罗马成品玻璃器上直接再造而成;后一种可能性从扎滚鲁克玻璃杯上所呈现的人为改造迹象上略见端倪。此外,本文还根据其前身Varpelev类型和后继E 230类型的年代范围推断此3型玻璃杯的时间框架大致为公元3世纪中期至4世纪中期。
