Satellite Missions for Atmospheric Composition and Air Quality Monitoring


Earth’s system is a coupled system where the different components (the atmosphere, the hydrosphere, the lithosphere, and the croyosphre) are constantly interacting at different spatial and time scales.

Atmospheric composition and thus air quality (what impacts human health as well as other lifeforms inluding agriculture) is a hot topic and active area of research. When it comes to air quality, measurements of pollutant concentrations like particulate matter and trace gases is not new and continues to develop and expand as technology keeps improving and measurement networks keeps growing.

However, like in atmospheric science and hydrology point based measurements can only do so much. For example, determining the water level or water speed at a point along a river stream requires an understanding of the surface elevation (known bathymetry when under water) and whether the point of interest is upstream or downstream the river. Similarly, how the concentration of a pollutant evolves is governed by the underlying driving forces most notably the wind field, the pollutant lifetime, and the nature of the chemical interactions that arise.

It is therefore critical that the evolution of different chemical elements (pollutants if they affect human life) are tracked and studied in detail. Some of the questions science is trying to answer when it comes to air quality include:

  • What are the spatial and temporal variations of the concentrations of pollutants?
  • How are local and regional air quality affected by long-range transport?
  • How does air quality and climate change drive each other?
  • How is air quality affected by metrology and how are pollutants dispersed by weather?
  • How can fluxes between different regions be quantified or estimated?

For these and other questions to be answered monitoring is required at the appropriate scale and temporal frequency of the underlying phenomena. Here then the role of satellite-based monitoring comes into play. A number of organisations have teamed up towards the same goal of making this monitoring a reality. A “virtual” constellation of satellites will be composed of three missions that will monitor air quality from space at unprecedented quality.

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Anak Krakatau Volcano Explosion as seen in SAR


The following two images (and animation) shows the processed synthetic aperture radar (SAR) data acquired before and after the explosion of the Anak Krakatau volcano. The two SAR data were acquired on two different satellite passes (ascending and descending respectively).

Following the explosion a landslide into the ocean of part of the volcano and the island led to a tsunami (concentric waves around the island can be seen in the after image). The two images are followed by an animation and a video.

InSight mission to Mars Lands Nov. 26


After a successful launch in May 5, 2018 the Insight mission sent to Mars to explore Mars’ interior structure is planned to land on November 26, 2018. The interesting part is the mission landing will be monitored by two cube satellites that were launched with Insight and have been traveling on their own since the launch as show in the launch video below. The landing can be watched live on Nov. 26, 2018.

Bible on Radar/SAR/Microwave Remote Sensing


Considered as the bible on microwave, radar/SAR remote sensing I had to have a copy of this compendium written by pioneers in the field. One of the images puts the 1000 page book to scale.

How Groundwater Extraction & Replenishing Causes Surface Deformation & Subsidence


Researchers at Caltech made the animations below which show the seasonal deformation and subsidence of Earth’s surface, respectively,  as a result of groundwater extraction and refilling. This occurs when soil and earth layers are compacted and undergo subsidence due to the decrease of upward hydrostatic pressure balancing the weight of the layers.

Surface deformation and subsidence of Earth’s surface is measured using Interferometric Synthetic Aperture Radar (ISAR). ISAR is also used for natural hazard assessment. This includes applications to regions of volcanic, tectonic (e.g. faults and mountains), and construction activities.


source: Caltech