Qin Dahe

Foliar δ 13C and δ 15N values of C3 plants in the Ethiopia Rift Valley and their environmental controls

The foliar C and N stable isotopic compositions (δ13C and δ15N) and the relationships between these compositions and environmental factors of C3 plants in the Ethiopia Rift Valley were investigated. There were three distribution patterns for foliar δ13C with mean values of −26.7‰±0.4‰, −29.7‰ ± 0.6‰, and −26.9‰ ± 1.2‰ in cold-moist, temperate-moist, and arid-hot environments, respectively. The δ15N values ranged from −1.4‰ ± 1.7‰ to 14.3‰ ± 0.1‰, with higher values under arid-hot conditions and the lowest values in plants growing at higher altitudes under cold-moist conditions. A strong negative relationship between mean annual precipitation and δ15N explained more than half of the observed variation in the δ15N values (r2 = 0.54, P < 0.001); a modest positive relationship was also found between δ15N and temperature (r2 = 0.32, P < 0.01). A weakly positive relationship existed between δ13C and temperature, and changes in δ13C values with precipitation and altitude followed quadratic curves. This suggests a shift in the effects of water and heat conditions caused by altitude on carbon isotopic discrimination.

Accuracy of TRMM precipitation data in the southwest monsoon region of China

Accurate, high-resolution precipitation data is important for hydrological applications and water resource management, particularly within mountainous areas about which data is presently scarce. The goal of the this study was to assess the accuracy of TRMM 3B43 precipitation data from the southwest monsoon region of China between 1998 and 2011 based on the correlation coefficients, regression, and geostatistical methods. We found a strong correlation between TRMM 3B43 data and observational data obtained from meteorological stations, but the TRMM 3B43 precipitation data was consistently lower than that obtained from the weather stations. The TRMM 3B43 data was significantly different from the data obtained by weather stations located in the northwest and northeast regions of the Hengduan Mountains. The spatial distribution of precipitation obtained from TRMM 3B43 was also different from meteorological data, but the deviation was predominantly distributed along the northern longitude and southern latitude. In addition, the TRMM data more accurately reflected the regional precipitation patterns. Our results indicate that the TRMM 3B43 data should be used for hydrological applications and water resource management at meteorological stations that have a sparse and uneven distribution of observation stations in the southwest monsoon region.

Climatic significance of stable carbon isotope in tree rings of Abies spectabibis in southeastern Tibet

The annually cross-dated stable carbon isotope of tree-ring α-cellulose ofAbies spectabibis collected from the southeastern Tibetan Plateau is used to examine its relationship with climatic parameters. The residual Δ13C series in treerings is constructed after removing the effects of age trend and rising CO2. We found a close relationship between Δ13C in tree rings and the relative humidity of September-November of the previous year measured at the nearby Nyingchi Meteorological Station, albeit a strong “lagged effect”. Thus we developed a transfer function to reconstruct the autumn relative humidity for the Nyingchi region, which explained 37.9% of the total variance (p < 0.001). Our results suggest a high frequency and moderate amplitude variance of the relative humidity before 1800, and the variance reversed afterwards.

Surface mass balance and its climate significance from the coast to Dome A, East Antarctica

Based on stake measurements conducted along the Chinese Antarctic traverse since Jan. 1999, we investigated the characteristics of surface mass balance (SMB) and related climate consequences from Zhongshan Station to Dome A, East Antarctica. Spatial analysis suggests that post-depositional processes have a great impact on surface morphology; thus, the representativeness of a single measurement should be discussed in conjunction with local climate features. The comparison among snow accumulation, ice sheet thickness, surface elevation, and ice velocity indicates that the bedrock topography has an indirect connection with the SMB patterns through controlling the surface topography and local climate. The observation reveals that the Lambert Glacier Basin has been experiencing increasing mass input (4.5%), whereas the inland area has experienced a 6% loss, since 2005. An overall estimation of the SMB along the route is 71.3±44.3 kg m−2 a−1, but the annual and regional variation is considerable. Tendency analysis shows that there are four sections with different SMB patterns as a result of three moisture sources and surface climatic discrepancy in the Antarctic inland. This study is the first to identify four SMB patterns from the coast to the Dome area and should provide a valuable contribution to modeling and remote sensing on a continental scale.

