Global Imager (GLI) on ADEOS-II
Question 1
Into what general category of EOS does the instrument fall?
The Global Imager is a Multispectral Sensor.
Question 2
What capture technology is used?
The satellite mechanically scans 12 picture elements (12 km) in the forward direction and 1600 km in the cross-track direction.
Question 3
Is the sensor active or passive?
Global Imager is a Passive Sensor.
Question 4
At what wavelength(s) does the sensor function?
The spectral range of the sensor is 0.375 – 12.5 μm (micrometers). See Spectrum Diagram below for details.
Question 5
What resolution does the sensor have – temporal and spatial?
Temporal
The satellite orbits the earth every 101 minutes and the cycle is repeated every 4 days. Data is collected on a daily basis.
Spatial
The spatial ground resolution is 1km at nadir for all channels. However, there are six 250m-resolution channels covering part of the wavelength bands similar to LANDSAT-TM.
Question 6
Is the sensor carried on an airborne or spaceborne platform? What is that platform – typically?
The sensor is carried on a satellite called ADEOS-2 (also known as MIDORI II). ADEOS stands for Advanced Earth Observing Satellite. It was launched to acquire data on global environmental changes (especially global warming).
Question 7
Who developed/launched/manages the sensor?
It was launched by the National Space Development Agency of Japan (NASDA), on the 14th December 2002 from the Tanegashima Space Flight Centre. In October 2003, the NASDA merged with two other organisations, the Institute of Space and Aeronautical Sciences (ISAS) and the National Aerospace Laboratory of Japan (NAL) to form the Japan Aerospace Exploration Agency (JAXA). This organisation was responsible for managing the sensor.The Satellite ceased operations on the 25th October 2003 when communications could not be re-established after a power anomaly (Kita, 2004).
Question 8
Can data be purchased from service providers?
The sensor operated for a period of seven months and the datasets are available from NASDA at the following URL
Yes - Earth Observation Centrer from JAXA
Question 9
What products are available?
Products are based on satellite data standard and the following is a full list
Question 10
At which main application areas is the sensor aimed?
The Main Application Area of the sensor was to collect data on global environmental change. 4 main headings: Atmosphere, Ocean, Land and Cryology. A sample of these are shown below:
Atmosphere – Cloud Type, Cloud Optical Thickness, Cloud Top Temperature
Ocean – Sea Surface Temperature, Dissolved Organic Matter, Weight of Suspended Minerals
Land – Vegetation Index
Cryology – Snow Grain Size, Sea Ice Distribution, Snow Cover Database
List 2 specific projects, where they have been reported, their goals and their outcomes.
As the sensor was only operative for 7 months, research carried out using data from it are limited. the following lists two:
Satellite Remote Sensing of Aerosols
The purpose of this project was to investigate whether data from the Global Imager could be used to detect aerosols above landmasses. Previous to this research, observations of aerosols over land were difficult as land surfaces have complex spectral reflectivity when compared to observations over the oceans, which are relatively homogenous. The Global Imager was the first sensor that was able to combine measurements from near-UV to IR wavelength. As most surfaces have low reflectivity in the near-UV spectrum, the use of data from the Global Imager was used to successfully detect aerosols in the atmosphere over land through the use of an algorithm developed by the authors. The outcome was a successful test during June 2003 when data from the Global Imager was used to retrieve the distribution and thickness of an aerosol plume from large forest fires in Eastern Siberia.
Source: Höller, R., Higurashi, A. and Nakajima, T. (2004) The GLI 380-NM – Application for Satellite Remote Sensing of Tropospheric Aerosol.
Available from: http://www.eumetsat.int/Home/Main/Publications/Conference_and_Workshop_Proceedings/groups/cps/documents/document/pdf_conf_p41_s2_hoeller_v.pdf
Ocean Remote Sensing Project for NOWPAP (Northwest Pacific Action Plan)
The purpose of this project was to develop and share information on Ocean Remote Sensing to the members of NOWPAP (China, Japan, Korea, and Russia). The primary environmental issue was to establish a monitoring system for the occurrence of biological events such as large-scale red tides (marine algal blooms), which causes damage to fisheries and can cause food poisoning from the consumption of affected fish. It also hoped to monitor eutrophication (phytoplankton blooms), which cause the red tides. Remote Sensing is especially useful in the monitoring of these ecological phenomena as they are generally large scale and can best be observed from space as they colour surface waters. Sensors such as Global Imager can also measure the amount of Chlorophyll-a in an area and changes in levels over time. The report found that Remote Sensing was a feasible method of assessing these phenomena.
Source: Anon. (2005) Integrated Report on Ocean Remote Sensing for the NOWPAP Region
Available from: http://cearac.nowpap.org/project/ireport.html
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