Name: Envisat ASAR AP Medium Resolution L1 [ASA_APM_1P]
Creator: European Space Agency
License: https://earth.esa.int/eogateway/documents/20142/1564626/Terms-and-Conditions-for-the-use-of-ESA-Data.pdf

Envisat ASAR AP Medium Resolution L1  [ASA_APM_1P]

Active Remote Sensing

ASAR

Imaging Radars

Envisat

Agriculture

Biosphere

Coastal Processes

Cryosphere

Human Dimensions

Land Surface

Natural Hazards and Disaster Risk

Ocean Waves

Oceans

Snow and Ice

Soils

Terrestrial Hydrosphere

Vegetation

<p>This ASAR Alternating Polarization Medium Resolution Image product has been generated from Level 0 data collected when the instrument was in Alternating Polarisation Mode. The product has lower geometric resolution but higher radiometric resolution than ASA_APP and contains one or two co-registered images corresponding to one of the three polarisation combination sub modes (HH and VV, HH and HV, VV and VH).</p>

<p>This product has been processed using the SPECAN algorithm and contains radiometric resolution good enough for ice applications and covers a continuous area along the imaging swath.</p>

<p>The ASAR AP L0 full mission data archive has been bulk processed to Level 1 (ASA_APM_1P) in Envisat format with the IPF-ASAR processor version 6.03.</p>

<p>Spatial Resolution: 150 m ground range x 150 m azimuth.</p>

European Space Agency, 2021, Envisat ASAR Alternating Polarization Medium Resolution L1 Product. IPF version 6.03.0

ASAR auxiliary data

ASAR Products Specification - Revision C

Envisat ASAR Sensor Performance, Products and Algorithms

Envisat ASAR Science and Applications

ASAR Product Handbook

ASAR Product Quality Disclaimer

ASAR Software Tools

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<p>Utilisation of this data is subject to ESA's Earth Observation Terms and Conditions.</p>

In cooperation with CONAE (Comisión Nacional de Actividades Espaciales), ESA is launching an Announcement of Opportunity for the international scientific community to access data from the SAOCOM mission for science and EO-based applications development.

Announcement of Opportunity for SAOCOM

<p>GEOSAT-2 Portugal coverage is a collection of 2021 data over the Portugal area, including islands. The available dataset has a cloud cover less than 10%, and is acquired up to 1m resolution with Geometric accuracy &lt;6m CE90 based on Copernicus DEM @10m.</p>

<figure class="centered-mobile-centered"><a data-lightbox="GEOSAT-2-Portugal" data-title="GEOSAT-2 Portugal 2021 - Spatial Coverage of the Dataset" href="/documents/20142/4279060/GEOSAT2_Portugal_Coverage.png"><img alt="GEOSAT-2 Portugal 2021 - Spatial Coverage of the Dataset" src="/documents/20142/4279060/GEOSAT2_Portugal_Coverage_Smaller.jpg/3e2c84ea-17e7-c8b6-ed57-b079e1851142?t=1677155961453&amp;download=true" style="margin: 10px;" /></a>

<figcaption style="text-align: center;"><i>GEOSAT-2 Portugal 2021 - Spatial Coverage of the Dataset</i></figcaption>
</figure>

<p>The following product types are available:</p>

<ul>
	<li><strong>Pan-sharpened (4 bands, 321 Natural Colours or 432 False Colours):</strong> A four-band image, resulting from adding the information of each multispectral band to the panchromatic band. The fusion does not preserves all spectral features of the multispectral bands, so it should not be used for radiometric purposes. Resolution 1m; Bands: All, R-G-B or Ni-R-G</li>
	<li><strong>Bundle: </strong>Panchromatic (1m resolution) + Multispectral bands (4m resolution): five-band image containing the panchromatic and multispectral products packaged together, with band co-registration.</li>
</ul>

<p>The available processing level is L1C orthorectified: a calibrated and radiometrically corrected product, manually orthorectified and resampled to a map grid.</p>

<table class="eogtable">
	<tbody>
		<tr class="eogtable-heading">
			<td rowspan="2">Product Type</td>
			<td colspan="2">Processing Level and Spatial Resolution</td>
		</tr>
		<tr class="eogtable-heading">
			<td>L1B (native)</td>
			<td>L1C (ortho)</td>
		</tr>
		<tr>
			<td>Pan-sharpened</td>
			<td>1.0m</td>
			<td>1.0m</td>
		</tr>
		<tr>
			<td>Bundle (PAN+MS)</td>
			<td>1.0m (P), 4.0m (MS)</td>
			<td>1.0m (P), 4.0m(MS)</td>
		</tr>
	</tbody>
</table>

