Based on five - layer wind speed, air temperature, humidity and vapor p ressure of the gradient tower of Zhangye National Climate Observatory built in 2007 from Sep tember 2007 to August 2008, the percentage of missing value was calculated, and the climate characteristics of Zhangye in different seasons were also analyzed. The reliability of data from the gradient towerwas checked by comparing with some other observational stations.
Research of the coupled heat-moisturemodelof soilwas developed in the 1950s based on the isothermalmodelof soilwater movement. It is closely related to atmospheric circulation, the use ofwater resources, agriculture and application of remote sensing technique, and italso increasingly became a focus in land surface process research. This paper introduces severalpopular coupled heat -moisturemodels of soil and their characteristics, and analyzes the test effects and the acting trend of thesemodels in some specific regions. Some problems atpresent researches and future development direction on the coupled heat-moisture model of soil are discussed finally.
A series of recent researchs focuses on the impact of climate change on agricultural production, land use, pollution and biodiversity, which implies the potential impactof climate change on food security is awidely debated and investigated issue. Nonetheless, the specific safety influence of food and feed for consumers has remained a less studied topic. This review identifies the various food safety issues from some literatures about climate change impacts on crop cultivation and livestock systems. According to general consensus, crop cultivation is recognized as a relatively susceptible partof the food and feed production sector thatcould be affected by climate change, variations in climatic parameters such as temperature, drought, precipitation, wind, and CO2levels are projected to have notable consequences on crops in terms of changes in the demand for fertilizer and pesticides, deterioration of the quality of soils,and expanding ranges of crop pests and altered transmission dynamics of insects, pests and plant diseases. Livestock production also could be heavily influenced by climate change, and the presence ofpathogenic bacteria in foods followingmore frequentextremeweather conditions, such as flooding and heatwaves. Therefore the challenges facing food securitywill pose new risks to human under the background of the global climate change.
The particular ecological and climatic effects of surface land dewfall resource were summarized simp ly, and the theoretic basis for exp loitation of land surface dewfallwas analyzed, especially the scientific ideas and technologicalmeasures for exp loitation land surface dewfallwere discussed from two sides of choosing the local climate condition and imp roving condensation face of dewfall.
In the paper, by using the data observed in“The Field Experiment on Land - atmosphere Interaction over Arid Region of Northwest China”, characteristics of atmospheric humidity, characteristics of soilwater content, characteristics of land surface parameterswith soil water content and other land surface parameters are analyzed. To validate the new surface parameters and parameterization formulae, the comparison is done between simulation and observation. It is found that the new surface parameters and parameterization formulae are better.
The mainly research development over Qilian Mountain region in recent ten years is reviewed in this paper. The most research work focused on climate change and water resource. There are a lot of results about the paleoclimate and the interannual variability of neoteric climate and water resource over the QilianMountain region. The exp loitation and utilization of airwater resource over QilianMountain has been focused in recent years, which should be a way to mitigate water shortage in arid and semi - arid region in northwest China.
A land-surface model is improved by using some new research results.Net radiation, surface temperature, sensible heat, latent heat and temperature, specific humidity and wind velocity in ground layer under precipitation condition are simulated by using the data observed at Dunhuang in the“Field Experiment on Interaction between Land and Atmosphere in the Arid Region of Northwest China”.The results show that the model is ameliorated well.The radiation flux and surface temperature simulation are better than energy. The simulation of the temperature, specific humidity and wind speed in ground layer is well because the ground layer is considered alone in this model.
Based on the mean monthly, maximum and minimum temperature series, the temperature changing characteristics in Urumqi airport in recent 50 years were analyzed in this paper. The results show that the mean annual temperature trends was 0.033 ℃/a, and there were obvious warming trends in spring, autumn and winter, the temperature tendency rate was 0.0949℃/a in winter, which was the largest. But the temperature in summer was dropping by the rate of 0.028℃/a. In recent 50 years, there were cold- warm- cold- warm evolution processes in Urumqi airport. A long cold period was in 1950s which was obvious in four seasons, a warm period was from 1961 to 1975, the second cold period was from 1976 to 1988, another warm period was from 1989 to 2000. 70% of anomalous cold years (seasons) were in 1950s and 41% anomalous warm years (seasons) were in 1990s. The mean annual maximum and minimum temperatures presented obviously increasing trend, and the latter was much steadier. From the results it is known that the minimum temperature would be more sensitive to monitor the intensity of greenhouse.From 1989 to 2000,abrupt warming occurred mainly in nighttime.These facts would contribute to study the temperature change in Urumqi airport.
