Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: AVHRR channels

Sortuj według:

Ogranicz wyniki do:

Influence of aerosol vertical profile variability on retrievals of aerosol optical thickness from NOAA AVHRR measurements in the Baltic region

Rozwadowska A.

Oceanologia

2007

No. 49 (2)

165-184

The expected influence of variability in atmospheric aerosol profiles on retrievals of aerosol optical thickness (AOT) from NOAA AVHRR measurements is analysed. In particular, the bias in the AOT retrieval due to the assumption of a climatological aerosol profile in the retrieval algorithm is studied. The bias is defined as the difference between AOT retrieved with an algorithm using a climatological aerosol profile, and the actual AOT employed in the calculations of radiances at the top of the atmosphere (TOA). The TOA radiances are simulated by means of the MODTRAN code for different aerosol profiles. Atmospheric conditions and solar and satellite angles used in the bias simulations are typical of the Baltic region. In the simulations, the maximum absolute value of the bias amounts to nearly 40% in channel 2 and 14% in channel 1 of AVHRR.

Sea surface temperature distribution during upwelling along the Polish Baltic coast

Krężel A., Ostrowski M., Szymelfenig M.

Oceanologia

2005

No. 47 (4)

415-432

Among over 150 maps of sea surface temperature in the Polish Baltic coastal region derived from satellite data during the warm period of the year (April-October) in 2000-2002, 41 cases were noted where its distribution showed characteristic features indicating the occurrence of coastal upwelling. The fundamental parameters of range, probability of occurrence and temperature modification caused by water from deeper sea layers raised by an upwelling event and spreading across the surface were established for three regions (Hel, Łeba and Kołobrzeg). The Kołobrzeg upwelling region had the largest spatial range (up to 5000 km2). The region with the smallest spatial range (Hel, up to 1400 km2) had the largest surface temperature amplitude (to 14°C), the largest maximum temperature gradient (5°C km2) and the largest average sea surface temperature decrease in the centre in relation to the background value.

The use of sequential satellite images for the calculating surface velocity vectors in the waters of the Gulf of Gdańsk

Żarki I., Krężel A.

Oceanological Studies

1999

Vol. 28, No. 3-4

35-44

The Maximum Cross Correlation method (MCC) modified with divergence checking was used to calculate the surface velocity field in the Gulf of Gdansk. The brightness temperature in channel 4 of the AVHRR taken 10 times between 6 and 9 August 1996 served as input data. The surface velocity vector distribution obtained with the use of MCC are compared with the results of a 3D hydrodynamic model and field observation of a drifting rhodamine spill during the POLRODEX?96 experiment.