GEOSAT-2 Portugal Coverage 2021

<p>A large number of European cities are covered by this dataset; for each city you can find one or more Cartosat-1 ortho image products and one or more Euro-Maps 3D DSM tiles clipped to the extent of the ortho coverage.</p>

<p>The Euro-Maps 3D DSM is a homogeneous, 5 m spaced Digital Surface Model semi-automatically derived from 2.5 m Cartosat-1 in-flight stereo data with a vertical accuracy of 10 m. The very detailed and accurate representation of the surface is achieved by using a sophisticated and well adapted algorithm implemented on the basis of the Semi-Global Matching approach. The final product includes several pixel-based quality and traceability layers:</p>

<ul>
	<li>The dsm layer (*_dsm.tif) contains the elevation heights as a geocoded raster file</li>
	<li>The source layer (*_src.tif) contains information about the data source for each height value/pixel</li>
	<li>The number layer (*_num.tif) contains for each height value/pixel the number of IRS-P5 Cartosat-1 stereo pairs used for the generation of the DEM</li>
	<li>The quality layer (*_qc.tif) is set to 1 for each height/pixel value derived from IRS-P5 Cartosat-1 data and which meets or exceeds the product specifications</li>
	<li>The accuracy vertical layer (*_acv.tif) contains the absolute vertical accuracy for each quality controlled height value/pixel.</li>
</ul>

<p>The ortho image is a Panchromatic image at 2.5 m resolution. The following table defines the offered product types.</p>

<table class="eogtable">
	<tbody>
		<tr class="eogtable-heading">
			<td>EO-SIP product type</td>
			<td>Description</td>
		</tr>
		<tr>
			<td>PAN_PAM_3O</td>
			<td>IRS-P5 Cartosat-1 ortho image</td>
		</tr>
		<tr>
			<td>DSM_DEM_3D</td>
			<td>IRS-P5 Cartosat-1 DSM</td>
		</tr>
	</tbody>
</table>

European Cities: Cartosat-1 Euro-Maps 3D

<p>The Atmospheric Carbon-dioxide Grating Spectrometer (ACGS) instrument is pushbroom spectrometer operating in NIR and SWIR bands which allows the measuring of CO2 mole fraction.</p>

<p>The available ACGS products have a temporal coverage between March 2017 and January 2020 (not all days included in the time frame):</p>

<ul>
	<li>L1A DS: Sample Dark Calibration sample product</li>
	<li>L1A GL: Sample Glint Sample products</li>
	<li>L1A LS: Sample Lamp Calibration sample product</li>
	<li>L1A ND: Principal-Plane Nadir Sample product</li>
	<li>L1A ZS: Sample Z-Axis Solar Calibration Sample</li>
	<li>L1B CAL DS: Sample Dark Calibration product</li>
	<li>L1B CAL LS: Sample Lamp Calibration product</li>
	<li>L1B CAL ZS: Sample Z-Axis Solar Calibration product</li>
	<li>L1B SCI GL: Sample Glint Science product</li>
	<li>L1B SCI ND: Principal-Plane Nadir Science product.</li>
</ul>

<p> </p>

<p>The Cloud Aerosol Polarization Imager (CAPI) is a pushbroom radiometer in VIS, NIR and SWIR bands for the observation of aerosols and clouds optical properties.</p>

<p>The CAPI products are available in a time range from July 2019 and January 2020 (not all days included in the time frame):</p>

<ul>
	<li>L1A ND: Principal-Plane Nadir product</li>
	<li>L1B ND 1000M: Principal-Plane Nadir products at 1000 m resolution (1375 nm, 1640 nm)</li>
	<li>L1B ND 250M: Principal-Plane Nadir products at 250 m resolution (380 nm, 670 nm, 870 nm)</li>
	<li>L1B ND GEOQK: Principal-Plane Nadir georeferenced at 250 m resolution</li>
	<li>L1B ND GEO1K: Principal-Plane Nadir georeferenced at 1000 m resolution</li>
	<li>L1B ND OBC: Principal-Plane Nadir on-board calibrator product</li>
	<li>L2 ND CLM: Principal-Plane Nadir cloud flag product.</li>
</ul>

TanSat AGCS and CAPI products

<div class="right-mobile-centered">
<figure class="right-mobile-centered"><a data-lightbox="AATSR Full Resolution image of the Iberian Peninsula from 28 October 2006. Land coverage is an RGB image from the 1.6, 0.87 and 0.55 µm radiance channels; Ocean coverage is from the 3.7 µm brightness temperature channel." data-title="AATSR Full Resolution image of the Iberian Peninsula from 28 October 2006. Land coverage is an RGB image from the 1.6, 0.87 and 0.55 µm radiance channels; Ocean coverage is from the 3.7 µm brightness temperature channel." href="/documents/20142/1363749/AATSR-Iberia-1.jpg"><img alt="AATSR Full Resolution image of the Iberian Peninsula from 28 October 2006" class="right-mobile-centered" src="/documents/20142/1363749/AATSR-Iberia-1-3-tm.jpg" /> </a> -
<figcaption style="text-align:center"><i>AATSR Full Resolution land and ocean cover image of the Iberian Peninsula from 28 October 2006</i></figcaption>
</figure>
</div>

