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Tree-ring width chronologies of Tsuga longibracteata (Fujian) and Chamaecyparis obtusa (Taiwan) were developed from southeast China, and climatic factors affecting the tree-ring widths of T. longibracteata and C. obtusa were examined. Similar correlations between tree-ring chronologies and climate data demonstrated common response of radial growth of the two species to climate. The radial growth of T. longibracteata and C. obtusa was mainly limited by autumn and winter temperature. In contrast, both chronologies are negatively correlated with precipitation in September of the previous year and September of the current year. Spatial climate correlation analyses with gridded land surface climate data revealed that variations in the ring width contain a strong regional temperature signal for southeast China. Spatial correlation with sea-surface temperature fields highlights the influence of the Pacific Ocean. Wavelet analysis reveals multi-decadal scale variability between 20 and 40 years, and higher frequency power for ring widths between 2 and 9 years, the typical range of ENSO. While ring widths appears to respond to temperature and the ENSO events, we highlight the need for far more detailed dendrochronological response studies for southeast China, particularly with regard to the role of temperature during winter. [ABSTRACT FROM AUTHOR]

Using the multi-source observation data from wind-profiling radar, microwave radiometer, Doppler weather radar, etc. during the blizzard event in 19-20 March 2012 in Urumqi, this paper analyzed the detailed characteristics of the atmospheric dynamics, thermodynamics, intensity and water vapor during the process of this blizzard weather. The findings suggest: (1) in the course of the blizzard weather, the near-surface atmosphere is mainly dominated by northwest airflows, the wind speed and relative humidity increase rapidly, temperature drops and air pressure ascends; (2) the blizzard weather this time is accompanied by cold front system whose entering time is about 16:00 BT 19 March; the shear line that develops from low to high is the position height of the frontal zone, and the variation of the high-level frontal zone directly reflects the altitude and layers where cold and warm air masses interact; (3) the radar equivalent reflectivity factor of the snowstorm process changes within the range 8-25 dBZ and its large-value zone is correlated well with the blizzard duration, the height for the formation of rain (snow) particles and the snow intensity; (4) before the occurrence of the blizzard, atmosphere is in the state of high temperature and high humidity, the maximum vapor density is around 6 g m, water vapor mainly stays under the height of 5,000 m; affected by cold front system, cold airs gradually lift warm and moist airs so that the vapor condenses and deposits into water drops and snow particles, forming the snowstorm in the end. [ABSTRACT FROM AUTHOR]

The Urumqi Institute of Desert Meteorology of the China Meteorological Administration carried out an atmospheric scientific experiment to detect dust weather using a wind-profiling radar in the hinterland of the Taklimakan Desert in April 2010. Based on the wind-profiling data obtained from this experiment, this paper seeks to (a) analyze the characteristics of the horizontal wind field and vertical velocity of a breaking dust weather in a desert hinterland; (b) calculate and give the radar echo intensity and vertical distribution of a dust storm, blowing sand, and floating dust weather; and (c) discuss the atmosphere dust counts/concentration derived from the wind-profiling radar data. Studies show that: (a) A wind-profiling radar is an upper-air atmospheric remote sensing system that effectively detects and monitors dust. It captures the beginning and ending of a dust weather process as well as monitors the sand and dust being transported in the air in terms of height, thickness, and vertical intensity. (b) The echo intensity of a blowing sand and dust storm weather episode in Taklimakan is about −1~10 dBZ while that of floating dust −1~−15 dBZ, indicating that the dust echo intensity is significantly weaker than that of precipitation but stronger than that of clear air. (c) The vertical shear of horizontal wind and the maintenance of low-level east wind are usually dynamic factors causing a dust weather process in Taklimakan. The moment that the low-level horizontal wind field finds a shear over time, it often coincides with the onset of a sand blowing and dust storm weather process. (d) When a blowing sand or dust storm weather event occurs, the atmospheric vertical velocity tends to be of upward motion. This vertical upward movement of the atmosphere supported with a fast horizontal wind and a dry underlying surface carries dust particles from the ground up to the air to form blown sand or a dust storm. [ABSTRACT FROM AUTHOR]

