rads_global_nrt_sla_20181014_20181015_001_800.png

Data are available through the following servers:

Service Resource Locator
  Near real-time (NRT) 
HTTP https://coastwatch.noaa.gov/cw_html/NearRealTimeSearch.html?region=ALL&product=sla&sensor=ALL&daysback=3&desc=sat
FTP ftp://ftpcoastwatch.noaa.gov:/pub/socd/lsa/rads/sla/daily/nrt
  Delayed-time (DT);  time series from 01 January 2012
FTP  ftp://ftp.star.nesdis.noaa.gov/pub/sod/lsa/rads/sla/daily/dt

Note:  the Sea Level Anomalies and the Geostrophic Currents variables are both included in the daily files:  Full time series from 2012-01-01 for DT.  NRT has SLA from 2017-02-13 and geostrophic currents from 2019-03-15.

 

Please acknowledge "NOAA CoastWatch/OceanWatch" when you use data from our site and cite the particular dataset as appropriate.

rads_global_nrt_sla_20181014_20181015_001_800.png

The NOAA Laboratory for Satellite Altimetry (LSA) sea surface height team produces 0.25-degree longitude/latitude Level-3 sea level anomaly (SLA) daily datasets by applying optimal interpolation to along-track satellite observations over the global ocean from a constellation of radar altimeter missions. Geostrophic currents are derived from the SLA and are included in the dataset.  Theses grids are produced with near-real time (NRT; 3-5 hour latency) data and a delayed-time (DT), improved accuracy, product is available for the time period 2012 to 2018. 

Sea Level Anomaly Product (pictured above)

The NOAA/NESDIS Laboratory for Satellite Altimetry provides near-real time (NRT) and delayed-time (DT) gridded Level-3 sea level anomaly (SLA) products. The data are produced by applying optimal interpolation to along-track satellite observations from a constellation of radar altimeter missions. The along-track altimetry data for each of the missions are from the Radar Altimetry Database System (RADS). This product is a global ocean product with a spatial resolution of 0.25-degree longitude/latitude. The near-real time gridded SLA product is available from February 2017 through the present. Currently, Jason-2, Jason-3, AltiKa, Cryosat-2, Sentinel-3A, and Sentinel-3B data are used in the processing of the NRT dataset. The NRT dataset is also part of NOAA’s OceanWatch Monitor. The delayed time SLA data are available for years 2012-2018. The DT data are of different quality than the NRT gridded SLA data. For each day, along-track data from all available missions are used and only final Geophysical Data Records (GDR)/Non-Time Critical (NTC) data are used in the processing of the DT dataset, making this product to be more accurate.

Geostrophic Currents Product

The NOAA/NESDIS Laboratory for Satellite Altimetry provides near-real time and delayed-time, zonal and meridional components of the geostrophic current. The currents are produced using the NOAA/NESDIS Laboratory for Satellite Altimetry's daily sea level anomaly grids and the conventional f-plane geostrophic current equations. At the equator, the beta-plane approximation is used. This product is a global ocean product with a spatial resolution of 0.25-degree longitude/latitude. The near-real time geostrophic currents are available from March 2019 through the present. The delayed time geostrophic currents are available for years 2012-2018. The geostrophic currents are variables within the NRT and DT SLA data files.

ugos_20190509_0.png  vgos_20190509_0.png

Figure:  NOAA LSA NRT Gridded Geostrophic Currents in m s-1 for 9 May 2019.  Left is zonal component (ugos), right is meridional component (vgos).  Black is land.  Gray is ice or missing data.

Radar Altimeter Database System

The Radar Altimeter Database System (RADS) is an effort of the Department of Earth Observation and Space Systems (DEOS) at TU Delft and the NOAA Laboratory for Satellite Altimetry to establish a harmonized, validated, and cross-calibrated sea level data base from satellite altimeter.

 

More information on NOAA/NESDIS LSA Multiple Altimeter Gridded Products

KeyDescription
Platform/Sensor

Jason-2; Jason-3; Sentinel-3A; CryoSat-2; SARAL

Measurement/Products

Earth Science >Oceans > Surface Sea Surface Height

DOI

n/a

Short Name

RADS-NRT-SLA-Daily-L3

Sample Filename

1-day: rads_global_nrt_sla_20170313_20170314_000.nc

Dataset Type

n/a

Processing Level

L3

Spatial Coverage

Global
180W-180E
90N-90S

Temporal Coverage

1 January 2017 - current

Latency

12 hours

Resolution

0.25x0.25 longitude/latitude degree

Projection

n/a

Swath Width

n/a

Sample Frequency

n/a

Temporal Repeat

Jason-2/Jason-3: 9.9156 days;
Sentinel-3A: 27 days;
CryoSat-2: 369 days;
SARAL: ~35 days

Orbital Period

Jason-2/Jason-3: 112.4 minutes;
Sentinel-3A: 101 minutes;
CryoSat-2: 100 minutes;
SARAL: 100.6 minutes

Orbit

n/a

Data Provider

Creator: Eric Leuliette, NOAA/NESDIS/STAR/SOCD/LSA

Formats

n/a

Keywords

Jason-2; Jason-3; Sentinel-3A; CryoSat-2; SARAL; sea surface height; sea level anomalies

Keywords (Beta)
Documentation: 

(♦ - non-government website)

Data Citation: 

Data Use Policy

LSA data are distributed at no cost to the users to promote scientific utilization of the data with the stipulation that the users of the data agree to follow the policy described below:

  1. LSA data are produced on a best effort basis.
  2. In publications, presentations, or on web pages based on LSA data the following acknowledgment should be included.
    "Altimetry data are provided by the NOAA Laboratory for Satellite Altimetry."

Please acknowledge "NOAA CoastWatch/OceanWatch" when you use data from our site and cite the particular dataset as appropriate.