Geoscience Reference
In-Depth Information
Chapter 3
Gravity Changes over Russian River Basins
from GRACE
Leonid V. Zotov, C.K. Shum, and Natalya L. Frolova
Abstract Gravity Recovery and Climate Experiment (GRACE) twin satellites have
been observing the mass transports of the Earth inferred by the monthly gravity
field solutions in terms of spherical harmonic coefficients since 2002. In particular,
GRACE temporal gravity field observations revolutionize the study of basin-scale
hydrology, because gravity data reflect mass changes related to ground and surface
water redistribution, ice melting, and precipitation accumulation over large scales.
However, to use the GRACE data products, de-striping/filtering is required. We
applied the multichannel singular spectrum analysis (MSSA) technique to filter
GRACE data and separate its principal components (PCs) at different periodicities.
Data averaging over the 15 largest river basins of Russia was performed. Spring
2013 can be characterized by the extremely large snow accumulation occurred
in Russia. Melting of this snow induced large floods and abrupt increase of river
levels. The exceptional maxima are evident from GRACE observations, which can
be compared to the hydrological models, such as Global Land Data Assimilation
System (GLDAS) or WaterGAP Global Hydrology Model (WGHM), and gauge
data. Long-periodic climate-related changes were separated into PC 2. Finally, it
was observed that there were mass increases in Siberia and decreases around the
Caspian Sea. Overall trend over Russia demonstrates mass increase until 2009, when
it had a maximum, followed by the decrease.
Keywords Earth's gravity field ￿ GRACE ￿ Hydrological changes ￿ MSSA
Search WWH ::




Custom Search