Interaction between wind and snow surface

The horizontal and vertical wind velocity fluctuations were measured using two sonic anemometers at a height of 135 cm above a snow surface under a transverse snow wave-forming condition. A snow-wave was formed when the wind at a height of 1 m blew at a speed of more than 7 m s^–1 after an approximate accumulation of from 10 to 20 cm of new snow on a snowfield. For example, when a snow-wave had a wavelength of 10 m and a wave height of 15 to 20 cm, the measured horizontal and vertical velocity components showed that they had a frequency peak of 0.7 Hz in coherence and co-spectrum corresponding to this wavelength. The results suggest that wind turbulence and snow-wave formation interact with each other.     

Dependence of climate forcing and response on the altitude of black carbon aerosols

Black carbon aerosols absorb solar radiation and decrease planetary albedo, and thus can contribute to climate warming. In this paper, the dependence of equilibrium climate response on the altitude of black carbon is explored using an atmospheric general circulation model coupled to a mixed layer ocean model. The simulations model aerosol direct and semi-direct effects, but not indirect effects. Aerosol concentrations are prescribed and not interactive. It is shown that climate response of black carbon is highly dependent on the altitude of the aerosol. As the altitude of black carbon increases, surface temperatures decrease; black carbon near the surface causes surface warming, whereas black carbon near the tropopause and in the stratosphere causes surface cooling. This cooling occurs despite increasing planetary absorption of sunlight (i.e. decreasing planetary albedo). We find that the trend in surface air temperature response versus the altitude of black carbon is consistent with our calculations of radiative forcing after the troposphere, stratosphere, and land surface have undergone rapid adjustment, calculated as “regressed” radiative forcing. The variation in climate response from black carbon at different altitudes occurs largely from different fast climate responses; temperature dependent feedbacks are not statistically distinguishable. Impacts of black carbon at various altitudes on the hydrological cycle are also discussed; black carbon in the lowest atmospheric layer increases precipitation despite reductions in solar radiation reaching the surface, whereas black carbon at higher altitudes decreases precipitation.     

Non-ENSO interannual rainfall variability in central Chile during austral winter

The first principal component (PC1) of seasonal rainfall anomalies in central Chile during winter (June–August) is used to analyze the circulation anomalies related to wet and dry conditions, when near-normal or neutral SST anomalies are observed in the equatorial Pacific, i.e., during non-ENSO conditions. Eight wet and eight dry winter seasons were defined as the upper and lower terciles of PC1 for 24 non-ENSO winters in the period 1958–2000. Unlike the single process attributed to ENSO, during non-ENSO winter seasons, there are several sources triggering or modifying the propagation of the stationary waves that impact the rainfall regime in central Chile. Unfortunately, the multiple processes that seem to be involved in the modulation of the interannual rainfall variability in central Chile, as seen in this work, limit the predictability of rainfall during non-ENSO conditions.     

Geology,Mineralogy, Geochronology,and Sulfur Isotope Constraints on the Genesis of the Luanling Gold Telluride Deposit,Western Henan Province,Central China

The Luanling gold telluride deposit in the Xiong'ershan region is located in the southern margin of the North China Craton. The deposit formed in four stages, that is, an early pyrite‐quartz stage (I), a pyrite‐molybdenite stage (II), a sulfide‐telluride‐gold stage (III), and a late carbonate stage (IV). Six species of telluride in stage (III) are recognized, including hessite, altaite, petzite, unidentified Au‐Ag‐Te mineral, empressite, and unidentified Ag‐Te‐S mineral. Gold occurs mostly as native gold and electrum along the microfractures of sulfides or the contact between sulfide and telluride. The mineralization temperature of stage I and stage III ranges from 296 to 377°C and 241 to 324°C, respectively. Tellurides in stage III precipitate at the log?_S2 from ?14.3 to ?7.3 and log?_Te2 from ?17.4 to ?9.4. The ores were formed in an oxidizing environment. The Re‐Os model ages of molybdenite are 162–164 Ma, which indicate that the main ore formation stage was in the Late Jurassic. The Re contents of five molybdenite samples from the Luanling deposit have a range of 36.32–81.95 ppm, except for one large value of 220 ppm, which indicates that the ore‐forming materials are mainly derived from a crustal‐dominated source. The δ³⁴S values of sulfides range from ?17.6 to ?6.2‰, whereas those of sulfates are from 6.8 to 11.5‰. The δ³⁴S_∑S value of the ore‐forming system is 0.0–3.7‰, indicating that the sulfur of the Luanling deposit derived from a deep igneous source. Mineral association and isotope data of the Luanling deposit, together with its geodynamic setting, imply that this deposit belongs to a part of the metallogenic system of the Nannihu‐Sandaozhuang, Shangfangou porphyry molybdenum deposits, and the Late Jurassic granitic intrusions.     

利用TDR对土壤含水量及土壤溶液电导率的同步连续测量

土壤含水量和可溶解的土壤盐分浓度的测定, 对了解土壤盐分的分布及移动具有重要的意义. 在内蒙古黄河流域灌溉玉米田的一个野外实验中, 利用TDR对土壤含水量及土壤溶液电导率进行了同时连续测量. 结果表明: 在降雨量较少的时期内, 当土壤水分从地下含水层向地表面移动的同时, 地下水中含有的盐分也通过作物根区层向地表移动;当灌溉或有强降雨存在时, 土壤表面蓄积的盐分在未能完全溶解于灌溉水及雨水之前, 大量的灌溉水及降雨通过土壤内的大空隙快速渗入土壤下层;余下的水分在完全溶解了土壤表面的盐分之后, 缓慢通过土壤小空隙下渗.     

Post-collisional magmatism of western Chukotka and Early Cretaceous tectonic rearrangement in northeastern Asia

The paper presents new data on the isotopic age and chemical composition of volcanic rocks from the Tytyl’veem and Mangazeika basins of western Chukotka superposed on Mesozoides of the Verkhoyansk–Chukotka Tectonic Region. The results of SIMS U–Pb zircon dating (121.4 ± 2.8 and 118.0 ± 2.0 Ma) corroborate the Aptian age of the Tytyl’veem Formation. This age, in turn, indicates its formation after closure of the South Anyui ocean (Neocomian), but before origination of the Okhotsk–Chukotka Belt (Albian–Campanian). Post-collisional Aptian igneous rocks are widespread in the northern Verkhoyansk–Chukotka Tectonic Region; the legth of the corresponding igneous province is no less than 1400 km. In geochemical characteristics, the post-collisional volcanic rocks occurring in Western Chukotka are similar with the rocks from Andean-type igneous belts.