MTNCLIM 2005 THEME: Climate Variability: Adaptation, Mitigation, and Restoration Response of Alpine Vegetation and Glacial Extent to Regional Climate Patterns in the Hengduan Mountains of Yunnan, P.R. China Baker, Barry (1,2); Ringler, Todd (2); and Moseley, Robert (3) Yunnan Provincial People's Government (1) TNC Climate Change Initiative, Boulder, CO 80302, (2) Colorado State University, Fort Collins, CO 80523, (3) TNC Yunnan Great Rivers Project, Kunming, Yunnan, PRC INTRODUCTION ABSTRACT We present results of repeat photographs taken over an eighty-year period (1923-2004) documenting changes in alpine vegetation and glaciers in the Hengduan Mountains of northwestern Yunnan, China. In addition, our analyses of historical climate station data show that mean annual temperature in the last two decades of the 20th century has increased at a rate of 0.6oC/decade and may be a primary driver of the changes documented in these photographs. We explore the connection between changes in alpine vegetation and glacier recession in northwestern Yunnan and regional climate change by analyzing 40 years of ECMWF reanalysis data. The reanalysis data is a blending of groundbased observations, satellite retrievals, and predictive weather models. While the reanalysis data are global in extent, we limit our analysis to a region of interest in southwestern China. ECMWF data and the Deqin station data are not entirely consistent. The two temperature time series are highly correlated but the warming trend is not captured in the reanalysis. Instrumentation of region glaciers and dendroclimatological studies are needed to gain better understanding of observed changes in vegetation and regionwide glaciers. RESULTS AND DISCUSSION The inter-annual variability of monthly average temperature The sensitivity of mountain ecosystems to human activities from the ECMWF reanalysis and the Deqin station data are and climatic drivers of change is widely recognized. Analyses highly correlated, however, the warming trend is not reflected of repeat photographs taken over an eighty-year period in the reanalysis (Fig. 4). (1923-2004) show changes are occurring in alpine vegetation The ECMWF under-predicts the magnitude of the precipita- and glaciers on Mount Kawagebo and Baima Snow Mountain tion by a factor of two. Some of the inter-annual variability is in the Hengduan Mountains of northwestern Yunnan, China captured in the ECMWF model (Fig. 5). Examination of the ECMWF vertical profile reveals the agement practices (i.e. the banning of fire) to shifts in vegeta- warmest period was 1958-1972 and the coolest was 1988- tion are unclear and insufficient for explaining the glacial 2001 (Fig 6b). data (Fig. 4) show that mean annual temperature has increased during the 20 century. We explore the connection th between changes in alpine vegetation and glacier recession Pair 1 year ban on fire for pasture maintenance but does not explain documented region-wide changes in glaciers. Records from mulation zone. Clearly, instrumentation of this glacier is needed. In addition dendroclimatological studies could help to untangle the effects of climate and management on movement of treeline and vegetation community shifts in this ECMWF and station data are not entirely consistent. Which tions from proxy data (Fig. 3) as well as local historical climate reanalysis. Changes in vegetation could be a result of the 30 are not representative of what may be occurring in the accu- anomaly (Fig. 7). widespread (He et al., 2003; 2004). Temperature reconstruc- effect, however, the mechanism is not evident in the ECMWF Changes in tongue of Mount Kawagebo’s Mingyong glacier ing in the late time periods and upward shift in the zero Mountain indicate that glacial recession in this region maybe the region were a result of a top-down, large-scale regional instruments on the Baishui glacier on Yulong Xue Snow Moun- ECMWF 500 mb regional temperature anomalies show cool- changes witnessed in this region. Studies on Yulong Snow We felt that the observed vegetation and