The new RSS SMAP Version 4.0 data spans the full mission, from 2 April 2015 to the present. Enhancement with this version include: 1) an improved land correction allowing retrievals closer to the coast (30-40km), 2) implementation of an improved sea-ice mask based on AMSR2, revised solar flagging, and inclusion of SSS uncertainty fields in the Level 3 (L3) products. Global coverage L3 data products include an 8-day running mean as well as monthly averages. Level 2 swath data are also available as part of the product release. They are available with a latency of 3 days for the Level 2 dataset, and 8 days and 1 month for the respective L3 products. The spatial resolution of the SMAP sensor and improved land correction with this V4.0 release allows for improved applications to coastal and regional studies. The image shows global maps of SSS (left panel) and associated uncertainties (right) on 27 March 2015 from the V4.0 L3 8-day running mean product.
The global average sea level is rising. Dr. Philip Thompson uses NASA Earth science data to explore how—and when—this will affect vulnerable communities.
Dr. Philip Thompson, Assistant Professor, Department of Oceanography, School of Ocean and Earth Science and Technology, University of Hawai‘i at Mānoa; Director, University of Hawai‘i Sea Level Center, Honolulu, HI
Research interests: Studying the drivers and impacts of sea level variability along with the impact of future sea level rise on the frequency of high-tide flooding events and water level extremes.
The PO.DAAC is pleased to announce the public release of an update to the GHRSST Level 4 MUR Global Foundation Sea Surface Temperature Analysis (v4.1) dataset.
The PO.DAAC is pleased to announce the release of the version 4.0 SMAP Sea Surface Salinity (SSS) data from Remote Sensing Systems (RSS). Enhancements over the previous release include:
The Cyclone Global Navigation Satellite System (CYGNSS), launched on 15 December 2016, is a NASA Earth System Science Pathfinder Mission that is designed to collect the first frequent space-based measurements of surface wind speeds in the inner core of tropical cyclones. Made up of a constellation of eight micro-satellites, the CYGNSS observatories provide nearly gap-free Earth coverage with a mean (i.e., average) revisit time of seven hours and a median revisit time of three hours. Primarily intended to be an ocean surface wind speed measuring mission, CYGNSS has been measuring science-quality ocean surface wind speed data since the beginning of the observation record on 18 March 2017. Following multiple years of data collection, CYGNSS has proven capable of estimating ocean surface measurements beyond wind speed. The PO.DAAC has just released the first version of the Level 2 Ocean Surface Heat Flux Science Data Record. This dataset was provided courtesy of CYGNSS Science Team investigators Derek Posselt (PI, JPL) and Juan Crespo (Co-I, JPL), and delivers time-tagged and geolocated ocean surface heat flux parameters in daily netCDF-4 formatted files with 25x25 kilometer footprint resolution from the Delay Doppler Mapping Instrument (DDMI) aboard the CYGNSS satellite constellation.
Animation of the ocean surface heat flux (top: latent heat; bottom: sensible heat) over the period 18 March 2017 to 30 June 2019 from the CYGNSS Level 2 Ocean Surface Heat Flux Science Data Record Version 1.0
The Coupled Ocean-Atmosphere Response Experiment (COARE) algorithm is used in this dataset to estimate the latent and sensible heat fluxes and their respective transfer coefficients. While COARE's initial intentions were for low to moderate wind speeds, the version used for this product, COARE 3.5, has been verified with direct in situ flux measurements for wind speeds up to 25 m/s. As CYGNSS does not provide air/sea temperature, humidity, surface pressure or density, the producer of this dataset obtains these values from the NASA Modern-Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2), which uses data assimilation to combine all available in situ and satellite observation data with an initial estimate of the atmospheric state, provided by a global atmospheric model. Since the MERRA-2 is updated on a monthly interval, this heat flux dataset is released in monthly increments.
More detailed dataset information can be found in the dataset user guide, with specific variable descriptions available in an Excel-formatted data dictionary.
Animation of the ocean surface heat flux over the period 18 March 2017 to 30 June 2019 from the Version 1.0 CYGNSS Level 2 Ocean Surface Heat Flux Science Data Record, which provides the time-tagged and geolocated ocean surface heat flux parameters with 25 x 25 kilometer footprint resolution from the Delay Doppler Mapping Instrument (DDMI) aboard the CYGNSS satellite constellation. The dataset can be accessed from the PO.DAAC Portal at https://podaac.jpl.nasa.gov/dataset/CYGNSS_L2_SURFACE_FL
The Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission, a joint partnership between NASA and the German Research Centre for Geosciences (GFZ), launched on 22 May 2018. It uses twin satellites to accurately map month-to-month variations in the Earth's gravity field and surface mass changes. It will continue the legacy data record of the first Gravity Recovery and Climate Experiment (GRACE) mission (2002-2017).
Conceptually very similar to the original GRACE mission, GRACE-FO consists of two identical satellites flying in formation around Earth at an initial altitude of approximately 490 kilometers and a nominal separation distance of 220+/-50 kilometers. Instruments on board the satellites precisely measure changes in the distance between them due to orbital perturbations caused by geographical and temporal variations in Earth's gravity field.
GRACE-FO will expand GRACE's legacy of scientific achievements. These include tracking mass changes in Earth's polar ice sheets and mountain glaciers (which impacts global sea level); estimating total water storage on land (from groundwater changes in deep aquifers to changes in soil moisture and surface water); inferring changes in deep ocean currents, a driving force in climate; and even measuring changes within the solid Earth itself, such as postglacial rebound and the impact of major earthquakes.
Figure 1. The global monthly mass anomalies distribution for Jan-2019 from GRACE-FO Level-3 Release-06 data
GRACE-FO mission datasets are archived and distributed by the PO.DAAC. The TELLUS GRACE-FO Level-3 Release-06 (RL06) datasets are described and discoverable via the PO.DAAC dataset information pages. The dataset information pages also provide access to the technical documentation, GRACE-FO Level-3 User Handbook, and guidance on how to cite the data.
