年 月 重庆师范大学学报(自然科学版) 摇 2012 5 May 2012 第 卷 第 期 ( ) 29 3 Journal of Chongqing Normal University Natural Science Vol. 29 No. 3 摇 Proceedings of the International Symposium on Conservation and 摇 Eco鄄friendly Utilization of Wetland in the Three Gorges Reservoir Research on Net Primary Productivity and Its Spatio鄄temporal Characteristics in the Three Gorges Reservoir Area ( Chongqing Section) During to * 1998 2007 , , 1 2 3 , 1 , 1 , 1 LI Yue鄄chen JIAN Tai鄄min HE Zhi鄄ming HU Xiao鄄ming ( , , , ; 1. College of Geography and Tourism Key Laboratory of GIS Application Chongqing Normal University Chongqing 400047 , ; 2. Chongqing Institute of Meteorological Science Chongqing 401147 3. School of Civil Engineering , , , ) Architecture and Construction Chongqing Jiaotong University Chongqing 400074 China Abstract: , (NPP) Based on the CASA model we report a remote sensing estimation of net primary productivity during 1998 to , , , , 2007 using SPOT/ VGT NDVI data vegetation鄄type coverage as well as meteorological and other data and we analyze its spatio鄄 : ) NPP ) temporal characteristics. Results show that 1 the volatility of during 1998 to 2007 drops on the whole. 2 Seasonal variation NPP : ( · -2 ) ( · -2 ) of during 1998 to 2007 shows the following regularity summer 675. 705 gC m > spring 368. 2 gC m > autumn ( · -2 ) ( · -2 ) , NPP ( · -2 ) 207. 944 gC m > winter 49. 495 gC m . In summer the maximum value of 1 022. 173 gC m occurred in ; NPP ( · -2 ) ) NPP 2000 the minimum value of 318. 321 gC m occurred in 2006. 3 values in the research region varied between · -2 , , 184. 8 and 515. 548 gC m during 1998 to 2007. High values were mainly distributed in northeast Chongqing such as Wuxi , , , , , Wushan Fengjie and in south east Chongqing such as Shizhu Wulong and others. Low values were distributed in Zhongxian ) Fuling and most of the main urban areas. 4 The highest productivity per unit area was found in regions of broad鄄leaved forests. : , Productivity was progressively lower in the following vegetation classifications bush fallow and irrigated grass vegetation coniferous , , , forest vegetation grassy marshland aquatic vegetation and water area. Key words: ( ); NPP; Three Gorges Reservoir area Chongqing section spatio鄄temporal characteristics Chinese Library Classification:X . Documet Code:A Artide ID: 鄄 ( ) 鄄 鄄 171 1 摇 摇 摇 1672 6693 2012 03 0156 07 摇 摇 Earth爷 s biosphere and ecological system is the in natural environmental conditions and thereby charac鄄 material basis of human survival and development. terizes the quality of the terrestrial ecological system, Vegetation is an important constituent of land ecological but it also acts as the main factor that adjusts the car鄄 systems, and plays an important role in regional cli鄄 bon sink of the ecological system and regulates ecologi鄄 [1鄄3] [6] mate change and the global carbon cycle . Vegeta鄄 cal processes . Describing the patterns of spatial vari鄄 NPP tive net primary productivity (NPP) refers to the accu鄄 ation of is therefore of vital significance for the e鄄 mulation of plant organic matter per unit area and unit valuation of terrestrial ecological systems, understand鄄 time; " net" refers to the deduction of autotrophic res鄄 ing the regulation of ecological processes, and estima鄄 piration from total photosynthesis in obtaining this ting carbon sinks on land. As a result, many domestic [4鄄5] NPP measure . is an important component of the and foreign scholars have conducted research on NPP[7鄄9] carbon cycle of Earth爷s surface. It not only directly re鄄 . flects the productive capacity of vegetative communities The Three Gorges Reservoir Area (TGRA) is lo鄄 Received * :03鄄27鄄2012 Foundation 摇 摇 :Open Foundation of Chongqing Meteorological Administration(No. kfji鄄201103);the Foundation of Chongqing Colleges and Universi鄄 tiea InnovationTeamsin Resouree Environment and Ecological Construction:the Foundation of Chongqing Geography Key Discipline. First author biograghy 摇 摇 :LI Yue鄄chen, male,professor,doctor,he mainly focuses on natural resources environmental remote sensing and GIS. , : 摇 摇 摇 摇 摇 摇 摇 LI Yue鄄chen et al 医Research on Net Primary Productivity and Its Spatio鄄temporal Characteristics ( ) No. 3摇 摇 摇 摇 摇 摇 摇 摇 in the Three Gorges Reservoir Area Chongqing Section During 1998 to 2007 157 [11] cated on the Yangtze River and is the throat of an eco鄄 and others . The zonal vegetation is subtropical ever鄄 logical barrier in the Yangtze River watershed. Com鄄 green broadleaved together with warm coniferous forest. plex natural conditions together with complex social and The TGRA is a special area functionally from an eco鄄 economic characteristics determine its ecological and logical economic perspective in China and the world. geographic importance. In terms of functional ecology, The Chongqing part of the TGRA accounts for 80% of the region is a special area in China because it is an the total, illustrating Chongqing爷s eco鄄economic signif鄄 ecological barrier of national significance with respect icance. to the environmental safety of the Yangtze River basin. 