A ground hydrologic model with inclusion of a layer of vegetation canopy that can interact with general-circulation model

In this paper, a ground hydrologic model(GHM) is presented in which the vapor, heat and momentum exchanges between ground surface covers (including vegetation canopy) and atmosphere is described more realistically. The model is used to simulate three sets of field data and results from the numerical simulation agree with the field data well. GHM has been tested using input data generated by general circulation model (GCM) runs for both the North American regions and the Chinese regions, The results from GHM are quite different from those of GHMs in GCMs. It shows that a more active concerted effort on the land surface process study to provide a physically realistic GHM for predicting the exchange between land and atmosphere is important and necessary.

The mechanism of energy storage by shearing the solar magnetic field

In this paper, a complete set of MHD equations have been solved by numerical calculations in an attempt to study the dynamical evolutionary processes of the initial equilibrium configuration and to discuss the energy storage mechanism of the solar atmosphere by shearing the magnetic field. The initial equilibrium configuration with an arch bipolar potential field obtained from the numerical solution is similar to the configuration in the vicinity of typical solar flare before its eruption. From the magnetic induction equation in the set of MHD equations and dealing with the non-linear coupling effects between the flow field and magnetic field, the quantitative relationship has been derived for their dynamical evolution. Results show that plasma shear motion at the bottom of the solar atmosphere causes the magnetic field to shear; meanwhile the magnetic field energy is stored in local regions. With the increase of time the local magnetic energy increases and it may reach an order of 4×10^25 J during a day. Thus the local storage of magnetic energy is large enough to trigger a big solar flare and can be considered as the energy source of solar flares. The energy storage mechanism by shearing the magnetic field can well explain the slow changes in solar active regions.

A consistent model of isolated force-free magnetic arches

The magnetic flux tube concentrating strong magnetic field is the basic configuration of magneticfield in the solar atmosphere. In the present paper, the equilibrium of isolated magnetic flux tube inthe solar atmosphere is discussed. In the viewpoint of mathematics, the boundary condition is nonlinearand the position of boundary needs to be determined by the physical condition although the equation ofmagnetic potential is linear for the linear force-free field. Analytical solutions to the arches of bothuniform circular cross-section and non-uniform cross section have been obtained. The results show thatthe nonlinear problem may have or not have any solution according to different azimuthal components of the magnetic field; the number of solutions to the nonlinear problem is four at most, and two in some cases. In the present paper, the analytical solutions to the approximations of both fat and slender arches are given in detail, and the general features of magnetic arch structure are shown.

高寒草甸生态系统陆地生物圈模式研究及应用

改进了适合于高寒草甸生态系统的陆地生态圈模式，分析了模式中温度变化与水分运动分层的物理原因，说明了气候状况对地表面能量交换的影响，给出了净辐射和蒸散量新的计算方法，提出了有很差分计算中具有二阶精度的Euler隐式格式，介绍了中国科学院海北高寒草甸生态站的气候概况和野外观测情况。最后利用本模式对高寒草甸生态站地区的土壤-植被-大气间水热交换过程进行了数值模拟，模拟值与实测值吻合较好。

考虑生物结皮影响的陆气湍流模式研究

在以前工作基础上，针对腾格里沙漠人工植被区陆气水热传输过程，提出了一个多层陆气耦合模式。特别给出了导水率的计算模型和修正后的根系吸水模式，考虑了结皮层对土壤水分入渗的影响以及植被演化的过程。陆面过程耦合模式分别对大气、植被、土壤作多层划分，以助于细致了解沿度分布的各物理量。同时，利用本模式对中国科学院沙坡头沙漠站人工植被区陆气水热交换过程进行了数值模拟，模拟结果与实测值吻合较好，可为当地合理利用水热资源和沙漠治理提供科学依据。

含尘大气近地层流底层流动特性及其摩阻系数

采用双向耦合的双流体模型，了大气悬浮沙尘的存在对大气边界层中流底层流动特性及摩阻系数的影响，计算并讨论了不同沙尘含量下含尘大气相对于无尘大气摩阻系数的变化，结果表明，摩阻系数的变化取决于悬浮沙尘的初始运动状态和质量载荷率。

Investigation of Vaporized Kerosene Injection in a Supersonic Model Combustor

Characteristics of vaporized aviation kerosene injection in a supersonic model combustor were preliminarily investigated. The electrically storage type heater has a volume capacity of heating kerosene of 0.8 kg up to 670 K at a pressure of 5.5 Mpa. The temperature to cause pressurized kerosene jet being fully vaporized in Quiescent atmosphere was found to be 550 K at 4 Mpa however the pressurized hot kerosene remains in liquid state within the tube. The correspondent jet spray in Mach 2.5 vitiated air cross-flow were visualized by using stop schlieren photograph.It was found the penetration depth of the hot pressurized kerosene jet is approximately same with the temperature varied from 290 K to 550 k. at pressure of 4 Mpa. This results showed that the atomization process of hot kerosene jet spray in supersonic combustor could be bypassed and directly transferred to be gas state at temperature 550 K and pressure of 4 Mpa.

