巴黎上空的夜光云

巴黎上空的夜光云

ByNASA中文

2022年7月12日 Noctilucent Clouds over Paris Credit & Copyright: Bertrand Kulik Explanation: It’s northern noctilucent cloud season. Composed of small ice crystals forming only during specific conditions in the upper atmosphere, noctilucent clouds may become visible at sunset during late summer when illuminated by sunlight from below. Noctilucent clouds are the highest clouds known and now established to be polar mesospheric clouds observed from the ground. Although observed with NASA’s AIM satellite since 2007, much about noctilucent clouds remains unknown and so a topic of active research. The featured image shows expansive and rippled noctilucent clouds wafting over Paris, France. This year, several northern locations are already reporting especially vivid displays of noctilucent clouds. Tomorrow’s picture: webb begins 巴黎上空的夜光云 影像提供与版权: Bertrand Kulik 说明: 这是北半球夜光云的季节。特定条件下才会形成于高层大气中的微小冰晶，在夏季末日落时受到下方阳光的照耀时，偶而会以夜光云之姿现身。夜光云是现知最高的云种，在地面观测中被归类为极地中层云。虽然自从2007年，NASA的中气层水冰特性观测卫星 (AIM)，就持续在观测它，但夜光云的特性仍有诸多不明之处，所以依然是很活耀的研究题目。这幅主题影像，呈现了带着波纹飘过法国巴黎上空的大片夜光云。在今年，已有数个北纬地区报导目暏了特别华丽生动的夜光云。 明日的图片:…

天空的脉络

天空的脉络

ByNASA中文

2019 July 26 The Veins of Heaven Image Credit & Copyright: P-M Hedén (Clear Skies, TWAN) Explanation: Transfusing sunlight through a still dark sky, this exceptional display of noctilucent clouds was captured earlier this month, reflected in the calm waters of Vallentuna Lake near Stockholm, Sweden. From the edge of space, about 80 kilometers above Earth’s surface, the icy clouds themselves still reflect sunlight even though the Sun is below the horizon as seen from the ground. Usually spotted at high latitudes in summer months the night shining clouds have made a strong showing so far during the short northern summer nights. Also known as polar mesopheric clouds they are understood to form as water vapor driven into the cold upper atmosphere condenses on the…