<div class="right-mobile-centered">
<figure class="right-mobile-centered"><a data-lightbox="AATSR Full Resolution image of the Iberian Peninsula from 28 October 2006. Land coverage is an RGB image from the 1.6, 0.87 and 0.55 µm radiance channels." data-title="AATSR Full Resolution image of the Iberian Peninsula from 28 October 2006. Land coverage is an RGB image from the 1.6, 0.87 and 0.55 µm radiance channels." href="/documents/20142/1363749/AATSR-Iberia-2.jpg"><img alt="AATSR Full Resolution image of the Iberian Peninsula from 28 October 2006" class="right-mobile-centered" src="/documents/20142/1363749/AATSR-Iberia-2-5-tm.jpg" style="margin-left:10px;" /> </a>

<figcaption style="text-align:center"><i>AATSR Full Resolution land cover image of the Iberian Peninsula from 28 October 2006.</i></figcaption>
</figure>
</div>

<p>The Envisat AATSR Level 1B Brightness Temperature/Radiance product (RBT) contains top of atmosphere (TOA) brightness temperature (BT) values for the infra-red channels and radiance values for the visible channels, on a 1-km pixel grid. Values for each channel and for the nadir and oblique views occupy separate NetCDF files within the Sentinel-SAFE format, along with associated uncertainty estimates. Additional files contain cloud flags, land and water masks, and confidence flags for each image pixel, as well as instrument and ancillary meteorological information.</p>

<p>This AATSR product [ENV_AT_1_RBT] in NetCDF format stemming from the 4th AATSR reprocessing, is a continuation of ERS ATSR data and a precursor of Sentinel-3 SLSTR data. It has replaced the former L1B product [ATS_TOA_1P] in Envisat format from the 3rd reprocessing. Users with Envisat-format products are recommended to move to the new Sentinel-SAFE like/NetCDF format products.&nbsp;</p>

<p>The 4th reprocessing of ENVISAT AATSR data was completed in 2022; the processing updates that have been put in place and the expected scientific improvements have been outlined in full in the <a href="https://earth.esa.int/documents/20142/37627/QA4EO-VEG-OQC-MEM-4538_User_Documentation_for__A_ATSR_4th_Reprocessing_Level_1.pdf" target="_blank">User Documentation for (A)ATSR 4th Reprocessing Products</a>.</p>

Envisat AATSR L1B Brightness Temperature/Radiance [ENV_AT_1_RBT]

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A Fast Registration request must be submitted to access these data collections. Following user authentication, access to the data are provided within two working days.

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Daniel Heywood

Mission

Earth Observation Satellite

TOPEX/POSEIDON

Joint Polar Satellite System - 2 planned for 2022

JPSS-2

Joint Polar Satellite System - 3 planned for 2026

JPSS-3

Joint Polar Satellite System - 4 planned for 2031

JPSS-4

Swarm-B

Swarm-A

Swarm-C

FY-3B

Nimbus-4

CloudSat

Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations

CALIPSO

GOSAT-2

GOSAT (Greenhouse gases Observing Satellite) is a JAXA (Japan Aerospace Exploration Agency) mission within the GCOM (Global Change Observation Mission) program of Japan. The GOSAT mission goals call for the study of the transport mechanisms of greenhouse gases such as carbon dioxide (CO2) and methane (CH4).

GOSAT-1

NOAA-20

TIROS

TIROS-N

GMS (Japan Geostationary Meteorological Satellite)

GMS-5

Star Camera Assembly (SCA) precisely determines the two GRACE satellite's orientation by tracking them relative to the position of the stars.

GRACE SCA

Instrument

The Laser Retro-Reflector (LRR) is mounted on the Earth-facing panel of Envisat close to the RA-2 antenna to support satellite ranging for precise orbit determination and RA-2 range measurement calibration. Laser tracking provides the distance between the spacecraft and the station and is assimilated in precise orbit determination. It will be used extensively during the commissioning phase and regularly during the mission to verify the stability of the positioning system.

Laser Retro-Reflector consisting of four corner cubes mounted in a small pyramid on the underside of the spacecraft. They provide a means of tracking the GRACE satellites from the ground for backup and orbit verification.