glacial changes in tain have shown decrease in mass and extent (He et al. 2004). (Figs. 1 and 2). The contribution of altered landuse and man- region. leads to the questions; i) are the station data incorporated in ACKNOWLEDGEMENTS the ECMWF?, ii) is the Deqin well sited?, iii) is there an urban ECMWF ERA-40 data used in this study/project have been provided by ECMWF/have been obtained from the ECMWF Data Server effect causing the local warming? REFERENCES He, Y., Zhang, Z., Theakstone, W. H., Chen, T., Yao, T., and Pang, H., 2003: Changing features of the climate and glaciers in China's monsoonal temperature glacier region. Journal of Geophysical Research, 108: D17, 4350, doi:4310.1029/2002/JD003365. Grid resolution is 275 km. The ECMWF N80 (125 km) grid in northwestern Yunnan to regional climate change by ana- may improve analysis. We need to answer the question “what lyzing 40 years of ECMWF reanalysis data. resolution is required to qualitatively understand the widespread changes in this region? He, Y., Yin, Y., Zhang, D. D., Yao, T., Yang, M., Zhang, Z., Pang, H., Gu, J., and Lu, A., 2004: Recent progress of the studies on environmental information in the glacial system, Mt. Yulong, China, Bridging Scales and Epsitemologies: Linking Local Knowledge and Global Sciences in Multi-Scale Assessments. Alexandria, Egypt. Yang, B., Braeuning, A., and Johnson, K. R., 2002: General characteristics of temperature variation in China during the last two millennia. Geophysical Research Letters, 29: 0, 10.1029/2001GL014485. Figure 6. Vertical profile for the ECMWF summer-time temperature (June, July, August, and September) interpolated to the Deqin station and anomalies; (a) profile for the 30 year period; (b) profiles of the anomaly (from the 1958-2001 mean) for each of the three fifteen-year periods. Figure 1. Repeat photo-pairs of the Mingyong Glacier on Mount Kawagebo (pair 1 and 2) and Baima Snow Mountain (pair 3) near Deqin in northwestern Yunnan, P.R. China. Arrows and lines indicate previous and current positions or change in conditions. Treeline is represented by the green line while the highest adult tree (> 2 m tall) is represented by the red arrow in photo-pair 3. b) a) Isobar Level (mb) Robert Moseley 2003 Isobar Level (mb) Joseph Rock 1923 CONCLUSIONS 1958-1972 1973-1987 1988-2001 Pair 2 Robert Moseley 2003 98°0'0"E ! . 1 2002 2002 Mongolia Sichuan Province Figure 3. Standardized temperature reconstructions for China. Data from Yang et al. (2002). The red dashed line represents the previous warmest period. China Figure 4. Time series of Deqin station monthly average temperature, monthly maximum and minimum temperature and interpolated ECMWF monthly average temperature. Xizang Province (Tibet) India Myanmar Year 1998 # ! Deqin Joseph Rock 1923 ! Project Boundary #Kawagebo # Robert Moseley 2003 Provincial and Country Boundary 0 30 60 120 Km 28°0'0"N 28°0'0"N Zhongdian Gongshan 270 m (67 m elev.) fire K Prefecture Boundary Baima Snow Mtn. 675 m (45 m elev.) Mountains Towns ! ! 3 4 ! . ! . Temperature (oC) ! . ECMWF Grid Points Standardize Temperature Legend Pair 3 Figure 5. Monthly precipitation time series comparison between Deqin station data and interpolated ECMWF reanalysis. Data were smoothed with a 12 point running mean filter. Project Area 80 m 1998 30°0'0"N 2 2004 110 m Sichuan Province Ninglang ! Weixi ! Myanmar Yulong Snow Mtn. # Lijiang ! ! Fugong 98°0'0"E JJAS Temperature Anomaly 100°0'0"E ! . 30°0'0"N 1958-2001 JJAS Mean Temperature (Kelvin) Precipitation (mm/month) Barry Baker 2002 Figure 2. Map of Mount Kawagebo, Baima Snow Mountain, Deqin with respect to the larger project area. Insert map of the Yunnan Great Rivers Project with respect to China and surrounding countries. ECMWF grid points are shown in red. Values for points 1 and 3 were interpolated to the Deqin station location. 100°0'0"E Year Year Year Figure 7. Large-scale regional ECMWF 500 mb summer-time temperature (June, July, August, and September) and anomalies (from 1958-2001 mean) for the three fifteen-year time periods.