Monitoring water from space: An illustration in Death Valley, California

Climate change and human activity are dramatically reshaping how water is distributed on Earth. High quality observations, as well as products that bridge the gap between low-level data and actionable information are needed to support the understanding of current and future water availability around the globe. Two new developments are now addressing these needs. The Surface Water and Topography Mission (SWOT) satellite mission is measuring water elevations with unprecedented detail, while the Observational Products for End-Users from Remote Sensing Analysis (OPERA) project is turning satellite observations into clear and interpretable maps of surface water extent. Together, these represent a paradigm shift in our ability to measure and monitor water from space. We demonstrate their capability by tracking the transformation of Badwater Basin in Death Valley, one of the driest, hottest places on Earth, into an ephemeral lake following extreme precipitation events starting with Hurricane Hilary in August of 2023.

气候变化与人类活动正显著重塑地球水资源的空间分布格局。为支撑全球范围内当前及未来水资源可获得性的研究与认知，亟需高质量观测数据，以及能够衔接底层原始数据与可落地应用信息的配套产品。两项全新的技术进展正切实满足上述需求：其一，地表水与地形任务（Surface Water and Topography Mission, SWOT）卫星计划正以空前的精细度开展水面高程测量；其二，遥感分析终端用户观测产品（Observational Products for End-Users from Remote Sensing Analysis, OPERA）项目则将卫星观测数据转化为清晰可读、易于解读的地表水范围测绘图。二者共同推动了我们从太空监测与测量水资源能力的范式革新。我们以追踪恶水盆地（Badwater Basin）的变化为例，验证其性能表现：该盆地坐落于死亡谷（Death Valley，地球上最干旱炎热的区域之一），在2023年8月飓风希拉里（Hurricane Hilary）引发的极端降水事件后，逐渐演变为季节性临时湖泊。