GRACE-derived surface water mass anomalies by energy integral approach: application to continental hydrology

2011 ◽  
Vol 85 (6) ◽  
pp. 313-328 ◽  
Author(s):  
Guillaume Ramillien ◽  
R. Biancale ◽  
S. Gratton ◽  
X. Vasseur ◽  
S. Bourgogne
Keyword(s):  
Surface Water ◽  
Water Mass ◽  
Integral Approach ◽  
Energy Integral ◽  
Continental Hydrology

Fast determination of surface water mass changes using regional orthogonal functions

2020 ◽  
Author(s):  
Guillaume Ramillien ◽  
Lucia Seoane
Keyword(s):  
Surface Water ◽  
Water Mass ◽  
Mass Density ◽  
Extended Kalman Filtering ◽  
Orthogonal Functions ◽  
Continental Hydrology ◽  
The Matrix ◽  
Range Rate ◽  
Along Track

<p>Approaches based on Stokes coefficient filtering and « mass concentration » representations have been proposed for recovering changes of the surface water mass density from along-track accurate GRACE K-Band Range Rate (KBRR) measurements of geopotential change. The number of parameters, i.e. surface triangular tiles of water mass, to be determined remains large and the choice of the regularization strategy as the gravimetry inverse problem is non unique. In this study, we propose to use regional sets of orthogonal surface functions to image the structure of the surface water mass density variations. Since the number of coefficients of the development is largely smaller than the number of tiles, the computation of daily GRACE solutions for continental hydrology, e.g. obtained by Extended Kalman Filtering (EKF), is greatly fastened and eased by the matrix dimensions and conditioning. The proposed scheme of decomposition is applied to the African continent where it enables to very localized sources of (sub-)monthly water mass amplitudes.</p>

Paleoceanographic evolution of the SW Svalbard margin (76°N) since 20,000 14C yr BP

2007 ◽  
Vol 67 (1) ◽  
pp. 100-114 ◽  
Author(s):  
Tine L. Rasmussen ◽  
Erik Thomsen ◽  
Marta A. Ślubowska ◽  
Simon Jessen ◽  
Anders Solheim ◽  
...  
Keyword(s):  
Surface Water ◽  
Water Mass ◽  
Atlantic Water ◽  
Subsurface Water ◽  
Planktic Foraminifera ◽  
Surface Conditions ◽  
Polar Surface ◽  
Warm Core ◽  
Heinrich Event ◽  
Benthic Environment

AbstractTwo cores from the southwestern shelf and slope of Storfjorden, Svalbard, taken at 389 m and 1485 m water depth have been analyzed for benthic and planktic foraminifera, oxygen isotopes, and ice-rafted debris. The results show that over the last 20,000 yr, Atlantic water has been continuously present on the southwestern Svalbard shelf. However, from 15,000 to 10,000 14C yr BP, comprising the Heinrich event H1 interval, the Bølling–Allerød interstades and the Younger Dryas stade, it flowed as a subsurface water mass below a layer of polar surface water. In the benthic environment, the shift to interglacial conditions occurred at 10,000 14C yr BP. Due to the presence of a thin upper layer of polar water, surface conditions remained cold until ca. 9000 14C yr BP, when the warm Atlantic water finally appeared at the surface. Neither extensive sea ice cover nor large inputs of meltwater stopped the inflow of Atlantic water. Its warm core was merely submerged below the cold polar surface water.

scholarly journals Recovery of Rapid Water Mass Changes (RWMC) by Kalman Filtering of GRACE Observations

2020 ◽  
Vol 12 (8) ◽  
pp. 1299
Author(s):  
Guillaume Ramillien ◽  
Lucía Seoane ◽  
Maike Schumacher ◽  
Ehsan Forootan ◽  
Frédéric Frappart ◽  
...  
Keyword(s):  
Kalman Filtering ◽  
Water Mass ◽  
Extreme Weather Events ◽  
Grace Data ◽  
Weather Events ◽  
Continental Hydrology ◽  
Realistic Description ◽  
Range Rate ◽  
Recovery Approach ◽  
Along Track

We demonstrate a new approach to recover water mass changes from GRACE satellite data at a daily temporal resolution. Such a product can be beneficial in monitoring extreme weather events that last a few days and are missing by conventional monthly GRACE data. The determination of the distribution of these water mass sources over networks of juxtaposed triangular tiles was made using Kalman Filtering (KF) of daily GRACE geopotential difference observations that were reduced for isolating the continental hydrology contribution of the measured gravity field. Geopotential differences were obtained from the along-track K-Band Range Rate (KBRR) measurements according to the method of energy integral. The recovery approach was validated by inverting synthetic GRACE geopotential differences simulated using GLDAS/WGHM global hydrology model outputs. Series of daily regional and global KF solutions were estimated from real GRACE KBRR data for the period 2003–2012. They provide a realistic description of hydrological fluxes at monthly time scales, which are consistent with classical spherical harmonics and mascons solutions provided by the GRACE official centers but also give an intra-month/daily continuity of these variations.

