The preliminary study on chemical characteristics of precipitation at Mt. Waliguan

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1 ACTA SCIEN TIAE CIRCUMSTAN TIAE Vol. 20,No. 4 J uly,2000 : (2000) :X517 :A 1, 1, 1, 1, 1, 2, 2 (1., ;2. ) : 1997 ( ).,. 59 p H,, p H 6. 4, ; S/ cm, ; NH 4 +,Ca 2 +,SO 4 2,Mg 2 +,Na +,NO 3,Cl, K +,F,,,NH 4 + Ca 2 + ;,. : ; ; The preliminary study on chemical characteristics of precipitation at Mt. Waliguan TAN GJie 1,XU E Husheng 1, YU Xiaolan 1,CHEN G Hongbing 1,XU Xiaobin 1,ZHAN G Xiaochun 2,J I J un 2 (1. Chinese Academy of Meteorological Sciences,Beijing ;2. Qinghai Meteorological Bureau,Xining ) Abstract :The paper presents the results in precipitation chemistry obtained at Mt. Waliguan (China Global Atmosphere Watch Base2 line Observatory) in The site is located in the semi2arid area in Northern China, and relatively isolated from the emissions of the population and industrial areas. The 59 samples were collected and analyzed for ph,conductivity and soluble inorganic components. The precipitation of that region is clean and neutral with the weighted average ph value of 6. 4 and the weighted average conductivity of S/ cm. The major ions are NH 4 +,Ca 2 +,SO 4 2,Mg 2 +,Na +,NO 3,Cl, F. Though ion concentrations are higher than those of precipitation at Lijiang station in South2west China,the distribution of the ions is close to those from Lijiang stations. The re2 sults indicated that the site is suitable for long term monitoring for the precipitation chemistry in northern China. Keywords :Mt. Waliguan ;precipitation chemistry ;analysis,80 [1 ], , [2 ]. [3 ],. ( ) ( Global Environment Facility, GEF), 1994, ( WMO) ( GAW) 20,, : ; : : (1958 ),, ( )

2 4 : 421, WMO2GAW, [4 ]. 1997, ( 3810 m, N, E). 10 km,, km 6 / km 2,. [4 ].,. WMO2GAW, 100 m. 100 m,.,,.,,,,, % 70 %,, 400 mm M. I. C AU.,, 11,. 9 :00,,,. 1. 3, PHS23B p H DDS2307 p H, ( 30 ml, p H, ), (4 ). (3 12 ). F,Cl,NO 3,SO 4 2, K +,Na +,N H 4 + Dionex DX500, AS12A (4 mm) A GA12 CS12 (4 mm) CG12, ASRS21,CSRS21 4 mm, 50 L, NaCO 3 / NaHCO 3 ( MSA). Ca 2 +,Mg 2 + Hitachi p H mm, ( 0. 5 mm) ( ), 59, 11 p H. 359 mm, p H 335 mm.

3 p H, p H S/ cm (p H 2 ).,,,,. 2 p H,, ;,, p H.. 1 p H Fig. 1 p H value and conductivity of precipitation at Mt. Waliguan 2 p H Fig. 2 The relationship of p H and conductivity value with precipitation amount Fig. 3 The variation ranges of ion concentration in the precipitation 3. N H + 4 Ca SO 4. NO 3 SO 4 2,. N H 4 + Ca 2 +, Ca 2 +,., Ca 2 + Mg 2 +, Ca [2,5,6 ]. N H 4 + Ca 2 +,,., p H,,,,. 4.,,, N H 4 + Ca 2 +., SO 4 2 NO 3