Cone Effect in Astronomical Adaptive Optics System Investigated by a Pure Numerical Simulation

It is well-known that cone effect or focus anisoplanatism is produced by the limited distance of a laser guide star (LGS) which is created within the Earth atmosphere and consequently located at a finite distance from the observer. In this paper, the cone effect of the LGS for different vertical profiles of the refractive index structure constant Cn2 is numerically investigated by using a revised computer program of atmospheric propagation of optical wave and an adaptive optics (AO) system including dynamic control process. According to the practice, the overall tilt for the tilt-correction mirror is obtained from a natural star and the aberrated wavefront for phase correction of the deformable mirror is obtained from a LGS in our numerical simulation. It is surprisingly found that the effect of altitude of the LGS on the AO phase compensation effectiveness by using the commonly-available vertical profiles of Cn2 and the lateral wind speed in the atmosphere is relatively weak, and the cone effect for some Cn2 profiles is even negligible. It is found that the cone effect does not have obvious relationship with the turbulence strength, however, it depends on the vertical distribution profile of Cn 2 apparently. On the other hand, the cone effect depends on the vertical distribution of the lateral wind speed as well. In comparison to a longer wavelength, the cone effect becomes more obvious in the case of a shorter wavelength. In all cases concerned in this paper, an AO system by using a sodium guide star has almost same phase compensation effectiveness as that by using the astronomical target itself as a beacon. Effect of dynamic control process in an AO system on the cone effect is studied in this paper for the first time within our knowledge.

Numerical Analysis of the Effects of Free-Stream Thermo-Chemical State on the Test Model Flow Field in High-Enthalpy Tunnel

The effects of the free-stream thermo-chemical state on the test model flow field in the high-enthalpy tunnel are studied numerically. The properties of the free-stream, which is in thermo-chemical non-equilibrium, are determined by calculating the nozzle flow field. A free-stream with total enthalpy equal to the real one in the tunnel while in thermo-chemical equilibrium is constructed artificially to simulate the natural atmosphere condition. The flow fields over the test models (blunt cone and Apollo command capsule model) under both the non-equilibrium and the virtual equilibrium free-stream conditions are calculated. By comparing the properties including pressure, temperature, species concentration and radiation distributions of these two types of flow fields, the effects of the non-equilibrium state of the free-stream in the high-enthalpy shock tunnel are analyzed.

Charles M. Breder, Jr.: Hypothetical considerations, 1931-1937

Charles M. Breder Jr. “hypothesis” diary is a deviation from the field diaries that form part of the Breder collection housed at the Arthur Vining Davis Library, Mote Marine Laboratory. There are no notes or observations from specific scientific expeditions in the document. Instead, the contents provide an insight into the early meticulous scientific thoughts of this biologist, and how he examines and develops these ideas. It is apparent that among Dr. Breder’s passions was his continual search for knowledge about questions that still besieged many scientists. Topics discussed include symmetry, origin of the atmosphere, origin of life, mechanical analogies of organisms, aquaria as an organism, astrobiology, entropy, evolution of species, and other topics. The diary was transcribed as part of the Coastal Estuarine Data/Document Rescue and Archeology effort for South Florida. (PDF contains 33 pages)

Global Climate Change Impacts in the United States: a state of knowledge report from the U.S. Global Change Research Program

