International Mass Loading Service
Summary
The Earth as a whole responses to external forces as an elastic body.
Putting an additional mass on the Earth's surface causes crust deformation.
Changes of loading mass result in variable displacements of the Earth's surface.
If not properly accounted, such variations distort precise geodetic measurements.
Periodic loading causes harmonic site
position variations which are detected in analysis of VLBI observations
and other space geodesy techniques.
Mass loading has four constituents: 1) changes of air mass that results in
change of surface air pressure; 2) changes in ocean level due to lunar and solar
tides; 3) changes in the ocean level due to wind and atmospheric pressure;
4) changes in soil moisture. These four loading are to be taken into account
in processing space geodetic data when precision better 1 cm is required.
Read more...
Mass loading is a substantially non-local effect. It is not sufficient to
know mass change in the point of interest. In order to compute mass loading
displacements, the mass change over entire Earth should be known. Changes in
pressure exerted by the atmosphere and the hydrosphere can be deduced from
the output of numerical weather models, numerical ocean models, and numerical
hydrology models. Handling the outputs of numerical models is not an easy task:
their size exceed 1 Tb/year. Handling the output and computing loading regularly
on a timely fashion is a challenge.
- The goal of the International Mass Loading
Service is to ingest outputs of numerical models, compute 3D
displacements caused by mass loading, and to disseminate the
results for the entire geodetic community on a regular basis,
continuously, and with low latencies. The service
is provided free of charge, and no registration is required.
3D loading displacements are provided as a) time series for
1272
space
geodesy sites; b) at a regular 2′ × 2′
grid; and c) as an on-demand on-line Internet service.
Download
In total, there are 5,469,184
files to download from this site. Loading is computed for
35,396,121,063,600
grid points in
606,661
global uniform grids at
2′ × 2′ resolution. To facilitate downloading loading
displacements or Stokes gravity coefficients induced by geophysical fluids,
the list of URLs for downloading can be generated by filling a web form:
-
Downloading of the precomputed
time series of displacements for 1272
space geodesy sites. in
EPHEDISP format.
This form will generate a list URLs of individual files or a control file
for wget. The series
are updated within 1 hour of availability of new data.
-
On-demand
computation of loading displacements for the list of sites that
a user supplies. After willing a web form, computation of mass loading
displacements is performed on our server.
-
Downloading of the precomputed loading
time series at the 2′ × 2′ regular grid
in netCDF format.
This form will generate a list URLs of individual files or a control file
for wget. The series are
updated within 1 hour of availability of new data.
-
Downloading or plotting the time series
of loading integrals computed over the whole Earth,
or over the ocean, or over the land.
-
Downloading of the precomputed
time series of Stokes coefficients of the contribution
of geophysical fluids to the geopotential in
AGRA format.
This form will generate a list URLs of individual files or a control file
for wget. The series are
updated within 1 hour of availability of new data.
- Smart downloading of the Mass Loading Service products.
- Current latency of the Mass Loading Service.
- List of changes of the Mass Loading Service.
Loading displacements were computed with software package
MALO.
Explore individual loadings
- Atmosphere pressure loading caused by
variations of the atmosphere pressure.
- Land water storage mass loading caused variations
of distribution of the water on land.
- Non-tidal ocean loading caused by water mass
re-distribution for reasons others than tides.
- Ocean tidal loading caused by water mass
re-distribution due to ocean tides.
Time series of the contribution of geophysical fluids
to the geopotential up to degree/order 64.
Publications
- L. Petrov, The International Mass Loading Service,
http://arxiv.org/abs/1503.00191.
- L. Petrov, J.-P. Boy, Study of the atmospheric pressure loading signal
in VLBI observations, Journal of Geophysical Research,
10.1029/2003JB002500, Vol. 109, No. B03405, 2004.
Full text in PDF (871Kb)
Bibliography
Similar services
Contact information
- To contact the maintainer of the International Mass Loading Service,
send a message to
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Service, send a message with subject subscribe to
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Service, send a message with subject unsubscribe to
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access to the International Mass Loading Service, send a message
with subject unlimited to
and provide the justification in the body of the message and
the IP address you are going to access to the service from.
Acknowledgment
This work was supported by NASA
Earth Surface & Interior program, grant NNX12AQ29G.
The GEOS-5 data used in this project have been provided by the
Global Modeling and Assimilation
Office (GMAO) at NASA Goddard Space Flight Center through the online
data portal in the NASA Center for Climate Simulation.
The MPIOM06 data used in this project have been provided by the the German
Research Centre for Geosciences (GFZ)
The FES2014 model has been developed, implemented and validated by the LEGOS,
NOVELTIS and CLS, within a CNES funded project.
The GOT-4.10c model was developed by R. Ray at NASA Goddard Space Flight Center.
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Last update: 2023.10.16_20:05:56