This article discussed about snow temperature variations and their impact on snow cover parameters. Automatic temperature recorders were used to sample at 10-minute intervals at the Tianshan Station for Snow-cover and Avalanche Research, Chinese Academy of Sciences. 10-layer snow temperature and the snow cover parameters were measured by the snow property analyzer (Snow Fork) in its Stable period, Interim period and Snow melting period. Results indicate that the amplitude of the diurnal fluctuation in the temperature during Snow melting period is 1.62 times greater than that during Stable period. Time up to the peak temperature at the snow surface lags behind the peak solar radiation by more than 2.5 hours, and lags behind the peak atmospheric temperature by more than 0.2 hours during all three periods. The optimal fitted function of snow temperature profile becomes more complicated from Stable period to Snow melting period. 22 h temperature profiles in Stable period are the optimal fitted by cubic polynomial equation. In Interim period and Snow melting period, temperature profiles are optimal fitted by exponential equation between sunset and sunrise, and by Fourier function when solar radiation is strong. The vertical gradient in the snow temperature reaches its maximum value at the snow surface for three periods. The peak of this maximum value occurs during Stable period, and is 4.46 times greater than during Interim period. The absolute value of temperature gradient is lower than 0.1°C cm for 30 cm beneath snow surface. Snow temperature and temperature gradient in Stable period∼Interim period indirectly cause increase (decrease) of snow density mainly by increasing (decreasing) permittivity. While it dramatically increases its water content to change its permittivity and snow density in Snow melting period. [ABSTRACT FROM AUTHOR]

The fresh snow density was observed with snow analyzer (Snow Fork) at Tianshan Station for Snowcover and Avalanche Research, Chinese Academy of Sciences from February 21 to March 5, 2009. Results show that fresh snow density increases from the 5th h to the 291st h after the snowfall, with an average rate of increase of 4.0×10 g/(cm·h) ( R = 0.943). Analysis shows that fresh snow density is negatively correlated with the compaction rate of fresh snow ( R = −0.960). Inversely, it is positively correlated with fresh snow viscosity ( R = 0.896). In relation to meteorological factors, ground temperature rising at a depth of 40 cm is the major driving factor of snow density increase. The temperature increase in fresh snow layer and the decrease in depth hoar layer have the most prominent impacts on the snow density increase in the afternoon. Principal component analysis shows that the determinant factors of fresh snow density change can be grouped into 3 types as follows: 1) dynamic factor contributes about 69.71% to fresh snow density change, with a significant effect from the 5th h to the 106th h after the snowfall; 2) exogenous energy factor contributes about 20.91% to it, with a significant effect at the 130th h; and c) endogenous energy factor contributes about 9.38% to it, with a significant effect at the 130th h and the 195th h. [ABSTRACT FROM AUTHOR]

Increasingly complex life forms were found in older biological soil crusts in the Gurbantaunggut Desert in Northwestern China. These crusts may play a critical role in mineral erosion and desert soil formation by modifying the weathering environment and ultimately affecting mineralogical variance. To test this hypothesis, variations in the morphological features and mineralogical components of successional biological soil crusts at 1 cm were studied by optical microscopy, SEM and grain size analysis. Concentrations of erosion-resistant minerals decreased with crust succession, while minerals susceptible to weathering increased with crust development. Neogenetic minerals were found in late stage crusts, but not in early stage crusts. Silt and clay concentrations were highest in early formation crusts and soil mean particle size decreased with crust succession. Cyanobacteria, lichen and moss were shown to erode and etch rocks, and secondary minerals produced by weathering were localized with the living organisms. Thus, more developed crusts appeared to contribute to greater mineral weathering and may be a major cause of mineralogical variance seen in the Gurbantunggut Desert. The greater activity and complexity of older crusts, as well as their improved moisture condition may function to accelerate mineral weathering. Therefore, protection and recovery of biological crusts is vital for desert soil formation. [ABSTRACT FROM AUTHOR]

