| This study aimed to explore tempo-spatial patterns of XinJiang's terrestrial carbon budgets and the mechanism of its responses to climate variability and change in past 20 years. For the research purposes, regional climate and soil database have been set up, and the OLECM, which is a process-based biogeochemical model, has been improved and applied. With supports of database and OLECM model, carbon fluxes, such as net primary production (NPP), soil heterotrophic respiration (HR) and net ecosystem production (NEP) from 1981 to 2000 have been quantified. The tempo-spatial pattern of carbon stocks in soils and vegetation has also been described. The paper carried on comprehensive analysising of the thorough delicacy to the spatial pattern of the precipitation and temperature at this period, from 50's in last century to the beginning of 20 centuries, in the studying area.The estimated results have suggested that:1. During 1981 to 2000, the estimated total terrestrial NPP in XinJiang varied between 0.149 Gt C and 0.195 Gt C, with a mean value of 0.175 Gt C (1 Gt = 1015 g), behaving obvious increasing trend (Trend=0.00142 Gt C/yr2, P<0.001). Comparing to 1980s, the mean annual total NPP in 1990s increased 0.014 Gt C. However, the changes were quite different for regions. Inter-decadal increases were found in TianShang Northen Region, KunLun Mountain and so on.Decreases mainly occurred in the TaCheng Region, ErQiSi River and WuLunGuHe River. For different landcover types, the biggest absolute growth quantity is other woodland, woodland and residentses, which to distinguish for the 64.19 gC/m2, 44.48 gC/m2 and 31.97 gC/m2, comparing to 1980s, decrease was only found in Shrub-land ecosystem is -14.39 gC/m2.Most parts of XinJiang had an inter-decadal increases in total NPP, expect the Northern ZhunGeer basin, the GuerBanTong desert and the Eastern plain of North KunLun Mountain, with a inter-decadal decreases of 1.91 gC/m2, 0.55 gC/m2 and 2.63 gC/m2 and the most of decrease is LuoBuWa region. Yi Lihe Valley, the Western of plain of Northern TianShang Mountain and KaShi-SaChe Delta had a inter-decadal increases in total NPP of 23.46 gC/m2, 38.29 gC/m2 and 41.58 gC/m2, from the result may be found the Western of plain of Northern TianShang Mountain is the most increase of Northern XinJiang and KaShi-SaChe Delta is the another region of Southern XinJiang.2. In the study period, HR fluctuated between 0.147 and 0.211 Gt C/yr, with an average of 0.173 Gt C/yr, increasing at 0.013 Gt C/yr2 (P<0.01). The increasing trend of HR was much higher than that of NPP, which resulted in the decreasing of NEP. In the past 20 years, the estimated total NEP changed between -36.4 to 25.7 Tg C/yr(1 Tg = 1012 g), equivalent of magnitude is 1.036 g C/m2/yr. The mean annual NEP was 1.7Tg C/yr, indicating that XinJiang's terrestrial ecosystems took up 33.9 Tg C carbon under the climate variations and atmospheric CO2 increases, which accounted for 2.7～3.0% of the China's total. On the region scale, most parts of XinJiang was carbon balanced, however, the significant difference of carbon sink and releases occurred in the different region of XinJiang from the past 20 years, the Land Ecosystem of XinJiang is weak carbon sink in the period, particularly in 90s , its carbon absorbs was 70% of the total quantity of sink from 1981 to 2000, from the later of 80s to the middle of 90s the absorb was began to grown clearly, the most growth was in the Northern of XinJiang last now. Meantime in the Southern of XinJiang is a weak sink status of CO2 absorb.3. In the past 20 years, the total terrestrial carbon stocks in XinJiang was about 7.49 Gt C, of which the stocks in vegetation varied in the range of 0.146～0.191 Gt C/yr with an average of 0.171 Gt C, and stocks in soils changed from 6.86 Gt C to 8.06 Gt C, with an average of 7.32 Gt C. The vegetations and soils carbon density was 0.11 kg/m2 and 4.5 kg/m2 respectively. The higher soil carbon density occurred in Southern of Zhun Geer basin and Yi Lihe valley, where soils carbon density is higher than 10～15 kg C/ m2 even higher than 30 kg C/m2,the parts of NanJiang of XinJiang of the highest soil carbon is such as KaShi-SaChe Delta with a value 7～10 kg C/ m2, the whole Kun Lunshang mountain is the smallest place with the mean value 1.2 kg C/ m2 and the highest is only 3.3 kg C/ m2, the smallest is 0.18 kg C/ m2.Nationally, the soils carbon density increased from southeast of XinJiang to northwest. The spatial distribution of vegetation carbon density also showed the decreasing trend from northwest to southeast and has two higher values regions locating at northwest where are the Ta Cheng basin and the Yi Lihe valley with a value 0.4 kg C/ m2. Nationally, lawns played a major role in terrestrial ecosystem carbon budgets. The smaller vegetation carbon density occurred in Southern of XinJiang with the mean value 0.0～0.1kg C/ m2and the whole Kun Lunshang mountain is the smallest place with near to 0 kg C/m2.4.The year rainfall variety curve that is a rising trend during the period of 50 years, its growning straight line as Y=0.4752 X+83.771 with a growth rate R 0.4752.The average rainfall of 50 years of Xinjiang is a 96.13 mm, can get in year change curve from the later of the 50's to the later of 80's the same level of ainfalls of the 96.13mm, but from the initial of 90's, the year average rainfall start increasing and keeping on gradually currently, but attain the mean level with 108.09 mm equally currently from 2000, its growning quantity got to the 11.86 mms, the rainfall is starting to risign quickly in 21 centuries.The year mean temperature variety curve that is a rising trend during the period of 50 years, its growning straight line as Y=0.02803 X+7.2487 with a growth rate R 0.028.The average temperature of 50 years of Xinjiang is a 7.98℃, can get in year change curve from the later of the 50's to the later of 80's the same level of temperature of the 7.70℃, but from the initial of 90's, the year average temperature start increasing and keeping on gradually currently, but attain the mean level with 8.84℃equally currently from 2000, its growning quantity attained to the 1.14℃, the mean temperature is starting to risign quickly in 21 centuries.
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