The TOPEX/POSEIDON Geophysical Data Record (GDR) contains global coverage altimeter data. The objective of the TOPEX/POSEIDON mission, launched in August 1992, is to determine ocean topography with a sea surface height measurement precision of 3 cm and a sealevel measurement accuracy of 13 cm. The dataset contains measurements from two altimeters, a NASA dual frequency (Ku and C band) instrument similar to the Geosat altimeter, and a French space agency (CNES) instrument which is a proof-of-concept solid-state altimeter (Ku band). It also contains Sea Surface Height (SSH), significant wave height, ionospheric correction, tides and other geophysical corrections. It is emphasized that this product is considered research data because of the form and content of the data. The data consist entirely of files comprising headers and data records which contain over a hundred parameters for each second. It is swath data and there are no images. Analysis software is the responsibility of the user. Calculation of sea surface height anomalies from the altimeter range and environmental corrections is the responsibility of the user. The data are arranged in 10 day cycles that are separated into 254 passes, each about 56 minutes.

The Jason-1 Geophysical Data Records (GDR) contain full accuracy altimeter data to measure sea surface height, with a high precision orbit (accuracy ~1.5 cm). The instruments on Jason-1 make direct observations of the following quantities: altimeter range, significant wave height, ocean radar backscatter cross-section (a measure of wind speed), ionospheric electron content (derived by a simple formula), tropospheric water content, mean sea surface, and position relative to the GPS satellite constellation. The GDR contain all relevant corrections needed to calculate the sea surface height. Sea surface height anomalies calculation and recommended data edit criteria are specified in the Jason-1 GDR User Handbook located in PO.DAAC Drive at https://podaac-tools.jpl.nasa.gov/drive/files/allData/jason1/L2/gdr_netcdf_e/docs/Handbook_Jason-1_v5.0_Sept2015.pdf

The Sensory Data Record (SDR) is similar to the GDR product except that it also contains waveforms, which are required for retracking. This is an expert level product. If you do not need the waveforms then the GDR should suit your needs.

The data in this publication map the beach and nearshore environment at Marconi Beach in Wellfleet, MA and provide regional context for the 2021 CoastCam installation that looks out at the coast shared by beachgoers, shorebirds, seals, and sharks. These data were collected as part of field activity 2021-022-FA and a collaboration with the National Park Service at Cape Cod National Seashore to monitor the region that falls within the field of view of CoastCam CACO-02, which are two video cameras aimed at the beach. Starting in February and ending in March 2021, U.S Geological Survey and Woods Hole Oceanographic Institute (WHOI) scientists conducted field surveys to collect position and orientation information for the CoastCam cameras and map the field of view. Two new reference marks were established in the Marconi Beach parking area to establish ground control for future surveys. Elevation data were collected using a real time kinematic – satellite navigation system (RTK-GNSS) receiver attached to a pole and walked on the beach. Point data of the beach face were collected along transects. Grain-size analysis was performed on sediment samples collected with a spade along multiple profiles from the bluff base to the intertidal zone. Aerial images of the beach for use in Structure-from-Motion were taken with a camera (Ricoh GRII) and a post-processed kinematic (PPK) system attached to a helium powered balloon-kite (Helikite) and high-precision GPS targets (AeroPoints) were used as ground control points. Bathymetry was collected in the nearshore using a single-beam echosounder mounted on a surf capable self-righting electric autonomous survey vehicle. Agisoft Metashape (v. 1.7.2) was used to create a digital elevation model with the collected imagery and this was merged with the bathymetry in MATLAB (v. 2020) to create a continuous topobathy product.

The Jason-1 Geophysical Data Records (GDR) Geodetic Mission contain full accuracy altimeter data, with a high precision orbit, provided approximately 35 days after data collection. The data are sorted into cycles that are approximately 11 days long and contain 280 pass files. The instruments on Jason-1 make direct observations of the following quantities: altimeter range, significant wave height, ocean radar backscatter cross-section (a measure of wind speed), ionospheric electron content (derived by a simple formula), tropospheric water content, mean sea surface, and position relative to the GPS satellite constellation. The GDR contain all relevant corrections needed to calculate the sea surface height.

The Sensory Data Record (SDR) is similar to the GDR product except that it also contains waveforms, which are required for retracking. This is an expert level product. If you do not need the waveforms then the GDR should suit your needs.

The Sensory Geophysical Data Record (SGDR) files contain full accuracy altimeter data, with a high precision orbit (accuracy ~1.5 cm). The instruments on Jason-1 make direct observations of the following quantities: altimeter range, significant wave height, ocean radar backscatter cross-section (a measure of wind speed), ionospheric electron content (derived by a simple formula), tropospheric water content, mean sea surface, and position relative to the GPS satellite constellation. The SGDR contain all relevant corrections needed to calculate the sea surface height. It also contains the 20Hz waveforms that are required for retracking. The SGDR is an expert level product, if you do not require the waveforms then the GDR/GPN or GPR will be more suited for your needs.

These data map the beach and nearshore environment at Head of the Meadow Beach in Truro, MA, providing updated regional context for the 2019 CoastCam installation. CoastCam CACO-01 are two video cameras aimed at the beach that view the coast shared by beachgoers, shorebirds, seals, and sharks. These data were collected as part of field activity 2021-014-FA and a collaboration with the National Park Service at Cape Cod National Seashore to monitor the region. In February 2021, U.S. Geological Survey and Woods Hole Oceanographic Institute (WHOI) scientists conducted field surveys to re-map the field of view of the CoastCam. Aerial images of the beach for use in Structure from motion were taken with a camera (Ricoh GRII) and a post-processed kinematic (PPK) system attached to a helium powered balloon-kite (Helikite). High-precision GPS targets (AeroPoints) were used as ground control points. Bathymetry was collected in the nearshore using a single-beam echosounder mounted on a surf capable self-righting electric autonomous Small Surf Vehicle (SSV). Agisoft Metashape (v. 1.7.2) was used to create a digital elevation model with the collected imagery and this was merged with the bathymetry in MATLAB (v. 2020) to create a continuous topobathy product.

This dataset contains the Global Mean Sea Level (GMSL) trend generated from the Integrated Multi-Mission Ocean Altimeter Data for Climate Research Version 5.1. The GMSL trend is a 1-dimensional time series of globally averaged Sea Surface Height Anomalies (SSHA) from TOPEX/Poseidon, Jason-1, OSTM/Jason-2, and Jason-3 that covers September 1992 to present with a lag of up to 4 months. The data are reported as variations relative to a 20-year TOPEX/Jason collinear mean. Bias adjustments and cross-calibrations were applied to ensure SSHA data are consistent across the missions; Glacial Isostatic Adjustment (GIA) was also applied. The data are available as a table in ASCII format. Changes between the version 4.2 and version 5.x releases are described in detail in the user handbook.