The study of the temporal and spatial variation of atmospheric water vapor has the important significance to show the response to climate change in the Taklimakan Desert. The series of monthly atmospheric water vapor from 1961 to 1998 are reconstructed using the observation data including the precipitation, ground water vapor pressure data over the period of 1961 to 2006 from 27 observation stations in its surrounding areas and meteorological data from the Tazhong station during 1999-2006. Then the relationship between atmospheric water vapor and ground vapor pressure is calculated and validated using the observation data for the period of 1976 to 2006 from 5 sounding stations (Hotan, Kuqa, Ruoqiang, Kashgar, and Minfeng). The temporal and spatial variation of atmospheric water vapor in the Taklimakan Desert and its surrounding areas is studied and then its distribution is generated. Results show that high value zone of atmospheric water vapor is mainly distributed in the northern Taklimakan Desert and the oasis-marginal belt of western desert and the value ranges from 14 to 15 mm. The low value center of atmospheric water vapor is in the hinterland of the desert and the value is only 7?8 mm. The annual variations of atmospheric water vapor show generally the increasing trend. However, the variation of atmospheric water vapor in the surrounding areas and the hinterland of the desert is insignificant during 1961?1986. The atmospheric water vapor changes abruptly after 1986 and increases clearly in the two regions. The variation trend accords with that of the precipitation's increasing significantly in southern Xinjiang for the recent 50 years. There is great error between the NCEP/NCAR reanalysis data of atmospheric water vapor and real data in the Taklimakan Desert. [ABSTRACT FROM AUTHOR]

The daily variation regularities of micro-meteorological features, such as the surface layer temperature and humidity profiles of the inner desert in summer, the temperature of sand bed, the radiation of the earth's surface and the heat balance, were analyzed by combination method and logarithm regression according to the data obtained from the Atmospheric Environmental Observation Station of Taklimakan Desert in July?August of 2006 and 2007. It has been shown that temperature inversion occurred near the surface layer at night in summer, the temperature increased with the height within a certain altitude range, and the reverse was true during the daytime. The ground surface radiation balance of the Taklimakan Desert was mainly positive; other radiation components (the global radiation, the reflective radiation, the ground upward long wave radiation and the net radiation) exhibited daily variation characteristics evidently and showed normal diurnal cycle, except for the downward atmospheric long-wave radiation. The heat exchange of the surface layer of the desert was dominated by turbulence sensible heat, and only a small portion of heat was transferred to the atmospheric surface layer in the form of latent heat. The surface sensible heat and latent heat changed with the increase and decrease of sun elevation angle, with maximum of the latent heat appearing in wee hours and the peak value of the sensible heat appearing at noon. Observation and analysis showed that heating effect of the underlying surface of the desert was great on the aerosphere; the surface was a high heat source during the day and became a weak cold source at night. [ABSTRACT FROM AUTHOR]

It is generally considered that the occurrence of glacial-interglacial gyrations can be explained with the Milankovitch theory. However, the solutions of some problems in the theory are currently not derived yet. After researching the eastward dust transport from Central Asia, we have found that there is a positive feedback mechanism between the eastward dust transport and the global temperature decrease. This magnifies the effect of solar radiation change in the high-latitude area of the Northern Hemisphere, and results in the occurrence of the global glacial epoch. The positive feedback mechanism starts with the reduction of solar radiation in the high-latitude area of the Northern Hemisphere. Subsequently, the global temperature decreases and global glacial epoch occurs, in which the pivotal factor is the eastward dust transport from Central Asia. With the theory of the positive feedback mechanism, some problems in the Milankovitch theory can be solved well. [ABSTRACT FROM AUTHOR]

For the zoning of snow hazard in China, on the principles of (a) comprehensive analysis integrated with dominant factors, (b) multi-level division, and (c) serving the agriculture and stock-raising, transportation and communication, we first classified China into two large zones according to the situation of snow or no snow distribution. Secondly, based on the climate and landform, properties of snow cover and main features of snow hazard, the large zone of snow hazard can be classified into three second-level regions. In order to obviously reflect the difference of snow cover quantity and snow hazard type as well as hazardous degree, twenty subregions (third-level) of snow hazard are further divided in detail. In addition, the boundaries and the principal features of the differences between the various snow hazard regions are provided. [ABSTRACT FROM AUTHOR]

A correction to the article "Tree-ring-based reconstruction of precipitation in the Changling Mountains, China, since A.D.1691" that was published in the June 1, 2012 issue is presented.