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Exploring the SWOT Pixel Cloud: A First Look at the Newest Product Release
Delve into the inaugural release of SWOT satellite data, including a quick assessment of the water mask provided by Level-2 products from the KaRIn instrument
Due to changes in Medium.com policy concerning non-members reads, implemented in Sep 2023, this post is also freely available on geocorner.net: https://www.geocorner.net/post/exploring-the-swot-pixel-cloud-a-first-look-at-the-newest-product-release
Introduction
The Surface Water Ocean Topography mission (SWOT) was launched on Dec 16, 2022, with the promise to be a game-changer for water level (sea and inland) monitoring. For the first time a space mission is meant to study nearly all of the water on the Earth’s surface by providing water height measurements with greater precision than ever before.
Despite its launch back in 2022, the First Public Release has been announced on Dec 5, 2023 (here), almost one year later, and at a “very early stage” and with “known limitations”, as mentioned in the release note. Up to now, I’ve seen no assessment of these first products released. Therefore, the objective of this post is to provide a preliminary examination, as well as a quick tutorial on assessing this data.
To streamline environment configurations, this post was entirely development on a Google Colab notebook, which will be made available at the end.
Area of Interest
First step is to define an Area of Interest (AOI) for our analysis. In this example, we will focus on a region of the the Amazon Forest known as Anavilhanas, located within a Brazilian national park along the Rio Negro. One efficient method to quickly obtain the desired coordinates is by using the site geojson.io. This platform offers an interactive map interface, allowing users to select their region of interest directly on the map. As a result, the corresponding GeoJSON data is displayed in the side panel (refer to Figure 1).
