气候变化对塔里木河来自天山的地表径流影响

塔里木河水资源主要来自天山南坡两条源流,选择西段阿克苏河和中段开都河-孔雀河作为研究区.1956-2003年研究河源山区气温呈持续升温且降水波动增加的趋势,其中1995-2003年升温强劲,升温速率高出48 a期间平均的3倍以上;降水自1986年后持续增加,20世纪90年代较80年代增幅达18%,并显示出河源山区湿岛向塔里木盆地扩展.因高山缺少气象观测,出山径流过程变化可以综合反映中高山带的气候变化.塔里木河来自天山的地表径流在1986-2003年间持续增长,以冰川融水补给为主的库玛拉克河,1994年以来年径流量增加已在前期平均值基础上提升了一个台阶;开都河以降水径流补给为主,1986-2002年出现了观测记录以来的丰水期,并使1986年后博斯腾湖水位快速上升,恢复到1958年记录的最高水位以上.两河年径流变化趋势基本相似,但也显示有西、中段的气候变化局部差异,出现丰枯水期的不一致;然而,在近16 a升温过程中,年径流增长幅度和快慢相近.     

Monitoring Large-Scale Tests for Nuclear Waste Disposal

Two large-scale “in situ” demonstration experiments and their instrumentation are described. The first test (FEBEX Experiment) involves the hydration of a compacted bentonite barrier under the combined effect of an inner source of heat and an outer water flow from the confining saturated granite rock. In the second case, the progressive de-saturation of Opalinus clay induced by maintained ventilation of an unlined tunnel is analyzed. The paper shows the performance of different sensors (capacitive cells, psychrometers, TDR’s) and a comparison of fill behaviour with modelling results. The long term performance of some instruments could also be evaluated specially in the case of FEBEX test. Capacitive sensors provide relative humidity data during long transient periods characterised by very large variations of suction within the bentonite.     

Field Measurement of Suction, Water Content, and Water Permeability

This paper presents a review of techniques for field measurement of suction, water content, and water hydraulic conductivity (permeability). Main problems in the use of field tensiometers are addressed and hints on how to improve tensiometer performance are given. Advantages and limitations of instruments for indirect measurement of suction including electrical conductivity sensors, thermal conductivity sensors, dielectric permittivity sensors, filter paper, and psychrometer are discussed. Techniques for water content measurement based on dielectric methods are then presented. These include time and amplitude domain reflectometry and capacitance. Finally, a brief overview of methods for measurement of water permeability in the field is presented.     

Cyclotron amplification of geomagnetic micropulsations Pc1 in the magnetosphere

A numerical analysis of cyclotron instabilities is carried out by computing the dispersion relation for a three component cold plasma-beam system. Rates of growth and damping for various values of the stream density are calculated from the dispersion relation. The rates of growth and damping increase monotonically as the number density of the proton stream increases. It is found that the frequencies at the rates of maximum growth and the damping decrease slightly to lower frequencies and a sharp peak at these frequencies becomes blunt. The minimum e-folding times of an ion cyclotron wave for (a) σ_s = 10⁻⁴, σ_i = 10⁻² and (b) σ_s = 10⁻¹, σ_i = 10⁻² are about 3·84 and 0·16 sec respectively in the vicinity of the equatorial plane at 6 Re, where σ_s and σ_i are the ratios of the beam density N_s and the helium ion (H₆⁺) density N_i to the total positive ions in the plasma-beam system.     

THE DELINEATION OF THE BEDROCK CONFIGURATION OF PART OF PORT JACKSON,NEW SOUTH WALES,WITH A BOOMER SYSTEM*

A high resolution Boomer system was used to investigate the bedrock configuration of part of Port Jackson, New South Wales. The continuous reflection profiling technique was successful in delineating a channel incised in bedrock under a thickness of up to 60 m. of unconsolidated sediment covered by up to 20 m. of water.     

AERIAL SURVEY: COLONY OF HONG KONG

This paper describes the planning and implementation of a very extensive aerial survey contract undertaken by Hunting Surveys on behalf of the Hong Kong Government. From photography carried out during January and February 1963, photogrammetric plotting at 1 : 600 and 1 : 1200 proceeded steadily over a period of 5 years to the point where all but the highest land in the Colony had been surveyed at one or other of these two large scales. The problems arising from the rather unique terrain conditions and the urban and industrial development of Hong Kong are dealt with mainly from the photographic and photogrammetric aspect but reference is made to the contribution of the Crown Lands and Survey Office of the Public Works Department of Hong Kong, who provided all ground control and undertook field verification.     

THE LAUSANNE CONGRESS

The International Society for Photogrammetry held the Xlth International Congress at Lausanne during July 1968. The authors review the activities of five of the seven I.S.P. Commissions.     

Pole-to-pole moisture conditions for the IGY

Summary A study of the mean atmospheric humidity conditions on a planetary scale during the IGY covering the calendar year 1958 is presented. The fields of mean precipitable water content and of the zonal and meridional transports of water vapor are analyzed for the entire globe. Zonally averaged values of the various quantities at several levels are presented in tabular form and compared whenever possible with previous results or indirectly are analyzed on the basis of information obtained from different sources. The structure of these fields is studied and the corresponding implications for the general circulations of the atmosphere are discussed. Finally the zonal water balance for all the globe is discussed and its implications analyzed.