31 1 2013 3 Journal of Arid Meteorology Vol. 31 No. 1 March 2013. J. 2013 31 1 62-69. doi 10. 11755 /j. issn. 1006-7639 2013-01 - 0062 211101 2000 ~ 2010 3 h 2. 5 2. 5 NCEP 2 5 ~ 7 02 11 05 ~ 08 2 ~ 8 m /s T - T d > 0. 6 > 300 m T - T d > 1. 1 > 500 m T - T d > 2. 1 > 800 m 1 008 hpa < 995 hpa > 1 030 hpa 1006-7639 2013-01 - 0062-08 doi 10. 11755 /j. issn. 1006-7639 2013-01 - 0062 P468. 0 + 28 A 10 30 a 1 3 11 1981 ~ 2000 4 500 hpa 2-6 12 7 1974 ~ 2003 8 2 ~ 5 9 13 2012-10 - 25 2012-12 - 02 41275128 1990 -. E - mail lookforhim@ 126. com
1 63 1 2000 ~ 2010 11 a 3 h 1 2. 5 2. 5 NCEP 14 00 ~ 24 3 ~ 5 15 6 ~ 8 9 ~ 11 12 2 1 km 4 300 m 16 300 ~ 500 m 500 ~ 800 m 800 ~ 1 000 m 6 17 12 a 2005 16 d 2000 1 2005 2000 6 18 RAMS 2005 1 2 SST Sea Surface Temperature 2. 1 2. 1. 1 1 10 a 20 d 6 30 d2008 2010 40 d 500 ~ 800 m 17 50% 2008 2010 < 300 m 19 1989 ~ 2002 14 a 2. 1. 2 2 4 ~ 7 80% 5 ~ 7 6 9 ~ 11 2. 1. 3 3 02 11 05 ~ 08
64 31 11 08 11 ~ 20 500 ~ 800 m 300 m 02 ~ 08 14 ~ 17 05 ~ 08 11 17 800 ~ 1 000 m 08 14 ~ 300 ~ 500 m 02 05 23 1 Tab. 1 d Interannual variability of Bohai sea foggy days /m 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 < 300 1 5 3 3 4 6 5 8 12 4 10 300 ~ 500 2 3 0 5 2 5 8 4 3 1 4 500 ~ 800 17 14 15 29 17 24 16 16 23 14 26 800 ~ 1 000 4 7 3 2 2 1 4 6 8 3 6 < 1 000 24 29 21 39 25 36 33 34 46 22 46 2 Tab. 2 d Monthly variability of Bohai sea foggy days 12 /m 1 2 3 4 5 6 7 8 9 10 11 < 2300 3 10 3 3 8 12 9 3 0 6 2 300 0~ 500 1 1 7 1 4 9 8 2 1 2 1 500 9~ 800 5 10 9 18 27 56 50 10 4 7 6 800 ~6 1 000 4 4 2 3 3 8 5 3 1 2 1 < 17000 13 25 21 25 42 85 72 18 6 17 10 3 Tab. 3 d Daily variability of Bohai sea foggy days /m 02 05 08 11 14 17 20 23 < 300 21 41 34 6 3 4 17 19 300 ~ 500 21 23 18 9 0 8 8 13 500 ~ 800 61 84 72 39 20 26 42 51 800 ~ 1 000 10 10 17 13 7 8 7 4 < 1 000 113 158 141 67 30 46 74 87 2. 2. 1 1 300 m 08 11 125 300 ~ 500 m 14 ~ 17 143 500 ~ 800 m 20 153 800 ~ 1 000 m 115 2. 2 1 000 m
1 65 2. 2. 2 8 m /s 2 < 300 m 2 m /s 5 m /s 7 m /s 1 2. 11 m /s 300 ~ 500 m 2 m /s 5 m /s 7 m /s 2. 24 m /s 500 ~ 800 m 3 m /s 7 m /s 8 m /s 2. 88 m /s 800 ~ 1000 m 2 m /s 8 m /s 11 m /s 3. 08 m / s 1 000 m 2 ~ 8 m /s 2. 72 m 2 ~ 8 m /s 2 ~ 3
66 31 T - T d > 0. 6 > 300 m T - T d > 1. 1 > 500 m T - T d > 2. 1 > 800 m 2 Fig. 2 The relationship between sea fog numbers with different visibility levels and wind speed 2. 2. 3 T - T d hpa < 995 hpa > 1 030 hpa T - T d < 1. 1 > 995 ~ 1 030 hpa 75% 3 300 m T - T d 0. 0 ~ 0. 4 0. 6 0 0. 04 300 ~ 500 m T - T d 0 0. 0 ~ 0. 7 1. 1 0. 11 500 ~ 800 m T - T d 0 0. 0 ~ 0. 7 2. 1 3. 11 800 ~ 1 000 m T - T d 0. 5 0. 0 ~ 1. 3 3. 2 0. 16 2. 2. 4 960 ~ 1 022 hpa 1 002. 2 hpa 4 800 ~ 1 000 m 1 000 ~ 1 030 hpa < 800 m 1 008 hpa 1 008 hpa < 997 hpa > 1 024 4 Fig. 4 The relationship between sea fog numbers with different visibility levels and the atmospheric pressure 2. 3 6 3 40 N 11 a 6 500 hpa Fig. 3 The relationship between sea fog 5 40 N number with different visibility levels and the difference between temperature and dewpoint 20 N 125 E 588