4 4 : ( : eq/ L) Table 1 The comparison of ion concentrations of the precipitation at Mt. Waliguan with other sites in/ outside China (Unit : eq/ L) p H, S/ cm SO 4 2 NO 3 Cl NH 4 + K + Na + Ca 2 + Mg ( ), ( ) ( ),., SO N H 4 + N H 4 +, N H 4 + SO [7 ], N H 3., N H 3, 4 Fig. 4 The ionic compositions of precipitation from Mt. Waliguan and Lijiang N H 4 + [8,9 ]., ( ) N H F ( 2 eq/ L),. 80 %. N H 4 +, K +, I,N H 4 +, K +., N H 4 +, K +,.,, K +. N H 4 + K +,,. Cl NO 3 SO Table 2 The results of principle component analysis NH 4 + K + Na + Ca 2 + Mg 2 +, %

5 ( 6 [ ]/ 6 [ ]). p H, [ HCO 3 5 Fig. 5 The ion balance of the precipitation samples ], [ HCO 3 [ HCO 3 ] = P CO2 H CO2 K a1 / [ H + ] ] [10,11 ] :, P CO2, ; H CO2, ; K a1, ;[ H + ]. 5, , , ;, Ca 2 +,Mg [ NO 3 6 (p H ). p ( [ SO 4 2 ]) pai, ( Ca 2 +,N H 4 + ), SO 4 2 NO 3 [6 ]. 5, p H, pai,p [ N H 4 + ],p [ Ca 2 + ], pai, p [ N H 4 + ],p [ Ca 2 + ], p H,, 6 Fig. 6 The relationship between the main ions and the acidity of precipita2 tion, N H 3, SO 2 NO x, p H SO 4 2 NO 3 N H + 4 Ca ,., 50 km, ( 3) 3., SO eq/ L, Cl.,Na +, SO 4 2 ]

6 4 : : 1. p H 6. 4, 3 Table 3 The comparison of ion concentrations of precipitation at Mt. Waliguan with water in Qinghai Lake Cl SO 4 2 Na + K +,meq/ L (1) (0. 29) (1. 27) (0. 02), eq/ L (1) (3. 94) (1. 44) (0. 62) : Cl S/ cm, ;2. N H 4 +,Ca 2 +,SO 4 2 Mg 2 +,Na +,NO 3,Cl, K +,F,,,N H 4 + Ca 2 + ; 2 3. SO 2 4,SO 4 NO 3 3 1, SO 4 2 ;4. (N H 4 + Ca 2 + ) p H, ;5.,, N H 4 +, K +,N H 4 +, K + ;6.,. :, [ 1 ] Galloway J N. The composition of precipitation in remote area[j ].J of Geophysical Res,1982,87 (11) : [ 2 ], Keene W C. [J ].,1993,13 (4) : [ 3 ],. [J ].,1997,42 (2) : [ 4 ] Tang Jie, et al. China global atmosphere watch baseline observatory and its measurement program[ Z]. CAMS Annual Re2 port [ 5 ] TAN G Jie et al. CAPMON precipitation chemistry data summary 1987 [ R ]. Atmospheric Environment Services Report : ARD 89 1,Downsview,Ontario,Canada,1989 [ 6 ] Hara Hiroshi, et al. The precipitation chemistry in Japan [J ]. Water,Air and Soil Pollution,1995,85 : [ 7 ],. [J ].,1996,7 (4) : [ 8 ] Lobert J M et al. Experimental evaluation of biomass burning emissions :nitrogen and carbon containing compounds[ A ] In : Levine J S(ed). Global Biomass Burning[ C], The MIT Press,Cambridge [ 9 ] Sanhueza E. The effects of vegetation burning on the atmospheric chemistry of the venezuelan savanna[ A ]. In :Levine J S (ed). Global Biomass Burning[ C]. The MIT Press,Cambridge [ 10 ] The Fourth Expert Meeting on the Acid Deposition Monitoring Network in East Asia. Technical Manual for Monitoring Wet Deposition[ A]. Final report of the fourth expert meeting on the acid deposition monitoring network in East Asia[ C]. Hi2 roshima, Japan [ 11 ] Vet Robert J. The Handbook of Environmental Chemistry[ Z], Volume 2, Part F. O Hutziger (ed). Springer2Verlag Berlin Heidelberg,1991