Posted by leopoldj 2 days ago
- frequent revisit, so can track even sub-monthly changes
- the L-band radar is at a wavelength (24cm) that penetrates vegetation canopy, removing a confounder from the measurement
- excellent spatial resolution that is relevant to urban scenes
The data volume is exceptionally high and required a lot of engineering effort. All radars are demanding, but this one was a new high-water mark.
(https://www.earthdata.nasa.gov/news/now-that-nisar-launched-...)
Pun fully intended, I'm sure.
The striping can have multiple sources so they need to study why there is an obvious footprint and then make the appropriate corrections.
> Originally, nine steps led to the base, but due to the sinking of the ground, an ongoing problem in Mexico City, fourteen more steps have been added.
So why didn't the monument itself also sink? Does it have piles going down to bedrock or something?
Also known as the morning star, also known as Venus.
There’s also the nocturnal / sunset aspect of Venus, noctifer/hesperus, so the evening star.
It all ebbs and flows so I guess everyone is right:)
(Also this not a uniquely Roman or Greek invention ofc)
So yes, it has an engineered foundation, a double-engineered foundation. The roads around it almost certainly do not. So it is plausible that the monument is not sinking as quickly.
What are the practical consequences of this today, and what is being done to remedy this?
Note in particular the last one, which is a classic. Roads, buildings, and all underground infrastructure is affected. As well as anyone else who uses that groundwater, as well as future users - because come groundwater reservoirs do not recover, the compaction is permanent.
Infrastructure degradation. Think overpass collapses or metro rail lines being misaligned.
> what is being done to remedy this
Not enough. CDMX faces the issue of multiple political entities with varying power making management difficult.
A lot of the subsidence happens in informal settlements [0] due to a mixture of political populism (no one would dare demolish an informal settlement and piss off voters).
Beijing used to have a similar issue, but a mixture of hukou, mass evictions, and mass demolitions helped alleviate the issue.
[0] - https://penniur.upenn.edu/uploads/media/02_Gutierrez.pdf
Thank you very much, Cloudlare.
NISAR is the first of its kind mission, jointly developed by ISRO and NASA. It is an L and S-band, global, microwave imaging mission, with capability to acquire fully polarimetric and interferometric data.
The unique dual-band Synthetic Aperture Radar of NISAR employs advanced, novel SweepSAR technique, which provides high resolution and large swath imagery. NISAR will image the global land and ice-covered surfaces, including islands, sea-ice and selected oceans every 12 days.
NISAR mission’s primary objectives are to study land & ice deformation, land ecosystems, and oceanic regions in areas of common interest to the US and Indian science communities.
NISAR mission will help to measure the woody biomass and its changes track changes in the extent of active crops understand the changes in wetlands’ extent map Greenland’s & Antarctica’s ice sheets, dynamics of sea ice and mountain glaciers characterize land surface deformation related to seismicity, volcanism, landslides, and subsidence & uplift associated with changes in subsurface aquifers, hydrocarbon reservoirs, etc.
Spacecraft Configuration
The Spacecraft is built around ISRO’s I-3K Structure. It carries two major Payloads viz., L & S- Band Synthetic Aperture Radar (SAR).
The S-band Radar system, data handling & high- speed downlink system, the spacecraft and the launch system are developed by ISRO. The L-band Radar system, high speed downlink system, the Solid-State Recorder, GPS receiver, the 9m Boom hoisting the 12m reflector are delivered by NASA.
Further, ISRO takes care of the satellite commanding and operations, NASA will provide the orbit maneuver plan and RADAR operations plan.
NISAR mission will be aided with ground station support of both ISRO and NASA for downloading of the acquired images, which after the necessary processing will be disseminated to the user community
The data acquired through S-band and L-band SAR from a single platform will help the scientists to understand the changes happening to Planet Earth."
Search for 'land subsidence insar mexico'
There must be other contributing factors too.
The nobel prize winner hopefully figures that out