Executive Summary: Observations show that warming of the climate is unequivocal. The global warming observed over the past 50 years is due primarily to human-induced emissions of heat-trapping gases. These emissions come mainly from the burning of fossil fuels (coal, oil, and gas), with important contributions from the clearing of forests, agricultural practices, and other activities. Warming over this century is projected to be considerably greater than over the last century. The global average temperature since 1900 has risen by about 1.5ºF. By 2100, it is projected to rise another 2 to 11.5ºF. The U.S. average temperature has risen by a comparable amount and is very likely to rise more than the global average over this century, with some variation from place to place. Several factors will determine future temperature increases. Increases at the lower end of this range are more likely if global heat-trapping gas emissions are cut substantially. If emissions continue to rise at or near current rates, temperature increases are more likely to be near the upper end of the range. Volcanic eruptions or other natural variations could temporarily counteract some of the human-induced warming, slowing the rise in global temperature, but these effects would only last a few years. Reducing emissions of carbon dioxide would lessen warming over this century and beyond. Sizable early cuts in emissions would significantly reduce the pace and the overall amount of climate change. Earlier cuts in emissions would have a greater effect in reducing climate change than comparable reductions made later. In addition, reducing emissions of some shorter-lived heat-trapping gases, such as methane, and some types of particles, such as soot, would begin to reduce warming within weeks to decades. Climate-related changes have already been observed globally and in the United States. These include increases in air and water temperatures, reduced frost days, increased frequency and intensity of heavy downpours, a rise in sea level, and reduced snow cover, glaciers, permafrost, and sea ice. A longer ice-free period on lakes and rivers, lengthening of the growing season, and increased water vapor in the atmosphere have also been observed. Over the past 30 years, temperatures have risen faster in winter than in any other season, with average winter temperatures in the Midwest and northern Great Plains increasing more than 7ºF. Some of the changes have been faster than previous assessments had suggested. These climate-related changes are expected to continue while new ones develop. Likely future changes for the United States and surrounding coastal waters include more intense hurricanes with related increases in wind, rain, and storm surges (but not necessarily an increase in the number of these storms that make landfall), as well as drier conditions in the Southwest and Caribbean. These changes will affect human health, water supply, agriculture, coastal areas, and many other aspects of society and the natural environment. This report synthesizes information from a wide variety of scientific assessments (see page 7) and recently published research to summarize what is known about the observed and projected consequences of climate change on the United States. It combines analysis of impacts on various sectors such as energy, water, and transportation at the national level with an assessment of key impacts on specific regions of the United States. For example, sea-level rise will increase risks of erosion, storm surge damage, and flooding for coastal communities, especially in the Southeast and parts of Alaska. Reduced snowpack and earlier snow melt will alter the timing and amount of water supplies, posing significant challenges for water resource management in the West. (PDF contains 196 pages)

First Biennial Ocean Climate Summit: Finding Solutions for San Francisco Bay Area’s Coast and Ocean. Proceedings of the Summit: April 29, 2008, Golden Gate Club, The Presidio San Francisco, California

Executive Summary: The marine environment plays a critical role in the amount of carbon dioxide (CO2) that remains within Earth’s atmosphere, but has not received as much attention as the terrestrial environment when it comes to climate change discussions, programs, and plans for action. It is now apparent that the oceans have begun to reach a state of CO2 saturation, no longer maintaining the “steady-state” carbon cycle that existed prior to the Industrial Revolution. The increasing amount of CO2 present within the oceans and the atmosphere has an effect on climate and a cascading effect on the marine environment. Potential physical effects of climate change within the marine environment, including ocean acidification, changes in wind and upwelling regimes, increasing global sea surface temperatures, and sea level rise, can lead to dramatic, fundamental changes within marine and coastal ecosystems. Altered ecosystems can result in changing coastal economies through a reduction in marine ecosystem services such as commercial fish stocks and coastal tourism. Local impacts from climate change should be a front line issue for natural resource managers, but they often feel too overwhelmed by the magnitude of this issue to begin to take action. They may not feel they have the time, funding, or staff to take on a challenge as large as climate change and continue to not act as a result. Already, natural resource managers work to balance the needs of humans and the economy with ecosystem biodiversity and resilience. Responsible decisions are made each day that consider a wide variety of stakeholders, including community members, agencies, non-profit organizations, and business/industry. The issue of climate change must be approached as a collaborative effort, one that natural resource managers can facilitate by balancing human demands with healthy ecosystem function through research and monitoring, education and outreach, and policy reform. The Scientific Expert Group on Climate Change in their 2007 report titled, “Confronting Climate Change: Avoiding the Unmanageable and Managing the Unavoidable” charged governments around the world with developing strategies to “adapt to ongoing and future changes in climate change by integrating the implications of climate change into resource management and infrastructure development”. Resource managers must make future management decisions within an uncertain and changing climate based on both physical and biological ecosystem response to climate change and human perception of and response to the issue. Climate change is the biggest threat facing any protected area today and resource managers must lead the charge in addressing this threat. (PDF has 59 pages.)

