ANALYSIS OF CLIMATE VARIABILITY IN THE JINSHA RIVER VALLEY

Monthly mean surface air temperatures and precipitation at 20 meteorological stations in the Jinsha River Valley(JRV) of southwest China were analyzed for temporal-spatial variation patterns during the period 1961-2010.The magnitude of a trend was estimated using Sen's Nonparametric Estimator of Slope approach.The statistical significance of a trend was assessed by the MK test.The results showed that mean annual air temperature has been increasing by 0.08℃/decade during the past 50 years as a whole.The climate change trend in air temperature was more significant in the winter(0.13℃/decade) than in the summer(0.03℃/decade).Annual precipitation tended to increase slightly thereafter and the increasing was mainly during the crop-growing season.Both the greatest variation of the annual mean temperature and annual precipitation were observed at the dry-hot valley area of middle reaches.Significant warming rates were found in the upper reaches whereas the dry-hot basins of middle reaches experienced a cooling trend during the past decades.Despite of the overall increasing in precipitation,more obvious upward-trends were found in the dry-hot basins of middle reaches whereas the upper reaches had a drought trend during the past decades.

Impact of land use and land cover changes on carbon storage in rubber dominated tropical Xishuangbanna,South West China

Land use and land cover(LULC)play a significant role in carbon regulation.South-China accounts for~65%of China’s carbon sink.In Xishuangbanna(South-China),rubber is expanding rapidly creating an urgent need to understand and monitor LULC change and how spatial variation affects carbon storage(CS).This is vital for the formation and implementation of better land use management practices.We studied LULC changes of 22-year period;addressing how these changes have affected the CS.We quantified LULC changes between1988 and 2010 using remote sensing methods and calculated CS changes using InvEST.Results showed that between 1988 and 2010,the rate of deforestation accelerated to 203.2 km^(2)y^(−1)and~23%of forest were lost.Conversion of natural forest to rubber was responsible for 78%of this deforestation.Rubber expansion rate was 153.4 km^(2)y^(−1).Changes to LULC drove a temporal CS reduction 0.223 Tg C/km^(2).Local stakeholders have strong economic interest in converting land to more profitable plantations.Government efforts is required to control land conversion through new policies and incentives to retain natural forest.Assessment of specific potential land use change will be required to avoid promoting the conversion of high carbon storage land uses to low carbon storage land uses.