Eleven monthly GRACE gravity field solutions are now available for analyses. We show those fields can be used to recover changes in water storage, both on land and the ocean, accuracies of 1.5 cm thickness when smoothed over 1000 km. The amplitude annually varying signal determined 1.0 cm. Results 30% better a 1500 km smoothing radius, 40% worse 750 radius. estimate component storage three large drainage basins (the Mississippi, Amazon, region draining into Bay Bengal), 1.0–1.5

Abstract Presented here are three mean dynamic topography maps derived with different methodologies. The first method combines sea level observed by the high-accuracy satellite radar altimetry geoid model of Gravity Recovery and Climate Experiment (GRACE), which has recently measured earth’s gravity unprecedented spatial resolution accuracy. second one synthesizes near-surface velocities from a network ocean drifters, hydrographic profiles, winds sorted according to horizontal scales. In...

Abstract The 2017–2027 United States National Academy of Sciences Decadal Survey (DS) for Earth Science and Applications from Space identified Mass Change (MC) as one five Designated Observables (DOs) having the highest priority in terms observations required to advance system science over next decade. In response this designation, NASA initiated several multi‐center studies, with goal recommending observing architectures each DO implementation within This paper provides an overview...

Time changes in global mesoscale sea level variances were observed with satellite altimetry between November 1986 and March 1988, showing significant, geographically coherent seasonal patterns. The NE Pacific Atlantic show the most reliable patterns, higher than their yearly averages both fall winter. response to wind forcing appears as major contributor signals; errors estimated inverse barometer due atmospheric pressure, residual orbit errors, state bias are evaluated found be negligible...

Streamflow from Arctic river basins has been increasing in recent decades response to warming climate. In addition being a sensitive indicator of global change, discharge is critical component the freshwater budget Ocean, where flows may slow rates North Atlantic Deep Water formation and heat transport by thermohaline circulation. However, quantifying entire Pan‐Arctic drainage troublesome using traditional stream gauging methods. Here we use satellite measurements variations continental...

Atmospherically forced, high‐frequency oceanic variability is investigated using different configurations of an ocean general circulation model. At periods less than 20 days, the dynamic response sea surface to pressure loading exceeds that due wind stress, and mostly barotropic. Energy at these aliases into satellite altimeter measurements height (SSHT). The global variance collinear (≈10 day) differences this modelled aliased SSHT between (2 cm)² (3.5cm)², depending on model configuration...

The stability and accuracy of the TOPEX Microwave Radiometer (TMR) measurement atmospheric path delay due to water vapor is assessed over interval from launch (August 1992) through June 1998. Detailed global comparisons are made with delays derived special sensor microwave imager (SSM/I) instruments a network 15 island radiosondes. results provide consistent evidence that TMR measurements included an instrument-related downward drift 1.0-1.5 mm/yr between October 1992 December 1996....

Estimates of the shape sea surface as determined from satellite altiméters have become increasing importance in geophysics, geodesy and physical oceanography. The most effective error reduction procedures used producing these surfaces been some version a crossing-arc analysis. problem with this procedure is absence an easy means evaluating noise structure final result. By recasting one objective mapping (optimal estimation) we both optimize obtain explicit estimate wave-number altimétric...

Abstract Gravity Recovery and Climate Experiment (GRACE) gravity data spanning January 2003–November 2005 are used as proxies for ocean bottom pressure (BP) averaged over 1 month, spherical Gaussian caps 500 km in radius, along paths bracketing the Antarctic Circumpolar Current’s various fronts. The GRACE BP signals compared with those derived from Estimating Circulation of Ocean (ECCO) modeling–assimilation system, to a non-Boussinesq version Regional Model System (ROMS). discrepancy found...

The technique of satellite altimetry is discussed. complexity the procedure for attaining highly accurate measurements sea level, and need a multidisciplinary approach are emphasized. Progress in oceanographic research reviewed, with emphasis on results from Skylab GEOS-3 missions, as well Seasat whose altimeter was first one designed applications. challanges that lie ahead, including improving overall measurement accuracy observations, development new techniques utilizing data, formulated....

In late 2009 to early 2010, the Gravity Recovery and Climate Experiment (GRACE) satellite pair observed a record increase in ocean bottom pressure (OBP) over large mid-latitude region of South East Pacific. Its magnitude is substantially larger than other oceanic events Southern Hemisphere found entire GRACE data records (2003–2010) on multi-month time scales. The OBP help understand nature similar signal sea surface height (SSH) anomaly by altimetry: SSH mainly due mass convergence....

