Earth Snapshot RSS Feed Twitter
 
 
 
 

Archive for Mosaics

New FAPAR/MGVI Raw Data Processor for Monitoring Vegetation Cover

October 2nd, 2009 Category: Climate Change, Earth Observation, Image of the day, Mosaics

FAPAR Index - Source and Processed products

FAPAR Index - Source and Processed products

FAPAR - Source Product

FAPAR - Source Product

FAPAR - Processed Product

FAPAR - Processed Product

Envisat’s Medium Resolution Imaging Spectrometer (MERIS) acquires multi-spectral imagery of the Earth, and is used to monitor the state and evolution of the terrestrial vegetation cover.

In particular, the MERIS Global Vegetation Index (MGVI), which corresponds to the Fraction of Absorbed Photosynthetically Active Radiation (FAPAR), is generated operationally as a standard level-2 product, using the radiation measured by MERIS over land surfaces.

This bio-geophysical product plays a critical role in the plant photosynthetic process and is regularly used in diagnostic and predictive models to compute the primary productivity of the vegetation canopies.

FAPAR has been established as a fundamental surface parameter by international organizations including the Global Climate Observing System (GCOS), charged with providing data on the Earth’s climate system.

Chelys has developed a new processor that is able to process and directly extract the FAPAR index from raw data (level-0) at a reduced or full resolution (but also from level-1), generating the relative false-colored image just a few seconds after the original data is ingested.

In the next few weeks, a processor that will systematically generate these vegetation index images will be incorporated in the SRRS (Satellite Rapid Response System). As soon as enough images have been collected, it will be possible to generate mosaics as well.

The World from MERIS – Summer 2008

September 11th, 2009 Category: Mosaics

The World from MERIS - Summer 2008

The World from MERIS - Summer 2008

Over 2000 Level0 Reduced Resolution products from the MERIS instrument onboard the Envisat satellite were collected in the time period from January to August 2008 and processed by the Chelys Satellite Rapid Response System (SRRS) to generate high quality images.
The images were projected to obtain this composite view using MOSRI, a real time mosaic generation system, which automatically removes clouds and shadows while combining the data.

The new mosaic is available at different resolutions in the MOSAICS section of the EOSnap website.

SAR-Sharpened MOSAIC of Italy

41.8N 12.4E

August 26th, 2009 Category: Image of the day, Mosaics

Italy

SAR-Sharpened Mosaic of Italy

SAR-sharpening of Sardinia

SAR-sharpening of Sardinia

The main image here was realized by merging ASAR and MERIS orthorectified Mosaics of Italy, generated by Chelys MOSRI, using a technique we call “SAR-Sharpening” due to its similarity to a method known as PAN-Sharpening.

PAN-Sharpening merges high resolution panchromatic and lower resolution multispectral imagery to create a single high resolution color image. “SAR-Sharpening”, on the other hand, uses a radar image instead of a panchromatic one.

In this image, we maintained the resolution of the MERIS sensor (250m) while greatly enhancing the level of detail using an ASAR mosaic with a 75m resolution.

The animated imagery focusing on Sardinia shows the improvements made through the SAR-Sharpening technique. Due to its resolution, the original color MERIS image clearly has a level of detail inferior to that of the ASAR image.

However, after the processing, the contours of the Italian terrain can be seen in great detail.

ENVISAT Sensor Coverage

ENVISAT Sensor Coverage

ASAR operates simultaneously with the other ENVISAT instruments. The image on the left shows the swath positioning of ASAR along with those of the other sensors.

Chelys is currently exploring the possibility of enhancing the capabilities of their SRRS (Satellite Rapid Response System) processors, enabling them to automatically generate SAR-Sharpened images for all zones in which ASAR and MERIS images overlap.

Updated ASAR Image Mode Medium Resolution Mosaic of Italy

41.8N 12.4E

August 25th, 2009 Category: Mosaics

ASAR Image Mode Medium Resolution Mosaic of Italy

ASAR IMM Mosaic of Italy (Draft Version)

ASAR Image Mode Medium Resolution Mosaic of Italy

ASAR IMM Mosaic of Italy (Final Version)

This image of Italy is an ASAR Image Mode Medium Resolution Mosaic created with products acquired between January and July 2009.

These source images were generated starting from ENVISAT/Asar products, using the Chelys Satellite Rapid Response System.

They were then projected, orthorectified (with a NASA Digital Elevation Model of 3 arcseconds of resolution) and merged in this mosaic by Chelys MOSRI, a real time mosaic generation system, at the original resolution of 75 meters (0.000833 degrees per pixel).

The entire mosaic was generated in less than 1 minute. This is the latest version of the ASAR processing algorithm used by MOSRI which eliminates the banding effect created by merging the various original images.

Orthorectified ASAR Mosaic of Italy – July 17th, 2009

41.8N 12.4E

July 17th, 2009 Category: Image of the day, Mosaics

Mosaic of Italy - June/July 2009

Mosaic of Italy - June/July 2009

This is a mosaic of Italy generated in real time using orthorectified ASAR images just a few seconds after product reception.

The mosaic is visualized using Google Earth and can be navigated using the features of that program; the image shown here is a screenshot of the GE interface.

The images here were captured over the last three weeks, in late June and early to mid-July. As more images are acquired over the next two weeks, the black spaces will be filled in.