Sensitivity analysis of glacier systems to climate warming in China

Data of 44 glacier systems in China used in this paper were obtained from Chinese Glacier Inventories and the meteorological data were got from Meteorological Atlas of Plateau of west China. Based on the statistical analysis and functional model simulation results of the 44 glacier systems in China, the glacier systems were divided into extremely-sensitive glacier system, semi-sensitive glacier system, extremely-steady glacier system and semi-steady glacier system in terms of glacier system＇s level of water-energy exchange, rising gradient of the equilibrium line altitudes and retreating rate of area to climate warming, their median size and vertical span distribution, and their runoff characteristics to climate warming. Furthermore the functional model of glacier system to climate warming was applied in this paper to predict the average variation trends of the 4 types of glacier systems, which indicate that different sensitivity types of glacier systems respond to the climate warming differently.

A METROD PREDICTING RESPONSE OF SEDIMENT YIELD TO POSSIBIE CHANGE OF PRECIPITATION DUE TO GLOBAL GREENHOUSE WARMING:AN EXAMPIE FROM NORTH FRINGE OF THE LOESS PLATEAU, CHINA

Starting from the supposition of time-space substitution, the Langbein-Schumm's Law was applied to deal with response of fluvial erosion System to the changes in mean annual Precipitation induced by global green-house warming. As a result, a simple method was put forward to predict change in sediment yield, with Ningxia Hui Autonomous Region in the northern fringe of the Loess Plateau of China as an example. Results show that, even the change in mean annual precipitation is the same, the direction and magnitude of the resultant chang in sediment yteld would be quite different in fferent physico-geographical zones. When mean annual precipitation is increased, sediment yield in arid or semi-arid areas with a mean anntal Peripitation of less than 400 mm will be increased, while sediment yield in sub-humid or humid areas with a mean annual precipitation of more than 400 mm will be decreased.Additionally, the complex response of fluvial erosion system in time series due to the lag of change in vegetation behind the changn in precipitation has also been qualitatively discussed in this paper.

The Response of Climatic Jump in Summer in North China to Global Warming

To reveal climatic variation over North China, the climatic jumps in summer in Beijing are analyzed using the data of precipitation of summer (June, July, August) during the period of 1841-1993, in which those missed before 1950 were reconstructed by the stepwise regression method with minimum forecast error. The climatic jumps at different scales are analyzed using different diagnostic methods with different decade (10-100 years) windows. Some new methods and ideas are proposed. The variance difference, the linear tendency difference, and the difference of power spectral distribution between the samples before and after the period at the moving point in the center of the series are compared with other methods (for example, Mann—Kendall test, t— test, and accumulative anomaly etc.). Considering the differences among the statistics above, a synthetic jump index is also proposed in order to get the definite jump points in the moving series. The results show that the climatic jumps in the area occurred in the 1890s, the 1910s and the 1920s, and mostly in the 1920s, which suggests that the local climatic jumps in North China have a simultaneous response to the global warming in the hundred-year scales. Key words Climatic jump - New diagnostic statistics - Synthetic jump index - Response to global warming This Study was supported by the “ National Key Programme for Developing Basic Sciences” G1998040901-1.

Lagged Responses of the Tropical Pacific to the 11-yr Solar Cycle Forcing and Possible Mechanisms

This paper uses two subsets of ensemble historical-Nat simulations and pi-Control simulations from CMIP5 as well as observational/reanalysis datasets to investigate responses of the tropical Pacific to the 11-yr solar cycle.A statistically significant 11-yr solar signal is found in the upper-ocean layers above the thermocline and tropospheric circulations.A warming response initially appears in the upper layers of the central equatorial Pacific in the solar maximum years in observations,then increases and shifts into the eastern Pacific at lagged 1-3 yr.Meanwhile,an anomalous updraft arises over the western equatorial Pacific and shifts eastwards in the following years with anomalous subsidence over the Maritime Continent.These lagged responses are confirmed by the historical-Nat simulations,except that the initial signal is located more to the west and all the responses are weaker than the observed.A simplified mixed-layer heat budget analysis based on the historical-Nat simulations suggests that the atmospheric forcing,especially the shortwave radiation,is the major contributor to the initial warming response,and the ocean heat transport effect is responsible for the eastward displacement of the lagged warming responses.In the solar maximum years,the zonal ocean temperature gradient in the western-central Pacific is reduced by the initial warming,and anomalous westerly winds appear over the western equatorial Pacific and extend into the eastern Pacific during the lagged years.These anomalous westerly winds reduce the wind-driven ocean dynamical transport,resulting in the initial warming in the central equatorial Pacific being amplified and the surface warming shifting eastward during the lagged 1-3 yr.