3.2 MeteorologIcal Conditions
21
The winter 1995/1 996 was characterized by strong ice formation. Because of
the long period of ice cover, it was called "ice winter". However, with 49 days of
ice cover the winter was not rated as extreme, but held rank 9 in a IOO-year-record
(Strubing 1996). After the Y nsen frost index (Y nsen 1991), which is calculated by
the number of days with frost (minimum of temperature < 0 Qq, the number of
days with ice formation (maximum of temperature < 0 QC) and the number of the
very cold days (maximum of temperature < -I () Qq, the winter 1995/1 996 is classified as a strong winter.
Water temperature
With the exception of some anomalies the trend of the water temperature corresponded with the long year mean in all three years and followed the air temperatures (Fig. 3.2.3). Conspicuous were the high temperatures in the summer of 1994
and 1995. The winter 1995/1 996 was characterized by long lasting low temperatures, which led to an ice cover in the Wadden Sea. The water temperatures In
1996 were striking by a negative deviation compared to the previous years.
- - - - - - -~-_- --1------ "",~.~ ·- -T--........ +--'-'-~-I -- -- - - --- - -- - - "'"
;-,...-t':'"'~V:: _~~:: _ _ _ _ _ _ _ _
-
:-:-:-~'"-t- __ ~_~ __ -+-:~: _' -"-: -: ~
Jan Feb Mar Apr May Jun Jul AUQ Sep Oct Nov Dec
Fig. 3.2.3 Water temperature in the years of observation at the weather station of Norderney,
data courtesy of the DWD
Atmospheric pressure
Special features were recorded in the development of the atmospheric pressure in
summer 1994 (Fig. 3.2.4). From the end of April to the end of August a general
high pressure period persisted. In the beginning of 1995 low pressure prevailed,
but in summer a long high pressure period developed similar to the year before.
The high pressure periods of the winter 1995/1996 were quite unusual. They were
only interrupted for a few days in February 1996. In summer 1996 no typical high
pressure period developed. The values varied a lot, indicating frequent weather
changes during this time.
21
The winter 1995/1 996 was characterized by strong ice formation. Because of
the long period of ice cover, it was called "ice winter". However, with 49 days of
ice cover the winter was not rated as extreme, but held rank 9 in a IOO-year-record
(Strubing 1996). After the Y nsen frost index (Y nsen 1991), which is calculated by
the number of days with frost (minimum of temperature < 0 Qq, the number of
days with ice formation (maximum of temperature < 0 QC) and the number of the
very cold days (maximum of temperature < -I () Qq, the winter 1995/1 996 is classified as a strong winter.
Water temperature
With the exception of some anomalies the trend of the water temperature corresponded with the long year mean in all three years and followed the air temperatures (Fig. 3.2.3). Conspicuous were the high temperatures in the summer of 1994
and 1995. The winter 1995/1 996 was characterized by long lasting low temperatures, which led to an ice cover in the Wadden Sea. The water temperatures In
1996 were striking by a negative deviation compared to the previous years.
- - - - - - -~-_- --1------ "",~.~ ·- -T--........ +--'-'-~-I -- -- - - --- - -- - - "'"
;-,...-t':'"'~V:: _~~:: _ _ _ _ _ _ _ _
-
:-:-:-~'"-t- __ ~_~ __ -+-:~: _' -"-: -: ~
Jan Feb Mar Apr May Jun Jul AUQ Sep Oct Nov Dec
Fig. 3.2.3 Water temperature in the years of observation at the weather station of Norderney,
data courtesy of the DWD
Atmospheric pressure
Special features were recorded in the development of the atmospheric pressure in
summer 1994 (Fig. 3.2.4). From the end of April to the end of August a general
high pressure period persisted. In the beginning of 1995 low pressure prevailed,
but in summer a long high pressure period developed similar to the year before.
The high pressure periods of the winter 1995/1996 were quite unusual. They were
only interrupted for a few days in February 1996. In summer 1996 no typical high
pressure period developed. The values varied a lot, indicating frequent weather
changes during this time.