微波遥感大气水的研究

在地面测量大气本身的微波辐射, 可以推算大气温度, 含水量, 臭氧和其他一些气体的浓度。采用大气中水汽吸收波段1.35cm和微波窗区8mm波段的辐射测量,可以遥感大气中汽态水含量和云中液态水的含量。本文通过对4个微波频段在大气中辐射传输的计算,可以看出在地面利用3mm波段遥感大气中的汽态水和云中液态水,尤其是遥感晴空汽态水含量将具有更高的灵敏度。开展3mm波段的辐射测量,将有利于连续精确地监测大气水的研究,这对中尺度天气预报和气候热平衡将起重要作用。     

遥感大气中汽态水和液态水含量的实验研究

根据微波在大气中的辐射传输理论，采用接收１．３５ｃｍ和８ｍｍ波段的大气噪音，推算大气中水汽和液态水含量，研制了双通道微波辐射计，进行遥感实验，文章中对微波辐射计测得的数据如何校正，展开了详细的讨论，这将在监测和利用空中水资源的科学实验中发挥作用。     

太湖二类水体水色遥感的大气校正问题探讨

基于简化的大气辐射传输模型,提出一种基于图像本身的水色遥感大气校正方法。根据清洁水体在绿光波段的离水辐射相对稳定的特点,来估算清洁水体像元在绿光波段的气溶胶参数,插值获取整幅图像在绿光波段的气溶胶参数,根据大气校正因子为1的假设,外推获取蓝、红波段的气溶胶参数。以太湖为研究区,对Landsat5TM蓝、绿、红波段进行大气校正,反演出离水辐亮度,进而获得水体的遥感反射率。对反演的水体遥感反射率与准同步实测的相应采样点水体遥感反射率进行了对比分析,结果表明,该方法有效地去除了大气效应对遥感数据的影响,经过大气校正的反射率值接近实测反射率值。     

基于6S模型的可见光、近红外遥感数据的大气校正

受大气吸收与散射的影响,电磁波在大气—目标物—遥感器途径传输过程中发生失真,造成目标地物反射辐射能量到达遥感器时被衰减。给计算地表反照率/反射率和地表温度等关键参数带来较大的误差。选择陆地卫星7号ETM+遥感影像的可见光、近红外波段数据,利用6S模型,进行大气辐射校正和反射率反演。同步气象数据用于遥感器所接受的大气顶部辐射的模拟、验证和评价6S对大气校正的可靠性。最后对ETM+可见光和近红外波段数据大气校正前后的反射辐射和均一化植被指数（NDVI）的变化进行了对比研究。     

微波遥感大气温度压力层结原理

一、引言 利用5毫米微波段大气辐射的地面遥感,可反演出大气温度压力层结。本文将讨论自然噪音、频率选择及反演方法等问题,作为地面微波遥感大气温度压力层结原理讨论,并为制造机器和遥感观测提供依据。     

3 mm波段烟幕插入损耗测量

为了满足3mm波段烟幕辐射特性和插入损耗特性测量的需要，研制了3mm波段烟幕特性自动测量系统——3mm辐射源和3mm辐射计／接收机一体机。一体机是对Dicke型辐射计的改进，在保持毫米波辐射计接收机高频前端不变的前提下，分别为辐射特性测量和插入损耗特性测量设计了独立的被动通道和主动通道，并在窄带的插入损耗测量的主动通道增加了中频锁相环路。探讨了该系统的烟幕插入损耗特性测量方法，实验结果表明：该系统能满足3mm波段烟幕特性自动化测量的要求。     

1.35厘米微波遥感大气湿度辐射计的研制

一、引言 为了实现有云天气大气温度湿度和压力层结的地面微波遥感探测,我们在75年与上无23厂北京大华仪器厂合作研制成功两台不同类型的5毫米波段微波辐射计后,76年又开始了1.35厘米和8毫米波段微波辐射计的试制。 氧分子在5毫米波段有一吸收带,5.67毫米(52.9GHz)的仪器是用来测量大气氧分子的     

