Dnieper estuary

Sand dunes along the Dnieper estuary, Ukraine

5 January 2008 00:00 UTC

Dnieper estuary
Dnieper estuary

A bright green shape, a bit like a duck, was first noticed in the MSG 24-hour day cloud microphysics RGB composite on 5 January 2008, situated along the Dnieper estuary in the Ukraine.

Last Updated

27 May 2022

Published on

04 January 2008

By HansPeter Roesli, Jochen Kerkmann (EUMETSAT) and Alex Kryvobok (UHMI, Ukraine)

At the same time it was noticed that the northern-most and most prominent green spot (shown by the red arrow) is slightly more reflective than the surroundings in the visible imagery (see Natural Colour RGB, 10:00 UTC).

The spots are located on the left side of the Dnieper estuary. An animated cloud-free scene shows that the spots are stationary (see Animation, 08:00–13:00 UTC), i.e. they most probably result from particular soil characteristics.

Inspecting the RGB components of the RGB image shows that the signal comes from the IR10.8–IR8.7 difference. In fact, IR8.7 is considerably colder than IR10.8 over the spots, adding green colour to the RGB. As an example the northern-most spot shows temperature difference of up to 6.4 K on 5 January 2008 at 09:15 UTC (see close-up look).

A strongly enhanced HRV image of the same date and time (see close-up look) confirms the higher reflectivity of this spot, as already indicated above. This points to sandy terrain. The sandy terrain of the northern most spot can be confirmed by combining the HRV with Google Earth (see Overlay). Google Earth shows a round area of sand dunes. The Dnieper estuary can be explored interactively by downloading either of the Google Earth files: RGB composite (KMZ) or HRV image (KMZ).

 

Sand dunes along the Dnieper estuary, Ukraine
Figure 1: Meteosat-9 24-hour cloud microphysics RGB, 5 January 2008, 10:00 UTC.
Animation 1 (08:00–13:00 UTC). Animation 2 (hourly, 09:15–24:15 UTC)


Additional content

Met-9 RGB composite from 16 April 2008, 09:15 UTC
Google Maps image of the Dnieper estuary
Soil type map of Dnieper estuary (1969) (Credit: UHMI)