2010 12 13 2010 12 23 2010 12 28 Observed Change of Climatic Regions and Desertification during the 20th Century Il-Ung Chung* Sang-Hye Shin** *Department of Atmospheric & Environmental Sciences, Gangneung-Wonju National University **Department of Atmospheric Sciences, Yonsei University (Received 13 December 2010, Revised 23 December 2010, Accepted 28 December 2010) 20 Köppen 5 A E C/D 1960 B 1970 1960 1990 2 (BW) 20 1991 2000 1961 1990 1 320 10 3 km 2 (BS) 1950 1960 Abstract : In this study, the characteristic features in both global change of the Köppen climate regions and desertification during the 20th century were investigated using observed data. The results of the analyses for the areal changes of Köppen climate regions show that the warmer climate areas and the colder climate areas were continually expanded and shrunk, respectively, over the entire period. Areas of C and D climate types show distinct increase and decrease, respectively, since 1960s. These changes seem to be understood by the direct consequences of global warming. Area of the dry climate was considerably expanded since 1970s so that its areal percentage during 1990s was increased by about 2% compared to during 1960s. Especially, area of the desert climates was increased by about 1 320 10 3 km 2 during the last decade, relative to the average for 1961~1990. This expansion can be interpreted as a desertification because most of the expansion (more than 98%) Correspondence: Il-Ung Chung, Department of Atmospheric & Environmental Sciences, Gangneung-Wonju National University, 120 Gangneung Daehagno, Gangneung, Gangwon, 210-702, Republic of Korea, Phone: +82-33-640-2325, Fax: +82-33-640-2320, E-mail: iuchung@gwnu.ac.kr
24 was from BS climate regions around deserts. Analysis for the regional desertification reveals that the most prominent expansion occurred in the northern Africa and in the central Asia since 1950s. The possibility of global warming as a cause of the desertification was prudently examined by inquiring intensification of the wintertime Hadley circulation. We found that Hadley circulation in boreal winter was significantly strengthened since 1960s. Key Words : Global Warming, Climate Change, Köppen Climate Classification, Climate Region, Hadley Circulation 50 IPCC (Intergovernmental Panel on Climate Change) 4 (IPCC, 2007) 280ppm 2005 379ppm 715ppb 1774ppb 270ppb 319ppb 1905 2005 100 0 8 1978 (sea ice) 10 3 3000 1961 2003 1 8mm 20 100 17cm 3000 10 Suckling and Mitchell(2000) 20 Köppen C/D Fraedrich et al.(2001) 20 15 Diaz and Eischeid(2007) 1987 2006 20 73
25 Köppen 20 Beck et al.(2006) 1951 2000 1986 2000 5 3 3 Fraedrich et al.(2001) Beck et al.(2006) 20 1970 IPCC(2007) UNCCD(United Nations Convention to Combat Desertification) 2 5 (WMO, 2005) 100 10 (Fraedrich et al., 2001; Beck et al., 2006; Kim et al., 2008) 1997 Charney(1975) 1998 Nicholson et al.(1998) 1980 1995 16 NDVI(Normalized Difference Vegetation Index) Piao et al.(2005) 1982 1999 18 NDVI 1980 1990 7 8 Mahowald(2007) Zeng and Yoon(2009) IPCC