海洋船舶的微波辐射遥感研究

根据微波辐射理论 ,船舶与海洋背景或陆地、岛屿表面的发射率相差很大 ,故使用毫米波辐射计可以探测海面上的船舶。讨论了海洋、天空及陆地等背景微波辐射特性 ,给出了计算船舶目标与海洋背景的天线温度对比度的公式 ,并给出 8mm及 3mm波段下几种背景的辐射温度曲线和不同高度下的海上目标的天线温度对比度的计算和测量数据 ,另外 ,介绍了毫米波辐射计探测海上船舶的实用的试验方法以及其应用前景。     

星载微波辐射计遥感大气温度廓线的数值模拟

为了充分了解微波被动遥感大气温度廓线的能力,为星载微波辐射计研制及今后的资料解释提供必要的技术基础,开展了采用50～60 GHz氧气吸收带内的7个通道反演大气温度廓线的数值模拟研究.利用微波辐射传输模型模拟了微波辐射计各通道亮度温度,在此基础上建立了大气温度廓线的统计反演方案.统计反演的数值试验表明,50～60 GHz微波通道对大气温度廓线有一定的遥感反演能力.     

大气程辐射遥感图像技术

大气程辐射遥感图像是遥感图像中各点大气程辐射遥感值按顺序排列所形成的、与地面状况无关的、仅与大气状况有关的、无法在自然条件下直接获取的遥感图像.就对地探测而言,大气程辐射是需消除的干扰因素,对于大气传输特性的研究、遥感图像的大气修正、区域大气遥感探测和大气环境质量遥感监测等则是宝贵的信息源.研究利用遥感数字图像和对应地面反射率、逐点分离、提取像元大气程辐射遥感值从而生成大气程辐射遥感数字图像有重要理论和应用价值.     

The presence of methane in the atmosphere of an extrasolar planet

Molecules present in the atmospheres of extrasolar planets are expected to influence strongly the balance of atmospheric radiation, to trace dynamical and chemical processes, and to indicate the presence of disequilibrium effects. As molecules have the potential to reveal atmospheric conditions and chemistry, searching for them is a high priority. The rotational-vibrational transition bands of water, carbon monoxide and methane are anticipated to be the primary sources of non-continuum opacity in hot-Jupiter planets. As these bands can overlap in wavelength, and the corresponding signatures from them are weak, decisive identification requires precision infrared spectroscopy. Here we report a near-infrared transmission spectrum of the planet HD 189733b that shows the presence of methane. Additionally, a resolved water vapour band at 1.9 mum confirms the recent claim of water in this object. On thermochemical grounds, carbon monoxide is expected to be abundant in the upper atmosphere of hot-Jupiter planets, but is not identifiable here; therefore the detection of methane rather than carbon monoxide in such a hot planet could signal the presence of a horizontal chemical gradient away from the permanent dayside, or it may imply an ill-understood photochemical mechanism that leads to an enhancement of methane.     

Importance of rain evaporation and continental convection in the tropical water cycle

Atmospheric moisture cycling is an important aspect of the Earth's climate system, yet the processes determining atmospheric humidity are poorly understood. For example, direct evaporation of rain contributes significantly to the heat and moisture budgets of clouds, but few observations of these processes are available. Similarly, the relative contributions to atmospheric moisture over land from local evaporation and humidity from oceanic sources are uncertain. Lighter isotopes of water vapour preferentially evaporate whereas heavier isotopes preferentially condense and the isotopic composition of ocean water is known. Here we use this information combined with global measurements of the isotopic composition of tropospheric water vapour from the Tropospheric Emission Spectrometer (TES) aboard the Aura spacecraft, to investigate aspects of the atmospheric hydrological cycle that are not well constrained by observations of precipitation or atmospheric vapour content. Our measurements of the isotopic composition of water vapour near tropical clouds suggest that rainfall evaporation contributes significantly to lower troposphere humidity, with typically 20% and up to 50% of rainfall evaporating near convective clouds. Over the tropical continents the isotopic signature of tropospheric water vapour differs significantly from that of precipitation, suggesting that convection of vapour from both oceanic sources and evapotranspiration are the dominant moisture sources. Our measurements allow an assessment of the intensity of the present hydrological cycle and will help identify any future changes as they occur.     