2 Data It is clear that research on this region has vital theoreti鄄 cal and practical significance. However, research in The information used in this analysis came from this field to the present time has mainly examined static three main sources: meteorological data, remote sens鄄 conditions, and has rarely focused on dynamic spatial ing data, and vegetation cover classification. Meteoro鄄 NPP and temporal changes in . So in order to illustrate logical data were mainly derived from temperature and the response of the TGRA vegetation to local and global rainfall records at 35 Chongqing meteorological sites, NPP change, we used the CASA model to estimate together with ground radiation data at a central site and within the TGRA during 1998—2007 and to analyze its its four surrounding sites. The data included monthly dynamic space鄄time characteristics. total precipitation, monthly mean temperature, monthly 1 Study Area total radiation, monthly net radiation, along with eleva鄄 tion and geodetic coordinates. Remote sensing data The TGRA of Chongqing is located in the upper came from Western China Environment and Ecological reaches of the Yangtze River (105毅49忆 ~ 110毅12忆E; Science Data Center ( http: / / westdc. westgis. ac. cn) 8毅31忆 ~ 31毅44忆N). The southeast and northeast parts of the National Natural Science Foundation Commis鄄 of the study area are at the junction of Chongqing with sion, SPOT / VEGETATION S10 ten鄄day East Asia veg鄄 Hubei, the southwest is bound by Sichuan and etation normalized index products which have spatial Guizhou, and the northwest is adjacent to Sichuan and resolution of 1 km, and dates from 1998 to 2007. Shanxi. The area studied includes 22 districts and Chongqing vegetation cover classification figure data counties ( including autonomous counties ) of were obtained by scanning the vegetation type map of 2 Chongqing and covers 46 158. 53 km with a total pop鄄 the Chongqing atlas, followed by geometric correction ulation of 19 235 000 ( of whom 12 432 400 are agri鄄 and rectification, vectorization, and then combining its [10] cultural) at the end of 2009 . 36 fine classes into 8 classes. The area is characterized by a humid subtropical 3 Methods monsoon climate. Spring comes early and the autumn late; winter is warm and the summer hot. The annual In this research, the CASA model is a model of an NPP average temperature is 15 ~ 18毅 C, with high annual ecological process. is mainly determined by two and daily range of air temperature. Average annual variables: light and effective radiation which is ab鄄 APAR precipitation is 1 150. 26 mm, unevenly distributed sorbed by plants ( ) and the light energy utiliza鄄 spatially. The TGRA of Chongqing crosses three major tion ratio (着). NPP x t APAR x t x t tectonic units: the Dabashan fold belt, east Sichuan ( , )= ( , ) 伊着( , ) (1) t x APAR x t fold belt, and the uplift fold belts of Sichuan, Hebei, where, is time, is spatial location, ( , ) is Hunan and Guizhou. The landform consists of the photosynthetically active radiation which is ab鄄 x t x t mountains and hills. The main types of soil are purple, sorbed by pixel during month. 着( , ) is the actual x t yellow, yellow brown, brown, lime, alluvial, paddy, light energy utilization rate of pixel during month. ( ) : 158 摇 摇 摇 Journal of Chongqing Normal University Natural Science http / / www. cqnuj. cn摇 摇 摇 摇 摇 摇 摇 摇 摇 Vol. 29 3. 1 Estimation of APAR (Tab. 1). The global monthly average maximal light The photosynthetic absorption of available radia鄄 energy utilization rate of aquatic vegetation, water and APAR -1 tion ( ) depends on the sun's total radiation and other ecological systems is 0. 389 gC ·MJ which is the proportion of radiation that is absorbed by vegeta鄄 calculated by the CASA model. FPAR tion ( ). FPAR can be determined by the nor鄄 Tab. 1 Vegetation types and corresponding parameters NDVI -1 malized difference vegetation index ( ) and vege鄄 of maximum light energy utilization gC·MJ tation type. highest light energy APAR x t SOL x t FPAR vegetation form ( , )= ( , ) 伊 伊0. 5 (2) utilization rate (着max ) SOL x t where, ( , ) is the total amount of solar radiation evergreen coniferous forest 1. 008 x t FPAR x t at pixel during month; ( , ) is the propor鄄 broad鄄leaved evergreen forests 1. 259 tion of available radiation that is absorbed by the vege鄄 deciduous conifers 1. 103 broadleaved deciduous forest 1. 044 tation layer; the constant 0. 5 is the proportion of the mixed forest 1. 116 sun爷s effective radiation that can be used by vegetation fallen leaves, hedges and savannas 0. 768 (wavelengths between 0. 38 and 0. 71 滋m). In a cer鄄 FPAR sparse shrubs 0. 774 tain range, there is linear relationship between Elfin forest thickets 0. 888 NDVI and (Ruimy and Saugier, 1994). The linear re鄄 grasslands 0. 608 lationship can be determined by the maximum and min鄄 Farm vegetation 0. 604 imum value of a certain vegetation type and the maxi鄄 摇 摇 Under actual conditions, 着 can be affected by FPAR mum and minimum value of .