The Ongoing Central European Drought Observed with GRACE Follow-On

2020 ◽  
Author(s):  
Eva Boergens ◽  
Andreas Güntner ◽  
Henryk Dobslaw ◽  
Christoph Dahle
Keyword(s):  
Time Series ◽  
Soil Moisture ◽  
Surface Water ◽  
Central Europe ◽  
Drought Index ◽  
Water Mass ◽  
Water Storage ◽  
Drought Indices ◽  
Severe Drought ◽  
Data Set

<p class="western">In the last three years Central Europe experienced an ongoing severe drought. With the data of the GRACE Follow-On (GRACE-FO) mission we are able to quantify the water deficit of these years. Since May 2018 GRACE-FO continues the observations of GRACE (2002-2017) allowing to compare the most recent drought with earlier droughts in 2003 and 2015.</p> <p class="western">In July 2019 the water mass deficit in Central Europe amounted to -154 Gt, which has been the largest deficit in the whole GRACE and GRACE-FO time series. In November 2018 the deficit reached -138 Gt and in June 2020 -147 Gt. Comparing these deficits to the mean annual water storage variation of 162 Gt shows the severity of the ongoing drought. With such a water mass deficit, a fast recovery within one year cannot be expected. In comparison to this, the droughts of 2003 with a deficit of -55 Gt and of 2015 with a deficit of -111 Gt were less severe.</p> <p class="western">The GRACE and GRACE-FO total water storage data set also allows for analysing spatio-temporal drought patterns. In 2018 the drought was centred in in the South-West of Germany and neighbouring countries while parts of Poland were hardly affected by the drought. In 2018 the drought reached its largest extent only in late autumn. However, the exact onset of drought is not determinable due to missing data between July and October. Both in 2019 and 2020 the centre of the drought is located further East and the months with the largest deficit were July and June, respectively. Also in the later years, the drought was more evenly spread out over the whole of Central Europe.</p> <p class="western">Additionally, we compared the GRACE and GRACE-FO data to an external soil moisture index and to surface water drought indices for Lake Constance and Lake Müritz. To this end, we derive a drought index from the GRACE and GRACE-FO mass anomalies. For the whole time series, the GRACE drought index shows a high congruency to the soil moisture drought index. Overall, the surface water drought index also fits well together with the GRACE drought index. However, the comparison reveals the influence of regional effects on surface waters not observable with GRACE and GRACE-FO.</p>

scholarly journals Impact of spatial resolution on simulated surface water mass transformations in the Atlantic

2007 ◽  
Vol 19 (3-4) ◽  
pp. 138-160 ◽  
Author(s):  
Sergey K. Gulev ◽  
Bernard Barnier ◽  
Jean-Marc Molines ◽  
Thierry Penduff ◽  
Jérôme Chanut
Keyword(s):  
Surface Water ◽  
Spatial Resolution ◽  
Water Mass ◽  
Simulated Surface ◽  
Water Mass Transformations

scholarly journals Especiación de metales pesados en la fracción disuelta de las aguas superficiales de la cuenca baja y la pluma del Río Manzanares, Estado Sucre, Venezuela

2016 ◽  
Author(s):  
Gregorio Martínez ◽  
William James Senior ◽  
Arístide Márquez
Keyword(s):  
Heavy Metals ◽  
Surface Water ◽  
Humic Acids ◽  
Water Mass ◽  
The State ◽  
Metal Concentrations ◽  
Hydrated Form ◽  
Anthropogenic Contributions ◽  
Del Rio ◽  
Dissolved Phase

This paper reports on the speciation of heavy metals (Cd, Pb, Cr, Cu, Ni, Mn, Fe, and Zn) in the surface water dissolvedfraction of the low basin and plume of the Manzanares River, in the state of Sucre, Venezuela, based on data taken at 22 stationsfrom July 1996 to June 1997. The total metal concentrations in the dissolved phase ranged from below detection levels to 0.01,0.02, 0.02, 0.10, 0.10, 1.03, 2.56, and 5.13 μmol L–1 for Cd, Pb, Cr, Cu, Ni, Mn, Fe, and Zn, respectively. Overall, the metalsstudied revealed a nonconservative behavior with removal at low salinities, likely due to anthropogenic contributions and toflocculation on account of Fe- and Mn-oxyhydroxide formation resulting from the shifts in pH and ion forces that ensue whenthe fresh waters of the river meet the marine water mass of the Gulf of Cariaco. The heavy metals in the dissolved fraction, inboth free and hydrated form, had a composition in which the largest proportions were associated with humic acids, thus beingmore readily available to organisms.

scholarly journals Surface water mass composition changes captured by cores of Arctic land-fast sea ice

2016 ◽  
Vol 118 ◽  
pp. 154-164 ◽  
Author(s):  
I.J. Smith ◽  
H. Eicken ◽  
A.R. Mahoney ◽  
R. Van Hale ◽  
A.J. Gough ◽  
...  
Keyword(s):  
Surface Water ◽  
Sea Ice ◽  
Water Mass ◽  
Mass Composition ◽  
Composition Changes

scholarly journals The flexural dynamics of melting ice shelves

2013 ◽  
Vol 54 (63) ◽  
pp. 1-10 ◽  
Author(s):  
Douglas R. MacAyeal ◽  
Olga V. Sergienko
Keyword(s):  
Surface Water ◽  
Antarctic Peninsula ◽  
Numerical Solutions ◽  
Water Mass ◽  
Gradual Increase ◽  
Ice Shelf ◽  
Ice Shelves ◽  
Supraglacial Lakes ◽  
Mass Loads ◽  
The Antarctic

AbstractA conspicuous precursor of catastrophic ice-shelf break-up along the Antarctic Peninsula, reported widely in the literature, is the gradual increase in surface melting and consequent proliferation of supraglacial lakes and dolines. Here we present analytical and numerical solutions for the flexure stresses within an ice shelf covered by lakes and dolines, both isolated and arrayed. We conclude that surface water promotes ice-shelf instability in two ways: (1) by water-assisted crevasse penetration, as previously noted, and (2) by the inducement of strong tensile flexure stresses (exceeding background spreading stress by 10–100 times) in response to surface water mass loads and ‘hydrostatic rebound’ occurring when meltwater lakes drain.

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