File:Arctic Vegetation Index Trend (WH).png
原始文件 (2,000 × 1,250像素,文件大小:1.83 MB,MIME类型:image/png)
说明
摘要[编辑]
描述Arctic Vegetation Index Trend (WH).png |
English: Over the past three decades, temperatures have risen faster in the Arctic than anywhere else in the world. Consequently, the growing season has gotten longer in the far northern latitudes, bringing major changes to plant communities in tundra and boreal (also known as taiga) ecosystems.
For decades, instruments on various NASA and NOAA satellites have continuously monitored vegetation from space. The Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Very High Resolution Radiometer (AVHRR) instruments measure the intensity of visible and near-infrared light reflecting off of plant leaves. Scientists use that information to calculate the Normalized Difference Vegetation Index (NDVI), an indicator of photosynthetic activity or “greenness” of the landscape. The map shows NDVI trends between July 1982 and December 2011 for the northern portions of North America and Eurasia. Shades of green depict areas where plant productivity and abundance increased; shades of brown show where photosynthetic activity declined. There was no significant trend in areas that are white, and areas that are gray were not included in the study. An international team of university and NASA scientists published their analysis of the NDVI data in Nature Climate Change in March 2013. The map shows a ring of greening in the treeless tundra ecosystems of the circumpolar Arctic—the northernmost parts of Canada, Russia, and Scandinavia. Tall shrubs and trees started to grow in areas that were previously dominated by tundra grasses. The researchers concluded that plant growth had increased by 7 to 10 percent overall. |
日期 | |
来源 | http://earthobservatory.nasa.gov/IOTD/view.php?id=80637 |
作者 | Ramakrishna Nemani of NASA’s Ames Research Center and Sangram Ganguly of the Bay Area Environmental Research Institute and NASA Ames |
许可协议[编辑]
Public domainPublic domainfalsefalse |
本文件完全由NASA创作,在美国属于公有领域。根据NASA的版权方针,NASA的材料除非另有声明否则不受版权保护。(参见Template:PD-USGov/zh、NASA版权方针页面或JPL图片使用方针。) | ||
警告:
|
文件历史
点击某个日期/时间查看对应时刻的文件。
日期/时间 | 缩略图 | 大小 | 用户 | 备注 | |
---|---|---|---|---|---|
当前 | 2013年3月16日 (六) 19:11 | 2,000 × 1,250(1.83 MB) | Sagredo(留言 | 贡献) | User created page with UploadWizard |
您不可以覆盖此文件。
文件用途
没有页面使用本文件。
全域文件用途
以下其他wiki使用此文件:
- cs.wikipedia.org上的用途
- en.wikipedia.org上的用途
- zh.wikipedia.org上的用途
元数据
此文件中包含有额外的信息。这些信息可能是由数码相机或扫描仪在创建或数字化过程中所添加。
如果文件已从其原始状态修改,某些细节可能无法完全反映修改后的文件。
水平分辨率 | 35.43 dpc |
---|---|
垂直分辨率 | 35.43 dpc |
使用软件 |