This study examines how scientists monitor Arctic melt ponds, pools of water forming on sea ice during summer, which absorb more sunlight than ice, creating a feedback loop affecting global climate. It reviews current satellites and field campaigns to acquire data; algorithms used to process it. It analyses over forty studies, comparing datasets, regions studied, and major limitations allowing to identify future research areas to improve Earth observations of melt ponds.

We review previous research into a group of fast-flowing Antarctic ice streams, the Foundation-Patuxent-Academy System. Previously, we knew relatively little how these ice streams flow, how they interact with the ocean, what their geological history was, and how they might evolve in a warming world. By reviewing existing information on these ice streams, we identify the future research needed to determine how they function, and their potential contribution to global sea level rise.

Polynyas are large openings in polar sea ice that can influence global climate and ocean circulation. After disappearing for 40 years, major polynyas reappeared in the Weddell Sea in 2016 and 2017, sparking new scientific questions. Our review explores how ocean currents, atmospheric conditions, and deep ocean heat drive their formation. These polynyas impact ecosystems, carbon exchange, and deep water formation, but their future remains uncertain, requiring better observations and models.

Lidar is commonly used to measure snow over global water reservoirs. However, ground-based and airborne lidar surveys are expensive, so satellite-based methods are needed. In this review, we outline the latest research using satellite-based lidar to monitor snow. Best practices for lidar-based snow monitoring are given, as is a discussion on challenges in this field of research.