Interpretation of sea ice using NOAA-AVHRR data

Kristina Ahlnäs, Risto Kuittinen, Eija Parmes

Research output: Book/ReportReport

Abstract

The different channels of the NOAA-AVHRR (National Oceanic and Atmospheric Administration-Advanced Very High Resolution Radiometer) satellites were studied to determine the best single channel and channel combinations to use in distinguishing between clouds, sea-ice types and open water. The study area was situated in the Bay of Bothnia, the northernmost part of the Baltic Sea, in the winter of 1987. The best channel combination for cloud separation was 124/RGB (Red Green Blue) making clouds bright yellow and open water blue. This combination worked well from mid-February through May. However, when available, as in NOAA-9, Ch 125/RGB was a better choice than Ch 124/RGB. Leads and open water could be seen in channel 5 but not in channel 4. The near IR channel 2, in combination with one thermal IR channel, 4 or 5, was also sufficient to separate clouds from ice. Image enhancement by exponential and logarithmic functions improved the interpretation of the image. Numerical interpretation with spectral and textural information of NOAA images was used to interpret clouds, water and sea-ice types. In this task contrast and entropy were used as textural parameters. Supervised and unsupervised methods were used in classification. The results showed that water, open ice, close ice and partly ridged as well as fast ice can be discriminated although discriminating between fast ice and clouds as well as fast ice and ridges is difficult. Entropy was a better textural parameter than contrast but an algorithm has to be developed to make the interpretation faster.
Original languageEnglish
Place of PublicationEspoo
PublisherVTT Technical Research Centre of Finland
Number of pages48
ISBN (Print)951-38-3805-6
Publication statusPublished - 1990
MoE publication typeNot Eligible

Publication series

SeriesValtion teknillinen tutkimuskeskus. Tiedotteita
Number1156
ISSN0358-5085

Fingerprint

AVHRR
sea ice
open water
ice
entropy
cloud water
winter

Keywords

  • seawater
  • clouds (meteorology)
  • ice forecasting
  • satellite images
  • interpretation
  • recognition

Cite this

Ahlnäs, K., Kuittinen, R., & Parmes, E. (1990). Interpretation of sea ice using NOAA-AVHRR data. Espoo: VTT Technical Research Centre of Finland. Valtion teknillinen tutkimuskeskus. Tiedotteita, No. 1156
Ahlnäs, Kristina ; Kuittinen, Risto ; Parmes, Eija. / Interpretation of sea ice using NOAA-AVHRR data. Espoo : VTT Technical Research Centre of Finland, 1990. 48 p. (Valtion teknillinen tutkimuskeskus. Tiedotteita; No. 1156).
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Ahlnäs, K, Kuittinen, R & Parmes, E 1990, Interpretation of sea ice using NOAA-AVHRR data. Valtion teknillinen tutkimuskeskus. Tiedotteita, no. 1156, VTT Technical Research Centre of Finland, Espoo.

Interpretation of sea ice using NOAA-AVHRR data. / Ahlnäs, Kristina; Kuittinen, Risto; Parmes, Eija.

Espoo : VTT Technical Research Centre of Finland, 1990. 48 p. (Valtion teknillinen tutkimuskeskus. Tiedotteita; No. 1156).

Research output: Book/ReportReport

TY - BOOK

T1 - Interpretation of sea ice using NOAA-AVHRR data

AU - Ahlnäs, Kristina

AU - Kuittinen, Risto

AU - Parmes, Eija

PY - 1990

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N2 - The different channels of the NOAA-AVHRR (National Oceanic and Atmospheric Administration-Advanced Very High Resolution Radiometer) satellites were studied to determine the best single channel and channel combinations to use in distinguishing between clouds, sea-ice types and open water. The study area was situated in the Bay of Bothnia, the northernmost part of the Baltic Sea, in the winter of 1987. The best channel combination for cloud separation was 124/RGB (Red Green Blue) making clouds bright yellow and open water blue. This combination worked well from mid-February through May. However, when available, as in NOAA-9, Ch 125/RGB was a better choice than Ch 124/RGB. Leads and open water could be seen in channel 5 but not in channel 4. The near IR channel 2, in combination with one thermal IR channel, 4 or 5, was also sufficient to separate clouds from ice. Image enhancement by exponential and logarithmic functions improved the interpretation of the image. Numerical interpretation with spectral and textural information of NOAA images was used to interpret clouds, water and sea-ice types. In this task contrast and entropy were used as textural parameters. Supervised and unsupervised methods were used in classification. The results showed that water, open ice, close ice and partly ridged as well as fast ice can be discriminated although discriminating between fast ice and clouds as well as fast ice and ridges is difficult. Entropy was a better textural parameter than contrast but an algorithm has to be developed to make the interpretation faster.

AB - The different channels of the NOAA-AVHRR (National Oceanic and Atmospheric Administration-Advanced Very High Resolution Radiometer) satellites were studied to determine the best single channel and channel combinations to use in distinguishing between clouds, sea-ice types and open water. The study area was situated in the Bay of Bothnia, the northernmost part of the Baltic Sea, in the winter of 1987. The best channel combination for cloud separation was 124/RGB (Red Green Blue) making clouds bright yellow and open water blue. This combination worked well from mid-February through May. However, when available, as in NOAA-9, Ch 125/RGB was a better choice than Ch 124/RGB. Leads and open water could be seen in channel 5 but not in channel 4. The near IR channel 2, in combination with one thermal IR channel, 4 or 5, was also sufficient to separate clouds from ice. Image enhancement by exponential and logarithmic functions improved the interpretation of the image. Numerical interpretation with spectral and textural information of NOAA images was used to interpret clouds, water and sea-ice types. In this task contrast and entropy were used as textural parameters. Supervised and unsupervised methods were used in classification. The results showed that water, open ice, close ice and partly ridged as well as fast ice can be discriminated although discriminating between fast ice and clouds as well as fast ice and ridges is difficult. Entropy was a better textural parameter than contrast but an algorithm has to be developed to make the interpretation faster.

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KW - clouds (meteorology)

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M3 - Report

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T3 - Valtion teknillinen tutkimuskeskus. Tiedotteita

BT - Interpretation of sea ice using NOAA-AVHRR data

PB - VTT Technical Research Centre of Finland

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ER -

Ahlnäs K, Kuittinen R, Parmes E. Interpretation of sea ice using NOAA-AVHRR data. Espoo: VTT Technical Research Centre of Finland, 1990. 48 p. (Valtion teknillinen tutkimuskeskus. Tiedotteita; No. 1156).