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1 RESOURCES SCIENCE Vol. 25 No. 3 May 2003 ( ) : 500L h - 120h 6h : ; ; cm d cm 514d ; : : ; ; ; :P :B : (2003) THE TEMPORAL CHANGE CHARACTERISTICS OF SEA ICE THICKNESS AND REGENERATION PERIOD OF SEA ICE IN LIAODONG GULF GU Wei GU Song2gang SHI Pei2jun LIU Yang CUI Wei2jia ( Key Laboratory of Environmental Changes and Natural Disaster of Ministry of Education of China Beijing Normal University ; Institute of Resources Science Beijing Normal University Beijing China) Abstract : It is the basis for estimation of the amount of sea ice resources to understand the changing charac2 teristics of sea ice thickness with the effect by some factors such as temperature. In this paper a freezing experiment in laboratory an observation in experimental sites and an analysis by historical data were per2 formed to study the changing characteristics of sea ice thickness affected by temperature and wind with time. Based on that a reformed cycle for sea ice was proposed. A 500L refrigerator was used in the laboratory its temperature was controlled at frozen time was hours the intermission obtained ice thickness was 6 hours. The observed location was northern of sea region of Liaoning Province. Ice surface temperature temperature above ice surface and surface temperature close to coast were observed while thickness of sea ice was observed at same time. And these data were compared with accumu2 lated temperature with from Hulu Island meteorological station. The conclusions of this study are as follows. The sea ice thickness increases in accordance with the temperature decrease or the nega2 tive accumulated temperature increase ; the greater wind speed the smaller of sea ice thickness formed ; the regenerated speed of sea ice in temperature with - 4 in Bohai region is 1. 86mΠd which means that pro2 ducing the sea ice on the thickness with 10cm needs 5. 4 days. The possible times for exploiting sea ice with : ; : : ; ( : 02010) : (1956 ) edu. cn

2 25 3 : 25 regenerated period of sea ice in each region of Bohai Sea were times in Liaodong Gulf times in Bohai Gulf times in Lai2zhou Gulf respectively. Key words :Sea ice thickness ; Bohai Sea ; Negative accumulated temperature ; Regenerated period of seaice ; L 45cm 40cm 1 ( : ) 35cm ; ; Fig. 1 Changes of sea ice thickness in different temperature with time Table 1 Correlation between sea ice thickness in different temperature and time h 120h ; 6h 3 4 ( ) ; 1 ; ( 112 ) :

3 ( 2) ( 2 = ) 2 Table 2 Correlation coefficients between sea ice thickness in different temperature and negative accumulated temperature Fig. 2 Relationship between sea ice thickness in different temperature and negative accumulated temperature : (2cm 40cm) 100m 67cm m 2 15cm 20cm cm cm

4 25 3 : 27 : 10cm 10cm ( ) 115m 4 ( ) ; ( ) 115m ( ( 3) 39h 115mm h mm h - 1 Table 4 Weather condition and wind at northern Sea area of 1 1 Changxing island ( January 27 th to 30 th 2002) NWN 3 ( ) 414m s NE 118m s - 1 NNE WSW ( Y) ( X) Table 3 Changes in sea ice thickness ( Y) at northern Sea area of Changxing island with time ( X) ( January 2002) Y Y = X X Y Y = X X Y Y = X X ) TR - 71S 5min 4 4 (9 16 ) 4 : > > > ; (7 9 ;16 19 ) 4 ; (19 7 ) 4 : > 5 4 Table 5 Daily mean values with four kinds of temperature Fig. 3 Changes of sea ice thickness at northern ( 5) 29 sea area of Changxing island with time ( ) 39h ( ( ) : N E) : ( 5) ( )

5 Fig. 4 Changes of temperature at northern Sea area of Changxing island with time (January 27 th to 30 th 2002) 5 Fig. 5 Relationship between sea ice thickness and negative accumulated temperature at northern Sea area of Changxing island h 39h 10h ( 49h ) 3 : ; 5

6 25 3 : 29 ; [1 ] ( ) ( 5 s m s ) ; : m m s - 1 ( 6 4 ) 2316cm cm(1 24 ) cm 25cm (518cm) 19 35cm 40cm (3714cm) 5d 7d ( 7) : (1 4 ; ; ) : : Fig. 6 Changes in sea ice thickness at Hulu Island with temperature wind speed and time in winter ( )

7 Fig. 7 Changes in sea ice thickness at Hulu island with temperature and wind speed of slide average value in winter ( ) Fig. 8 Temporal changes of sea ice thickness at Hulu island with negative accumulated temperature in winter ( ) 4 ; ;

8 25 3 : ( ) [3 ] 10cm 10cm - 4 ( ) 115mm h - 1 [3 ] 316cm d - 1 ; cm d - 1 ( 8) ( 6) ; 70 30d 50d 23 % ; 50 % cm d [4 ] Table 6 Ice periods of each sea area in Bohai Sea in 1970s and 1990s 70 (d) (d) : Table 7 Days of accumulated temperature with temperature - 4 at each area of Bohai Sea ( annual mean value from 1961 to 1990) - 4 ( ) (d) Table 8 Regenerated rate of sea ice with temperature - 4 obtained from historical data at Hulu island - ( ) (cm) 4 (cm d - 1 ) ( ) : 40d 70d 20d 40d d 20d mm h cm d - 1 ; 1186

9 ( - 4 ) 10cm d ( 10cm ) ( ) : Π2002 ( References) : d 39d [ 1 ] (1) : ; : ; (2) cm d cm 514d [ 4 ] ( 10cm ) 173. ( ) : cm (3) [ M]. : YANG Guo2jin. Engineering of Sea Ice[M]. Beijing : Oil In2 dustry Press [ 2 ]. [J ] (3) : DUAN Zhong2dong YANGJi2dong OU Jin2ping et al. Statis2 tical Analysis of Probability Distribution of Extreme Ice Thick2 ness in the Bohai and Northern Huanghai Seas[J ]. Journal of Oceanography of Huanghai & Bohai Seas (3) : [ 3 ] [ M] 1 : DING De2wen et al. An Introduction to Engineering Sea Ice [M]. Beijing :Ocean Press [J ] (2) 168 GU Wei SHI Pei2jun LIU Yang et al. The Characteristics of Temporal and Spatial Distribution of Negative Accumulated Tem2 perature in Bohai Sea and North Yellow Sea [J ]. Natural Resources (2) : Journal of