La estructura y propiedades magnéticos de las nanopartículas de Fe50Ni50 obtenidas mediante el método de explosión eléctrica de hilo

[Es]Actualmente ninguna área científica es ajena a la revolución de la nanociencia; las nanopartículas atraen el interés de muchos investigadores desde el punto de vista de la ciencia fundamental y para sus aplicaciones tecnológicas. Las nanopartículas ofrecen la posibilidad de fabricar sensores que sean capaces de detectar desde un virus hasta concentraciones de substancias patógenas que no pueden ser detectadas por los métodos convencionales. Hoy en día existes 82 tratamientos contra el cáncer basadas en la utilización de nanopartículas y los materiales composite con nanopartículas se utilizan como medio de protección frente la radiación del rango de microondas. En la rama de ciencias ambientales, las nanopartículas metálicas sirven como materiales anticontaminantes. En este trabajo se ha estudiado la estructura y las propiedades magnéticas de las nanopartículas de FeNi preparadas mediante el método de explosión eléctrica de hilo. Con la técnica de Rayos–X(DRX) se ha determinado que las nanopartículas se cristalizan en un sistema cúbico FCC con un parámetro de celda de 3.596 Å, también, se ha obtenido el tamaño de dominio coherente que es de 35 nm. La muestra se ha sometido a un programa de temperatura controlada para seguir la evolución de la estructura cristalina y del tamaño del cristal, tanto en atmósfera oxidante como en vacío. Para el aprendizaje de los microscopios utilizados en este trabajo, se ha asistido al curso “Fundamentos de microscopia electrónica de barrido y microanálisis” impartido por SGIker de la UPV/EHU. Se han empleado los microscopios electrónicos SEM y TEM para obtener imágenes de gran resolución de la muestra y analizar su contenido elemental. Partiendo de las imágenes sacadas por el SEM se ha calculado el valor medio del tamaño de las partículas de la muestra, 58 nm. Mediante el Mastersizer 2000 se ha medido el tamaño de las partículas y/o agregados por método de difracción láser, disgregando la muestra todo lo posible hasta conseguir el tamaño medio que se aproxime al de una sola partícula, 100nm. Por último, para la caracterización magnética se ha servido del VSM que mide el momento magnético de una muestra cuando ésta vibra en presencia de un campo magnético estático, consiguiendo una imanación de saturación de 125 emu/g. Hemos fabricado y caracterizado las nanopartículas magnéticas de hierro-níquel y los resultados obtenidos han sido enviados a un congreso especializado de ciencia de materiales (ISMANAM - 2013, Italia).

“El Niño” study based on analysis of ocean surface temperatures 1935-57

ENGLISH: The following report describes the findings of an "El Niño" project carried out at the Department of Meteorology of the University of California, Los Angeles, at the request of, and with funds provided from, the Inter-American Tropical Tuna Commission. The project was, in its early stages, supervised by Professor M. Neiburger, but was in June 1959 transferred to Professor J. Bjerknes, who thereby became the sole author of this final report. Readers who may be interested in the general background of knowledge of the maritime meteorology of the Eastern Pacific are herewith referred to Professor Neiburger's final report of the "Subtropical Pacific Meteorology Project." That report, submitted in September 1958 to the Office of Naval Research, summarizes the results of all the meteorological soundings released at sea since 1949 from California in the north to Peru in the south. The soundings off Ecuador and Peru were all taken by the "Shellback" expedition during July 1952. Important as this first exploration of the atmosphere over the Eastern Equatorial Pacific was, it did not even begin to explore " El Niño " itself, which is confined to the southern summer season and, moreover, only reaches catastrophic proportions in a few exceptional years. SPANISH: Este estudio da a conocer los resultados de una investigación que, bajo el nombre de Proyecto "El Niño", ha sido efectuada en el Departamento de Meteorología de la Universidad de California, Los Angeles, a solicitud de la Comisión Interamericana del Atún Tropical y con fondos provistos por ésta. En sus primeras etapas, el proyecto fué supervisado por el Profesor M. Neiburger, pero en junio de 1959 fué transferido al Profesor J. Bjerknes, quien de este modo vino a ser el solo autor de este informe final. A los lectores interesados en los conocimientos de fondo de la meteorología marítima del Pacífico Oriental se les recomienda consultar el informe final del Profesor Neiburger intitulado "Subtropical Pacific Meteorology Project". Este informe, sometido a la "Office of Naval Research" en septiembre de 1958 sumariza los resultados de todos los sondeos meteorológicos efectuados en el mar desde 1949 en el área entre California en el norte y Perú en el sur. Todos los sondeos frente al Ecuador y el Perú fueron hechos por la Expedición "Shellback" durante el mes de julio de 1952. Importante como fué esta primera exploración de la atmósfera sobre el Pacífico Ecuatorial del Este, ni siquiera comenzó a explorar "El Niño" en sí, que se confina a la estación de verano en el sur y, más aún, sólo alcanza proporciones catastróficas en unos pocos años excepcionales.

陆面过程的模式与观测研究