Modification of three ice-core d 18 O records from an area of high melt

Abstract Stable oxygen isotope ratios (δ18O) of three shallow ice cores (extending back to 1963) from Urümqi glacier No. 1 at the headwater of Urümqi river, Tien Shan, northwest China, were used to test the relationship between δ18O and contemporaneous surface air temperature (T a). The ice cores were dated using the seasonal stable-isotopic signals, and seven insoluble particulate β-activity horizons associated with known nuclear tests. Although a strong positive relationship exists between δ18O in precipitation and Ta at our study site, this relationship is not preserved between the annually averaged ice-core δ18O records and the local temperature due to post-depositional modification. These results indicate that the processes forming the ice-core chemical records in areas of high melt must be understood before the δ18O record can be confidently interpreted as a climatic indicator.

Mountain inhabitants’ perspectives on climate change, and its impacts and adaptation based on temporal and spatial characteristics analysis: a case study of Mt. Yulong Snow, Southeastern Tibetan Plateau

Based on the results of questionnaires issued to 202 local residents in the Mount Yulong Snow region, southeastern Tibetan Plateau, this study analyzes mountain residents’ perspectives on climate change and its impacts, their strategies to adapt to climate change impacts, including their willingness or otherwise to become ecological migrants, and some of the factors that influence their perceptions. Overall, local perception of climate change and its impacts corresponds to the patterns of observed climate change revealed by climate records. The intensity of climate change perception shows a highly significant correlation with residents’ age and villages’ elevation gradient. Most respondents did not believe that climate change affected crop growing and their yields, but the number of crop insect pests was thought to be increasing slightly and the crop growth period to be extending. Nearly all respondents believed that climate change seriously affects the mountain tourism economy, and their way of life and spiritual world. Persistent drought in recent years has forced mountain dwellers to adjust industrial structure, save water in the agricultural economy, participate in mountain tourism and work outside the home in order to adapt to climate change impacts and supplement their meager farm incomes. Additionally, residents expect to receive government compensation and relief to mitigate natural disaster damage.

Progress regarding climate change during recent years

Global warming has been a key international issue, particularly with respect to changes in global climate and its effects, since IPCC-AR4. Here, the latest research results and trends in radiation forcing, greenhouse gases (GHGs), aerosols, ocean water and global sea level, temperature and precipitation in the Antarctic and Arctic are reviewed with respect to changes in global climate. The literature review conducted herein was restricted to papers published in Science and Nature from 2008 to 2010. This paper supplies valuable references for studies on global change and other associated studies, as well as for the fifth assessment report of the IPCC.

