中国近海及其邻近海域海气热通量的模式计算

应用美国宇航局Goddard地球观测系统四维资料同化系统计算和分析了近海海域感热通量和潜热通量的季节性变化规律和地理分布特征.结果表明,近海各季感热通量冬、秋季较大,春、夏季较小.其地理分布特点是冬季感热通量的分布随纬度变化十分明显,纬度越高感热通量越大,且等值线分布密集.在台湾以东、日本以南海域,感热通量等值线呈西南一东北走向.在南海海域,感热通量比周围海域略低,感热通量等值线在该海域呈一低值倒槽分布;潜热通量冬、秋季在台湾东北部、日本南部和东南部海域形成最大值区,等值线呈西南东北走向.春、夏季在黄海海域存在潜热通量的极小值区,同时春季在日本南部海域存在潜热通量的极大值区或最大值区.因为台湾以东、日本以南海域正好是黑潮流经的区域,所以此海域的热通量与黑潮有密切关系.     

应用高频红外碳硫仪测定农用地土壤样品中有机质含量

应用高频红外碳硫仪测定农用地土壤样品中的有机质,避免了传统方法中的试样液体转化环节,测定效率高,但存在土壤样品电磁感应低和基体影响较大等问题。本文通过实验优化了样品称样量、助熔剂铁和钨的添加量等测定条件,结果表明：当样品称样量为0.05g、助熔剂铁添加量为0.40g、钨添加量为1.50g时,有机质测定效果最佳。通过土壤标准物质进行验证,方法检出限为0.003%,相对标准偏差（RSD,n=7）小于4%,测定值与认定值的相对误差小于5%,且不同分析人员的测定结果间没有显著差异。采用本法与重铬酸钾容量法对甘肃省农用地土壤样品进行测定,两种方法测定值的绝对误差为-0.25%~0.28%,测定结果之间呈极显著线性正相关（R²=0.9736）,表明两种方法的一致性很好。本方法的检出限、精密度、准确度均满足农用地土壤样品有机质测定要求。     

华南地区新石器早中期动物骨中羟磷灰石的污染鉴别及机制——以广西桂林甑皮岩遗址为例

了解古代人（动物）骨羟磷灰石的污染,是对其开展C、O稳定同位素分析以揭示其食物来源和栖息环境的前提条件。目前,我国在此方面开展的研究较少,华南地区尚无报道,由此导致我们对此区域人群生存方式的变迁以及农业的产生与扩散等一些重要考古学问题,仍缺乏深入的了解。本文以广西桂林甑皮岩洞穴遗址（新石器早中期）出土的20例动物骨为研究对象,以10例现代骨为参照,对以上原始样品以及预处理后的样品进行了红外光谱分析,并对预处理后的样品进行了C、O稳定同位素分析,以期实现骨羟磷灰石的污染鉴别和探讨其机制。根据已发表数据和本研究10例现代骨的红外光谱及其指标（IRSF、CO₃/PO₄、FW85%）,未经化学处理前的原始样品中,3例样品检测出明显的外源污染（方解石）,剩余17例原始样品中仅余3例为未受污染样品。经预处理后,含方解石样品（n=3）红外谱图显示,其结构内仍有方解石残存;剩余17例不含方解石的样品中,12例样品的红外指标皆已符合现有标准（IRSF≤4.2和CO₃/PO₄≤0.6）,样品可用数量显著提升。20例骨羟磷灰石的C、O稳定同位素分析进一步显示,去污染样品与污染样品的δ¹³C和δ¹⁸O值存在明显差异,污染样品的同位素数据更多反映了埋藏环境对其的影响。骨羟磷灰石的污染机制可能主要与华南地区特有的石灰岩地质环境密切相关。由此,进一步完善华南地区出土骨样的预处理方法并挑选出未受污染的样品,是今后开展稳定同位素分析的必经之路。

     

Near-real-time one-kilometre Soil Moisture Active Passive soil moisture data product

The coarse resolution soil moisture (SM) data from NASA SMAP mission have been steadily produced with the expected performance since April 2015. These coarse resolution observations could be downscaled to fine resolution using fine scale observations of SM sensitive quantities from existing satellite sensors. For operational users who need near-real-time (NRT) high resolution SM data, the downscaling approach should be feasible for operational implementation, requiring limited ancillary information and primarily depending on readily available satellite observations. Based on these principles, nine potential candidate downscaling schemes were selected for developing an optimal downscaling strategy. Using remotely sensed land surface temperature (LST) and enhanced vegetation index (EVI) observations, the optimal downscaling approach was tested for operational producing a NRT 1 km SM data product from SMAP. Comprehensive assessments on the 1 km SM product were conducted based on agreement statistics with in-situ SM measurements. Statistical results show that the accuracy of the original coarse spatial resolution SMAP SM product can be significantly improved by 8% by the downscaled 1 km SM. With respect to the in-situ measurements, the 1 km SM mapping capability developed here presents a clear advantage over the SMAP/Sentinel SM data product; and it also provides better data availability for users. This study suggests that a NRT 1 km SMAP SM data product could be routinely generated from SMAP at the centre for Satellite Applications and Research of NOAA NESDIS for operational users.     

The first large format Si:Sb BIB arrays

The first 128×128 Si:Sb blocked impurity band (BIB) detectors, manufactured by Rockwell International, are sensitive detectors from 10 to at least 40 m. While further work is required to make these arrays suitable for the low backgrounds of space infrared telescopes, they can be used now for observations from the ground and aircraft.     

On open cluster physical parameters from 2MASS data

The near infrared range has opened a new window to study stellar populations in the Galaxy, in the Local Groud and beyond. Despite the large and growing use of these data, insufficient efforts have been made in the direction to calibrate stellar physical parameters such as age, reddening and distance. This can also be achieved using near infrared and optical data together. Furthermore, the huge amounts of photometric data available now and in the incoming years, demand the development of automated and statistical isochrone fittings to cope with such data. With this in mind, we analyse 2MASS data in order to determine physical parameters for a sample of 9 open clusters. As a first step, we determined the age, reddening and distance values for each cluster applying the classical isochrone fitting (by eye). Subsequently, we employed an automated procedure which compares synthetic colour-magnitude diagrams to observed ones, making use of the likelihood statistics to find the best solution. We also carried out structural analyses of the clusters using stellar radial density profiles. Both classical and statistical isochrone fittings revealed that there can be disagreement between physical parameters obtained from near infrared data analysis and the literature corresponding ones, most based on optical and UV data. Concerning the observed cluster structures, they were studied for the first time. We found evidence of various dynamical stages in the sample.     

Silicate absorption in heavily obscured galaxy nuclei

Spectroscopy at 8–13 μm with T-ReCS on Gemini-S is presented for three galaxies with substantial silicate absorption features, NGC 3094, NGC 7172 and NGC 5506. In the galaxies with the deepest absorption bands, the silicate profile towards the nuclei is well represented by the emissivity function derived from the circumstellar emission from the red supergiant, μ Cephei which is also representative of the mid-infrared absorption in the diffuse interstellar medium in the Galaxy. There is spectral structure near 11.2 μm in NGC 3094 which may be due to a component of crystalline silicates. In NGC 5506, the depth of the silicate absorption increases from north to south across the nucleus, suggestive of a dusty structure on scales of tens of parsecs. We discuss the profile of the silicate absorption band towards galaxy nuclei and the relationship between the 9.7-μm silicate and 3.4-μm hydrocarbon absorption bands.