Response of Alpine Vegetation and Glacial Extent to Regional Climate... in the Hengduan Mountains of Yunnan, P.R. China

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
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.
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
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-
leads to the questions; i) are the station data incorporated in
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?
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,
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.
Isobar Level (mb)
Robert Moseley 2003
Isobar Level (mb)
Joseph Rock 1923
Pair 2
Robert Moseley 2003
Sichuan Province
Figure 3. Standardized temperature reconstructions for China. Data from Yang et al. (2002).
The red dashed line represents the previous warmest period.
Figure 4. Time series of Deqin station monthly average temperature, monthly maximum
and minimum temperature and interpolated ECMWF monthly average temperature.
Xizang Province (Tibet)
! Deqin
Joseph Rock 1923
Project Boundary
Robert Moseley 2003
Provincial and Country Boundary
120 Km
270 m (67 m elev.)
Prefecture Boundary
Baima Snow Mtn.
675 m (45 m elev.)
Temperature (oC)
. ECMWF Grid Points
Standardize Temperature
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
110 m
Sichuan Province
Yulong Snow Mtn.
JJAS Temperature Anomaly
1958-2001 JJAS Mean Temperature
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.
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.