阿拉巴马河上的阳光

An astronaut aboard the International Space Station shot this photo of large meanders of the Alabama River while orbiting over the southern United States. The river’s smooth water surface reflects sunlight back toward the astronaut’s camera, producing an optical phenomenon known as sunglint.
NASA/Woody Hoburg

In this June 26, 2023, photo taken from the International Space Station, sunlight shines off the smooth waters of the Alabama River in a phenomenon known as sunglint. When photographing Earth, astronauts often take advantage of sunglint’s tendency to increase the contrast between water surfaces and surrounding land surfaces.

In the 1960s, the Alabama River was dammed, creating Dannelly Reservoir (the large shining area at center left). Construction of the dam also raised water levels upriver. This resulted in flooding at several points along the river. These flooded zones are typical of floodplains—the low, flat areas immediately next to larger rivers. In this image, flooded zones appear as irregular, bright shapes extending away from the river, like at Gee’s Bend (center bottom).

Text Credit: Justin Wilkinson

Image Credit: NASA/Woody Hoburg

国际空间站上的一名宇航员在美国南部上空的轨道上拍摄了阿拉巴马河的大型蜿蜒河段。这条河平静的水面将阳光反射回宇航员的相机，产生了一种被称为日光反射的光学现象。
影像来源: NASA/Woody Hoburg

在2023年6月26日从国际空间站拍摄的这张照片中，阳光照射在阿拉巴马河平的平静水面上，形成了一种被称为日光反射的现象。在拍摄地球时，宇航员经常利用日光反射来增加水面与周围陆地表面之间的对比度。

在20世纪60年代，阿拉巴马河筑坝，形成了达内利水库（位于左侧中部的大片闪光区域）。大坝的修建也提高了上游的水位，导致河流沿线的几个地方出现洪水。这些被淹没的区域是洪泛区的典型特征，即紧邻大河的低洼平坦地区。在这张图像中，洪泛区表现为不规则的明亮形状，从河流向外延伸，比如在吉斯弯（底部中央）处。

文稿来源: Justin Wilkinson

影像来源: NASA/Woody Hoburg