Minimize ASAR Product and Algorithms
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The information provided in this page is applicable to the latest ASAR products, available to users via Fast Registration. To register for these products users will need to log in using their ESA EO-SSO account. If you do not already have an account you can register here.

Level 0 products are derived from the raw satellite data and are the lowest level product available. Level 1 products are then processed from L0 products. Higher level products (Level 2) can then be derived from L1 products; however, this is currently only done with Wave mode. The general layout for all products includes the following records:

  • Main Product Header (MPH) - The MPH has a fixed length and the format is identical across all ENVISAT products.
  • Specific Product Header (SPH) - The SPH is defined for each product and provides additional information related to the processing, which is applicable to the whole product.
  • Data Set (DS) - The DS contains the instrument's scientific measurements that are either measurement data sets (MDS) or annotation data sets (ADS).

Further details are provided in the ASAR product specifications. All ASAR products are provided in ENVISAT format and are processed by the ESA PF-ASAR processor. For information on the latest version of PF-ASAR, see the Processor Releases page.

The specifications for the ASAR data products currently made available by ESA are shown in the ASAR Product Table below. Detailed information on all ASAR products can be found in the ASAR Product Handbook.
 

 

Product ID

Product Name

Nominal resolution (m - range x azimuth)

Pixel Spacing (m)

Coverage (km - range x azimuth)

Equivalent No. Looks

IMP_1P

Image Mode Precision

30 x 30

12.5

56-100 x 100

>3

IMS_1P

Image Mode Single-Look Complex

9 x 6

natural

56-100 x 100

1

IMM_1P

Image Mode Medium resolution

150 x 150

75

56-100 x 100

40

APP_1P

Alternating Polarisation Precision Image

30 x 30

12.5

41-106 x 100

>1.8

APS_1P

Alternating Polarisation Single-Look Complex

9 x 12

natural

41-106 x 100

1

APM_1P

Alternating Polarisation Medium resolution

150 x 150

75

41-106 x 100

50

WSM_1P

Wide Swath Mode Medium resolution

150 x 150

75

400x 400

11.5

WSS_1P

Wide Swath Mode Single-Look Complex

11.5-20 x 117

7.8x80

400x 400

1

GM1_1P

Global Monitoring Mode  Image

1000 x 1000

500

400x 400

7-9

WVI_1P

Wave Mode Imagette and power spectrum

9 x 6

natural

5 x 5

1

WVS_1P

Wave Mode Image Spectra

-

-

5 x 5

-

WVW_2P

Wave Mode Ocean Wave Spectra

-

-

5 x 5

-

Table 1. ASAR L1 product types. *Range width depends on swath used.

 

ASAR data products are currently available through a number of different sources:

  • High resolution precision and single look complex (SLC) IM, AP and WS products are available through EOLI and the ESA Online Dissemination Service
  • Medium resolution IM, AP, WS and GM products are available through the EO Data Gateway
Wave products are available from the ESA Dissharm FTP server

High Resolution products

High resolution products are processed from the Level 0 data upon request using the On-The-Fly (OTF) service. These products are not archived but are processed when a product is selected, usually becoming available within a few minutes. The products processed in this manner are:

  • ASA_IM__0P
  • ASA_IMP_1P
  • ASA_IMS_1P
  • ASA_AP_0P (including Co-polar (APC), Cross-polar horizontal (APH) and Cross-polar vertical (APV))
  • ASA_APP_1P
  • ASA_APS_1P
  • ASA_WS__0P
  • ASA_WSS_1P

Once registered, users can access the Level 1 OTF standard service using either EOLI or the Online Dissemination Service. The EOLI Client for browsing the ASAR catalogue and ordering products can be downloaded here. The Online Dissemination Service can be accessed here. To access products through EOLI or the Online Dissemination Service users will need to log in using their ESA EO-SSO account. As Level 0 data is not part of the OTF standard service access is granted only in exceptional circumstances. To access the Level 0 products, users will have to submit a data service request through their Earthnet account justifying and describing their data needs. For more details on the OTF service, please see the ASAR OTF FAQ page.

 

Medium Resolution products
Medium resolution products were processed operationally using the version of PF-ASAR available at the time of processing. More recently medium resolution products have also been processed from the Level 0 data during a bulk processing activity. Therefore, these products have been archived and are available for immediate download. The products available in this manner are:

  • ASA_IMM_1P
  • ASA_APM_1P
  • ASA_WSM_1P
  • ASA_GM1_1P

Once registered, users can access the Level 1 products through the EO Data Gateway. To access products the EO Data Gateway users will need to log in using their ESA EO-SSO account.

 

Wave products
Wave products were processed operationally using the version of PF-ASAR available at the time of processing. Therefore, these products have been archived and are available for immediate download. The products available in this manner are:

  • WVI_1P
  • WVS_1P
  • WVW_2P

Once registered, users can access the Level 1 and Level 2 wave products though the ESA Dissharm FTP server (envwave-ftp-ds.eo.esa.int) using the credentials provided at registration. Information on ASAR Wave Mode data can be found in the 'Envisat ASAR Wave Mode Product Description and Reconstruction Procedure' document here. The purpose of this document is to provide the user community with information to reconstruct and interpret the ocean wave spectral information within the ASAR WV products.

 

Minimize ASAR Auxiliary Data Files

The ASAR Auxiliary Data Files are available here