GRACE LRR

Precise orbit determination relies on the data from the GPS receivers providing full global coverage of orbit data. The alternative method of Satellite Laser Ranging (SLR) is used as a supporting and independent means for orbit determination. Its limitation is the rather poor global and temporal coverage, but the SLR data is free from ambiguities and directly related to the terrestrial reference frame.

Each of the Swarm satellites is equipped with a Laser Retro-Reflector (LRR) of novel design for external calibration and validation of the onboard GPS receiver. A basic requirement for LRR is to enable the worldwide SLR station network to track the satellite with high accuracy and with a sufficiently high link budget under both night and daytime ranging conditions.

The PRARE (Precise Range and Range-Rate Equipment) instruments, carried aboard ERS-1 and ERS-2, were developed for precise satellite range determination leading to higher-accuracy altitude measurements.

PRARE

A spectrometer is a scientific instrument used to separate and measure spectral components of a physical phenomenon. Spectrometer is a broad term often used to describe instruments that measure a continuous variable of a phenomenon where the spectral components are somehow mixed. In visible light a spectrometer can for instance separate white light and measure individual narrow bands of colour, called a spectrum, while a mass spectrometer measures the spectrum of the masses of the atoms or molecules present in a gas. The first spectrometers were used to split light into an array of separate colours. Spectrometers were developed in early studies of physics, astronomy, and chemistry. The capability of spectroscopy to determine chemical composition drove its advancement and continues to be one of its primary uses. Spectrometers are used in astronomy to analyse the chemical composition of stars and planets, and spectrometers gather data on the origin of the universe. Hyperspectral radiometer—An advanced multispectral sensor that detects hundreds of very narrow spectral bands throughout the visible, near-infrared, and mid-infrared portions of the electromagnetic spectrum. This sensor’s very high spectral resolution facilitates fine discrimination between different targets based on their spectral response in each of the narrow bands. A device that is designed to detect, measure, and analyse the spectral content of incident electromagnetic radiation. Conventional imaging spectrometers use gratings or prisms to disperse the radiation for spectral discrimination.

Spectrometers

Interferometric radiometers are passive imaging instruments for imaging radiation emission from a target scene.

Interferometric Radiometers

By combining different radar images of the same location – a technique known as interferometry – tiny millimetre-scale ground motion can be identified.

Interferometers

A technology demonstration that uses laser interferometry to measure fluctuations in the separation between the two GRACE spacecraft.

GRACE INTERFEROMETER

The accelerometer serves to measure all non-gravitational accelerations on the GRACE satellite due to air drag, solar radiation pressure or attitude control activator impulses initiated by the attitude and orbit control system (AOCS).

GRACE ACC

The Accelerometer measures the Swarm satellite's non-gravitational acceleration in its respective orbit. The instrument helps scientists to study factors that cause non-gravitational accelerations such as air drag, winds, Earth albedo, and direct solar radiation pressure on the spacecraft.

HRPAN

SAPHIR

The Advanced Technology Microwave Sounder (ATMS), a cross-track scanner with 22 channels, provides sounding observations needed to retrieve profiles of atmospheric temperature and moisture for civilian operational weather forecasting as well as continuity of these measurements for climate monitoring purposes. Like the long heritage of its predecessors, ATMS combines all the channels of the preceding AMSU-A1, AMSU-A2, and AMSU-B sensors into a single package with considerable savings in mass, power, and volume.[Source: NPP home page, http://npp.gsfc.nasa.gov/atms.html].

ATMS

TRSR

The SSTI (Satellite to Satellite Tracking Instrument)is a state-of-the-art GPS receiver that has been designed to operate in a low-Earth orbit environment. The objective is to provide the SST-hl (Satellite-to-Satellite Tracking - high/low) contribution to the gravity field recovery, by the simultaneous tracking of up to 12 GPS satellite signals. In addition, SSTI provides data for precise orbit determination; it is also used for real-time on-board navigation and attitude-reference-frame determination. The SSTI instrument is based on the Lagrange architecture, a flight-proven device of Laben, Milan, Italy, a unit of Thales Alenia Space, Italy

SSTI

GAP (GPS Attitude and Positioning Experiment) instrument objective is to measure S/C velocity and attitude as well as TEC (Total Electron Content) of the ionosphere. The relative phase delay of signals in both the L1 and L2 bands from a GPS satellite occulted by the limb ionosphere provide large-scale (1000's of km) information on how the total electron content responds to magnetospheric perturbations. GAP consists of two components:
- GAP-A: Three single-frequency (L1) GPS receivers and four patch antennas. This package is being used to provide an accurate absolute time reference, spacecraft 3-D attitude, and post-processed spacecraft position and velocity.
- GAP-O: The objective is to provide ionospheric tomography observations.

Envisat ASAR AP Medium Resolution L1 [ASA_APM_1P]

Envisat ASAR Alternating Polarisation Medium Resolution Image

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