Investigation of the cloudiness-Albedo feedback using analogue satellite images

J. Mika, A. Rimóczi-Paál

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Abstract

A classical assumption for the dependence of planetary albedo on horizontal cloud coverage (α = α0 (1 - n) + αnn) is empirically verified for two areas in the Carpathian Basin (Hungary). The albedo values are derived from METEOSAT-2 analogue images by a special technique developed by Rimóczi-Paál and cloudiness is determined visually from the same images. A filtering by averaging of 3-7 pictures of the same day is applied to decrease the likely errors due to differences in the slope angle. A close linear regression between albedo and cloudiness is established with a regression coefficient close to αn0, but the parabolic fit shows considerable differences in ∂α/∂n for different values of n. For climate-modelling purposes the subsample of medium cloudiness (0.31 ≤ n ≤ 0.70) is also investigated. Linear and parabolic regressions give less accurate but still highly significant fit with about one half of total variance in albedo "explained" by cloudiness changes. These calculations based on half-yearly grouped subsamples are repeated for 3-monthly grouped ones, with no marked difference in conclusions. The estimated value of ∂α/∂n is higher than αn - α0 especially for the warm/warming-up half-year, but the difference is not much beyond the error deviation of the regression estimations. The peculiar importance of accurate quantitative determination of cloudiness-albedo feedback is demonstrated using an independent estimation of the sensitivity of regional cloudiness in Hungary on hemispheric temperature changes.

Original languageEnglish
Pages (from-to)323-335
Number of pages13
JournalAtmospheric Research
Volume21
Issue number3-4
DOIs
Publication statusPublished - 1988

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cloud cover
albedo
slope angle
satellite image
climate modeling
warming
basin
temperature

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

Investigation of the cloudiness-Albedo feedback using analogue satellite images. / Mika, J.; Rimóczi-Paál, A.

In: Atmospheric Research, Vol. 21, No. 3-4, 1988, p. 323-335.

Research output: Contribution to journalArticle

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