六盘山华北落叶松林分蒸腾特征及其影响因素

[目的]林分蒸腾作为土壤-植物-大气连续体的关键过程,是森林生态系统中重要的水分输出项,可占森林总蒸散的50％以上,探究林分蒸腾对环境因子的响应规律可为科学指导造林及林水综合管理提供理论依据和数据支持.[方法]以国家林业和草原局宁夏六盘山定位站为依托,在2016年生长季(5—9月),对六盘山半湿润区的华北落叶松(Lar...     

The transpiration of water at negative pressures in a synthetic tree

Plant scientists believe that transpiration-the motion of water from the soil, through a vascular plant, and into the air-occurs by a passive, wicking mechanism. This mechanism is described by the cohesion-tension theory: loss of water by evaporation reduces the pressure of the liquid water within the leaf relative to atmospheric pressure; this reduced pressure pulls liquid water out of the soil and up the xylem to maintain hydration. Strikingly, the absolute pressure of the water within the xylem is often negative, such that the liquid is under tension and is thermodynamically metastable with respect to the vapour phase. Qualitatively, this mechanism is the same as that which drives fluid through the synthetic wicks that are key elements in technologies for heat transfer, fuel cells and portable chemical systems. Quantitatively, the differences in pressure generated in plants to drive flow can be more than a hundredfold larger than those generated in synthetic wicks. Here we present the design and operation of a microfluidic system formed in a synthetic hydrogel. This synthetic 'tree' captures the main attributes of transpiration in plants: transduction of subsaturation in the vapour phase of water into negative pressures in the liquid phase, stabilization and flow of liquid water at large negative pressures (-1.0 MPa or lower), continuous heat transfer with the evaporation of liquid water at negative pressure, and continuous extraction of liquid water from subsaturated sources. This development opens the opportunity for technological uses of water under tension and for new experimental studies of the liquid state of water.     

空气中氯化氢废气的净化和回收

研究了以水吸收空气中不同含量的氯化氢废气的吸收条件,对HCl的吸收率达到99%以上,获得的盐酸溶液浓度随吸收液温度的降低和空气中氯化氢浓度的增加而增加.将1.2~1.5mol/L稀盐酸减压蒸发浓缩,当真空度为0.08MPa时,先蒸出的80%左右的液体中氯化氢含量都很低,并且可以获得8.7mol/LHCl的盐酸进行回收,但以制备5.8mol/L的盐酸更经济.据此提出了空气中氯化氢废气的净化和回收工艺流程.     

光电成像系统分析中大气传输特性计算的几个问题

利用美国大气传输特性软件LOWTRAN，对常用的基于气象学能见距离的大气透射比公式及中波和长波红外透射比进行了分析．结果表明：气象学能见距离透射比公式可以较好地描述美国标准大气下可见光的光谱透射比和平均透射比，但其向紫外和红外波段的适用性需要慎重处理；在高温和潮湿条件下，中波红外波段的大气平均透射比在路径的起始阶段衰减较快；但在一定距离外，中波红外波段的大气平均透射比优于长波红外波段。     

土霉素菌渣热解液的理化特性及成分分析

采用元素分析仪、水分测定仪、粘度计、GC-MS等分析了土霉素菌渣热解液理化特性和成分。热解液油相C元素含量比较高,达到了50%(质量分数)以上,热解液油相和水相中N元素分别占6.48%(质量分数)和7.89%(质量分数),O元素分别占27.89%(质量分数)和13.54%(质量分数)。温度为300～600℃热解液的油相粘度为6 980～8 913mPa·s,水相粘度为324～372mPa·s;热解液的油相密度为1.089 8～1.127 9g/cm3,水相密度为1.041 9～1.075 6g/cm3。热解液腈类物质较多,油相和水相分别占了23.69%(体积分数)和9.32%(体积分数);热解液油相与水相中碱性氮化物体积分别占0.83%和1.46%;热解液油相与水相中非碱性氮化物体积分别占1.56%和0.35%;其余的有机物体积在油相与水相分别占3.30%和4.11%。分析结果为进一步资源化利用提供了技术指导。