From dbe78f38266b7869584fd39e42b5fff0edc51cf1 Mon Sep 17 00:00:00 2001 From: Cassie Nickles <44206543+cassienickles@users.noreply.github.com> Date: Mon, 26 Aug 2024 14:01:07 -0700 Subject: [PATCH] Update SWOT_Datum.qmd --- quarto_text/SWOT_Datum.qmd | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/quarto_text/SWOT_Datum.qmd b/quarto_text/SWOT_Datum.qmd index 110d3705..5dd4845b 100644 --- a/quarto_text/SWOT_Datum.qmd +++ b/quarto_text/SWOT_Datum.qmd @@ -5,11 +5,11 @@ subtitle: Community Tutorials ### Use the Handbook -Please first see the [SWOT Data User Handbook](https://archive.podaac.earthdata.nasa.gov/podaac-ops-cumulus-docs/web-misc/swot_mission_docs/D-109532_SWOT_UserHandbook_20240502.pdf?_ga=2.76536725.1816513343.1724259518-1354658737.1715875596) sections 3.3.3 on the reference ellipsoid and 11.3.1 on the geoid. In addition, section 3.1.23 gives detailed information about Height with section 3.1.24 elaborating on Sea Surface Height Anomalies and 3.1.25 elaborating on Water Surface Elevation over inland waters. +Please first see the [SWOT Data User Handbook](https://archive.podaac.earthdata.nasa.gov/podaac-ops-cumulus-docs/web-misc/swot_mission_docs/D-109532_SWOT_UserHandbook_20240502.pdf?_ga=2.76536725.1816513343.1724259518-1354658737.1715875596) sections 3.3.2 for the ITRF, 3.3.3 on the reference ellipsoid and 11.3.1 on the geoid. In addition, section 3.1.23 gives detailed information about Height with section 3.1.24 elaborating on Sea Surface Height Anomalies and 3.1.25 elaborating on Water Surface Elevation over inland waters. ## Community Tutorials -As a summary, SWOT data is referenced to the WGS84 reference ellipsoid as a first step, and in a second step referenced to the EGM2008 geoid that references WGS84. To get a direct conversion with another dataset, it is easiest to transform all local data to the EGM2008 geoid. We recognize this conversion is different globally and depending on the data being used to compare, but we have collected a few community examples of direct comparisons to share below: +As a summary, SWOT data is referenced to the WGS84 reference ellipsoid as a first step, and in a second step referenced to the EGM2008 geoid that references WGS84 for the vertical datum. To get a direct conversion with another dataset, it is easiest to transform all local data to the EGM2008 geoid. For the horizontal datum, SWOT uses ITRF 2014 in reference to the WGS84 reference ellipsoid. We recognize these conversions are different globally and depending on the data being used to compare, but we have collected a few community examples of direct comparisons to share below: #### 1. Comparing **USGS gage** data and SWOT data in the **United States** - [Python Notebook](../notebooks/datasets/SWOT_USGS_Comparison.ipynb)