26 20 A B C D E f m w S W w s f w s f T F 18 6cm 10 R/25 R cm 10 R/25 R<2T 28 70 6 R<2T 70 6 R<2T 14 6 6 70 R (cm) T BS-BW 1 2 3 10 3 w s 3 10 C C C 10 0 10 0
27 Köppen 1936 20 Köppen 1 5 (A, B, C, D, E) 2 3 13 5 (B) (BS) (BW) Martonne 1999 AI(aridity index) (P) (T) AI P(mm) T( C)+10 (1) Charney(1975) Tanaka et al.(2004) 200hPa V fl V fl (Krishnamurti, 1971) V fl V fl V fl kfi fl fl (2) (streamfunction) (velocity potential) D D fl V fl 2 (3) D Poisson (2) D(spherical harmonic expansion) Tanaka et al.(2004)
28 max 200hPa 3 3 Tanaka et al.(2004) 3 (orthogonal spatial patterns) [ (t,y)] *(t,x,y) [ (t,y)] *(x,y) * (t,x,y) (4) x, y, t 4 Köppen (Climatic Research Unit, CRU) CRU TS 2.1 (Mitchell and Jones, 2005) 0 5 1901 2002 102 20 100 10 10 10 Köppen 1 20 ECMWF 40 (Uppala et al., 2005) 200hPa 1957 9 2002 8 1961 2000 40 2 5 2 1971 2000 30 200hPa
29 (DJF) (JJA) 5 5
30
31 3a 1990 10 1961 1990 0 44 1 6 0 8 1998 3 1990 10 1961 1990 Köppen 4 13 Köppen 5 5 13 5 6 (A) 20 20 23 08 20 23 59 0 51 (B) 20 28 73 1930 1970 50 27 43 30 1 8 29 27 1 8 2 638 1 10 3 km 2 11 8 30 (C) 20 20 16 17 15 64 20 16 74 (D) 1960 23 59 24 18 23 15 1960
32 (E) 20 20 8 43 20 7 25 1 18 1 729 4 10 3 km 2 7 7
33 Köppen 20 2 10 1990
34
35 A BS BW C D E 864.9 10 3 km 2 3,503.1 103km 2 1,320.3 10 3 km 2 2,073.8 10 3 km 2 1,277.7 10 3 km 2 24.8 10 3 km 2 A - 13.6 0.0 5.2 0.0 0.0 BS 31.7-98.3 14.6 7.2 11.8 BW 0.0 32.6-0.0 0.0 0.0 C 68.3 30.8 0.0-1.5 0.0 D 0.0 22.4 0.0 76.7-88.2 E 0.0 0.7 1.7 3.5 91.3 - (A) 864 9 10 3 km 2 BS A 31 7 BW BW 1 320 3 10 3 km 2 BS BW 98 3 BW BS BW BS BW BS A C D BW E 1 7 BW E BW 5 5 7a 5 100 0 66 0 91 1 34 0 54 0 76 100
36 7b 20 1950 1980 303mm 231mm 72mm 10 20 1950 16mm 1960 20 20 64mm 39mm 1940 1970 8 8 BS BW BS
37 20 1960 1980 226 5 10 3 km 2 BW 1950 1980 853 9 10 3 km 2 1950 1980 2 2 10 0 6 1950 1980 10 Nicholson et al.(1998) 8b BS 40 144 8 10 3 km 2 BW 30 639 7 10 3 km 2 30 3 2 BW 20 8c BS 20 1950 1950 434 3 10 3 km 2 BW 1940 10 1950 50 191 4 10 3 km 2 1950 2 4 BW BS BS BW 8d BS 1970 80 20 20 1 036 1 10 3 km 2 BW BS 1970 80 20 20 1 084 5 10 3 km 2 1970 80 20 1 7 8 BS BW BS 98 0 10 3 km 2 BW 1950 1980 425 6 10 3 km 2 10 274 9 10 3 km 2 BW 1950 1980 1 7 10 0 5
38
39 20 Chen et al.(2002) 1990 Hu and Fu(2007) 1979 IPCC 4 (IPCC, 2007) 21 Lu et al.(2007) 9 ECMWF 40 200 1961 2000 40 4 10 27 5 12 15 1960 1990 (DJF) (Tanaka et al. 2004, Mitas and Clement, 2005; Song and Zhang, 2007; Takemoto and Tanaka, 2007) 10 1 2 3 40 20 40
40
41
42 20 Köppen 5 20 100 A E C/D 1960 B 1970 1960 1990 2 (BW) 20 1991 2000 1961 1990 1 320 10 3 km 2 (BS) 20 BS BW 1950 Charney(1975) 1960 21 IPCC 30 20 21 20 21
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