Recent results using wind and sea surface temperature data from satellites high-resolution coupled models suggest that mesoscale ocean–atmosphere interactions affect the locations evolution of storms seasonal precipitation over continental regions such as western US Europe. The processes responsible for this coupling are difficult to verify due paucity accurate air–sea turbulent heat moisture flux data. These fluxes currently derived by combining satellite measurements not coincident have...

This study examines high‐frequency sea level variations forced by changes in surface atmospheric pressure and wind their sensitivity to different forcing mechanisms, bottom topography resolution, amount of friction a barotropic ocean model. Optimal model performance, defined terms the explained variance satellite altimeter data, is found when using relatively strong friction, equivalent damping timescale only few days over deep ocean, with minimal smoothing. Spatial optimal parameter seem...

Geosat altimetric data for November 1986 to December 1988 are used estimate sea level differences between the Sargasso Sea and slope waters across Gulf Stream region, averaged 73° 61°W, comparable areas Kuroshio extension 143° 156°E. (south minus north) in both regions higher fall. Their projection onto an annual cosine peaks late September-mid-October, with 9 cm (Gulf region) 6.9 (Kuroshio amplitudes, accounts about 60% of variance. Residual errors due water vapor, orbit, state bias shown...

The 26 December 2004 Indian Ocean tsunami was the first earthquake of its magnitude to occur since advent both digital seismometry and satellite radar altimetry. Both have independently recorded event from different physical aspects. seismic data has then been used estimate fault parameters, a three‐dimensional ocean‐general‐circulation‐model (OGCM) coupled with information simulate satellite‐observed waves. Here we show that these two datasets consistently provide source using independent...

The capability of global navigation satellite system reflectometry (GNSS-R) altimetry to map mesoscale sea surface height (SSH) fields is analyzed using synthetic measurements derived from a high-resolution (1/10°) numerical model the North Pacific. As an example, we consider GPS and GLONASS constellation transmitters assume six reflection-capable receivers onboard Constellation Observing System for Meteorology, Ionosphere, Climate satellites in high-inclination (720 km, 72°) orbits. An...

Measures of mesoscale variability in the Semtner‐Chervin 1/4° and Los Alamos Parallel Ocean Program (POP) 1/6° models were compared with those obtained from TOPEX/POSEIDON (T/P) data. The objectives these comparisons two‐fold: first was to validate using altimetry as a measure real ocean, second evaluate effect increased model resolution/decreased horizontal friction. Mesoscale root‐mean‐square (rms) sea surface height (SSH), eddy kinetic energies, length scales used quantify variability....

Sea level residuals relative to a 2‐year mean sea in the Gulf Stream downstream of Cape Hatteras (between 80°W and 50°W longitude) are studied using Geosat altimetry between November 1986 December 1988. Spectral slopes computed at four nominal locations along (72°W, 65°W, 60°W, 55°W) range −1.5 −0.9, significantly less steep than −2.5 spectral slope found Bermuda. Because increased short‐wavelength energy, spectra tend become more “white” going eastward, but this trend is not statistically...

Mesoscale eddies constitute the most energetic component of variability ocean currents. Sea level variations measured by Geosat radar altimeter are used to study spatial and temporal scales eddy motion. An attempt is also made map evolution field in region Agulhas Current south Africa, where motions among strongest world. The results demonstrate that has provided an unprecedented opportunity from space sea associated with ocean.

Recent analysis of ocean bottom pressure (OBP) data from the Gravity Recovery and Climate Experiment (GRACE) satellites reveals strong El Niño/Southern Oscillation (ENSO)‐like oscillating phenomena in subpolar gyre North Pacific. The oscillation is further enhanced by subtracting OBP values subtropical gyre, indicating a mass imbalance between these two northern gyres time‐scales. Such features have not been reported before. Motivated satellite observations, non‐Boussinesq model that...

Satellite altimetry and gravimetry are used to determine the mean seasonal cycle in relative sea level, a quantity relevant coastal flooding related applications. The main harmonics (annual, semiannual, terannual) estimated from 25 years of gridded altimetry, while several conventional altimeter "corrections" (gravitational tide, pole inverted barometer) restored. To transform absolute levels, model vertical land motion is developed high-resolution mass inversion satellite gravimetry. An...

Estimates of the effectiveness an altimetric correction, and interpretation sea level variability as a response to atmospheric forcing, both depend upon assuming that residual errors in corrections are uncorrelated among themselves with level, or knowing correlations. Not surprisingly, many highly correlated since they involve properties ocean surface's them. The full (including their geographically varying time mean values), show correlations between electromagnetic bias (mostly height wind...