Variation of Thornthwaite Moisture Index in Hengduan Mountains, China

The Thornthwaite moisture index, an index of the supply of water (precipitation) in an area relative to the climatic demand for water (potential evapotranspiration), was used to examine the spatial and temporal variation of drought and to verify the influence of environmental factors on the drought in the Hengduan Mountains, China. Results indicate that the Thornthwaite moisture index in the Hengduan Mountains had been increasing since 1960 with a rate of 0.1938/yr. Annual Thornthwaite moisture index in Hengduan Mountains was between –97.47 and 67.43 and the spatial heterogeneity was obvious in different seasons. Thornthwaite moisture index was high in the north and low in the south, and the monsoon rainfall had a significant impact on its spatial distribution. The tendency rate of Thornthwaite moisture index variation varied in different seasons, and the increasing trends in spring were greater than that in summer and autumn. However, the Thornthwaite moisture index decreased in winter. Thornthwaite moisture index increased greatly in the north and there was a small growth in the south of Hengduan Mountains. The increase of precipitation and decrease of evaporation lead to the increase of Thornthwaite moisture index. Thornthwaite moisture index has strong correlation with vegetation coverage. It can be seen that the correlation between Normalized Difference Vegetation Index (NDVI) and Thornthwaite moisture index was positive in spring and summer, but negative in autumn and winter. Correlation between Thornthwaite moisture index and relative soil relative moisture content was positive in spring, summer and autumn, but negative in winter. The typical mountainous terrain affect the distribution of temperature, precipitation, wind speed and other meteorological factors in this region, and then affect the spatial distribution of Thornthwaite moisture index. The unique ridge-gorge terrain caused the continuity of water-heat distribution from the north to south, and the water-heat was stronger than that from the east to west part, and thus determined the spatial distribution of Thornthwaite moisture index. The drought in the Hengduan Mountains area is mainly due to the unstable South Asian monsoon rainfall time.

A review about the research on adaptability in climate change: present situation and tendency.

Analyses on adaptability in climate change field emerge concurrently with the growing awareness to climate change itself.It is of important significance for reducing the vulnerability of climate change and increasing the adaptability and adaptive capability of human beings to understand the research approaches,analysis content under present situation and international tendency of research on the adaptability in climate change based on literature review in this field.In this paper,the concept of adaptability in climate change and its application as well as the relations between the adaptability and the adaptive capability,and between the response capability and the resilience are analyzed.Moreover,the four focus research fields including the effect of the assumed adaptability,specific adaptation options,relative adaptive capability of different countries,regions or communities,and practical adaptation initiatives are reviewed,and a general summary of adaptability research orientation(e.g.community-based adaptability,bottom-up approach and adaptation processes) is carried out.

Tropospheric pyruvate changes in the remote area of northwestern China

Pyruvate is a light carboxylate in the troposphere and can act as potential cloud condensation nuclei. Due to its low concentrations, however, little work has been done on the species in precipitation. Past 43-year record of pyruvate was recovered from an ice core of Glacier 1 at 43°06′N and 86°49′E in the remote East Tianshan, northwestern China. It was revealed that pyruvate varied over a relatively large range with some below the detection limit, while part of it is so high as to be up to 70 ng·g−1. With an average concentration of 4.1±8.1 ng·g−1 (mean±1σ, N=543), pyruvate is a minor species in comparison with other carboxylates. It is also low as compared with its precipitation in other parts of the world, suggesting a difference in its major source flux. The record revealed high pyruvate concentrations in the late halves of the 1950s and 1980s, but low in the late 1950s, late 1970s, and middle 1990s. The variation trend in the past 43 years is closely correlated with that of acetate, a major carboxylate from anthropogenic pollution to the atmosphere, indicating that tropospheric pyruvate in the remote area of northwestern China is probably a by-product in acetate formation.Pyruvate is a light carboxylate in the troposphere and can act as potential cloud condensation nuclei. Due to its low concentrations, however, little work has been done on the species in precipitation. Past 43-year record of pyruvate was recovered from an ice core of Glacier 1 at 43°06′N and 86°49′E in the remote East Tianshan, northwestern China. It was revealed that pyruvate varied over a relatively large range with some below the detection limit, while part of it is so high as to be up to 70 ng·g−1. With an average concentration of 4.1±8.1 ng·g−1 (mean±1σ, N=543), pyruvate is a minor species in comparison with other carboxylates. It is also low as compared with its precipitation in other parts of the world, suggesting a difference in its major source flux. The record revealed high pyruvate concentrations in the late halves of the 1950s and 1980s, but low in the late 1950s, late 1970s, and middle 1990s. The variation trend in the past 43 years is closely correlated with that of acetate, a major carboxylate from anthropogenic pollution to the atmosphere, indicating that tropospheric pyruvate in the remote area of northwestern China is probably a by-product in acetate formation.