Reconstructing GRACE-type time-variable gravity from the Swarm satellites

The Gravity Recovery and Climate Experiment (GRACE) mission has enabled mass changes and transports in the hydrosphere, cryosphere and oceans to be quantified with unprecedented resolution. However, while this legacy is currently being continued with the GRACE Follow-On (GRACE-FO) mission there is a gap of 11 months between the end of GRACE and the start of GRACE-FO which must be addressed. Here we bridge the gap by combining time-variable, low-resolution gravity models derived from European Space Agency’s Swarm satellites with the dominating spatial modes of mass variability obtained from GRACE. We show that the noise inherent in unconstrained Swarm gravity solutions is greatly reduced, that basin averages can have root mean square errors reduced to the order of $$\text {cm}$$ cm of equivalent water height, and that useful information can be retrieved for basins as small as $$1000 \times 1000\,\hbox {km}$$ 1000 × 1000 km . It is found that Swarm data contains sufficient information to inform the leading three global mass modes found in GRACE at the least. By comparing monthly reconstructed maps to GRACE data from December 2013 to June 2017, we suggest the uncertainty of these maps to be $$2{-}3\,\text {cm}$$ 2 - 3 cm of equivalent water height.

Remote sensing data for assessing the equivalent water height (EWH) variety versus the level of forest disturbance in Central Siberia

The forests of the permafrost zone of Central Siberia are influenced by natural and anthropogenic factors. Using remote sensing data, disturbed areas of forest cover are detected in the IR range as an anomalies of the surface temperature, which are significant for a long time (~20 years). Long-term changes in the temperature balance of the surface affect both the state of the lower soil horizons and the dynamics of the seasonally thawed layer, and, therefore, can affect the variation in the water balance and groundwater runoff. For the area of interest, a trend is shown of ~20% increase in the total area of disturbances per last two decades. A correlation analysis between large-scale thermal anomalies of the underlying surface and the series of gravimetric data on Equivalent Water Height (EWH) parameter is performed for the territory of the two river basins of the Nizhnyaya Tunguska and Podkamennaya Tunguska (Central Siberia). As a first approximation we estimated the relationship between the forest and on-ground cover disturbance and thermal anomalies of the underlying surface, which affect the seasonal dynamics of groundwater.

Analysis of GRACE satellite measurements over seismically active areas of the strongest earthquakes

The study is devoted to the analysis of the features of the change in the parameter EWH (Equivalent Water Height) over the geoid from the satellite measurements of the GRACE space system in seismically active areas of the strongest underwater earthquakes. The GRACE satellite data archive was created. An interpretation of the disturbed state of the geomedium using digital maps of the spatial distribution of the parameter EWH is performed.