1 67 30 N 6a 2005 16 95 E d 2000 1 d 6 588 35 N 5 2000 ~ 2010 6 500 hpa gpm Fig. 5 The 500 hpa average geopotential height in June from 2000 to 2010 500 hpa 6b 150 E 160 E 588 2. 4 7a > 90% Fig. 6 6 2005 a 2000 b 500 hpa gpm The 500 hpa geopotential height in more foggy days year 2005 a and less foggy days year 2000 b Fig. 7 7 2005 a 2000 b 1 000 hpa % The 1 000 hpa relative humidity in more foggy days year 2005 a and less foggy days year 2000 b
68 31 35 N 7b 35 N > 90% 32 N 25 N 8 8 2005 1 000 hpa a 850 hpa b 2000 1 000 hpa c 850 hpa d g cm - 1 hpa - 1 s - 1 Fig. 8 The 1 000 hpa a and 850 hpa b water vapor flux in 2005 1 000 hpa c and 850 hpa d water vapor flux in the year of 2000 Unit g cm - 1 hpa - 1 s - 1 3 17 17 11 12 19 16-17 19 11 a
1 69 16 2009 5 6 13-15 2010 28 1 41-48. 7 2012 30 3 374-379. 8 J. 2011 29 2 174-181. 9 J 2008 38 3 359-366. 2006 23 supplement 68-72. 12 J. 2008 26 3 71-76. 13 2004 26 3 28-37. 14 2005 36 1 36-42. 15 2006 28 1 26-34. 1. M. 1983. 352. 2. 2007 1 18. 2005 J. 2008 26 2 63-66. D. 2006. 3. 19. J. J. 2006 24 3 47-51. 2009 26 4 11-14. 4. J. 27 3 263-270.. J. 2012 30 1 114-118.. J.. J.... 10. J. 2008 3 7-12. 11. J... J.. J.. J. 16. J. 2009 27 1 16-23. 17. J. 2010 9 3 9-14. Characteristics and Generating Mechanism of Sea Fog in Dalian of Liaoning Province TANG Pengyu HE Hongrang YANG Xiangrong Meteorology College PLA University of Science and Technology Nanjing 211101 China Abstract Based on the conventional meteorological data of every three hours from 2000 to 2010 and the monthly average field reanalysis data of NCEP 2. 5 2. 5 the various characteristics of atmospheric environmental elements during sea fog generation in Dalian was analyzed and infuluences of the environmental elements on the generating and dissipating of sea fog were studied then the environmental conditions which was beneficial to the sea fog s generation were obtained. At the same time the interannual variability and seasonal characteristics of Dalian sea fog were analyzed and the circulation situation and moisture conditions which causing the abnormal more and less sea fog were compared to study the circulation situations of Dalian sea fog generation and dissipation as well as the moisture sources. The results show that Dalian sea fog mainly occurred in spring and summer especially in May to July in a day sea fog mainly occurred from 02 00 to 11 00 and usually dissipated after sunrise in the morning. East or south winds with 2-8 m /s were most conducive to the occurrence of Dalian sea fog. When sea fog occurred and T - T d was more than 0. 6 the visibility would be forecasted more than 300 m and T - T d was more than 1. 1 the visibility would be forecasted more than 500 m and when T - T d was more than 2. 1 the visibility would be forecasted more than 800 m. Sea fog frequency reached a peak at 1 008 hpa when air pressure was less than 995 hpa and more than 1 030 hpa no sea fog generated basically. The sea fog in Dalian were mostly advection fog. The sea fog frequency was related to the south monsoon airflow at the west side of the western Pacific subtropical high when the subtropical high enhanced the moisture over the tropical ocean surface could be directly transported to the Dalian area by the southwest monsoon airflow and when the advection moisture encountered cold underlying surface the sea fog occurred in the coast of Dalian. Key words Dalian sea fog statistical characteristics generation mechanism